The RV needed some electrical work to keep the batteries in tip top shape. I learned the hard way that neglecting your batteries gets really expensive really fast! It also sucks when they don't hold a charge at all. The system was poorly designed from the factory. The generator had its own starter battery (full size car battery), there are 2 batteries for the coach, and another battery for the engine. I rewired the generator starter to connect to the engine starting battery and wired the 'generator' battery into the main coach bank. This allows 3 batteries to power the coach and one for the truck / generator. This also simplifies my charging system by reducing it from 3 banks to 2 banks.
I picked up a morning star PWM solar charging system to control the power from the solar panel. I think its a 20W, but I'm not really sure. It was originally hooked into the coach batteries with no regulator other than a diode to prevent discharge at night. This system uses PWM to increase the amps (by the voltage drop from 17 to 13.7) and will drastically reduce water consumption in the batteries. I added about 700mL of water to the 2 batteries in the coach bank and they are only a year old! It comes with a digital monitor that gives the good stuff like solar amps, max amps, amp hours etc. I'll still need to add the trimetric to get the real deal on amp usage because this only monitors the amps from solar, not the amps being used. It is a 2 bank charger and 90% goes to the coach bank, and 10% goes to the truck battery. Its 4 stage (boost, bulk, float, and desulfination)
My 60A inverter was the non-smart design so it would also charge at 13.7 all the time and never reach a float charge. This will also evaporate the batteries much quicker than it should. I added a charge wizard for only $25 (the inverter is normally ~$200) and now it has 4 stages for proper charge control. The directions said to plug it in for 2 days per month and then unplug it! Yeah right, I'm way to lazy to do that! Hopefully the solar will keep it good, but at least I can leave it plugged in to have full function of the 115V stuff and not cook the batteries.