Question about wiring new battery charger on the battery side of the latching relay.

[BTUs4You]

I'm changing the charger section of the Parallax electrical center to a Xantrex 60 amp charger. I'm also adding two Optima AGM batteries as a second battery bank. I installed a manual isolating switch that allows me to turn off all batteries, use only battery bank #1, only battery bank #2, or use both battery banks. The charger will charge up to three banks of batteries.

My question is about the original two batteries on the tongue of the trailer which I call bank #1. Presently they're wired through a latching relay and if the relay is in the "store" position, the charger will not charge the batteries. I'm thinking of wiring my new charger to the battery side of the latching relay so the batteries will charge any time I'm plugged into 110V, regardless of whether the switch is in the store or use positions.

What do you think? Is this OK, or is it not wise? Since I have a manual battery switch that will turn off both battery banks if want to, I'm thinking there's no real downside. What am I missing?

Thanks!
Mac

[Melody Ranch]

What you did already is great. (I did the same thing on a couple of my old Airstreams. I see not benefit from doing the other mods you mention...just tinkering...even though it would work, but really?...Why?

[idroba]

i don't really understand the new store/use switch on the later AS's, but what you propose sounds reasonable to me. If you can isolate battery banks, and charge multiple banks I think you have a good system which can be used in multiple ways.

Repeat: I do not know the logic or system for the relay system you have now. One day I may get out of the 70's era.... grin.

[BTUs4You]

I just spoke with Dan at Airstream and he advised that some chargers can drain power from batteries when they're not charging (not connected to 110 V or not turned on), thus the reason for the original Paralax charger wiring to the load (house) side of the relay. I'm now going to call Xantrex to make sure my charger will not draw a load when it's not charging. If I'm assured that it won't I think I'll wire the charger to the line (battery) side of the relay.

Dan also advised me to install 50 amp breakers between the batteries and the charger and load. This seems reasonable especially since I've got massive AGM batteries going in where a short could cause some serious damage.

Off to the NAPA store I go.....