bigredbrick

I usually don't use the travel trailer more than 3 days at a time and always without hook-ups. I just got back from doing 5 days with 2 new Napa Group 24dcm RV/marine batteries. The converter in the trailer appears to not have a battery charge controller when plugged in at the house and I found out that my truck can't charge the batteries, even after repairing a corroded wire to the plug on the truck. The trailer is a '94 Kit which is definitely not high-end. So without spending an arm and a leg, how do I control charging from the converter and how do I set it up to charge with the truck? Do you have a good article to learn me all about charging/maintaining RV batteries? We didn't lose electrical power and hopefully I didn't damage the batteries.
Thanks

j_martin

My tow vehicke has a Maxi-ISO relay and a 6 gauge wire to the trailer connector, then 10 G from there to the towed vehicle battery (also fused, of course) The RV (fiver) powers the lights on a second trailer (bass boat) so there's a drain on it. At night this system will keep the rv battery around 80% charged. Any lighter wiring and it would go flat due to the voltage drop and lighting drain.

The best way to support a towed vehicle battery is to install a towed vehicle battery charger. It is a TSR (Transistor Switching Regulator) boost circuit regulated to properly charge a 12V battery. The usual charger is rated 10 amps and weighs about a pound. Price for the entire install kit runs 100 - 150 bucks.

What it does is convert (for example) 11V at 12.5A to 13.8V at 10 amps right at the RV battery. Through 35' of 10 - 12 gauge wiring and a connector and a relay, 11V is about what you'd have to work with at the RV battery. They work well. Anybody that sells tow bars for a dingy vehicle will usually also have the battery charger as the towed vehicle's remote brake system will use power on the road when towed.

I'm holding out for a 30 amp version so I can reliably charge my RV batteries after a day or 2 of boondocking. I have 2 group 29's (about 250 AH capacity). Now I rely on a 60 amp Boondocker charger to top them off an AC motor generator set. Works well, but it's a bother.

On the money side of things. An RV charger should keep the battery charged at the least, and a good one will maintain it well. For less than $150 you can buy a 4 stage charger. The difference between that and 1994 technology, which might still be a ferroresonant transformer charger, is the difference between a set of Wal-Mart batteries giving 1 year of service vs. 5 years. (in my experience, anyhow)