Batteries

[DonB]

We are new Gemini owners and are finding many differences between our old and new rig.
I like keeping a battery maintainer working during the winter. Old rig kept all batteries charged from the chassis battery, not on the Gemini, after a couple weeks coach batteries are down a bit. Can I put a maintainer on the coach batteries and how, there are heavy lead wires going all directions! It would have been good to have a connection built in!
That also raises another question, do the coach batteries charge when the engine is running. Did on the old one.
DonB

[Laco]

Not sure which Gemini you have, but on ours, if plugged into shore power and the use store switch is in use mode, the converter will keep the house batteries charged, but not the chassis battery. Mercedes apparently does not want that cross connect to exist, so if I am parked, or stored for any period of time I just put a small smart charger on the chassis battery connections under the hood. To answer your other question, on ours, while driving the engine alternator charges both the chassis battery and the house batteries. Can't imagine that yours wouldn't too.

[DonB]

Laco,
Thanks for the quick reply. Our unit is on a Ford chassis (2017 Gemini). The battery maintainer on the chassis battery does not seem to charge the coach battery. I should have identified the chassis, sorry.
So I'm still looking for someone who might know. Yes I could put a battery disconnect switch on it, but prefer the maintainer.
DonB

[Laco]

Ford or Mercedes chassis, the Thor installed converter when plugged into shore power and the use/store in use, should charge the house batteries. If yours isn't while you are still under warrantee, get the dealer to check it for you. As far as the chassis battery don't know about the Ford, but Mercedes for some reason does not want third party converters charging their chassis battery. I plan to permanently install a small smart charger connected to chassis battery, and plugged into 120 Volts onboard somewhere, so when I plug it in, it will automatically charge and float the chassis battery. Just haven't gotten to it yet, but I do have the smart charger, just now using it with alligator clips and separately plugged into shore power.

[Bob Denman]

It's not that tough to find a Battery Tender that has multiple outputs... Get one of those, and it'll even take care of your lawn tractor and motorcycle at the same time.

[DonB]

Anyone have an idea why the battery tender on the chassis battery won't charge the coach battery?
I have battery switch set on "store" is that an issue?
Batteries charge when on a shore line.

[Laco]

Originally Posted by DonB

Anyone have an idea why the battery tender on the chassis battery won't charge the coach battery?
I have battery switch set on "store" is that an issue?
Batteries charge when on a shore line.

Switch must be in use for the connection to house batteries.

[16ACE27]

Originally Posted by DonB

Anyone have an idea why the battery tender on the chassis battery won't charge the coach battery?
I have battery switch set on "store" is that an issue?
Batteries charge when on a shore line.

Because you "have battery switch set on "store"".

[gmc]

Originally Posted by DonB

Anyone have an idea why the battery tender on the chassis battery won't charge the coach battery?
I have battery switch set on "store" is that an issue?
Batteries charge when on a shore line.

You can try with switch in 'use', but...

Unless the engine is running, plugged into shore power, or Genny running, I would expect the coach and chassis batteries would be isolated...
I expect a battery maintainer on the chassis battery won't cause the batteries to be joined...

[16ACE27]

Originally Posted by gmc

You can try with switch in 'use', but...

Unless the engine is running, plugged into shore power, or Genny running, I would expect the coach and chassis batteries would be isolated...
I expect a battery maintainer on the chassis battery won't cause the batteries to be joined...

That's probably true because the maintainer probably doesn't increase the voltage enough to trigger the BIRD. But if he is in STORE it certainly will never cross over if with a full battery charger.