Van Dwellers: Adding Extra Batteries to Your Van Dwelling

Most vehicles on the road today come with 12v Auxiliary power outlets mounted on the dashboard. My Chevy Express Van has two, one on each side of the dog house (in cab engine cover). Rated at about 20 amps you can plug in all sorts of nifty accessories that will make your van dwelling life more comfortable and versatile. There's only one problem, run your TV, laptop or travel oven too long and when it comes time to leave there may not be enough power left to start the engine.

The answer to this problem is simple, straight forward, and not extremely expensive if you follow the KISS principle of Keep it Simple, Stupid.

If you go to your local auto parts store or RV dealer and ask them "How can I isolate a second battery so I won't drain the starting battery" they will likely aim you toward an electronic battery isolator that may cost the better part of $100. I've used them in the past and they've often caused more problems then they've solved. Today's computer controlled cars are sensitive to any electrical add on device that may require you to modify the original wiring. Such was the case with my 2001 GMC, the charging system became unreliable with the modifications required to make an electronic isolator work.

All you really need to prevent your House Batteries (those designated for running accessories) from draining the start battery is a simple 12v Continuous Duty Solenoid. A likely candidate is the Cole Hersee 24059BP or something comparable rated at about 85 amps.

By hooking your 12v batteries together in a Parallel configuration (Pos. to Pos. and Neg. to Neg.) you can tie together as many batteries as you like and still have a 12v system. With the solenoid placed in the Pos. cable coming from your van battery and going to your house batteries so that it is energized only when the ignition switch is in the on position your house batteries will be charged when your motor is running and completely separate of your vehicle electrical system when the motor is not running.

Some people have asked if they must install a larger alternator to charge the extra batteries. No, the original equipment alternator will work just fine. By increasing the size or amperage of the alternator all you gain is the batteries will recharge a little faster. Most often this just isn't worth the expense.

What type of battery should be used for the House Portion of your Van Dwelling? This is pretty much a matter of what you can afford. Optima Batteries are a sealed battery that requires no venting. A nice but rather expensive touch. As I have a couple good deep cycle marine batteries I will get by with those for now.

Cables to make the connections between the batteries are available in various lengths with terminal ends installed for between $3 and $10. My local Napa Auto parts store had a nice selection.

Two $7 battery boxes from Walmart and in no time I've got a good source of 12v power that won't drain my starting battery.

You can mount your batteries in a number of places. Under your bed frame, or some have mounted their's in front of the passenger seat as they travel alone. Myself, I'll be building a cabinet that will house both the battery system, and the 110v AC system complete with electrical outlets. But that's for another article.