Battery Charging Systems

Submitted: Wednesday, Feb 02, 2011 at 09:36
ThreadID: 84060 Views:2304 Replies:2 FollowUps:1
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My sister has a Holden Colorado with a dual battery system fitted to the vehicle. They have now got a Camper Trailer with a dry cell battery.
(12 volt cca@-18c is 800 rc@ 25c is 175)

They want to charge all three batteries from the vehicle. They have been told the dry cell battery has to be charged at a different rate. Their is apparently a system to do so. If anyone can help with what to buy and where to buy it.
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Reply By: trainslux - Wednesday, Feb 02, 2011 at 14:38

Wednesday, Feb 02, 2011 at 14:38
Hi Fj Ute.

The way I understand what you have written is that the dry cell battery for the camper is a cranking battery.?? is this so?

I would assume that the better battery for a camper would be a deep cycle in agm configuration of at least 100 amp hrs rating.

Voltage drop is the issue for charging a battery back in the camper.
So run good sized wire, and good connectors at the tow ball, 50amp anderson plugs seem to be the weapon of choice.

Short answer is that you can charge all batteries together when driving.
Alternators can put out 80+ amps, so can easily take care of the initial bulk stage of charging, its crude, but will work to a point.

This, if given enough travel time, and depending on how many amp hrs have been used in the battery should get you back up to near 80 % or more state of charge.
The last 15% or so takes a bit longer.
This is where a dc dc charger can help, or a solar panel/ reg setup.
Or just plug into 240 if at a caravan park, and use a good quality step charger to top up the batteries overnight.

Hope this helps a bit, but I think we need some clarification on what type of battery they are running in the car as a 2nd battery, and also the type in the camper trailer.


AnswerID: 443923

Reply By: turkey380 - Thursday, Feb 03, 2011 at 15:04

Thursday, Feb 03, 2011 at 15:04
Do not try to charge 3 batteries from one alternater. Each battery will take 25 amps so if you have a 80 amp alt. You will burn it out as it will get too hot
AnswerID: 444033

Follow Up By: trainslux - Friday, Feb 04, 2011 at 10:57

Friday, Feb 04, 2011 at 10:57
Only if all the batteries are very low in state of charge.
Rekon they have over 100amp alts in those vehicles, but happy to be proven wrong.

Isolator will isolate the crank battery anyway, so only have 2 batts that need charging.

I think you will be fine running 3 batts with the system you described.

I run 3 batteries, have done so with no problems for 4 years now.

FollowupID: 716226

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