Dual Battery or no dual battery

Submitted: Wednesday, Nov 16, 2016 at 18:35
ThreadID: 133784 Views:4047 Replies:13 FollowUps:0
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Just traded in my Prado which had an installed dual battery system to run my 40l engel in the back of the car and the electrics ( led lights, shower pump ) for my camper trailer which had no battery.I now have a new prado and upgraded the camper trailer which comes with a battery. My question is , do I need a second battery in my car to safe guard not being able to start in a remote location or is the second battery in the camper sufficient ? Is a dual battery in the car and one in the camper over kill?
Any thoughts out there? Cheers Mike.
ps I also have a 140watt solar panel
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Reply By: Frank P (NSW) - Wednesday, Nov 16, 2016 at 19:34

Wednesday, Nov 16, 2016 at 19:34
If you're going to stay with a fridge in the car, I would go for a second battery in the car.

Presuming you keep your fridge, if you don't do the second battery which battery will run your fridge when you're camped up? If it's the car you run the risk of flattening your crank battery. If it's the camper you'd better have a dc-dc charger and possibly solar in the camper to keep up with electrical demand. I'd be doing that anyway.

Personally I don't think a second battery in the car and another in the camper is overkill. That's what I'd set up, particularly as you are contemplating remotelocations.


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AnswerID: 605945

Reply By: Member - Rod N (QLD) - Wednesday, Nov 16, 2016 at 19:36

Wednesday, Nov 16, 2016 at 19:36
As long as you do not run anything from the vehicle battery while the engine is not running you should be OK.
AnswerID: 605946

Reply By: Notso - Wednesday, Nov 16, 2016 at 19:49

Wednesday, Nov 16, 2016 at 19:49
I'd go for the second battery in the vehicle. Better to have too much rather than too little!
AnswerID: 605948

Reply By: gbc - Wednesday, Nov 16, 2016 at 20:05

Wednesday, Nov 16, 2016 at 20:05
I've got 3 in the camper and one extra in the car so you already know which way I lean. If a didn't have a fridge in the car I probably wouldn't have dual batteries in it though.
AnswerID: 605952

Reply By: swampy - Wednesday, Nov 16, 2016 at 20:18

Wednesday, Nov 16, 2016 at 20:18
its all personal but 2 identical batteries in the camper . Typically 2 larger batteries can fit in camper generally .
Fit some sort of isolation between vehicle and camper batteries .
Fit a low volt cut out to both car and camper to prevent over discharge .

AnswerID: 605953

Reply By: Robin Miller - Wednesday, Nov 16, 2016 at 20:19

Wednesday, Nov 16, 2016 at 20:19
There is no need for a second car battery for that reason, its mostly dead weight.

Whats important is that you have a means to start car if you accidently discharge its battery.

After all , a jump starter is just a second and small battery , smaller than your campers battery.

You need to be sure that you can move campers battery to the car and make a quick connection - I just use a short 50amp Anderson on the car and matching one to a 20ah gel cell.
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AnswerID: 605954

Reply By: Glenn C5 - Thursday, Nov 17, 2016 at 10:05

Thursday, Nov 17, 2016 at 10:05
Is the battery in your camper a starter battery or a deep cycle (agm ) battery ? If its a deep cycle I don't think it will be any good as a starter battery.
AnswerID: 605963

Reply By: Alloy c/t - Thursday, Nov 17, 2016 at 15:37

Thursday, Nov 17, 2016 at 15:37
2 things , apart from your solar panels how are you charging the c/t battery ? The obvious is of course an Anderson plug that is connected to your vehicle battery via an isolator of some form , .. personally would would also put in another battery in the new vehicle then run something like … from start batt to Aux via DC- DC charge regulator then nice and heavy wire from AUX to C/T battery via Anderson connection and appropriate fuses , lets you keep the Fridge in the vehicle while away from camp and minimal chance of draining the start batt …..after all a fridge in the vehicle is not just for camping or touring ,
AnswerID: 605968

Reply By: phantom - Thursday, Nov 17, 2016 at 15:48

Thursday, Nov 17, 2016 at 15:48
I had a 50A in car charger and relay installed so I can use a 75AH thumper for the times that I want to use the fridge. Other times, the thumper and fridge come out to keep the weight down.
The beauty of this is that it is portable, can jump start the car if needed and fitted / removed when wanted. I lash them down to the the tie down points.
AnswerID: 605969

Reply By: Sigmund - Friday, Nov 18, 2016 at 09:52

Friday, Nov 18, 2016 at 09:52
Q is whether the CT battery will start your car if needed. My guess is yes as a one-off, without significant damage.

I'd put a 2nd battery in the CT. My rule of thumb is 2 x 100 aH batteries there to run a 40l fridge and some lights for around 5 days, depending on conditions.

Apart from all that, with a new wagon I wouldn't be expecting starting problems so unless you have to run a fridge in the car, don't bother adding capacity there. If you make few stops or if you substantially increase the insulation around the fridge, you could still be able to run one in the wagon without a 2nd battery but you'd want insurance in the form of a fairly high level voltage cut-out. The fridges I've seen offer 10.5 or 11v cut-outs which is too low, but I think you can get an inline cut-out from Jaycar and the like that allows a higher setting.

Take this with a grain of salt. I'm no sparky. Just comes from some hard-won experience.
AnswerID: 605980

Reply By: Batt's - Friday, Nov 18, 2016 at 12:29

Friday, Nov 18, 2016 at 12:29
So many different scenarios come to mind but personally I think it comes down to that fitting a 2nd battery to the vehicle would be the best option using a decent size dual purpose battery say 105 ah at least so starting your vehicle will be covered and you can run your fridge for a day or two when you go away without the camper on other trips.

Also remember you can fit all the batteries you want to your camper but if your out on a day trip and it's setup back in camp your jumper leads won't be long enough so you could be in for a long walk.

If you only run you fridge in the camper and never use it in the car you can also look and buying one of those new jump starter packs to keep in the glove box just in case.
AnswerID: 605988

Reply By: Mike & Kendra -Prado1 - Friday, Nov 18, 2016 at 15:37

Friday, Nov 18, 2016 at 15:37
Thanks everyone for your ideas. Decided to go with the battery in the CT ( 150 AGM) , which will be replenished by car the battery whilst driving and when camping I will use the solar panels to keep fridge AND lights going in the CT. For an emergency was thinking of using a thunder jump starter if something was left on accidentally in the car to drain main car battery.Must admit bit nervous not having the dual battery as a back up.

AnswerID: 605993

Reply By: philldeb - Saturday, Nov 19, 2016 at 08:02

Saturday, Nov 19, 2016 at 08:02
You have virtually answerd
you own question as you are a bit nervous about not
having a duel battery set up well its apparently wot you need
AnswerID: 606007

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