Since we are on the topic of this, and I don't think this question deserves another thread, maybe sombody more knoledgable in this subject, can answer me this quick question ??
I always thought it is best to charge a "Deep Cycle" marine type battery at a low rate of Amps.
In other words, you will get more life and dependability from your battery if it is always trickle charged instead of being blasted with high amperage from the alternator. Thats why I went with solar panels instead of just running a fat cable to the trucks battery.
Isn't this the correct when it comes to charging Deep cycle batteries ???
For significantly discharged batteries, nope, and for some manufacturers they advise against it. Even for Flooded cell batteries you pump in high currents until the voltage or heat or gassing reaches a limit. Also a low charge rate will take forever to get you charged up. For a battery on standby, making up for minor self discharge or light use discharge, no big deal, it won't accept high currents anyway, at least not for long.
Many battery manufacturers have their charging charts posted on their web sites. 3 or 4 stage curves are common. Bulk, absorption, trickle (float), equalize, and some have a specific de-sulfation mode or cycle.
The question I think you are really bringing up though would be worded more like this:
Does the truck charging system really fully charge my camper battery? Should I use a trickle charger in addition to my normal truck charging between trips?
The truck is not optimized to fully or delicately top off your stating battery the way a fancy 3 stage charger would. However it runs at high enough voltage that it gets things pretty close quickly without overcharging the battery. Starting batteries are OK with this and I think it is fair to say most truck starting batteries are still flooded cell chemistry. Chronic undercharging is not healthy over time.
Most camper batteries these days are using AGM which is a sealed battery appropriate for installing inside campers requiring no outside venting. They prefer a higher charging voltage then flooded cells. Take into account voltage drop and temperature differences between your alternator/starting battery and your camper battery due to connections and wire distance, getting the last bit of charge into the AGM may or may not happen, depends on your setup. Having a solar or AC charger running while the truck engine is off helps overcome self-discharge losses and ensures it is not chronically undercharged. This does not require much current though. If you plug into shore power your camper 12VDC converter is charging your battery. With the typical FWC supplied charger, you can plug in an "intelligent" charging module for about $30 that gives the converter the ability to become a 4 state charger, one of those is a weekly equalizer cycle. I believe the factory supplied solar charger has the same capability. I have both systems, but only really use the solar - it is on all the time, don't have to think about it, so I do not bother to plug the camper into shore power when it is sitting in the driveway. The drive home bulk charged it, the solar takes it the rest of the way.
Here is the smart charger add-on for our IOTA standard converters.
http://www.iotaengineering.com/iq.htm
