Friday, September 22, 2023


RVelectricity: Battery safety, plus Mike’s new SoftStartUp video

Today I discuss safety when working with flooded cell batteries, and in particular when used with a solar panel charge controller. Also, I introduce you to my brand-new SoftStartUp plug-in controller video and explain several ways it can be used.

Dear Readers,

I’ve got a two-fer for you-fer (hah!)

Here’s a quick note about safety around flooded cell batteries. I wasn’t aware that a modern solar panel charge controller can fail in direct short-circuit mode, but this one did.

It wouldn’t shut off charging, so the battery acid was boiling when the cap was popped off to check the water level. Read on…

From one of my moderators on the RVelectricity Facebook Group

Just a reminder!  Be sure you are checking your battery(s) on a regular basis. I was having a discussion with a group member regarding the voltage one should see on the battery with the converter at rest. I took my meter out to check it. When I checked the battery two weeks prior and all was well.  

Took off the battery cover, saw acid on top, took off one of the caps (with glasses on) and the battery was boiling. There was about 1/4″ of the plates exposed.  

Long story short, just replaced a defective solar charge controller that was over-charging the battery. You don’t need to be paranoid, but make sure you are checking it on a regular basis. And, always have glasses on when checking the fluid levels. It wouldn’t hurt to have them on when checking the voltage. Safe travels!

Please wear safety glasses!

Got it? That’s right. ANY time you’re checking the water level in a battery be sure to wear safety glasses. It only takes one splash of sulfuric acid in your eyes to blind you. And that goes double when you’re working around any electrical system. If you accidentally create a short circuit, there can be sparks flying. And those sparks are tiny bits of super-heated copper traveling at supersonic speeds. See below…

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Watch for sparks!

It really hurts if one of these sparks lands on your hand or in your shoe, so you certainly don’t want to take a direct hit in your eyes. Here’s what this looks like in a short-circuit current demonstration I created in my FunkWorks Lab a few years ago.

Note that there’s one spark that bounced off the clamp of the meter. Of course, for these lab tests I had on safety glasses, as did my son who was running the camera.

Second Verse: Here’s my new SoftStartUp video

I just published this video a couple of days ago, and it shows me trying out the new SoftStartUp plug-in controller in four different ways: powered by a 15-amp home outlet, a 2200-watt Honda Inverter Generator, a Jackery Explorer 2000 Pro, and with a home generator transfer switch for emergency power. I’ll be publishing another video in about two weeks with lots more details. Watch it HERE.

Lot’s more testing coming out of my FunkWorks Lab this summer, so stay tuned. Let’s play safe out there….

Send your questions to me at my RVelectricity forum here.

Mike Sokol is an electrical and professional sound expert with 50+ years in the industry. His excellent book RV Electrical Safety is available at 



  1. Thanks for great video, and many other great contirbutions.
    Note on the video. Black table, black cables, black solar backup. Very hard to see how the setups were arranged.
    I have set up my house to run from my RV generator as you mentioned. Took a LOT of work. For one, single pole generators mean all circuits must use that hot pole in the house. Most important is to either 1) be sure to disconnect your house from city line power, or face phase problems, or risk frying city linefolk. They frown on that. or 2) run all house circuits needing backup power to a SUB box which has a disconnect. Still must disconnect from city. And remember that power from most gens will be single pole, box must use only one hot.

  2. Mike, my house has an MTS switch and wiring for a generator. I have refrigerators and a 20 amp 240 circuit for a well pump running off the generator circuit. Is there a similar SoftStartUp for 240 volts? I’d like to trade my noisy 7/12 kw generator for a nice 3 kw Honda for better fuel mileage.

    • They tell me a 240-volt/50-amp version will be available in January. And I’m promised a review sample before it hits the streets.
      However, I don’t know of any 3kW generator with a 240-volt output for your well pump. What are you planning to use?


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