Between my last set of lengthy automotive travels and this upcoming trip, I have owned two pop-up truck campers. The first camper was a Sunlite Skyhawk SB… quite nice… it had an auxiliary battery, propane system, a fridge, fan, heater, etc… It insulated you quite a bit from the great outdoors (which was a disappointment actually) and it weighed a ton (IE it did not perform very well off-road.) I really did like the fan however… it was a godsend on a warm evening. More on that later. Anyhow, we sold the Sunlite and purchased an Aliner Truck Cabin which proceeded to fall apart on us. The saga was so horrendous, I devoted a whole web page to it here. So now we are back to some basics here… a simple truck cap, a home made sleeping platform, and some ingenuity.
Because both Teresa and I really enjoyed the fan in our Sunlite, I decided to try to make something work in our new truck. I would need to be able to run a fan all night long to stay comfortable in warm climates and that would require some power. Of course, because I’m such a geek, I also plan on bringing a couple of different electronic items with me including a laptop, an external USB hard drive, a digital camera or two and a printer. So I’ve got to figure out a decent 12v/120v electrical system for our rig.
- You really need to use a high quality deep cycle battery if you want to get any life out of your auxiliary battery. (One of the batteries in my old rig leaked acid all over the place and destroyed some carpet… Ick!)
- Battery isolators do not do a very good job at keeping your auxiliary battery charged, and they can overcharge your battery.
I was determined not to have these problems again. So I consulted with an expert. My friend had worked on hybrid cars in the past so had a good bit of experience with batteries. She recommended that I get a battery charger and run it through a second inverter. I spoke with other friends who suggested a secondary alternator, but that presented more of a mechanical challenge than I was willing to deal with. Here is what I came up with (I’m not an electronics engineer so bear with my horrendous drawing and the misspellings.)
The Vector 700 watt inverter (VEC062) is directly wired into the main battery and I have a Vector 35 amp smart battery charger (VEC1092A) running off of the 700 watt inverter. I can use this setup to charge my main battery. For my auxiliary system, I ordered a high powered 70 amp SPDT relay… it actually shipped from India! Apparently, a 70 amp relay is pretty darn rare. This relay automatically switches power from the alternator/main battery (when the key is in the ignition) to the auxiliary battery (when the ignition is off). My 350 watt inverter (VEC061) plugs into the relay so it has power full time from the highest capacity power source. I purchased an Optima Yellow Top 55 amp/hour deep cycle battery for the auxiliary battery.
I also built an electronics tower to hold all this stuff. Here are some pics of what it may look like when completed.
Any electronics engineer would have cringed when they heard what I did next. I drilled a hole in the truck’s firewall and ran a wire through it from the main battery. Basically, I had a wire, going through the firewall, without a grommet OR a fuse. I could have totally destroyed my car’s main battery if that wire touched ground (IE any part of the car frame). Oops! Anyhow, I did eventually get the grommet and an 80 amp fuse. And yes, my main battery still works.
Anyhow, tonight I’ve actually got the tower completely wired up and ready to rock. I have the wires in their proper places in the truck, I’ve done some continuity testing on the tower of power, and I have verified the relay is working as it should. I’ve hooked the aux battery to the tower and verified that all the things that should be getting power are, and things that should NOT be getting power are not. So tomorrow, I will wire the “tower of power” to the auxiliary battery and the truck. If no wires melt and no batteries blow up, we should be in good shape!
Note the all important empty beer glass on the table.