Saturday, April 1, 2023


RV Electricity – Just Ask Mike (J.A.M.): Drop-in Lithium battery update

By Mike Sokol

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) with the subject line – JAM.

Dear Readers,
Just a quick update on last week’s JAM Session about the problems associated with dropping in a Lithium battery without checking if your battery charger (be it part of your converter or inverter) can provide the higher charging voltage needed, and higher charging current possible, by Lithium Iron Phosphate batteries. Reread that article HERE.

Overview on dropping in Lithium batteries

In a nutshell, installing a Lithium battery in an RV with an older charger won’t allow the battery to come up to full charge, topping out around 75%. So instead of 100 amp-hrs of storage, it can now provide only 75 amp-hrs of storage.

I’ve also discovered that some RV battery chargers have a desulfation cycle which creates pulsed voltages into a standard lead-acid battery. If that function is not permanently disabled it could destroy your expensive Lithium battery in short order. Yikes!!!

Yes, I’m being watched…

In addition to my normal readers, I also have a lot of manufacturers reading my articles. In fact, here’s a note I received from Briter Products about last week’s JAM Session. Note that while many Lithium battery manufacturers claim their products are “drop-in” or “plug-n-play”), Briter has never claimed their own batteries were “drop-in”.

Hello Mike,  I liked your article from 12/13 regarding the “drop in replacement” topic with lithium batteries. We knew this was going to be a big problem because who really wants to know their fully functional chargers or inverters need to be replaced to get the advantages of lithium. Because of that Briter built in the state of charge display and has never claimed that the batteries were drop in replacements.

Thank you,

But wait, there’s more…

In addition to Briter Products, last week I also received a phone call from my contact at Progressive Dynamics who wants to collaborate with me on an article (and possibly a video) about how to tell if your RV converter or inverter is safe to use with your new Lithium battery, as well as guaranteeing that you’ll get all the storage capability you just paid for. Look for that article and video sometime in January.

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 Sokol is an electrical and professional sound expert with 50+ years in the industry. His excellent book RV Electrical Safety is available at For more info on Mike’s qualifications as an electrical expert, click here.
Join Mike’s popular and informative Facebook group.
And you don’t want to miss Mike’s webcasts on his YouTube channel.

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2 years ago

The Progressive Lithium Chargers are too hot for unsupervised use on Li batteries. They charge to and hold at 14.4 volts and over time, especially during storage or periods of low use will degrade the Li batteries. I spoke to them 3 years ago about the need for at least a float mode, and they ignored me. Also, it is very true that they have a hard wired equalize function that will cause problems for Li and even AGM batteries, as you point out.

24 days ago
Reply to  Bob

Are you referring to progressive dynamics (their LI compatible units)? If so, which converter/charger would you consider safe and appropriate for LI?

2 years ago

Can’t wait to get the video to see if my inverter/charger will work! BTW, do we have to be on Facebook to enjoy your articles? I used to get weekly reads from you!!!

2 years ago


I really value your expertise in RV electrical. Having just bought and RV that requires 50amp service, I’m looking to purchase a smart surge protector for it. Previously, I used a Progressive Industries 30 amp ems device, which worked well. However before I simply buy Progressive’s 50 amp ems device, I wanted to know if it is still one of the best.

Although I haven’t seen a recent evaluation for these types of devices, I have read that you encourage people to read the specifications. Given that I think the less expensive Hughes Autotransformers PWD50-EPO looks impressive. The marking material states:

  • 4,800 Joules
  • Smart Circuit Analyzer will shut down power to RV if a dangerous event occurs and an alert will be sent to your smartphone
  • Plug-n-play – Only 4 second delay power on after plugging in
  • Built in 90 second power-on delay after a fault to protect your AC unit
  • Complete LED Park Power Diagnostics with wired

What are your thoughts?

2 years ago

Mike…I appreciate the work you’re doing here. A friend of mine is a master marine electronic technician and serves on the standards board and has been messing with and testing lithium variations for about the last decade. Rob wrote an article that is pretty massive on lithium from DIY systems to drop ins …and has kept it up do date each year with new edits. I think you might enjoy reading it. He runs a yacht service business up in Maine and does testing and reporting for a variety of organizations. His customers have supplied him with a large pile of lithium batteries that have been ruined in use…which were sold as drop ins…I think you will enjoy his analysis and remarks…especially how he has now come around a bit on drop ins. Check it out if you have the time:

2 years ago
Reply to  Cam


Great point. That white paper that Rob wrote is spot on and a great resource for anyone contemplating getting lithium batteries.

2 years ago

Please address the issue of the lithium battery pulling too much current from the vehicle alternator. Some internet experts are saying lithium can draw enough current to (literally) burn up your alternator. Thanks.

Ray Cordero
2 years ago
Reply to  Marvin

Long Long Honeymoon just did a youtube video on this subject too. They had to replace their alternator for a new one that provided up to 375 amps to help charge their lithium batteries while driving.

2 years ago

If your converter does not list battery types, especially one for Lithium, then it will not charge to 100%? And if it is not a combo inverter/charger, very likely not what you want.
Is that too simple, is there more to it?

2 years ago
Reply to  Mike Sokol


Your second last paragraph is just not true. I have had lithium batteries for the past 2.5 years and I do NOT have a charger that has a lithium setting yet I have no trouble getting my lithium bank up to 100% SOC. Most chargers I have seen with a lithium setting are not ones I would use because of the charge profile.

As a previous comment above suggested read and understand Rob’s white paper on lithium batteries at Marine How To for a good understanding on the care and feeding of lithium batteries.

Teresa Meyer
2 years ago

I’m excited about this information on lithium batteries and most effective support equipment. I haven’t a clue how to “read” a converter/ inverter to find info I need. Thanks so much- I feel hopeful.

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