Flooded Lead-Acid Battery Dangers…

Hint: It’s not about getting shocked!

Welcome to my J.A.M. (Just Ask Mike) Session, a weekly column where I answer your basic electrical questions. If you’re a newbie who’s never plugged in a shore power cord (or ask – what’s a shore power cord?), or wonder why your daughter’s hair dryer keeps tripping the circuit breaker, this column is for you. Send your questions to Mike Sokol at mike (at) noshockzone.org with the subject line – JAM. Today I discuss flooded lead acid battery safety.

Dear Mike,

My husband is getting ready to pull out the golf cart batteries in our trailer, and I told him to be careful. Do you have a checklist of how to do this safely? What about things to avoid? —Evelyn

Dear Evelyn,

Great question and very timely. Here’s a list of most of the things to keep in mind when removing batteries for storage and maintenance charging over the winter.

1)  Always wear safety glasses!

I know what it’s like to be nearly blind. All I have to do is take off my glasses and I have 20/800 vision and literally can’t recognize a face just a few feet in front of me. Splashing battery acid in your eyes is a sure way to create permanent vision loss, so always wear safety glasses around any battery work.

2) Remove all jewelry before you proceed…

Metal jewelry and RV batteries don’t mix. If you accidentally get your wedding ring or bracelet in a short circuit, there will be hundreds of amperes of current flow that will turn your jewelry red or yellow hot in seconds. And yes, it will burn like holy heck and can create muscle or nerve damage rapidly. So remove everything metallic from yourself BEFORE you touch an RV battery connection.

3) Take a picture, it will last longer

I will get dozens of emails in the spring asking me how to reconnect the batteries. Note that if you get them wired backwards, for even a second, it will blow the inverter fuses (at the very least) and possibly do all sorts of other damage to any of your DC appliances like your refrigerator.

So, mark all cables with white electrical tape and a Sharpie marker BEFORE you take anything apart. Then take a few close-up pictures of how they were connected. It will save a ton of grief later, I guarantee you.

4) Disconnect the negative battery terminal FIRST!

When disconnecting the wiring of any vehicle 12-volt battery system, it’s important to disconnect the negative terminal from the battery first, then you can disconnect the positive terminal safely. When installing the wiring you’ll reverse the sequence—so you’ll reconnect the positive battery terminal first, then the negative battery connection.

If you don’t do it in that order, then it’s possible to have the wrench that’s on the positive battery terminal make contact with the metal frame of the RV. This will weld the wrench in place, and if you get your metal bracelet or ring in the middle, it will cause things to heat up quickly.

How hot, you ask… Take a look at this temperature chart above and think about how much that would burn.

5) Holy Pants, Mike! What did you do?!

Finally, make sure to wash your hands carefully, and never touch your clothing when working with lead-acid batteries. It only takes a tiny bit of sulfuric acid on your clothes to rot out the fabric in a few days.

Yes, these are my own pants that suffered this fate while I was working with some 6-volt FLA batteries. I don’t think it’s stylish at all, but at least I relearned my lesson, which is why I’m passing this on to you, as well.

OK, everyone. Remember that electricity is a useful and powerful force, so we all need to pay attention to safety precautions while using it.

Let’s play safe out there…. Mike