Originally Posted by Rusty years
Frisbee, I just related the same problem and have gone with the fact that my Magnum doesn't charge the house batteries. I put a 110 receptacle in the battery bay and leave a trickle charger plugged in always.
Rusty, I hope you meant to say your chassis batteries aren't being charged by the Magnum. If your house batteries aren't then you have a problem. The Magnum inverter/charger, by design and function charges the same batteries it uses for inverting.
If your RV doesn't have the ability to charge the chassis batteries, then you have 3 choices. To do what you have and leave a charger on the chassis batteries. I would recommend an intelligent or 3 stage charger. You can do nothing. Some RVs don't tap into chassis batteries for things you use when stopped. Most do tap into the chassis batteries for things like your dash radio, keyless entry, alarm system, and gas/smoke alarms. Finally, you can let the house bank charge the chassis batteries. Using a marine battery isolator is the right easy to go and it gives you a battery boost function built-in.