Battery Drain?

[Rcraig3]

I have not had luck with keeping my battery charged in our 16’ Bambi Sport. Anytime it is not hooked to shore power, it completely drains. I purchase a marine grade battery and a year latter it is trash. How can I check for an electrical drain or troubleshoot this problem? Has anyone else had this problem recently?

[Wazbro]

There are phantom draws even with set to store position that will run batteries dead in 2-3 weeks on most trailers. Adding a true battery disconnect switch to eliminate them will help. A couple common ones are the propane detector, the inverter and sometimes the sub-woofer.

[ROBERT CROSS]

It is a well-researched concern.

The easiest fix...a battery isolation switch.

Bob
🇺🇸

[field & stream]

It’s complicated. You might get more specific responses if you provide us with more information: what type of battery (regular lead acid, AGM, lithium?), size of battery in Ah, how long does it take to draw down, how is use/store switch set?

For starters, all batteries lose voltage over time even if they are not hooked to anything — the rate depends on battery chemistry. The Airstream use/store switch is not a true disconnect switch, it leaves several things powered. Once a lead acid battery is run down too far (your description “completely drains”) it loses ability to hold a charge.

To know what is going on you need a shunt based battery monitor like a Victron 712 and to troubleshoot you will need a multi meter. Or, professional help!

[JeffKim]

More detail, if you are consistently draining a lead-acid battery below 50%, damage occurs and it will eventually no longer keep a charge. The only way to know is to either watch the voltage carefully (50% is something like 11V) or install a battery monitor/shunt as @f&s describes.

In our dearly departed 16' Bambi, we originally had AGM batteries and didn't have a clue what their charge state was until I put the shunt in. It wasn't too difficult installing it in the rats nest under the dinette seat. We also found out that we used a lot more electricity than we thought and the next year put in lithium batteries.

Also, with parasitic loads, a switch is nice as @wazbro says but if you're storing for any length of time remove the batteries and keep them on a trickle charger (lead-acid) or disconnect the negative.

[Boxite]

This association of forum participants really should get a commission for selling battery systems that are largely unneeded and unnecessary.

It’s unimportant what type battery the OP has if there is a constant parasitic drain on the system…. He/She merely needs to discover the drain and isolate it.

A true battery disconnect is a good solution … and completely irrelevant as for type of battery.