Discovery: How to keep main batteries and house batteries full when in storage.

[Colton2015]

My storage facility only has house outlets. Can I use a heavy duty extension cord to plug the coach to outlet. Will it charge the chassis batteries? Must the main and auxillary bottons in the coach be on along with the disconnects that are in the battery compartment? Will this charge the house batteries as well?
Thank you!

[sevd]

You can plug your coach in with an adapter to a regular 15/20 amp house outlet. BUT, be careful to make SURE there are no large draws on the power. You can burn the cord. My coach automatically detects whether you have 30 or 50 amp service, and automatically sheds any excess demand. But for a lower 15-20 amp source, I have to select that in my inverter control panel. I learned that the hard way and luckily only ruined the extension cord and didn’t damage anything else. I am not sure if you need the battery disconnect ON for it to charge. That’s a good question. I’ll have to try that.

[IAlreadyGot1]

The owners manual may provide information on the battery charging system for your coach. It may be set up where shore power initially charges the house batteries and once they’ve reached a set voltage, a relay/solenoid closes that allows charging voltage to reach the chassis batteries. If that’s the case, you would need to set the charger to draw less than 15A.

The disconnect switches remove loads from the batteries when in the “open” or “off” position. Think of them as being on the output side of the batteries whereas the charging voltage is on the input side of the batteries. An “open” disconnect switch will not prevent the batteries from receiving a charging voltage. You may want to open both house and chassis battery switches to minimize loads and reduce the amount of charging necessary to keep the batteries fully charged. Also, be sure to turn off the inverter while in storage. With the inverter on, the batteries could be discharged in the event of a power outage.

[AlanTerry]

SOLAR

[IAlreadyGot1]

Originally Posted by AlanTerry

SOLAR

Solar is an option, provided that the RV is parked outside, with sufficient sun exposure and the system is designed to provide adequate charging throughout the year.

The single word solution, however, leaves the original questions unanswered. Regardless of the source of generation that provides a charge to the house batteries, we don’t know if the chassis batteries will also receive a charge. Under suitable conditions, the OP could install separate panels and charge controllers for each bank. Either way, solar would come at a much greater cost than plugging in to an available outlet.

[VentanaOdyssey]

Our storage is a covered site so solar is a no go. We switched to AGM batteries and shut off the disconnect switches and be sure to turn off the inverter disconnect. We have zero power drain as shown on my Victron SmartShunt app. I have left it like that in freezing weather for several months with batteries still at 95% plus charge. During the winter I always make a trip to storage to start the coach and drive it 5 or so miles to heat up the engine, transmission and tires. I also run the generator. So far never had an issue.

[Persistent]

Originally Posted by Colton2015

My storage facility only has house outlets. Can I use a heavy duty extension cord to plug the coach to outlet. Will it charge the chassis batteries? Must the main and auxillary bottons in the coach be on along with the disconnects that are in the battery compartment? Will this charge the house batteries as well?
Thank you!

Plugging in to shore power

You can use an adapter to plug your shore power cord into a 20 amp 120 volt outlet. A 10 gauge extension cord can be used for longer distances. As posted above there will be a limit to how much you can run at the same time.

Normally you will not burn up a 10 gauge extension cord unless it is defective. The home branch circuit breaker will trip first. Any cord smaller than 12 gauge could get hot and melt or smoke.

A new cord will either state the gauge on the packaging, or not. If not, then it is too small. Get a different one.

A 100 amp 12nvolt battery charger will use 10 amps from the shore outlet. A 50 amp will use 5 amps. Easy for the 20 amp 120 volt outlet.

Disconnect Switches

Different RV's are wired differently. Some owners make custom changes to their RV's.

A disconnect switch next to the battery bank must be "on" to charge. A disconnect switch next to the entry door most likely needs to be "on". Of course the battery charger must be "on".

Some systems have a battery charger that is combined with an inverter. In this case the device must be "on" to power the battery charger. A built in transfer switch should switch the inverter function "off" and the battery charger "on" when shore power is present.

You can test the system to see if it is charging by measuring the voltage on the battery terminals. Voltage should be above 13 volts while charging. It may take deeply discharged batteries 4 to 8 hours to rise up to 13 volts.

The Aux button may be a shut off switch for the engine start battery. It probably needs to be "on" to charge the engine start battery. Test it the same way the house battery bank is tested. The house battery may need to be fully charge before the engine start battery voltage will start to rise.

[donr103]

I went to 20amp solar.. 2ea 100w flex panels.. one did the trick.. just glued them down and eternabond tape.. cheap and easy..
Good luck and keep us posted

[alank]

I don't know what coach you have or what equipment.
I turn everything OFF and store for about a month before I see 12.4V on the batteries. Then I connect the charger/inverter to 12V, turn on both the house and chassis switches by the door, and plug into a 20A circuit until they go into float charge, then turn everything OFF and unplug.

[NCmountians]

I have a 2021 Discovery LXE. When I'm not using it I turn off the disconnect and the two power switches by the front door. The batteries seem to still drain down after a few weeks. Any ideas? My 2008 Excursion would maintain a charge over a long period of time.