Question re Solar regulator

If I'm running a fridge which draws on average 2amps/hr and I have a solar panel producing again on average 6amps/hr
We have....fridge 2amps/hr for 24hrs=48amps draw down
Solar panel.....6amps/hr over say 7hrs=42amps in
Therefore I will never overcharge battery (100amp/hr agm)
DO I REALLY NEED A REGULATOR??

Cheers
Richard
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Reply By: olcoolone - Wednesday, Jun 02, 2010 at 16:57

Wednesday, Jun 02, 2010 at 16:57
A regulator regulates the charge (voltage) going into the battery from the solar panels.

Most deep cycle batteries like somewhere between 14.5v up to 15v with 14.5 to 14.7 being the average, solar panels will put out over 18v if unregulated.

If you put 18v in to any12v battery for a long period there would be a good chance of destroying it and causing injuries to anyone near by if it explodes.

Amps have nothing to do with charging a battery with in reason, if you charged a battery with 1 amp it would be slower to charge then with 15 amps but what makes a battery charge is voltage.

I'm not going to get in to the hard facts, chemistry or the science of charging batteries and start talking gobblygook because like most people you will get lost.

So yes you need a regulator.
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Follow Up By: Lex M (Brisbane) - Wednesday, Jun 02, 2010 at 17:11

Wednesday, Jun 02, 2010 at 17:11
Here we go again.
A solar panel is a constant current device. Hooked to a battery the voltage will depend on the type of battery, state of charge of the battery, temperature etc. Under the circumstances it should never get to anything like 18volt.

If you have a battery that can take a continuous 6 amp charge without damage, and want to risk it, then go for it.

I'd use a regulator.

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Follow Up By: Lex M (Brisbane) - Wednesday, Jun 02, 2010 at 17:16

Wednesday, Jun 02, 2010 at 17:16
And to be correct your question should read.

If I'm running a fridge which draws on average 2 Amphours/hr and I have a solar panel producing again on average 6 Amphours/hr
We have....fridge 2 Amphours/hr for 24hrs=48 Amphours draw down
Solar panel.....6 Amphours/hr over say 7hrs=42 Amphours in
Therefore I will never overcharge battery (100 Amphour agm)
DO I REALLY NEED A REGULATOR??
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Follow Up By: ModSquad - Wednesday, Jun 02, 2010 at 17:34

Wednesday, Jun 02, 2010 at 17:34
Guys,

As you are well aware from many previous posts about solar and electrics that have been moderated, a replies such as this where another replier is taken to task on his statement is none other than antagonistic behaviour that all too often escalates into unsavoury debates.
No more discussion will be tolerated where the advice of another is debated within another person’s post.

Please post your own ideas as a reply and allow the OP to determine what is best for their needs.

The number of Complaints we have been recieving is beyond belief and we therefore feel the need to make these announcements for all to see.

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Follow Up By: olcoolone - Wednesday, Jun 02, 2010 at 17:47

Wednesday, Jun 02, 2010 at 17:47
Lex I think you have misunderstood the question and answer.

Most regulator will limit voltage and not current, an unregulated solar panel will deliver in excess of 18v at certain times, this is to high for safe battery charging.

A solar panel regulator will not regulate current but it will regulate voltage to an acceptable level for charging.

Of course a solar panel is a constant current variable voltage device and I don't know where you got the idea of it being any different in my post.

Lex do you understand what a regulator does?

I'm sorry if I mislead anybody and I would suggest not to take any notice of my post and ask it to be removed on the grounds I was incorrect and may of mislead someone.

I'm starting to get really sick of this forum again as the MOD SQUAD said!



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Follow Up By: Member - Richard L (WA) - Wednesday, Jun 02, 2010 at 17:55

Wednesday, Jun 02, 2010 at 17:55
Thanks to all for replys...........will get a reg

Cheers
Richard
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Follow Up By: Mike DiD - Thursday, Jun 03, 2010 at 08:15

Thursday, Jun 03, 2010 at 08:15
Lex M is right.

If you connect a "48 volt" Solar Panel to a 12 volt Lead Acid battery it will start to charge it at exactly the same current as a "12 volt" panel would.

If you don't have a regulator connected and you don't disconnect the panel manually, a "12 volt" panel will overcharge the battery with exactly the same timing as a "48 volt" panel.

To understand that you can connect a Solar Panel directly to a battery, means you have to understand that Solar Panel is a constant-current source - unlike every other source of DC around us.
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Follow Up By: olcoolone - Thursday, Jun 03, 2010 at 09:43

Thursday, Jun 03, 2010 at 09:43
Thats what I said didn't I?

"A regulator regulates the charge (voltage) going into the battery from the solar panels.

Most deep cycle batteries like somewhere between 14.5v up to 15v with 14.5 to 14.7 being the average, solar panels will put out over 18v if unregulated.

If you put 18v in to any12v battery for a long period there would be a good chance of destroying it and causing injuries to anyone near by if it explodes."



The remark about the current was intended to show current has very little to do with charging a battery......as the original post by Richard L (WA) was only regarding current and not voltage.

What I said
"Amps have nothing to do with charging a battery with in reason, if you charged a battery with 1 amp it would be slower to charge then with 15 amps but what makes a battery charge is voltage. "

He made no mention about voltage only current, I made mention about voltage and remarked what more or less current will do regarding charging batteries.

The remarks I made about current had nothing to do with solar panels.



As I said
"A regulator regulates the charge (voltage) going into the battery from the solar panels."

Obviously I must be wrong so please tell me where I went wrong and what I don't understand?



So please don't twist things around to make me look stupid!













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Follow Up By: olcoolone - Thursday, Jun 03, 2010 at 10:01

Thursday, Jun 03, 2010 at 10:01
That would be right!
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Follow Up By: jdwynn (Adelaide) - Thursday, Jun 03, 2010 at 11:44

Thursday, Jun 03, 2010 at 11:44
Guru's, I’m not questioning what you say but I'm not sure I understand it. We have 2/80w solar panels. In shade we get (about) 0.5 – 1.0 amps coming into our Steca regulator and in clear sun we might have 10 - 12 amps. So how can you call panels a constant current device when the current changes? Or do you mean "constant" is different from "varying"? As Pauline Hanson said, “please explain”. Cheers
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Follow Up By: Maîneÿ . . .- Thursday, Jun 03, 2010 at 12:19

Thursday, Jun 03, 2010 at 12:19
jdwynn,
the Voltage is stated as 'constant' the Amps is 'varying'

Maîneÿ . . .
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Follow Up By: Mike DiD - Thursday, Jun 03, 2010 at 12:24

Thursday, Jun 03, 2010 at 12:24
"So how can you call panels a constant current device when the current changes?"

If you connect a "24 volt" 160 watt panel in sunshine to a 24 volt battery it will put about 5 amps into it.

If you connect a "24 volt" 160 watt panel in sunshine to a 12 volt battery it will put about 5 amps into it.

If you connect a "24 volt" 160 watt panel in sunshine to a 6 volt battery it will put about 5 amps into it.

If you connect a "24 volt" 160 watt panel in sunshine to the 10 Amp terminals of a Multimeter (essentially a short circuit) it will put about 5 amps into it.

If you connect a "24 volt" 160 watt panel in sunshine to a 240 volt powerpoint - no, it won't put out 5 amps.

If you connect a "24 volt" 160 watt panel in moonlight to a 24 volt battery it won't put 5 amps into it.







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Follow Up By: Mike DiD - Thursday, Jun 03, 2010 at 12:36

Thursday, Jun 03, 2010 at 12:36
This post has been read by the moderation team and has been moderated due to a breach of The Trolling Rule .

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Follow Up By: Mike DiD - Thursday, Jun 03, 2010 at 12:40

Thursday, Jun 03, 2010 at 12:40
This post has been read by the moderation team and has been moderated due to a breach of The Trolling Rule .

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Follow Up By: jdwynn (Adelaide) - Thursday, Jun 03, 2010 at 12:45

Thursday, Jun 03, 2010 at 12:45
Thanks Mainey & Mike, got it now I think - tricky stuff. I've only played with 12v so this beyond my experience. Cheers

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Follow Up By: Bonz (Vic) - Thursday, Jun 03, 2010 at 17:06

Thursday, Jun 03, 2010 at 17:06
So Mike the battery effectively regulates the voltage is that correct?
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Follow Up By: Mike DiD - Thursday, Jun 03, 2010 at 17:11

Thursday, Jun 03, 2010 at 17:11
"the battery effectively regulates the voltage"

- if you're charging a battery of around 100 amphour from a constant-current source of around 5 to 10 amps, then yes. When the battery reaches full charge, that's when the voltage will start to rise above 14 volts.
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Follow Up By: jdwynn (Adelaide) - Thursday, Jun 03, 2010 at 17:13

Thursday, Jun 03, 2010 at 17:13
Been stewing on this thru the day a bit. On top of what Bonz has asked, how does the battery handle bulk/float voltage differences from a charger?

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Follow Up By: Bonz (Vic) - Thursday, Jun 03, 2010 at 17:14

Thursday, Jun 03, 2010 at 17:14
hmm Mike, we need to shake hands I reckon and discuss this, I would love to know how the solar cells regulate the current if the voltage varies, as Ohms rule would suggest otherwise. This is very interesting.
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Follow Up By: Mike DiD - Thursday, Jun 03, 2010 at 17:35

Thursday, Jun 03, 2010 at 17:35
"I would love to know how the solar cells regulate the current if the voltage varies"

The problem is every other DC source around us keeps the voltage fairly constant as you vary the load resistance.

A Solar Panel keeps the current fairly constant as you vary the load resistance - that's just the way it is. It's standard practice to test the current output of a solar panel by connecting an ampmeter (virtually a short-circuit) across the solar panel terminals.

Look up the data sheet for any solar panel and find the voltage-current curve - the current is fairly constant from 18 to zero volts.


"as Ohms rule would suggest"
- Ohms law tells you how much current will flow if you know the voltage and resistance - but a solar panels internal resistance is very high, so it doesn;t matter if you change the load resistance - it's swamped by the panel internal resistance.
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Follow Up By: Bonz (Vic) - Thursday, Jun 03, 2010 at 18:00

Thursday, Jun 03, 2010 at 18:00
Thanx Mike, I will go look that up. Very interesting.

Olcoolone, sorry for hijacking your reply mate!
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Follow Up By: Lex M (Brisbane) - Thursday, Jun 03, 2010 at 18:21

Thursday, Jun 03, 2010 at 18:21
quote
"Most regulator will limit voltage and not current, an unregulated solar panel will deliver in excess of 18v at certain times, this is to high for safe battery charging."

"A solar panel regulator will not regulate current but it will regulate voltage to an acceptable level for charging."

"Lex do you understand what a regulator does?"
end quote.

Yes I do. It regulates current while monitoring battery voltage.

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Follow Up By: olcoolone - Thursday, Jun 03, 2010 at 18:47

Thursday, Jun 03, 2010 at 18:47
So Lex a solar regulator is a current regulator and not a voltage regulator?

Why do the refer to them as solar voltage regulators and never solar current regulators?

Perhaps I was wrong and I apologise.
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Follow Up By: Lex M (Brisbane) - Thursday, Jun 03, 2010 at 19:30

Thursday, Jun 03, 2010 at 19:30
"Why do the refer to them as solar voltage regulators and never solar current regulators?"

They do occasionally. Also "Solar regulator" "Solar Controller" "Solar power regulator" "Solar charge controller" and on and on.

"Solar charge controller" makes sense to me.
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Reply By: Member -Dodger - Wednesday, Jun 02, 2010 at 16:59

Wednesday, Jun 02, 2010 at 16:59
In short YES.

It is always good to have a regulator on any panel/s over 30watt.
Thus when the battery becomes fully charged the regulator goes into maintenance mode bringing the battery up to its full potential.
This way you can have your panel connected to the fully charged battery when the fridge is running thus maintaining the battery in a fully charged state until nil sun.
I used to have a handle on life, but it broke.

Cheers Dodg.

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Reply By: Maîneÿ . . .- Wednesday, Jun 02, 2010 at 18:17

Wednesday, Jun 02, 2010 at 18:17
Richard,

My relevant *personal use* factual information is as follows:

I have used;
1 x 100 ah USA made Deep Cycle sealed battery (not agm)
powered by 1 x 80 Watt BP solar panel
running a fridge that did draw 2.8 ah (no longer have it)

I did N0T use a regulator.

I used this system for at least 24 months, with no apparent damage to the battery
BUT - maybe I was just really really lucky :)

I'm not telling you to do it, I'm telling you what I’ve done

However, I also believe for 1 x solar panel to "average 6amps/hr" (or even 6 Amphours/hr) over the day, it would have to be an unrealistically large panel
This reason is why you probably don't need a regulator?

If we knew the brand/model of solar panel then we could answer with more accurate and relevant information for you.

Maîneÿ . . .
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Follow Up By: Member - Richard L (WA) - Wednesday, Jun 02, 2010 at 19:08

Wednesday, Jun 02, 2010 at 19:08
Thanks Mainey.........My panel is 80 watt also

Richard
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Reply By: Robin Miller - Wednesday, Jun 02, 2010 at 19:17

Wednesday, Jun 02, 2010 at 19:17
Hi Richard

The mechanism by which the battery can be damaged is when for a number of reasons - maybe after a long run , you pull up with the battery mostly charged , the fridge is cold , and isn't on and the solar panel delivers its maximum current into the battery for some time , overcharging it as it has little load.

P.S. When you say panel averages 6 amps -> this implies maybe 8 / 10 amps peak which means this could happen quickly particularly if your battery type is non-vented.
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Follow Up By: Member - Richard L (WA) - Wednesday, Jun 02, 2010 at 20:05

Wednesday, Jun 02, 2010 at 20:05
Thanks Robin

In my case we would be in a static setup for perhaps 2 weeks.....so with only the solar panel as source of charge I would probably run out of charge.....therefore my ?? for a regulator.......my panel would only give a peak of 6amps I think

Richard
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Follow Up By: Maîneÿ . . .- Wednesday, Jun 02, 2010 at 23:14

Wednesday, Jun 02, 2010 at 23:14
Richard,
Yes, "peak" Amps - not 'average' as I commented on earlier :-)

Good to see you make the decision to get a regulator, now just get a good one

Maîneÿ . . .
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Reply By: Mike DiD - Wednesday, Jun 02, 2010 at 21:40

Wednesday, Jun 02, 2010 at 21:40
This post has been read by the moderation team and has been moderated due to a breach of The Moderation Complaints Rule .

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