Thursday, September 21, 2023


RVelectricity™ Newsletter Q and A’s: Lithium batteries; Campground pedestals

The following are a couple of questions from my new RVelectricity™ Forum on These are regarding lithium battery charging and what to do when you encounter bad campground power at the pedestal.

Lithium Battery Charging

Q: What do you think would be the best way to charge my lithium batteries in my RV while on the road? I think I may need to install a specific converter to charge them while driving, as from what I understand, my current one is not optimal for lithium batteries. Let me know what you think. Thanks. —Joe

A: You’ll want something like a REDARC BCDC 1225D DC to DC charger that will boost your alternator voltage to full charge your lithium battery while limiting the charging current to protect the alternator. You’ll also need to run a heavy wire and Anderton connector between your truck and trailer to handle the charging current. Note that even a 25-amp charger will fully recharge a 100 amp-hr battery in about 4 hours of driving. —Mike

[The following is an ad from Google.]

Bad Campground Power

Q: This summer we encountered what I would consider unacceptable electrical service at a U.S. Forest Service campground in coastal North Carolina. Thanks to an inexpensive “plug-in” voltmeter inside the coach, I became aware of very low voltage, often dropping below 100 volts. Further research with a conventional voltmeter at the pedestal, I not only confirmed those low readings, but discovered that it was only on one leg of the 50-amp connection; the other leg registered near 130 volts.

The off-site management of the campground was essentially non-reachable except by email, non-responsive, and seemingly uncaring. Even the campground host’s complaints about her low voltage fell on deaf ears. Perhaps I was lucky, since my AC labored through our stay and we had minimal problems (primarily the microwave kicking out), but it left me with these questions:

1. While my AC and microwave both seem to still work satisfactorily, could I have incurred damage which may rear its ugly head somewhere in the future?

2. Should I have involved the local code enforcement authorities (considering that the campground electrical system may not meet code)? Likewise, should I have contacted the local electrical utility?

3. What action would you take if you found a campground electrical supply unacceptable and the campground management unresponsive?

Thank you. —James

[The following is an ad from Google.]

A: Sadly, the National Electrical Code doesn’t have an actual minimum voltage violation. They have a suggested min/max range, but even 100 volts isn’t a violation.

Yes, extended running at 100 volts can damage your air conditioner and residential refrigerator, but not your microwave. But it is cumulative damage which can shorten the compressor life by years.The voltage droop on one leg is likely due to current imbalance in the split-phase distribution system. It could be a simple fix for the campground, but unfortunately, I can’t get any of the campground groups to fund me or allow me to teach them how to correct it.

If you have pictures and contact info for the campground, you can email them to me at and I’ll try to sort this out. But I’ve been fighting this battle for 10 years and the campgrounds don’t respond to my inquiries.

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.

Check out my new RVelectricity Forum on Feel free to ask me your electrical questions there.

For information on how to support RVelectricity and No~Shock~Zone articles, seminars and videos, please click the I Like Mike Campaign.



  1. We were staying at Thousand Lakes RV Park in Torrey, Utah last winter. After plugging into the 30 amp outlet our EMS implied there was a open neutral. I then plugged into the 20 amp circuit using a dogbone and got the same result. We were only there one night and had plenty of solar, but we pay for working electrical. I contacted the owner the next morning and felt he really didn’t care.
    A friend of ours was there a couple of months ago and had a similar problem at his pedestal. He contacted the owner and got the same feeling.

  2. My MH is in covered storage at my home where I have a 30 / 50 amp pedestal. Should I keep the shoreline plugged into the pedestal to keep the house batteries charged or should I disconnect the shoreline and instead use my 12v Battery Tender 1.25amp automatic battery charger & maintainer? It will be in storage about 4 months where it’s common for temps to be below 0.
    My house batteries are flooded.

    • I think that a dedicated Battery Tender by itself is a better option. I’ve seen a number of RV converter/chargers fail and boil out the house batteries with devastating results.

      • Our AGM batteries failed after two years. We never get below 70% SOC. According to our Victron 712 battery monitor these batteries were being charged at 21 volts at some point. I had heard previously of WFCO’s failing and overcharging batteries.
        After buying new batteries I pulled the WFCO’s reverse polarity fuses disabling the charger and use our solar to keep the batteries charged. We’re not big users of power, were in Arizona, and the solar kept the batteries charged.
        I since was given a working unit from a friend and the old suspect unit was recycled. However, we added 300 additional watts to our roof this past summer and have no problems keeping our batteries full. Both reverse polarity fuses are pulled.
        We have always carried a stand-alone 20 amp battery charger if needed, so we’re good there.
        After reading of other similar issues with the WFCO charger I’ll never really trust it again.

  3. The NEC recommends that the maximum combined voltage drop for both the feeder and branch circuit shouldn’t exceed 5%, and the maximum on the feeder or branch circuit shouldn’t exceed 3%. This recommendation is a performance issue, not a safety issue.
    Most electrical utilities will guarantee the +/- 5% to their customers however there are times during the winter months that an electrical utility will intentionally overload circuits, dropping the voltage to reduce icing on transmission and distribution lines. This may take the voltage to customers beyond the 5% +/-


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