Thor Forums

[gmc]

Originally Posted by Oneilkeys

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However, the way the charging system is set up in the Axis (and most - if not all - Thor RVs), when the generator is running the Trombetta is opened and both the chassis and house batteries are charged at the same time. Since the house batteries will be around 12v when I turn on the generator, it is not possible to over charge them in an hour or so of generator time. However, the chassis battery will probably start out in the 12.5v range.

My first question is - should I worry about over charging the chassis battery if I keep the PD4655 in the high charge mode for a hour or so to put the maximum charge on my house batteries.

My second question is - since I want to put the maximum number of amp hours back into the house batteries, is it necessary to put a circuit breaker between the house battery and the Trombetta to keep the chassis battery from being charged when I want all the charging amps to go to the house batteries? I don't really understand how the charger charges the three batteries (two house and one chassis). Does it divide the 55 charging amps among the three batteries equally? Is there someway that it senses the voltage in the batteries and charges the lower voltage batteries at a higher rate? If it charges the batteries equally, it seems to me that unless I isolate the house and chassis batteries, I will only be putting in 2/3 of the charging amps into the house batteries and could overcharge the chassis battery over multiple days of running the generator

My high school physics 50+ years ago leaves this a little fuzzy.

OK... so it is just a single charger - it has one output - that will be used to charge whatever is connected to it...

Whatever form of battery control - when the chassis and house batteries are tied together (for charging or EMER start) - they are in parallel with each other - and will try to equalize voltage between them.

So actually - if the house voltage is lower than the chassis - the chassis battery will flow current to the house along with the charger until all are equalized - and then all will charge together...

Certainly can disconnect the chassis battery (via breaker or disconnect) if you prefer - but really shouldn't hurt anything to have it in there (unless you are overcharging all three...)