camper trailer battery system

Submitted: Monday, Feb 07, 2005 at 07:05
ThreadID: 20199 Views:11605 Replies:7 FollowUps:7
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Hi, I have just recently purchased a camper trailer and wish to but a battery system in the tool bin to run my fridge and some lights, I have a dual battery sytem in my cruiser, what would I need to run and recharge this system at a minimal cost.
Any help will be appreciated.

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Reply By: Rosco - Bris. - Monday, Feb 07, 2005 at 09:02

Monday, Feb 07, 2005 at 09:02

If you're only looking to recharge and using a 7 pin trailer plug, the reversing light spot is spare. Hook the battery up to that on the trailer side (and to the earth of course) with the power supply on the vehicle wired in through a relay so it's disconnected when you start the vehicle.

Some ppls have a heavier wire setup but the above is all we use and it works fine for charging up whilst on the move.

AnswerID: 97050

Follow Up By: Baz (NSW) - Monday, Feb 07, 2005 at 09:15

Monday, Feb 07, 2005 at 09:15
Hey Rosco took the Disco out for a play on the weekend, awesome car had a ball, very happy with our choice should of bought a Landy ages ago.

FollowupID: 355655

Follow Up By: Rosco - Bris. - Monday, Feb 07, 2005 at 09:23

Monday, Feb 07, 2005 at 09:23
Good to hear Baz, I'm sure you'll find a wee tad of a difference from your previous rig.


FollowupID: 355660

Follow Up By: Member - JohnR (Vic) - Monday, Feb 07, 2005 at 09:55

Monday, Feb 07, 2005 at 09:55
Vive la difference.....

Reckon it seemed like beaut to drive mate, a lot lighter on the go than the Patrol but then they may be totally different loaded. Goodonyas. Will Kerry get a drive?
FollowupID: 355670

Follow Up By: Baz (NSW) - Monday, Feb 07, 2005 at 11:08

Monday, Feb 07, 2005 at 11:08
Hey john i'll MM you don't want to hijack Davids thread.

FollowupID: 355687

Reply By: Baz (NSW) - Monday, Feb 07, 2005 at 09:11

Monday, Feb 07, 2005 at 09:11
Hi David we have the Arrid Twin Charger to do this it is connected via 6mm wire and an Anderson plug to the car it is specificly designed for when you have a battery in the camper or caravan to compisate for voltage drop, ring the 12volt shop or if you are in Sydney in Auburn or visit the Aridd web site, i think Pirahna or Redarc have a similar product as well.

AnswerID: 97052

Follow Up By: Member - JohnR (Vic) - Monday, Feb 07, 2005 at 09:51

Monday, Feb 07, 2005 at 09:51

Reckon you are going skinny on the cable though to the battery on the camper. The higher drop would mean it will take a lot longer to charge. It could take a good days driving. It will depend a bit on where you have your higher current draw items like fridge and the like though. In the car with a separate circuit probably ok. We put a 25mm square cable ex-240v supply in Nick's to the back of the car for minimal drop.

Don't forget the total distance to the battery or the use point in the trailer for totalling the distance
FollowupID: 355668

Reply By: flappa - Monday, Feb 07, 2005 at 09:17

Monday, Feb 07, 2005 at 09:17
Other then I would question having the battery in a metal toolbox , (mines ina battery box on the A frame) , I run a Redarc Battery isolater , thick cable (6mm) , thru to an Anderson plug , to the Trailer Battery. Works fine.
AnswerID: 97054

Reply By: Ray Bates - Monday, Feb 07, 2005 at 09:58

Monday, Feb 07, 2005 at 09:58
Hi. Don't be fooled with all those twincharge things that are on the market. They are not necessary if your cabling in up the the mark. Another point to remember is cable size. I ran some 8mm auto cable in mine but when you buy auto cable it is measured on the OD of the plastic covering and therefore you are not getting what you thought you were getting. The best measurment for cable is AWG (Australian Wire gauge) This cable is measure on the cross sectional area of the conductor. All you should need is a good quality soliniod isolator in the engine bay of the car wired to the ingition system i.e the soliniod is open when the ignition is off so as not to drain your main battery. I am using 4awg cable in my set up via an Anderson 175amp plug. These items are not cheep but worth the extra cost of instalation. In regards the a toolbox versus a battery box I cant see much differance as long as they are well ventalated. You probably cannot buy 4awg cable from an auto shop. I got mine from Altronics catalogue No. W 4200 (red) & W 4202 (black) another word of caution Don't get confused with American SWG as their standard are the exact opposite to ours
AnswerID: 97061

Follow Up By: Ray Bates - Monday, Feb 07, 2005 at 10:24

Monday, Feb 07, 2005 at 10:24
I forgot to mention. Don't try and run your cable throgh a 7pin plug be it the large type or small. The connectors inside these plugs are too small to get large enough cable in. THAT INCLUDES THE NEGATIVE RETURN. Have you battery charging system on a seperate cuitcuit
FollowupID: 355675

Reply By: muzzimbidgie - Monday, Feb 07, 2005 at 13:26

Monday, Feb 07, 2005 at 13:26
Go back a few threads, sat or sun I think, someone was asking the same question and got some good comments.
AnswerID: 97089

Reply By: crozdog - Monday, Feb 07, 2005 at 13:52

Monday, Feb 07, 2005 at 13:52
Hi Bluesman,

I went through a similar question recently. There is a lot of info here - just do some searches. Have a look on PostID: 19933 for my comments on a similar question recently.

For me I decided not to charge from the car alternator as I had plenty of battery capacity in the trailer for what I do, & I don't have an isolator fitted. Instead I mounted 4 x 80Ah batteries in 2 banks connected via a marine battery switch (ie off bank 1, both banks, bank 2 about $30 at Witworths) & bought a charger that provides a float voltage (about $80 delivered). This means that when the camper is in storage, all the batteries are always on charge (via the both bank position of the switch) & therefore fully charged when I head out.

I suggest that you start at the basics eg:
- define your budget - "minimal cost" means different things to different peple
- do your research,
- think about how, where & how frequently you will use it.
- remember that high capacity deep cycle batteries are expensive, like any battery need some TLC & can cost more than the rest of the system (I managed to pick up mine at the right price) ;-)
- calculate your Ah draw & determine how long it will be before you will need to recharge. I have a spreadsheet that helps this heaps - I think I picked it up off the yahoo groups page. Let me know if you want me to email it to you.
- determine how long you will be away from mains power eg bush camping vs stopping in c'van parks
- can your existing dual battery setup easily accomodate an additional battery (eg alternator capacity)? This may be a limiting factor.
Once you've done that add any other requirements then design your system. I went through about 3 or 4 designs & costings on paper before actually buying anything.

Clearly defining YOUR requirements greatly assists your ability to build/buy a system that does exactly what YOU want from it.

Other things I'd add are:
- use the biggest cable (sq mm) you can,
- don't rely on the chassis for an earth return (I know lots do, but I consider cable to be cheap compared to the hassle of finding often intermittent faults)
- ensure you use fuses or DC circuit breakers to protect everything.
- you may want to consider making a distribution board in the trailer for your circuits instead of just connecting them via a fuse straight onto the battery. This is what I have done via an Anderson Plug. That way all circuits are individually switched & fused. When I pack up, all electricals get safely stowed & there is no wiring exposed to be inadvertantly damaged.

Let me know if you want to bounce some ideas around or find out a bit more about my setup.

AnswerID: 97092

Follow Up By: David Au - Tuesday, Feb 08, 2005 at 15:35

Tuesday, Feb 08, 2005 at 15:35
CrazyDog '4 x 80Ah batteries' does not make you a hero! LOL
FollowupID: 355876

Reply By: TheUndertaker - Monday, Feb 07, 2005 at 16:00

Monday, Feb 07, 2005 at 16:00
Bluesman , as you say you already havea dual system in your cruiser all you realy need is : heavy gauge + and - from your existing aux batt to the batt in trailer, use anderson plugs and wire of a minimum 6/8mm square,
AnswerID: 97108

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