Battery Voltage

[Mrjkq]

QUESTION: My AS when not in use is stored away from our home, as of yet I've not pulled the trigger on a generator. My voltage now reads 11.9, how low can I SAFELY let it drop before rechargeing?

[AtomicNo13]

You are already there....

[OTRA15]

Originally Posted by Mrjkq

QUESTION: My AS when not in use is stored away from our home, as of yet I've not pulled the trigger on a generator. My voltage now reads 11.9, how low can I SAFELY let it drop before rechargeing?

It is my understanding that 11.9 is already too low, and that you have started to damage your battery.

[Mrjkq]

Thanks, bringing it home tomorrow for an over night charge.

[nvestysly]

Originally Posted by Mrjkq

Thanks, bringing it home tomorrow for an over night charge.

Your plan sounds like a good one. You may need to bring it home now and then to charge the batteries until you purchase a generator.

Some related comments...

Are you disconnecting the batteries when you put the trailer in storage? I'm not entirely familiar with the new model trailers but there is some type of switch (typically near the door) that connects/disconnects the batteries from the system. During storage it makes sense to disconnect the batteries.

The little bit I know about new Airstreams indicates that even when you "disconnect" the batteries with the switch by the door you haven't really completely disconnected all parasitic loads. I'm sure somebody else with chime in here but I'd suggest a manual switch that connects and disconnects the positive terminal of the battery system. You can find this type of switch at an auto parts store or RV dealer.

Unless something has changed for new Airstreams, the 24V converter (it's also the charger for your batteries) leaves a bit to be desired. As recently as 2012 Airstreams were sold with single-stage converters and these don't do a great job charging and maintaining your battery voltage. Check other threads on the subject of multi-stage chargers. I'm not aware that Airstream has started building trailers with multi-stage units so it's likely that your trailer will benefit from an upgrade.

[Mrjkq]

Aware of disconnect etc, also aware of the draw from the propane detector & appreciate above comments. My plan tomorrow is to fully charge the battery's then return the AS to storage, disconnect the - cable & see how it goes. I'm putting off buying that 2000w generator until next spring as I won't need it until then aside from this charging situation. Again everyone, thanks for your in put.

[alano]

Always safer to disconnect the negative terminal, not the positive terminal. By disconnecting the negative terminal you eliminate the possibility of shorting the positive terminal to the chassis, thus causing a dead short across the battery.

[Mrjkq]

Originally Posted by alano

Always safer to disconnect the negative terminal, not the positive terminal. By disconnecting the negative terminal you eliminate the possibility of shorting the positive terminal to the chassis, thus causing a dead short across the battery.

Is it necessary to disconnect both negative terminals or just one?

[Mrjkq]

I brought the AS home this afternoon. When I left the storage facility my voltage was still at 11.9. I drove the 6 miles to my house, unplugged the umbilical & checked it again, this time it read 12.1. I've noticed in the past that even after an overnight charge (& unplugging) it still only reads only 12.6 to 12.8, its been like that since I picked up the coach in July. It's been in storage for over 6 weeks unplugged so I guess the voltage drop should be expected.

[KJRitchie]

12.6 to 12.8 is the resting voltage and indicates 100% charge. If you disconnect the negative battery terminal it should stay that way well over a month. If you are not planning to use the trailer for several months pull the batteries and take them home and put on a maintenance charger. Its probably a good idea while at home to check the specific gravity of each cell with a hydrometer.

Kelvin

[Al and Missy]

Originally Posted by Mrjkq

Is it necessary to disconnect both negative terminals or just one?

If you have two batteries, you can leave the cable between the two negative posts, but any wire going away from the batteries should be disconnected.

Al

[Mrjkq]

Well, after charging overnight I returned the AS to storage. I checked the voltage & it read 12.9, so I disconnected the negative battery cable before leaving. Hopefully they will maintain that level or close to it until our next trip in early February.