12V system for charging a battery in a van

Submitted: Tuesday, Apr 29, 2003 at 20:08
ThreadID: 4643 Views:3827 Replies:6 FollowUps:1
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I wish to set up a battery in my van and wish to do it myself, but being a novice at electrical work , I don't know where to start.
Trickle chargers, solinoids, ect, can anyone help?
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Reply By: Dozer - Tuesday, Apr 29, 2003 at 20:28

Tuesday, Apr 29, 2003 at 20:28
Your options are to have an auto spark fit up a charging system off the cars main circuit and/or buy a charger and when you reach a park you can charge it up manually.
I have an inverter in my van that charges the battery when there is power or supplies 240 when there is not (until te battery dies that is)
AnswerID: 18710

Reply By: herkman - Tuesday, Apr 29, 2003 at 20:38

Tuesday, Apr 29, 2003 at 20:38
Good evening!

You need to tell us more, because it will greatly impact onto how you set it up.

Here is a few things you need to tell us.

1. How are you intending to charge the battery, is it off the tow vechicle, or are you going to do it from 240 volt external.

2. What is the battery to be used for, you need to list the wattage of all that will use the battery.How long each day are you to use each item.

3. What type of battery will you be using, as there also could be venting requirements. Are you intending you travel over rough roads for long periods.

4. Do you understand the differance in Auto type cabling, compared with other types.

5. Do you understand how to set up the towing vechicle, if you want it to charge up the extra battery, do you understand the pro's and con's of the various ways of doing this.

6. Do you have access to the means of making proper crimps, or silver soldering your terminals.

Whilst all of this may sound a little daunting, but provided you know what you want to achieve, and have a basic knowledge of DC power, and you are not prepared to cut the corners, you will be OK. You need to know how voltage drop occurs, and what you can do to reduce it.

Here a couple og good sites, that you need to download, because they contain vital information to get the material to do the job.


Has lots of usefull facts for you understand.


Explains about cable requirements.


This give you aditional information.

Now do not let this put you off, but to do a good safe job, you will have to use the right materials, or the system will not work to the best, and could actually be unsafe or a fire risk.

Come back off line if you need more help at



Col Tigwell

AnswerID: 18716

Reply By: Frank - Tuesday, Apr 29, 2003 at 21:50

Tuesday, Apr 29, 2003 at 21:50
Hi Al,

I use the Pirahna dual battery system in my vehicle. I run the normal starting battery, an deep cycle auxilliary under the bonnet and another deep cycle battery in my camper. I have never had to worry about any of the batteries, as the system looks after itself. Once the car is started, the charge goes to the battery which requires it. The battery in the camper is connected directly to the under bonnet auxilliary, so that when charging swaps from the main battery to the auxilliary, the camper battery gets charged at the same time. Make sure you use the correct gauge wiring and use an "Anderson plug" between car and van.

AnswerID: 18746

Reply By: Solar King - Wednesday, Apr 30, 2003 at 07:29

Wednesday, Apr 30, 2003 at 07:29
Al buy yourself a Redarc Battery Isolator for $110
Anderson 50 amp plug
40 amp LARGE blade fuse
Enough 6mm2 twin sheathed wire to do a double run so that you in fact have a positive and negative lead of a combined total of 12mm2
Mount the Redarc Battery Isolator as close as practical to the battery as possible. Connect the wires using high class crimp terminals like Hella or AMP brand, using a proper crimping tool.
This setup will work perfectly if you follow the above guidlines.
AnswerID: 18784

Reply By: Member - Dave- Wednesday, Apr 30, 2003 at 09:58

Wednesday, Apr 30, 2003 at 09:58

I have an aux. battery in vehicle and another in the trailer. I set mine up slightly different as I have two fridges. One for day to day use and one for storage. The storage fridge remains in the vehicle and the day to day fridge comes out into the camper when we are stopped. Because of this my aux. battery in the car is not connected to the aux. battery in the trailer. I can flaten aux in vehicle and not in trailer and visa versa.

How I charge both is through a "Smart Charger" which is similar to Piranha etc. They come in two different amp ratings, a max of 40 amps and 80 amps. Mind you your vehicle has to be at the optimim charge and the minum current usage by the vehicle to get 80 amps of charge. ie. if driving with lights on etc this robs the potential to charge the extra batteries. The 80 amp set up uses two different leads into the unit and two seperate leads out (max. of 40 amps each). They both can be connected to the one battery or to seperate batteries. They have the usual voltage sensing cut outs like all the rest. It keeps the batteries in parallel until the starting battery reachs 12.2 volts and disconnects the parallel circuit. Again when charging the main battery has to reach 13.8 volts before it will start to charge aux batteries.

I wired my own which was not very hard. Use all the advise in the other replies as to fuses, wire size and especially anderson plugs. However I soldered instead of crimping.

The unit was a lot cheaper than the piranha and (correct me if I am wrong, as I am sure someone will, lol) I dont think the piranha unit has the availability to seperate the two batteries with one unit if you chose to do this. There is advantages in keeping both aux. batteries paralleled as well. ie if everthing when stopped is used from the trailer then why not get use the aux. battery in the vehicle as well in parallel.

I spent around $200 all up with plugs etc. One of my mates but his into a 4x4 shop and had his wired to work like mine and cost $1200. Could not see it! The other thing I did was put the wires in a split flexible condut (cant think of right name at the moment) which is available in any spare parts and fed it through the chassis for protection. The condut was also protection from rubbing against metal.

The answer is know what you are going to use and where you are going place your gear when stopped to choose the best system.

I carry a battery charger but never used it. If at powered sight run fridges on 240, only lights on battery. Recently used lights only on one battery for two weeks without problem. (mind you not in the trailer reading all night either.)

Hope this helps.
AnswerID: 18801

Reply By: Wombat - Wednesday, Apr 30, 2003 at 17:01

Wednesday, Apr 30, 2003 at 17:01
Hey Big Fella,

Couldn't find an actual diagram but try this link http://www.aroundoz.com/diy_archive/fridge_car_wiring.htm
AnswerID: 18831

Follow Up By: Old Jack - Saturday, May 03, 2003 at 17:31

Saturday, May 03, 2003 at 17:31
This site has actually made a fare effort to be factual, and most of all safe! Best online effort I've seen for a while at trying to explain a job to a layman.

FollowupID: 11966

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