Batteries —we love 'em, and we hate 'em.
Love them, because with good batteries we can get away from the traditional campgrounds and out into awesome locations away from the crowds.
Hate them, because they keep going dead in storage, or run out of power prematurely while we're camping.
I've written about both problems, why these things happen, and how to prevent it. You can read more about why batteries die in storage, and more about how to keep them from going dead while camping.
If you follow the recommendations in those blogs you'll have fewer problems, especially if you use the factory-installed Battery Disconnect switch when you've got the Airstream in storage. It should be set to either "STORE" (in the case of electronic battery disconnect switch) or "OFF" (for a mechanical disconnect).
But, frustratingly, you may still find that the batteries die in storage.
That recently happened to some friends of ours, who mentioned it in a video. They were preparing to leave on a trip, and found that their lithium batteries were showing zero voltage. That means the batteries got drained so low that they went into self-protection mode, and shut themselves off.
You might very reasonably ask why this happens. The short answer is: the factory-installed switch may not disconnect the batteries from everything.
On Airstream trailers made before model year 2023, the propane leak detector is left on after you flip the Battery Disconnect switch. Even though the current drain from a propane leak detector is small, it adds up over time.
If you're worried about some of the optional items you may have attached directly to the batteries – like a Victron SmartShunt, TPMS repeater/booster, or Victron VE.Direct Bluetooth Dongle – don't be. They draw so little power in standby mode that you don't need to worry about them. They generally draw a milliamp or so, which means that they can be "on" for months without causing a significant problem.
How to determine whether your RV is losing power in storage
If you have an amp-hour meter installed (by Victron, Bogart Engineering, Xantrex for example), you can find out very easily if your trailer or motorhome is using power when it is in storage. Just put the factory-installed battery disconnect switch to the STORE or OFF position, then check the amp-hour meter. It should show zero draw on the battery.
Any negative amount shown on the meter is a drain on your batteries, and will cause them to go dead in storage eventually.
I recommend doing this test at night, so that your rooftop solar panels aren't throwing off the results.
If you don't have an amp-hour meter installed, but your batteries are going dead in a matter of weeks during periods of storage, it's likely that there is something drawing power from the batteries. Or, it's possible the batteries may be bad and unable to hold a charge.
The fix
A good way to prevent this problem is to install a real battery disconnect switch, meaning one that is mounted near the batteries and cuts off everything.
Having a switch, like the one in the green circle in the photo, means you can easily and completely shut off the power from the batteries. Open the battery box, flip the switch, and walk away.
It's also handy if you do your own work on your Airstream. You'll save a lot of time, compared to unbolting or unscrewing battery wires every time you need to fiddle with something electrical.
In the photo above, you may notice that I've upgraded the wiring to 1/0 gauge (big fat cables), and that one red wire is disconnected. That's because I was in the process of upgrading to a 2,000 watt inverter. When I was ready to attach the final cable, I just turned the battery disconnect to OFF, then attached the red cable without fear of accidentally creating a short and a big scary spark.
Keep in mind that everything in the 12 volt power system (including ALL of the wires pictured above) will remain energized if the Airstream is plugged in. That's because the power converter is supplying 12 volt power.
So, unplug the Airstream from shore power when you're working on the 12 volt DC system, too.
Choose the right switch for your situation
You can find different types of battery disconnect switches available from lots of places. They are commonly installed on boats and RVs and other machines that are left in storage a lot, so they're not expensive. The one I bought cost $15.
Last piece of advice: Shop thoughtfully for your switch. There are many different formats. Think about:
- the type of terminals that are on your batteries
- the amount of space available
- whether you'd need to make a custom cable to attach the switch.
Even after shopping carefully, I had a "gotcha" moment when installing this particular switch, because it requires a certain amount of space underneath the switch. I hadn't realized that when I bought it, and this forced me to rotate it so that one end hung off the side of the battery.
If you do find you need to install a battery disconnect switch, you'll find it immensely helpful. If you're not comfortable or don't have the tools to work on electrical stuff, any RV dealer or mobile tech should be able to install one for you.