Compressor Fridge

Submitted: Wednesday, Nov 06, 2013 at 18:34
ThreadID: 105023 Views:1912 Replies:3 FollowUps:19
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I have a couple of questions that i need help with.
1st Do solar panels on your roof charge while you are driving.
2nd If your anderson plug is not plugged in to your vehicle when you are traveling
does your 12v compressor fridge still run off your batteries in your van.
Cheers
Humpback
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Reply By: baz&pud (tassie) - Wednesday, Nov 06, 2013 at 19:04

Wednesday, Nov 06, 2013 at 19:04
Hi yu humpback
If it was our van, the answer to both questions would be yes, and would assume it would be the same with yours.
Cheers.
Baz
Go caravaning, life is so much shorter than death.

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AnswerID: 520975

Reply By: Member - Rosco from way back - Wednesday, Nov 06, 2013 at 19:09

Wednesday, Nov 06, 2013 at 19:09
G'day Humpback

1 ......... Yes/no. It has the capacity to do so, however the alternator puts out more juice. Both will contribute to the charging until the battery is charged, at which time the voltage regulator on each will open the circuit to prevent over charging the battery.

2 .......... It will if the fridge is connected to the van battery, until it drops to the low voltage cut-off point of your fridge.
AnswerID: 520977

Follow Up By: Shaker - Wednesday, Nov 06, 2013 at 19:52

Wednesday, Nov 06, 2013 at 19:52
The solar panel regulator won't contribute to the charging while the vehicle alternator is charging!

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FollowupID: 801577

Follow Up By: Member - Rosco from way back - Wednesday, Nov 06, 2013 at 19:55

Wednesday, Nov 06, 2013 at 19:55
Please explain.
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Follow Up By: oldtrack123 - Wednesday, Nov 06, 2013 at 20:46

Wednesday, Nov 06, 2013 at 20:46
Shaker posted:{quote"
The solar panel regulator won't contribute to the charging while the vehicle alternator is charging![endquote]
HI
Strange I must have been imaging the ampmte rreadings I have been seeing all these years!!

The true story is both will contribute until the battery reaches a state of charge voltage of either the Solar reg or theealternator reg
"CUT BACK "point
AT that point one will turn ofF or reduce output the other will continue to charge
.IT may even reach the point when the Alternator output reduces to ZERO & the solar will actually supply the vehicle electrics

IF the BATTERY voltage drops due to l ad or reduction in solar output BOTH will put in energy!!


PeterQ
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FollowupID: 801585

Follow Up By: Shaker - Wednesday, Nov 06, 2013 at 22:25

Wednesday, Nov 06, 2013 at 22:25
The solar regulator will detect the voltage coming from the alternator & stop charging, the same reason tha you can't hook up 2 sets of panels unless they run through one solar regulator!
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FollowupID: 801599

Follow Up By: oldtrack123 - Wednesday, Nov 06, 2013 at 22:52

Wednesday, Nov 06, 2013 at 22:52
HI

Well then I have been imagining the results I have been getting for years with just such an arrangement

THe ALTRNATOR VOLTAGE has nothing to do with it
IT is the battery voltage that determines just what EACH will contribute

And who said you cannot hook up two panels with different regulators ??

They will each do the same ,each will contibute until the regulation pointswith a PWM reg] are reached
ONE may then cut back before the other,but the battery will be near fully charged

BUT there is a complication with MPPT regs due to the constant sampling being carried out to find the M, P. Point
YOU SHOULD TRY IT SOME TIME
you may learn something!!


PeterQ
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FollowupID: 801601

Follow Up By: Shaker - Wednesday, Nov 06, 2013 at 23:29

Wednesday, Nov 06, 2013 at 23:29
I DID, & I LEARNT THAT I GOT NO CHARGE!
I had solar on the camper & hooked up a portable set, the result was virtually no input.
There is also no need to be a smart ass!

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FollowupID: 801602

Follow Up By: oldtrack123 - Wednesday, Nov 06, 2013 at 23:42

Wednesday, Nov 06, 2013 at 23:42
HI
Well your results are not typical!!

Perhaps your battery was already fully charged

You would need to give a lot more details as to battery voltage, panel voltage, solar reg type & set points etc before your results could be explained

Perhaps the solar panel was not higher enough voltage especially IF it was an Ebay special[not with a M P P P @ around 17V ]
IT may even have a MPPT reg.

BUT YOUR EXPERIENCE proves absolutely nothing !

PeterQ
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FollowupID: 801603

Follow Up By: Lucko - Thursday, Nov 07, 2013 at 12:26

Thursday, Nov 07, 2013 at 12:26
My experience is the same as Shakers. I've been running 2 X 100aH deep cycles in the ute, a VSI12 Redarc under the bonnet and a 130W panel on the canopy roof with a Morningstar Sunsaver 10A controller. My wattmeter tells me that, with the engine running, the alternator output is higher than that of the panel. It seems to act like a diode auction - whichever is higher (ampwise), makes the contribution to the battery bank. Just my observations.

Mark
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Follow Up By: oldtrack123 - Thursday, Nov 07, 2013 at 13:58

Thursday, Nov 07, 2013 at 13:58
HI Mark

The Redarc is what is giving you THAT result
OR HIgh resistance connection /cables from the crank battery to the house battery
If the connection between the CRANK battery & the house battery is low resistance [AS IT SHOULD BE, iF you want allternator assisted charging of the house battery] The voltage at BOTH the CRANK battery & the HOUSE battery should be VERY CLOSE to the same
Certanly no more than about 0.2V different

IT is a simple electrical fact that the two batteriies when connected together SHALL have the same voltage IF ALL, CONNECTIONS ARE good & cables are large enough for the c,urrent flowing[to miinimise VOLTAGE DROP]

HoweverIF you are simply saying the ALternator is simply suppliying MORE AMPS than the SOLAR ,YES THAT is what one would expect >
The solar would at the best only have around 7A available compared to the alternator 60< .100A
That is different to saying NO CHARGING CURRENT FROM THE SOLAR or the the solar shuts the alternator down
Which can occur at times !WHEN the house battery is near fully charged.



Unfortunately MANY /MOSTdo not meet those requirement!

I would suggest both you & Shaker have your system checked out by someone who understands the effects of of load AMPS on VOLTAGE DROP.


PeterQ
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Follow Up By: Shaker - Thursday, Nov 07, 2013 at 20:55

Thursday, Nov 07, 2013 at 20:55
I spoke to two suppliers of solar panels today, both said if you are using 2 separate arrays they should run through a single solar regulator.

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Follow Up By: Andrew D. - Thursday, Nov 07, 2013 at 22:41

Thursday, Nov 07, 2013 at 22:41
Shaker if you want to sore with eagles, don't arque with the unknowing who think they know. There are those that can create miracles and they should be avoided as they are the all knowing forum junkies that do nothing else than fill up all RV forums daily with bad and scare mongering information. Obviously the opponent is clueless on DC.
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FollowupID: 801679

Follow Up By: Andrew D. - Thursday, Nov 07, 2013 at 22:46

Thursday, Nov 07, 2013 at 22:46
"I spoke to two suppliers of solar panels today, both said if you are using 2 separate arrays they should run through a single solar regulator."
that is not entirely correct and would suggest the suppliers are clueless.
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FollowupID: 801681

Follow Up By: oldtrack123 - Thursday, Nov 07, 2013 at 23:13

Thursday, Nov 07, 2013 at 23:13
HI Shaker

IF you had to ask a panel supplier it is obvious you have very little electrical Knowledge on the subject
BUT the suppliers are correct,
if two arrays or parallelled panelsc are involved it is better to have them both connected to the one regulator

IF you read back carefully & try to understand what has been posted by Rocoe & myself you will see why !

It is simply because ONE regulator WILL reduce or shut off before the other AS THE BATTERRY APPROACHES FULLY CHARGED

BUT UP TO THAT POINT BOTH panels WILL put out there own available output
AGAIN provided they have been correctly wired & with very near the same VOLTAGE drop in their cables when under full load!!

NOW just to refer back again, this is only true if the regualtor is a PWM type
IF MPPT types , both regulators will go crazy tring to seek the Max Peak Power point

AN alternator reg is not a MMPT type, So as long as the panel also has a PWM reg, BOTH WILL WORK TOGETHER again up to the NEAR fully charged point

NOW if you do not understand the terms MPPT & PWM do a wiki search .


Solar DC is a lot more complex than many think simply because of the panels have some unusual charaeristics as power supplies !

Just one other point, some battery DC to DC chargers do not allow both sources to charge at the same time by the DESIGN OF THE CHARGER
BUT A simple VOLTAGE sensitive RELAY type battery isolator with good heavy wiring [for the distance & load current ]
will allow very effective combined charging when it is realy need
[LOW SOC batterries]
THERE ARE MANY, MANY OUT THERE, DOING JUST THAT

Myself included for over 30years

PeterQ
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FollowupID: 801682

Follow Up By: oldtrack123 - Thursday, Nov 07, 2013 at 23:20

Thursday, Nov 07, 2013 at 23:20
HI Andrew

Perhaps you could make a valuable? contribution ,showing your knowledge on the subject???


PeterQ
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FollowupID: 801683

Follow Up By: Shaker - Friday, Nov 08, 2013 at 10:13

Friday, Nov 08, 2013 at 10:13
It's hard to know who to believe, reputable companies that deal with solar equipment every day, or faceless people on a forum.

All I know is when I plugged a portable solar kit in to my camper to assist the built in panels, I had a very low battery that evening. The next day I left the portable kit out of the equation & solar charging resumed.
I have since fitted a larger solar regulator to the camper, bypassed the regulator on the portable kit & have no further issues, & no, I don't claim to be an expert!
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FollowupID: 801703

Follow Up By: oldtrack123 - Friday, Nov 08, 2013 at 12:20

Friday, Nov 08, 2013 at 12:20
HI shaker
Yes it is a problem
But first you should understand that most of the time with companies you are dealing with SALES PERSONS with no actual qualifications just sales speil

On forums all one can do is ATTEMPT "to sort the wheat from the chaff"

That often requires asking sensible valid follow up questions until one undertstand enough to" sort the wheat from the chaff"

The detais lthat one is prepared to put into their posts/could /should give some indication of their knowledge base

PeterQ
retired electician/ /ex electrical service centre [commercia l& industrial] manager /senior technician
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FollowupID: 801721

Follow Up By: Andrew D. - Friday, Nov 08, 2013 at 13:42

Friday, Nov 08, 2013 at 13:42
"bypassed the regulator on the portable kit"
when you are dealing with crap solar regulators that come with portable panels and the regulator is mounted on the panel with crap undersize wiring and low quality copper cable to the battery, you would get substantially superior input with the portable solar panel directly connected to the solar regulator next to the battery.
When using quality solar regulators which are a cheap investment for expensive AGM batteries having to separate arrays with 2 QUALITY solar regulators is not an issue. With Morningstar solar regulators you can have 5 units in parallel. Presently there is so much cheap crap product in the solar industry and at every turn unqualified people flogging the stuff that dont have a clue, like many that post here as qualified advice.
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FollowupID: 801731

Follow Up By: oldtrack123 - Friday, Nov 08, 2013 at 14:20

Friday, Nov 08, 2013 at 14:20
Andrew D. posted:
[1]"bypassed the regulator on the portable kit"
when you are dealing with crap solar regulators that come with portable panels and the regulator is mounted on the panel with crap undersize wiring and low quality copper cable to the battery, you would get substantially superior input with the portable solar panel directly connected to the solar regulator next to the battery.


[2]When using quality solar regulators which are a cheap investment for expensive AGM batteries having to separate arrays with 2 QUALITY solar regulators is not an issue.

3] With Morningstar solar regulators you can have 5 units in parallel.
[4]Presently there is so much cheap crap product in the solar industry and at

[5]every turn unqualified people flogging the stuff that dont have a clue, like many that post here as qualified advice.
Thumbs UpThanked 1FollowUp 17 of 17



HI Andrew
I like it
[1] A very definite YES
but highlight:
[a] reg as near as possible to the battery'
[b]Heavy good quality cables to minimize voltage drop & energy loss

[2] YES, we Agree but with the qualification they be PWM regs not MPPT regs, which can go crazy trying to match each other settings
Many solar panels from Ebay now have very cheap VERY very basic regs, hardly worth the postage rate
I suspect THAT may be why Shakers cannot get a charge from his solars when both connected

[3]
yes but within the regs rating

[4]
Sadly only to true

[5]YES !!!


PeterQ
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FollowupID: 801733

Reply By: Robert O - Thursday, Nov 07, 2013 at 20:36

Thursday, Nov 07, 2013 at 20:36
Maybe I missed something in reading all these comments but can someone tell me why you would travel without connecting the Anderson plug. From recent experience with my new off road van I found to run a compressor fridge (215ltr.) for more than 24hrs you need at least 2x120AH deep cycle batteries and at least 400w solar panels.(and Generator backup for inclement weather).
Anyone disagree?
AnswerID: 521059

Follow Up By: Andrew D. - Thursday, Nov 07, 2013 at 22:45

Thursday, Nov 07, 2013 at 22:45
but can someone tell me why you would travel without connecting the Anderson plug"
Well you wouldn't, however the issue is majority/well all are wired incorrectly
400W solar panels is at the bottom of requirement for 215L fridge
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FollowupID: 801680

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