Solar Panel/Battery/Invertor query ???

Hi all,
Am getting ready to head out prospecting once more and have re-organised my Troopy layout (again!)

I have a dual battery set-up in the engineroom, with a HD lead running aft and connected to a 20w Solar Panel regulator mounted on the front passengers seat pillar.

I have just re-located my 1200w inverter from it's original (rear) location - connected directly to the auxilliary battery - now to alongside the panel regulator.

My intention was to then connect the inverter direct to the panel regulator, with short leads to the load terminals of the regulator ...... but only when needed.

Haven't physically yet connected the two together ....... as last night, running it through my brain cell ....... normally I would only use the inverter at night, camped, which means, of course, no sun ... ergo : the inverter is really running of the auxilliary battery THROUGH THE PANEL REGULATOR ... and not directly off the battery.

Is this proper and safe and efficient ... or should I re-think and again re-connect the inverter DIRECT to the auxilliary battery ???

Your help would be much appreciated .......... thanks.












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Reply By: Angler - Wednesday, May 26, 2010 at 10:32

Wednesday, May 26, 2010 at 10:32
I certainly don't profess to be an expert in electronics, (only about 40 years experience) Consider this: If you run your inverter at full output you would probably need in excess of 100Amps to supply the output given no losses. It would be a really exceptional solar regulator if it was capable of controlling that sort of current.
Obviously you must connect your inverter direct to the battery and not through the regulator.

Enjoy your trip and best of luck digging.
AnswerID: 418193

Reply By: Member -Signman - Wednesday, May 26, 2010 at 10:40

Wednesday, May 26, 2010 at 10:40
You could connect the inverter to the output of the regulator- which I assume is connected directly to you aux. battery via substantial cable !!

AnswerID: 418195

Reply By: Maîneÿ . . .- Wednesday, May 26, 2010 at 10:41

Wednesday, May 26, 2010 at 10:41
Pedro

Connect the inverter direct to the dual battery system
(with a fuse @ battery end of (+) cable)

Maîneÿ . . .
AnswerID: 418196

Reply By: Member - bungarra (WA) - Wednesday, May 26, 2010 at 11:00

Wednesday, May 26, 2010 at 11:00
NO!

connect to the aux battery only. You would be asking the 20 amp regulator to supply maybe 100amps at inverter peak load through its load terminals

If the regulator has a LV cut out for its supply load (that is from aux battery through the regulator to the devices load) ..(nothing to do with the input from the panels)..then you could connect the inverter to the aux battery via a relay from the regulator.

In this way the load to the inverter is direct from the aux battery but the regulator is protecting the battery from a low voltage cut out using the switching relay that connects the actual inverter current draw to the aux battery.

This works perfectly for me simply because my solar regulator has a low voltage protection on the supply output.

I use this to charge my detector batterys if using the inverter. Otherwise I use the 12v charging lead to the detector battery which is only drawing 1.2 amps to charge the battery. Using the inverter to run the detector battery charging is an inefficient use of power unless of course you are also using other 240 v appliances as well.

Happy detecting!

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AnswerID: 418202

Reply By: Mandrake's Solar Power- Wednesday, May 26, 2010 at 11:33

Wednesday, May 26, 2010 at 11:33
I think this has been said before but - Isn't having a live 240 volt setup in-car just a tad dangerous ??
That inverter mounted inside the cab will need to be disconnected while travelling I would think ...

Cheers

Steve
AnswerID: 418207

Follow Up By: ChipPunk - Wednesday, May 26, 2010 at 11:43

Wednesday, May 26, 2010 at 11:43
No.
They are safer than a domestic AC supply.
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Follow Up By: Member -Signman - Wednesday, May 26, 2010 at 11:43

Wednesday, May 26, 2010 at 11:43
Hiya Steve
Most (if not all) inverters have a local on/off switch..

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Reply By: ChipPunk - Wednesday, May 26, 2010 at 11:51

Wednesday, May 26, 2010 at 11:51
A "20W solar panel regulator"....
Meaning a 20W solar panel?

Feeding an inverter that probably has at least 5W idling/standby consumption and will take well over 1200W at full load - ie, SIXTY times the output of the solar panel on a great-sun day?

Forget any advantage to wiring the inverter close to the regulator.
Although it won't damage the regulator (unless it's a "noisy" inverter), there is simply no point.

Fat cables as close to the aux battery as possible.
Inverter cables rated to match or exceed its fuses (probably 100-120A etc) unless the cables upstream fuse (ie, battery fuse - if fitted) is smaller.
(Battery fuse - not required if physical security is used - ie similar risks as a starter motor.)
AnswerID: 418210

Follow Up By: Member - Andrew (QLD) - Wednesday, May 26, 2010 at 12:01

Wednesday, May 26, 2010 at 12:01
Considering solar regulator ratings probably don't go down that low, and aren't usually rated in Watts, I would guess it would be a common 20A regulator.

Andrew
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Follow Up By: ChipPunk - Wednesday, May 26, 2010 at 12:13

Wednesday, May 26, 2010 at 12:13
Sorry - I hit the wrong reply button - see below (R7).
Me - the idiot.
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Reply By: ChipPunk - Wednesday, May 26, 2010 at 12:11

Wednesday, May 26, 2010 at 12:11
Ditto.
But it's the panels that count.

Even if 200W my comments are (obviously?) still valid.

If 2,000W, it may be less obvious, but it is still correct.

I was tackling it from a magnitude-comparison angle rather than the complexities of a system design. (Always loads off your main/primary source etc.)
AnswerID: 418214

Reply By: Member - John and Val - Wednesday, May 26, 2010 at 12:35

Wednesday, May 26, 2010 at 12:35
Pedro,

The output side of the solar regulator should already be connected directly to the auxilliary battery. Hence, if you connect the inverter to the output side of the regulator it is in fact connected to the auxilliary battery, which is what you require.

The problems with this though - The wiring probably isn't heavy enough to supply the 100+ amps needed to run the inverter flat out. AND - as already said, having 240v in the vehicle when travelling is not a good idea. For this reason, I'd maybe supply the inverter through an Anderson plug and disconnect it when not in use.

If the cable is heavy enough from the controller to the battery, by all means connect the inverter in there on the battery side of the controller.

HTH

John

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Follow Up By: Member - Pedro the One (QLD) - Wednesday, May 26, 2010 at 13:40

Wednesday, May 26, 2010 at 13:40
Thanks also for your input, John.

For the record my Regulator has three sets of terminals :
Solar Panel ...... Battery ......Load .

I do use Anderson Plugs exclusively -
is the logic here :
HD cable and Plug from Invertor and
HD cable and Plug from LOAD output from Regulator
and
Connect when required ??:

OR
you said "If the cable is heavy enough from the controller to the battery, by all means connect the inverter in there on the battery side of the controller. "

It is heavy enough .... do you mean both sets of cables to the ONE "battery" terminal on the Regulator/controller, foregoing the LOAD terminals ??

OR
Forget the Regulator totally and Anderson Plug direct to the battery, fused of course.

Sorry to all for being long-winded but I travel solo deep into the bush for long periods so it is critical that I 'get it right FIRST' ...... just hate being stranded throughpoor planning/preperation/knowledge !!!




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Follow Up By: Member - John and Val - Wednesday, May 26, 2010 at 19:39

Wednesday, May 26, 2010 at 19:39
Pedro,
Back at last! I had a comprehensive reply set up hours ago, carefully worded not to offend anyone too much and covering everything that mattered - went to upload and found the site was down, lost the lot!! So here's a short straight from the hip version :

You need to connect the inverter to the auxilliary battery, but since you already have a heavy cable running from the battery to the interior, you could simply connect to that cable. I'd connect, via Anderson plug, to the "battery" terminal on the solar controller (not to the "load" terminal, as the controller probably won't pass the current that the inverter is capable of demanding.) In other words I'd go with your first "OR", which, from an electrical point of view, is the same as your second "OR".

A few thoughts:

Every wire connected to the positive terminal of the battery should have a fuse fitted close to the battery. Although your inverter is capable of pulling 100+ amps, I doubt that you'll ever use anything like its full output. I'd fit a 30 amp fuse to protect the wiring, and expect it to survive for ever.

Safety and inverters in vehicles :

The 240V from an inverter (depending on the inverter) is, like the 240V in your home, a sinusoidal alternating voltage with an average potential of 240 volts. The peak voltage is actually over 400V. That's enough to force a lethal current through your body if things go wrong. Some inverters allow their output side to float, i.e. it's not referenced to anything, unlike the supply in your home, which is referenced to ground. With these you'd really need to contact both of the 2 wires to get a shock. Others do connect one of the output wires to ground (i.e. the body of the vehicle), just like your domestic supply. The vehicle body becomes an electrode. The other wire is now averaging a potential difference of 240V with respect to the vehicle. Damaged insulation due to abrasion or otherwise, or a connection that fails, or an "off" switch that isn't off, can create a situation where you could touch the live conductor and the vehicle simultaneously, resulting in a thrill that could last a lifetime, brief though it might be!!. There are enough unknowns here to make it impossible to reliably assess the risk. To render it safe, recommend disconnecting the inverter when it's not in use - Anderson Plug is perfect.

There's been mention of RCD's (residual current devices). These monitor the currents in the two high voltage wires and look for any differences. They should be identical unless there is current leaking out of the system, as could happen if it was passing through your body. They cut off the supply if any significant imbalance is detected. They are now installed routinely in mains situations, and I'd strongly recommend using one with an inverter. They are not expensive, some are available in oversized 3 pin mains plugs.

HTH

John



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Follow Up By: oldtrack123 - Wednesday, May 26, 2010 at 21:05

Wednesday, May 26, 2010 at 21:05
HI John
"and I'd strongly recommend using one with an inverter. They are not expensive, some are available in oversized 3 pin mains plugs. "
As posted below ,A RCD cannot function with an isolated supply.

Are you sure you are referring to a RCD ¬ an over current CB with the 3pin plug type .
AS far as I am aware no such APPROVED devise exists @ this time
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Follow Up By: Member - John and Val - Wednesday, May 26, 2010 at 21:56

Wednesday, May 26, 2010 at 21:56
oldtrack,

As said above, I'm referring to an RCD - Residual Current Device. In essence they consist of two windings on a common core, one carrying the current in the active lead, the other the current in the neutral lead. The windings are connected antiphase, so that provided the 2 currents are exactly equal they cancel each other out. A further multiturn winding is also present to sense any magnetic field due to imbalance in the currents. These devices will usually disconnect both sides of the circuit within 30 mSec if an unbalance of 50 mA is detected.

IF the inverter output is fully isolated from ground (the vehicle) then without the alternative current path they will not operate. The secondary of some inverters however is NOT isolated, one side is returned to battery negative, hence the vehicle body. With the voltage involved it is prudent not to assume that ANY inverter is reliably isolated. You are right - if the 240V side is not connected to the vehicle the RCD will not function. If it is though, whether intentionally or due to water ingress, insulation breakdown, etc the RCD may prove an inexpensive life saver. I wouldn't be without one when working with 240V in a vehicle.

John
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Follow Up By: Member - Pedro the One (QLD) - Wednesday, May 26, 2010 at 22:23

Wednesday, May 26, 2010 at 22:23
Again thanks, John.

Just finished 'the Origin thing' up here ........!!

I also was perplexed by the site going down .... spent an hour or more trying to upload my photos'. Finally worked out it was this site and not me ??

Your info/advice is much appreciated.
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Follow Up By: oldtrack123 - Wednesday, May 26, 2010 at 22:30

Wednesday, May 26, 2010 at 22:30
Hi John

I totally agree with you on the possible dangers with ANY inverter.or generator
Although many SEEM to believe those dangers are exaggerated
The non isolated types are deadly & have caused several deaths in AUS, are now banned from sale I believe.
The failure of insulation anywhere in the system is exactly the reason they are all potentially dangerous & this includes gennys as well

However for a RCD to work ,it must be correctly wired in the correct location.

I am not aware of ANY plug in types being available ,could you advise of brand etc of the one you refer to??
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Follow Up By: Member - Andrew (QLD) - Wednesday, May 26, 2010 at 22:46

Wednesday, May 26, 2010 at 22:46
OT123,

Do you mean something like the following adapter models:

- Clipsal lifesaver 463RC Safety Switch Plug Adapters
- Powerguard 951 portable plug adapters
- Single RCD (Safety Switch) Outlet

Andrew
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Follow Up By: oldtrack123 - Wednesday, May 26, 2010 at 23:02

Wednesday, May 26, 2010 at 23:02
Hi John
Unfortunately NONE of those will provide protection with an isolated genny in normal operation
They are designed for use with an EN or MEN system.
If a fault developed within the inverter or genny they MAY detect that as a suitable earth neutral bond & MAY trip on a 2nd external fault.
However if the faults are between them & the load they will offer NO protection.

I think a lot of people may be using them under false assumptions that they are protected.

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Follow Up By: Member - John and Val - Thursday, May 27, 2010 at 08:24

Thursday, May 27, 2010 at 08:24
The sort of thing I'm talking about is shown in all of Andrew's links. These things do require a separate current path in order for a current unbalance to operate them. That path can arise due to leakage within the inverter/generator (ie upstream of the RCD) coupled with a fault downstream. If the 2 points are linked by a human body, it can hurt! As oldtrack says, an RCD will not detect 2 faults on the downstream side of the RCD.

Think we've exhausted this topic! I have nothing more to say!

Cheers

John
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Follow Up By: oldtrack123 - Thursday, May 27, 2010 at 13:06

Thursday, May 27, 2010 at 13:06
Hi John
You obviously understand how the RCDs function
However Andrews thread is misleading @ the best & dangerous if people believe that simply plugging in a portable RCD gives them protection.
IT DOES NOT.
The most likely area of that first fault ,that makes an earthed line [EN]l will be upstream of the RCD & as you agree the RCD will not protect

IT IS IMPORTANT THAT ALL UNDERSTAND THIS
Peter
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Follow Up By: Member - Andrew (QLD) - Thursday, May 27, 2010 at 14:22

Thursday, May 27, 2010 at 14:22
Peter,

Please don't turn around a simple posting to links of portable RCD plug adapters by me and say that the posting is misleading.

Acknowledge the fact that they exist, and don't accuse me of posting dangerous information. I am well aware of their limitations and uses, and agree that they are not effective in many of the situations we are talking about, however they do exist and do work for other situations.

You've had your say Peter and now it is time to let it go and not turn other's statement around. There is no doubt that all parties understand how they work, it is just each is attacking the conversation from a different perspective. I believe John has summed it up nicely in the end. :)

Andrew
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Follow Up By: oldtrack123 - Thursday, May 27, 2010 at 15:08

Thursday, May 27, 2010 at 15:08
HI Andrew
I am sorry if you have taken offence BUT
"Always use a Safety Switch at the Inverter if one isn’t built in - it’s very cheap protection against a fatality"
To me can only be read one way :
If you plug in a portable RCD unit into your inverter or genny you are safe.
You have not qualified that statement in any way.
Again I repeat A portable RCD plugged in to a standard fully isolated genny offers NO PROTECTION
Can you explain how it does??
I do do not like to think people have a false trust in something that will not work as expected ,especially when lives are concerned
John has made that assumption on your article.
Incidently I think overall the article is very good.
Peter
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Follow Up By: Member - Andrew (QLD) - Thursday, May 27, 2010 at 15:58

Thursday, May 27, 2010 at 15:58
Peter,

Take a deep breath, stand back from the keyboard and read who said these statements you are attacking.....you will find that someone owes someone an apology ;)

I think we need to step away from this conversation and let others read for themselves. You have made your point, several times, and this is all that needs to be said. If "others" have stated something wrong, then good on you for correcting this issue, just don't go around keeping the fire burning as there is no brownie points to score.

All said with a positive attitude and not meaning to be nasty. i hope you understand.

Andrew
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Follow Up By: oldtrack123 - Thursday, May 27, 2010 at 16:19

Thursday, May 27, 2010 at 16:19
HI Andrew
I do owe you an APOLOGY
It a seems I have attributed the statement:
"and I'd strongly recommend using one with an inverter. They are not expensive, some are available in oversized 3 pin mains plugs""
to you
I mistakenly believed you were the authour of the link posted by John[Inverters]
&Member - John and Val posted:
"The sort of thing I'm talking about is shown in all of Andrew's links."

So again I apologise for naming you & not carefully checking the actual authors of the article
Peter
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Follow Up By: oldtrack123 - Thursday, May 27, 2010 at 16:26

Thursday, May 27, 2010 at 16:26
Hi Andrew
A PS
the inverter link :
http://www.exploroz.com/Vehicle/Electrics/Inverters.aspx
has this statement:
"Always use a Safety Switch at the Inverter if one isn’t built in - it’s very cheap protection against a fatality"
PETER
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Reply By: Member - Pedro the One (QLD) - Wednesday, May 26, 2010 at 13:10

Wednesday, May 26, 2010 at 13:10
Many thanks for all the responses ..........

Firstly, a whoops .... my regulator is, of course, 20AMPS - not 20 WATTS !!
My apologies for the mistake !!
********************************
Member -Signman replied:
You could connect the inverter to the output of the regulator- which I assume is connected directly to you aux. battery via substantial cable !!

Yes , direct with very substantial cables direct to the auxilliary battery ...that is what I intended ie: using the LOAD terminals of the regulator.
****************************************************

bungara (WA) replied:
I use this to charge my detector batterys if using the inverter. Otherwise I use the 12v charging lead to the detector battery which is only drawing 1.2 amps to charge the battery. Using the inverter to run the detector battery charging is an inefficient use of power unless of course you are also using other 240 v appliances as well.

Correct - a very inefficient use of power - I only ever use 12vDC charging leads for almost everything ...... the Invertor is only for emergency 240v use, plus peace of mind ??
***********************************************************
Mandrake's Solar Power replied:
I think this has been said before but - Isn't having a live 240 volt setup in-car just a tad dangerous ??
That inverter mounted inside the cab will need to be disconnected while travelling I would think ...

Correct - both points. But I did say "...... but only when needed. " ....... and "normally I would only use the inverter at night, camped, "
And correct, Signman, mine does have a local ON/OFF switch also.
**************************************************

Maîneÿ . . . replied:
Connect the inverter direct to the dual battery system
(with a fuse @ battery end of (+) cable)

I am only resisting this method 'cause my dual battery system is almost flush to the engine side firewall, thus blocking the thru-wall access point ............ major job (for me!).
If I can SAFELY go via the regulator - that is my preferred option.

************************************************
Many thanks for the other replies :

I can understand the logic of direct to the Auxilliary battery.
But, as bungara (WA) says
" If the regulator has a LV cut out for its supply load (that is from aux battery through the regulator to the devices load) ..(nothing to do with the input from the panels)..then you could connect the inverter to the aux battery via a relay from the regulator. "

How can I ascertain if 'my regulator' has this ?
***********************************************
Maybe a photo of my layout would help ??

END RESULT - so far .... still unclear if it is possible/safe/etc....





AnswerID: 418222

Follow Up By: ChipPunk - Wednesday, May 26, 2010 at 14:36

Wednesday, May 26, 2010 at 14:36
The key is that the important electrical path of from the battery to the inverter - that is your heavy current path.
The solar regulator probably contributes much less power/current, but is usually optimised to provide max power(/voltage) to the battery.
But if the solar reg is connected mid-way, big deal - the batt-inv cable should be far heavier than the required solar cable hence negligible voltage drops for the solar.
(If there are solar cable voltage drops, and the solar regulator's sense terminal is separate to its output terminal, then the best may be regulator to the inverter or between batt & inv with the "Sense" going direct to the battery - provided the battery voltage doesn't drop too low! But you aren't using that sort of reg anyhow....)


Provided normal protection measures are followed, there should be no safety issues. The distribution issue is more a case of minimising losses.


I am still curious as to why 230V AC from an inverter is considered more hazardous than in a home?
Often they are totally isolated - hence floating - so you can touch either (but NOT both!) output and NOT get shocked.

But a normal RCD will make the inverter output as safe as an RCD'd mains supply (tough some RCDs may be more prone to false tripping - especially non-sinusoid inverters or loads).
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Follow Up By: Member - Pedro the One (QLD) - Wednesday, May 26, 2010 at 18:04

Wednesday, May 26, 2010 at 18:04
Photo's as promised ..........

This is what I want to do :
Image Could Not Be Found
Currently (pardon !!) the two wires from the Invertor are just tucked behind ... not connected .


This is my Regulator :
Image Could Not Be Found

Close up of Terminals :
Image Could Not Be Found

The heavier cables (centre terminals) are DIRECT TO/FROM the Aux. battery.

The lighter wires (RH terminals) DESCEND from the roof-mounted Solar Panel.

The two wires at the LH side of the regulator are from the 1200w Inverter, but obviously not yet connected.

My plan was to connect them to the DC LOAD terminals on the Regulator, as pointed out - ONLY when camped and only when required.

Maybe this info will help ???????????

Mainey ... will reply your MM tonight .... and thanks.
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Follow Up By: Maîneÿ . . .- Wednesday, May 26, 2010 at 18:28

Wednesday, May 26, 2010 at 18:28
ChipPunk,

I believe you will find RCD's will N0T save you from being electrocuted

But I’m sure as hell not going to test your idea, will allow you that pleasure

Maîneÿ . . .
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Follow Up By: ChipPunk - Wednesday, May 26, 2010 at 18:41

Wednesday, May 26, 2010 at 18:41
I didn't say that - I totally support SAA's dislike of the term "Safety Switch".

What I am saying is that - excluding false tripping - RCDs will work on inverters the same as on mains.
No earthing is required.
The statement elsewhere on this site about requiring a earth (stake etc) is incorrect. (My mate has just messaged the EOTeam about this.)


Why not test my idea? Surely your RCDs have a test switch? Just un-earth its supply.
Or connect a resistor of (say) 6.8 k-Ohms or less from the un-earthed RCD's active output to an earth elsewhere.


I can't prevent false beliefs. I merely try to educate and enlighten.
The choice is yours.

(Caveat: If RCD construction and specification has altered over the past ~decade so that it actually allows detection of an earth current, all bets are off. But surely the Regulators aren't that stupid?)
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Follow Up By: ChipPunk - Wednesday, May 26, 2010 at 18:51

Wednesday, May 26, 2010 at 18:51
Pedro,

Where is the input power cabling for the inverter?
Else, please state what your max inverter load will be.

The inverter will require 110A or more under full load - hence at least 6G if not 4G or heavier cabling.

You regulator only accepts 10G.
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Follow Up By: Member - Andrew (QLD) - Wednesday, May 26, 2010 at 19:51

Wednesday, May 26, 2010 at 19:51
Pedro,

After assisting a mate with the "exact same" solar regulator today, i can say that the maximum load on the regulator is 25A for a short time, with a 30A blade fuse inside to further protect the regulator.

Whilst you could connnect the inverter to the dc load side for less than 300w loads as a guess, it is preferable to direct connect it to the battery with much larger cable than shown.

Andrew
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Follow Up By: oldtrack123 - Wednesday, May 26, 2010 at 20:57

Wednesday, May 26, 2010 at 20:57
HI ChipPunk
You say

#1 "What I am saying is that - excluding false tripping - RCDs will work on inverters the same as on mains.
No earthing is required. "
#2 "The statement elsewhere on this site about requiring a earth (stake etc) is incorrect. (My mate has just messaged the EOTeam about this.) ""
#3 "Why not test my idea? Surely your RCDs have a test switch? Just un-earth its supply. "
#4 "Or connect a resistor of (say) 6.8 k-Ohms or less from the un-earthed RCD's active output to an earth elsewhere."
#5 "I can't prevent false beliefs. I merely try to educate and enlighten.
The choice is yours."
#6 "(Caveat: If RCD construction and specification has altered over the past ~decade so that it actually allows detection of an earth current, all bets are off. But surely the Regulators aren't that stupid?)"

Sorry to say ChipPunk but you have a lot to learn.
#1 A RCD will not function on an isolated [floating} power source!!!
An EARTH NEUTRAL Connection is required but A MEN[earth stake] is not required
#2 That is correct ,the rules state that "an earth stake [ ground connection] is neither required or recommended"
#3 You are obviously unaware that THE test button does NOT PROOVE THE CIRCUIT IS CORRECT. It purely tests the mechanism.
#4 Yes that would be a suitable test & it will not trip the RCD
Certainly not one I would advise an amateur to attempt ,he would prove the RCD cannot trip but may not be with us to tell us

#5 If my beliefs are INCORRECT, Perhaps you could explain HOW the RCD will trip on a floating [isolated] power source""
Simple explanation of how/where the out of balance current flows???

#6 NO, the basic operation of an RCD has not altered over the last 50yrs
They still operate on a core balance principle
CURRENT IN ACTIVE & NEUTRAL MUST BE EQUAL within about 30milliamps for standard RCDS & 20 milliamps for critical locations such as hospitals nursing homes ,ambulances [ yes they use inverters]etc


I do hope that IF you are going to educate & enlighten others YOU GET YOUR FACTS RIGHT FIRST.
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Follow Up By: oldtrack123 - Wednesday, May 26, 2010 at 22:50

Wednesday, May 26, 2010 at 22:50
Hi ChipPunk
"Caveat: If RCD construction and specification has altered over the past ~decade so that it actually allows detection of an earth current, all bets are off. But surely the Regulators aren't that stupid?) "

There is a new devise coming on to the market, A Residual Voltage Devise
It does not monitor active & neutral currents but detects any voltage between line & earth WIRING ,trips if that voltage reaches about 40v & requires about 5milliamps to trip.
A lot more on this site:
http://caravanersforum.com/viewtopic.php?f=2&t=8782&start=80
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Follow Up By: ChipPunk - Wednesday, May 26, 2010 at 23:10

Wednesday, May 26, 2010 at 23:10
Dear oh dear.
Look up how an RCD works and let me know if it IS NOT an imbalance in the 2 lines.
Or conversely, explain how an RCD "measures" the current to earth. A current probe perhaps?

An MEN is a Mains Earth-Neutral connection. It's main purpose is to clear downstream faults (blow fuses etc). It is used at generation sites (eg, domestic mains suppliers, inverter outputs), at domestic site switchboards, and in certain other situations (eg, large DC rectifiers).
Not that it is relevant (due to how an RCD works) but you are saying an "An EARTH NEUTRAL Connection is required but A (Mains) EARTH NEUTRAL [earth stake irrelevant] is not required". I do not disagree with your statement.

You state it yourself - it is an imbalance in the core. Where the imbalance goes is irrelevant - it could be to earth or heaven.


If you are talking about a person connected across "active-neutral", then yes - the system must be earth referenced for the RCD to operate (assuming sufficient current does pass through you).
I realise I did not make that clear - I was focused on an inverter in a vehicle whereby it doesn't mater if the (floating) inverter's "active" shorts to the chassis/body - it is floating. And the inverter's output Earth-Neutral connection (ie MEN) should blow fuses etc if an equipment fault occurs. But that is the dilemna for any "supply authority", however a colleague had an old requirement to earth-stake mobile inverters "for safety reasons" throw out and reversed some decades ago.


It sounds to me as if we both understand the workings of an RCD. It's probably that I have used them in non-AS3000 situations - ie, inverters and other non-earthed systems, and it is easier for me to separate the normal AS3000 MEN and earthing requirements from "generation" facility requirements.

If you pick any of my reasoning shortcomings, or reckon an RCD's operation is NOT dues t a core imbalance, then please respond.

FYI - the test function was a controversy. Was it to test the mechanics, or cause a core imbalance and hence the mechanics as well. I don't recall the outcome, but I suspect it either required an earth (else how could you create the imbalance?) else was merely an electro-mechanical trip test for non-earthed systems, and for "exercising moving parts" as was/is common practice in UPS and similar protection systems (which were typically 3-6 monthly "trip" tests).
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FollowupID: 688368

Follow Up By: ChipPunk - Wednesday, May 26, 2010 at 23:19

Wednesday, May 26, 2010 at 23:19
Sorry OldTrack, I missed your 2nd reply.

The earth current/voltage monitoring will obviously require earthing. So is that currently specified & mandated, approved and in use etc?

I haven't read your linked thread, but reading the opening posts it sounds as if systems have NOT been supplying their own MEN, or where main-bypass switching is present, they are NOT using dual-pole switching (Active & Neutral).

If that is the case, it's amazing that something that was approved and implemented 2 decades ago for inverters with main-bypass has not gained further ground.
But then again, that's the advantage of deregulation etc.

I'll read the link more fully later....

Thanks. It may prove very interesting....
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FollowupID: 688371

Follow Up By: ChipPunk - Thursday, May 27, 2010 at 01:51

Thursday, May 27, 2010 at 01:51
Just to close this entire thread (the original question is now answered & solved).

OldTrack - I read the link. I read nothing new. I even read someone that said the same as I - that was someone called oldtrack.

Even the standards etc quoted were saying the same as I - that earth staking is NOT recommended (in the relevant situations).

As to whether the RCDs work or not - I found contradictory statements.
But when (f.ex) there was a writer and a "qualified electrician" that expressed surprise that an RCD did NOT trip after said electrician cut through and hence shorted the AC conductors (ahead of a downstream A-N fault), well, what can I say!
Whoever said an RCD will trip if there is a load or person between Active and Neutral (or L1 & L2)?
That's the job of a fuse or circuit breaker, but unfortunately the ~2k Ohm resistance of the average person (or 30mA RCD trip current as a comparison) won't trip such overload protection.

I admit that I got bored during page 3 and skipped to skim the last page.
I don't know if the RVD detects a person across L1 & L2, but otherwise I saw nothing that contravenes what I wrote earlier.
RCDs do not require an earth to operate. The "fault" may require an earth to conduct away the 30mA etc, but NOT the RCD.
But RCDs will not protect a person strapped between Active and Neutral - there must be a leakage elsewhere.
If 30mA is the concern, use the 10mA medical RCDs. Both are based on the old Rule Of Thumb (as I recall) of 1mA & 10mA through the heart (1mA fibrillation; 10mA stoppage).

Other than AS3000:2007 now including some generating sources, things seem unchanged to me.
They even include double-pole switching and a local MEN when an inverter or generator with mains backup is switched to the inverter or generator supply. (Hence as per my colleague's circa 1990 approval, when on mains, the mains supplies the earth and switchboard MEN.)

If there are still issues with anything I have written, please address it specifically - do not refer me to non-specific or non-authoritarian sources.
Chances are that if you have to rely on external resources but can't isolate and present the specific section, it won't be as authoritarian as my sources.
That doesn't mean I am not wrong, but please provide the argument against my argument. Or ask for clarification of my argument.
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FollowupID: 688385

Follow Up By: oldtrack123 - Thursday, May 27, 2010 at 14:45

Thursday, May 27, 2010 at 14:45
Hi ChipPUNK
Perhaps we are misreading what each is saying so to clarify:.

"Even the standards etc quoted were saying the same as I - that earth staking is NOT recommended (in the relevant situations). "

I totally agree an EARTH [terra firma ]stake is not required or recommended as per many of my posts
However there can be confusion with the term "EARTH'[further posts on this are in the link]
In the case of a van ,motor home, or vehicle "earth"it can be floating & usually is unless plugged into mains supply [have no connection with terra firma].
My point still is that the leakage current due to the fault has to return to the source via the earthing conductor[earthing system]
IT cannot do that unless a bond has been made between the one line of the source & the earth wiring
If no such bond, the RCD cannot operate
Do we agree?If not perhaps you can explain!!

"As to whether the RCDs work or not - I found contradictory statements.
But when (f.ex) there was a writer and a "qualified electrician" that expressed surprise that an RCD did NOT trip after said electrician cut through and hence shorted the AC conductors (ahead of a downstream A-N fault), well, what can I say! "

Obviously if the active a neutral were severed with out contact to terra firma the RCD would not operate

"Whoever said an RCD will trip if there is a load or person between Active and Neutral (or L1 & L2)? "

No one I hope .It cannot trip

"I don't know if the RVD detects a person across L1 & L2, but otherwise I saw nothing that contravenes what I wrote earlier."

No magic answer there I doubt if any one will be able to develop a devise that can detect the difference between a normal load & a human

"RCDs do not require an earth to operate. The "fault" may require an earth to conduct away the 30mA etc, but NOT the RCD.

Now sorry this is the kind of statement I find very hard to understand.
HOW can the RCD possibly operate IF there is NO path for the leakage back to the source???? Please explain !!!
PS. I did note your heaven or earth return in a previous post but cannot see how that can work with an isolated power source & a vehicle it which is not connected to terra firma!!
Again please explain!!

"RCDs will not protect a person strapped between Active and Neutral - there must be a leakage elsewhere. "

Totally agree & that leakage must have a return path to the source,as above!!!
.

"Other than AS3000:2007 now including some generating sources, things seem unchanged to me."

The applicable standard which applies to "transportable structures & vehicles ' is AS/NZs 3001:2008 ,to be read in conjunction with AS 3000:2007

"They even include double-pole switching and a local MEN when an inverter or generator with mains backup is switched to the inverter or generator supply. (Hence as per my colleague's circa 1990 approval, when on mains, the mains supplies the earth and switchboard MEN.) "

YES for permanently fixed & hard wired installations in the vehicle,etc
and carried out by a certified electrician[as per AS 3001:2008]
However they do not make a MEN system only an floating EARTHED NEUTRAL system with a genny or inverter supply.
THERE IS A DIFFERANCE

Not a portable unit.
For a portable units the RCD must be built in & hard wired into the power source [Work place health & safety req IN all states].
With very good reasons which I am sure you would understand!!!

"If there are still issues with anything I have written, please address it specifically - do not refer me to non-specific or non-authoritarian sources.
Chances are that if you have to rely on external resources but can't isolate and present the specific section, it won't be as authoritarian as my sources.
That doesn't mean I am not wrong, but please provide the argument against my argument. Or ask for clarification of my argument. "

Can you post your authoritarian sources which contradict anything I have said????
Remembere we are talking about "Transportable structures & vehicles etc"
NOT fixed installations as in AS3000: 007[there IS a DIFFERANCE}
Also please explain where requested
Peter



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FollowupID: 688493

Follow Up By: ChipPunk - Thursday, May 27, 2010 at 16:48

Thursday, May 27, 2010 at 16:48
I can confirm testing.

Two RCDs.
- Neither would trip from their inbuilt tester unless they were earthed. (Good! That means it is more than a mechanism test - it is a full core-balance circuit & break test. I expect that Standards would have defined it as such.)

- Both tripped when their downstream (Active) was leaked to earth.
That's exactly what I said would happen.


"HOW can the RCD possibly operate IF there is NO path for the leakage back to the source???? Please explain !!!".
I said (or intended) that the RCD itself does NOT have to be earthed. It is only the power source and leakage that have to be reference - ie, the hydro-plant or inverter or genny is earth referenced (staked) as is the human, possum or cat.
The RCD itself only required the core imbalance - and that is between L1 & L2.

Is that clear?


Step 2:
(Hence why...?) "the authorities" do not recommend earth referencing a floating system because you can touch one side of a floating system and you will be fine.
By earth referencing - ie, the MEN system - touching one side is safe and the other is "fatal".
The RCD will only operate in the latter if the toucher has enough leakage to earth. (As you said, RCDs do not protect against Active-Neutral loads - whether they be halogen downlights, human, or appliances.)

Whether to earth or not is an awkward decision - it is a bit like the decision to mandate seat belts to save lives (but at the time, seat-belts would save you in 70% of accidents and and kill you in the other 30%).

Similarly for the earthing of inverters and generators.
For a floating system you can touch either conductor (L1 or L2) without harm. 100% success
In a MEN system, touching one is deadly, the other not. 50% success.
So why create a hazardous situation?....
.... because fault combinations add complexity.
Start connecting other loads and an L1 to chassis fault in one and an L2 to chassis fault in the other means the poor person that spans both chassis is shocked. 100% hazard.
But the authorities in their wisdom decided that given the average application of (portable) inverters and generators, it is (statistically) safer to leave them floating.
Hence the earthing "not recommended". (However I expect it is recommended if you are supplying a collection of white goods and other metal-exposed appliances. If you do then do it. It you power PCs, plugpacks, TVs, radios etc, then I also suggest that you not earth reference.)

Whilst RCDs could protect against an earth-referenced fault, the authorities do not regard RCDs as something that should be relied upon - they may fail to operate. (That was their traditional attitude and was still apparent in AS3000:2007.)

And as we have agreed, RCDs will not protect against a 2-line fault - ie, L1 to L2 or Active to Neutral - aka a "load".


Does that clarify what I have been trying to say?

If it doesn't, then all I can suggest is have another look at the link you posted. Else read up on RCD operation and understand how the MEN distribution system works, and why.
If you want the Authoritative source, refer to AS3000. If it contradicts what I have said, please quote the relevant section AND its context. (I don't have ready access to SAA publications at the moment.)

Or to repeat the test I did and tell me that an RCD does NOT trip if it is not earthed. (Use a resistor - not an organic breather.) (PS - I used mains, not inverter etc.)


And now I have just been told that I have a duty of care on this issue.
This site has apparently gone against the recommendations of regulations and authorities and have allegedly been so informed.
(I think that's what I was told - obviously a reference to what I said above...)

Is this site incorporated? LOL!
Oh well, this site is safe unless someone follows the earth stake recommendation and that results in injury. Then authoritative references will have to be provided or argued.
Or has that since changed? I still haven't caught up with recent changes... urghh!
Been away too long - I can't even tell if that verbal was in jest...
And for legal reason, I'll now shut up.
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FollowupID: 688520

Follow Up By: ChipPunk - Thursday, May 27, 2010 at 16:56

Thursday, May 27, 2010 at 16:56
PS - I am talking about inverters and gennys etc that readers on this forum/site will use.
Those that come under OH&S and other regulations cover themselves and are not an issue.

I have inverters that provide their own MEN point (so as to clear load faults) yet they are fully isolated from earth.
I know too that organisations like telcos and transport do the same, and when a mains bypass is used, the mains supplies the earth (as per AS3000) but when on inverter supply, it is the inverter that supplies the MEN (not the building MSB). Or at least they used to....
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FollowupID: 688522

Follow Up By: oldtrack123 - Friday, May 28, 2010 at 10:48

Friday, May 28, 2010 at 10:48
Hi ChipPunk
I'll take yor last post first :
"have inverters that provide their own MEN point (so as to clear load faults) yet they are fully isolated from earth"


This seems to be where you have a problem, understanding how the term "earth can /is used in different ways
It can mean ,Terra firma, or a floating system where it has no connection with terra firma as in vehicles.
How can a inverter in a floating system be MENed??
IT can only be neutral linked @ the source What advantage would doing other wise have?
Again you use the term MEN when I believe you mean EN.
Then how can a EN system be considered floating It has an floating earthed neutral.
The other problem I think you have is that all your remarks apply to gennys &/or inverters being hard wired to to semi permanent portable buildings where of course they are wired as a conventional source ,in accordance with AS 3000 with the existing MEN system

Perhaps you need to get AS 3001: 2008 which specifically deals with situations such as on this forum

NO MEN unless connected to mains supply .where the MEN is before the feed to the van or vehicle.[at the switchboard.

If a generator or inverter is permanently fitted & hard wired into the van ,an EN system is made NOT a MEN system [only ONE switched earth to neutral link made ].
Van RCD will function correctly.
If a portable fully isolated genny is connected via the van inlet socket there is no EN link .
The van RCD is not functional.
Also as stated before A portable non isolated genny or inverter is a potential death trap without a PERMANENTLY fitted & wired RCD .

Now to your previous post:
"Two RCDs.
- Neither would trip from their inbuilt tester unless they were earthed. (Good! That means it is more than a mechanism test - it is a full core-balance circuit & break test. I expect that Standards would have defined it as such.) "

Again lets be specific , how where was this earth because as you say the RCD has no[direct] connection to earth ???
How/where did the test button magically make this connection to earth ???

-" Both tripped when their downstream (Active) was leaked to earth.
That's exactly what I said would happen. ""


Exactly , that's what should happen & an earth return was need back to the neutral for that to happen.!!

"Does that clarify what I have been trying to say?
If it doesn't, then all I can suggest is have another look at the link you posted. Else read up on RCD operation and understand how the MEN distribution system works, and why.
If you want the Authoritative source, refer to AS3000. If it contradicts what I have said, please quote the relevant section AND its context. (I don't have ready access to SAA publications at the moment"

Yes it does & as I had suspected all your remarks are connected with standby or power supplied to on site structures by gennys or inverters
Hard wired into a MEN system as per AS3000 .

NOT RELEVANT TO THIS FORUM or those situations covered by AS 3001: 2008
Peter
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FollowupID: 688618

Reply By: Mandrake's Solar Power- Wednesday, May 26, 2010 at 22:10

Wednesday, May 26, 2010 at 22:10
In reference to the LOAD terminals on regulators ...
I just enquired of my supplier - If I had a 20 Amp reg and used the LOAD terminal what is the maximum output I can have and what is the consequence of going over that amount ...
The answer is 22 Amps MAX and then PHUTTT !

But that is my Juta Brand of MPPT controller - maybe others are different ...

Cheers

Steve

AnswerID: 418317

Follow Up By: ChipPunk - Wednesday, May 26, 2010 at 23:23

Wednesday, May 26, 2010 at 23:23
"PHUTTT !" as in self destructs, or as in a fuse blows or it shuts down or simply doesn't keep up (but non-destructively).

At the moment I can't think of anything that doesn't go PHUTTT when it tried to output more than it is capable of.
The issue is whether that is destructive.....
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FollowupID: 688372

Follow Up By: Member - Pedro the One (QLD) - Wednesday, May 26, 2010 at 23:29

Wednesday, May 26, 2010 at 23:29
OK - NOW WE APPEAR TO BE GETTING SOMEWHERE .... !!

Great, thanks Steve - this sounds like the knowledge I needed.
AND :
Great, thanks Andrew (QLD) _ same again !!

AND also to everyone else who contributed/responded/commented !

Lots of "technical stuff" was beyond me obviously BUT my knowledge has increased greatly.

General consensus indicates that I abandon my original intention of "invertor direct to regulator" concept.

I think I understand better now the reality : of the invertor trying to 'suck' out more more than the regulator can give ... if I hook up more than say 300w to the invertor.
Is that correct ??

Thusly : will return to my original connections :
a/ .... Solar Panel to Regulator

b/ .... Regulator to Aux. Battery via Anderson plug.

c/ .... Invertor to Aux. Battery via Anderson plug.

Bit of a bastard, actually ... I have only just cut the original Anderson plug off my HD cables ... now I'll have to re-do two sets .... bummer .

NOTE:
At no time will/or was the Invertor to be connected to the battery AT THE SAME TIME THAT THE PANEL WAS CONNECTED TO THE REGULATOR !

For general info : I do have a second folding and regulated 120watt solar panel and a third battery - which system is totally portable and seperate from the vehicle system .... this supplies power for my camp lights, detector chargers, laptop (DVD's at night are cool !) aerated spa bath, pedestal fan and other little comforts.( LOL - really! )

So, as you all may gather I try and cover all my bases AND I do like to rough it 'out there' in comfort.

Once again .... am really impressed with the depth of the replies and the generosity of the responders. Many, many thanks ....

And SWMBO has just decided that these replies have obviously saved me from getting 'electro-plated' when I am away on my lonesome ...... she thanks you, too !!
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FollowupID: 688374

Follow Up By: ChipPunk - Wednesday, May 26, 2010 at 23:41

Wednesday, May 26, 2010 at 23:41
You are correct, but I can only repeat - you connect inverters to batteries etc.

But I don't understand why you have an either-or situation.
Most would keep the regulator connected in case the panels can supply power. Why not?

But how many panels would you need to supply (say) a "300W" inverter?
300W in perfect conditions (sun & alignment)?
600W when a cloud passes?
800W later in the day?

If you only have 300W of panels - is it ok if the (say 250W) load dies when there is a power shortfall?
Luckily that will mean the inverter shuts down - if a brown out situation were to occur, would you load protect itself?

Hence why batteries or other power backup are used. Chargers like solar panels then supply what they can whenever they can.
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FollowupID: 688375

Follow Up By: Member - Pedro the One (QLD) - Thursday, May 27, 2010 at 00:31

Thursday, May 27, 2010 at 00:31
ChipPunk ...........

"You are correct, but I can only repeat - you connect inverters to batteries etc. "

Yep, I know you can connect invertors to batteries ... isn't that their prime function ?
My original proposal was just that .... but through the Regulator .
***************************************
"But how many panels would you need to supply (say) a "300W" inverter? "

Sorry, never said a 300w Invertor ... it is a 1200w/2400w Invertor .
BUT, if I correctly understood the general thrust of the thread itself, attempting to draw more than say "300w," via the 20Amp regulator would/may cause the afore-mentioned "PHUTTT."
*************************************

"If you only have 300W of panels .... "

My PANEL is 120 watts but is not relevant to the thread .....
as I had stated earlier that the invertor was only possibly used incamp and at night .... ergo, no sun .....and that I would have it dis-connected.
***********************************

Not having a shot here, just correcting a mis-conception ............

My, my ......... never realised that electrics was such a controversial subject ??????????????
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FollowupID: 688382

Follow Up By: ChipPunk - Thursday, May 27, 2010 at 01:26

Thursday, May 27, 2010 at 01:26
I was only basing the 300W on your earlier reply. (I think I asked for intended loads even earlier.) By 300W inverter I meant 300W inverter load (not its rating).

But my understanding was that your "connection through the regulator" was merely as a connection point. Why would a battery be connected "through" a regulator to an inverter?
But if it were to be, then obviously the reg's capacity is a limiting factor.
But I took the reg to merely be like a "distro block". Hence what the regulator itself can handle is irrelevant - ie, from the panels to its load being a battery or "loads".

But as was stated early on, the inverter is connected to the battery. Not the regulator.
The rest is merely to educate those that want to understand why.
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FollowupID: 688384

Reply By: Maîneÿ . . .- Friday, May 28, 2010 at 08:21

Friday, May 28, 2010 at 08:21
Guys, have a coffee and relax.

I believe this thread has become a technical nightmare, the people who want, or maybe *need* the correct information, probably don't fully comprehend some of the technical statements made above, they just want the facts in a simple to read and understand format.

As I've said, " I believe you will find RCD's will N0T save you from being electrocuted "

Maîneÿ . . .
AnswerID: 418503

Follow Up By: Member - Pedro the One (QLD) - Friday, May 28, 2010 at 11:18

Friday, May 28, 2010 at 11:18
Me (the OP) am now happy .... relatively speaking !!!

My problem WAS solved .... what I originally wanted to do was not right !!
I now understand :

If I was going to 'draw' less than 300w I COULD hook up the Invertor to the Panel Regulator
AND
If I was going to 'draw' more than 300w I SHOULD NOT hook up the Invertor to the Panel Regulator .

Golly - I do hope I have that right !

Please : ALL posters ......... accept my thanks ..................!


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FollowupID: 688624

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