Caravan Batteries

Submitted: Wednesday, Apr 07, 2010 at 19:09
ThreadID: 77534 Views:3074 Replies:5 FollowUps:11
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Hi all, this is my first post. I am a bit concerned about the amount of power that our 3 way fridge draws from 2 x 120 ah deep cycle batteries whilst we are travelling during the day, even though the van is connected through an Anderson 50amp plug.There is no 50amp fuse between the Anderson connection and the batteries only a 20amp fuse that has blown once.

signed Worried Colin
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Reply By: Member - Graham H (QLD) - Wednesday, Apr 07, 2010 at 19:14

Wednesday, Apr 07, 2010 at 19:14
The first thing to come to mind is what size wire are you using from the battery in the car right back to the batteries in the van.

It should be at least 6 B&S or 6 gauge which is a lotttttt heavier than 6mm automotive

Thats what I use with 60 amp resettable fuses at BOTH ends
AnswerID: 412012

Follow Up By: Member - Colin William A (SA) - Wednesday, Apr 07, 2010 at 21:51

Wednesday, Apr 07, 2010 at 21:51
Hey , thanks all of you. My first thought was cable size, but can't be sure what it is? Also amazing the wattage draw 300+, that's quite a drain..
Thanks again
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Follow Up By: Maîneÿ . . .- Thursday, Apr 08, 2010 at 08:39

Thursday, Apr 08, 2010 at 08:39
Collin,
How do you work out the " amazing the wattage draw 300+ " ???

Maîneÿ . . .
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FollowupID: 682053

Follow Up By: Honky - Thursday, Apr 08, 2010 at 17:25

Thursday, Apr 08, 2010 at 17:25
I don't think the issue is the 3 way fridge but the recharge amps the batteries would want if low.
I had a 20 amp circuit breaker on my anderson plug and it would trip all the time due to trying to charge the batteries ( 2 x 105s ) Not to sure what the wire is as I no longer have the vehicle but changing to a 40 amp fixed the problem.
Not to sure what amps a half full wetcell battery would try to pull from the charging system but I know it will labour the motor when I first connect the anderson plug to the camper trailer.

Honky
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Follow Up By: Member - Colin William A (SA) - Thursday, Apr 08, 2010 at 21:54

Thursday, Apr 08, 2010 at 21:54
Thanks you goys for all the imput...Had a closer look at connections this morning before hitting the road..Anderson plug inside looks as though its been over heating...purchased new one in Norseman...currently in Salmon Gum WA and will lay up here tomorrow and rewire it...will also pick up circuit breaker to install close to batteries when we get to Esperance...
Thanks again...Not so worried now Colin
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Follow Up By: Member - Graham H (QLD) - Thursday, Apr 08, 2010 at 22:02

Thursday, Apr 08, 2010 at 22:02
A resettable fuse is a lot safer A breaker will reset but a resettable fuse wont except if you do it.

Just clean the anderson plug contacts with some baking soda. They are 50 amp at least so wont be them overheating.

MIne were pretty dirty but werent getting hot

Unless you have a very big soldering iron or an equally big set of crimps you wont be able to fix it satisfactorily.

6 B &S wire is 10mm sq and comes in single strand in either red or black so you wont mistake it if you have it

Its nearly 3/8in in diameter

6 mm automotive is usually twin flex and much much smaller It is actually only 4.8mm sq


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FollowupID: 682154

Reply By: Mandrake's Solar Power- Wednesday, Apr 07, 2010 at 20:34

Wednesday, Apr 07, 2010 at 20:34
3 Way fridges are notoriously heavy on Amps possibly close to 10 Amps when compressor kicks in - There could also be a higher surge occasionally at that moment and your 20 amp fuse just does what it is supposed to - Phut !
I'd check the current draw when the fridge is operating .. There is also the possibility of a short circuit while travelling perhaps a certain bounce of the springs affects it ?

Good luck finding it ...

Cheers

Steve

AnswerID: 412029

Follow Up By: Lex M (Brisbane) - Wednesday, Apr 07, 2010 at 20:58

Wednesday, Apr 07, 2010 at 20:58
"3 Way fridges are notoriously heavy on Amps possibly close to 10 Amps when compressor kicks in"

Compressor in a 3 way fridge. I don't think so.
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FollowupID: 682017

Follow Up By: Mandrake's Solar Power- Wednesday, Apr 07, 2010 at 21:28

Wednesday, Apr 07, 2010 at 21:28
Well I dropped a clanger didn't I ...
Never mind the principle remains that there is a heavy drain on 12 volt system due to the Ammonia Evaporator heating element - I just had a look at a Dometic user manual and it showed a 325 watt heating element for one of its 3 - way fridges .
I guess that explains the current draw ...

Cheers

Steve

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FollowupID: 682019

Follow Up By: Member No 1- Thursday, Apr 08, 2010 at 07:29

Thursday, Apr 08, 2010 at 07:29
yep..just an standard electrical heating element

Why arent these things (heavy on the power) explained to the customers when they buy such things?
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Reply By: Matt(WA) - Wednesday, Apr 07, 2010 at 23:43

Wednesday, Apr 07, 2010 at 23:43
1. You should be running your fridge off 12v supply direct from alternator through 12 pin plug with min 6mm wire.
2. Anderson plugs should be charging batterys
3. Batterys should be seperate circuit to fridge supply, but switchable when required.
4. A 3way 12v element starts at 125w for a dometic/electrolux 90lt. So your draving min 10amps.
5. There should be circuit breakers close to the batterys from the anderson plug supply.

Hope this helps

Matt

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AnswerID: 412057

Follow Up By: Member - Graham H (QLD) - Thursday, Apr 08, 2010 at 08:19

Thursday, Apr 08, 2010 at 08:19
If that is so I wonder why my van was built with 6 B&S to both the fridge and the batteries via an Anderson plug.

I wouldnt use a flat 7 or 12 pin plug ever.

A large round 7 pin has much better contact area on the pins and the Anderson is best of all.

You need fuses at both ends, as when travelling if something shorts you want a fuse to blow not a breaker resetting when you still have the problem.


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Follow Up By: Racey - Thursday, Apr 08, 2010 at 09:40

Thursday, Apr 08, 2010 at 09:40
I agree with Graeme.

As already mentioned these 3 way frigs are notorious for power consumption which is why I use a 12v compressor frig. It's like leaving your head lights on. One of the problems with charging the van batteries from the car is the the van batteries rarely get fully charged due to the voltage drop from the car alternator. I see recently Projecta and Redarc have 12v to 12v chargers which do provide the correct charge to the remote batteries; not cheap though over $300.

Cheers

Racey
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Reply By: TerraFirma - Thursday, Apr 08, 2010 at 10:20

Thursday, Apr 08, 2010 at 10:20
I suspect that a 12v compressor fridge would be better served whilst underway and that the 3 way be used once you arrive via Gas. Or alternatively do not connect the 3 way fridge to the 12v source , use ice or techni ice en route and then gas once you arrive. The 3 way fridge isn't the best performer via 12v anyway so I am only hoping to make some suggestions, hope thats OK.
AnswerID: 412092

Follow Up By: Maîneÿ . . .- Thursday, Apr 08, 2010 at 20:38

Thursday, Apr 08, 2010 at 20:38
Once the Alternator is charging the battery system, the battery will then happily power a 3 way fridge, only when stopped should you then put it on gas.

Maîneÿ . . .
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Reply By: Member - Charlie M (SA) - Thursday, Apr 08, 2010 at 22:10

Thursday, Apr 08, 2010 at 22:10
Hi
As above post said minimum 6bs wire. fridge drawers 14.5 amps on my amp gauge set-up in my old van had it connected to two 105ah batteries, and connected with 6bs wire and 50amp resetable C B worked well when travelling.
Setting up new van with 8bs wire and same C B
Cheers
Charlie
AnswerID: 412198

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