If your charger is showing 1 amp that's perfect. When any of the batteries begin to fail you'll see that 1 amp start to creep up. Unfortunately no one knows when or if a battery will fail and that's the problem. I have found that the chassis system is usually the problem that most have to deal with. But the same can happen with the house setup. That said, it might be best not to use the prosine because it charges both house and chassis batteries. If the starting battery or one of the starting batteries fail (in the case of a diesel) and the prosine ramps up (LIKE IT DID ON ME-TWICE
) it will push a bad wet cell battery to the point of off gassing. Mine got so hot I couldn't touch it. Not good if you're not on top of it. I now know if I see something like 9 amps on the display after leaving it on overnight, something is wrong
The twin low amp chargers would be the safest method. Leaving the inverter in the charge mode for long perionds of time without monitoring it might be a mistake.
There is no way for someone to go out every couple of weeks and turn on the Prosine for a day?
If the batteries are in good shape that should do it. Just have them make sure it has dropped off to one or two amps on the display when they go to turn it off. That will show all is well. The separator will keep the chassis and house systems separate when the charger is off (provided it's working correctly). Make sure the water pump, radio switch, and any lights are off. Keep the inverter in the off mode with the charge setting on.
Here is a thought:
Maybe you can find some kind of industrial timer (with a backup clock) that can handle something like 15 amps and have it come on from time to time say 6 hours once a week; something like that. Fairly hard to jack up something on a 6 hour charge. You will first have to check if the prosine charger mode will activate with the charge switch in the on position when the timer comes on. Try it by plugging your shore power in with the prosine in the charge on mode and see if the display shows anything. That way it keeps the charge time low, plus you have a smart charger doing what it does best. If a battery does go bad, you'll only loose one bank or the other. Hopefully you only have one house battery. As far as the starting batteries, if you do have two, big deal. You would have to change em both out anyway if one failed. I would still have someone look at the van from time to time. I have friends with RV's that have never had any problems with storage and they are using cheap .7 amp chargers. I'd rather be on the safe side myself. Good luck.