• NA8M
    I'm contemplating changing my lead acid batteries for lithium. When this happens I will change my battery charger. Currently the battery charger runs on 110v and replaced the OEM converter. I have ground deployed solar. My system is 12v.

    My question: While on the road to a boondocking location (I will travel from Michigan to Texas, for example) I often stop in a parking lot or CoE campground. With my "lead mine" setup my batteries recharge from the engine alternator and are "ready to go" when I hit the next parking lot after a day's drive. It is working.

    When I swap in the lithium will my alternator charge my batteries like it does now? I might drive four or five hours. Will I have to add something to boost the battery voltage? Will I run my onboard generator to charge the lithium? I travel in a Class A RV.

    I'm not really sure how the alternator current gets to the house batteries.

    I apologize if Ray has already answered this question.

    Bill, NA8M
  • Ray
    It depends on what's already wired into the Class A. I'm not as familiar with the wiring as with a truck and trailer, but usually with lithium, you want to add a regulator/isolator device between the alternator/charging batteries and the lithium house batteries. Lithium batteries can take much higher charge amperage than lead-acid so may overload the alternator.
    There are many different devices on the market. Some are just switches that isolate and cut off if the amperage gets too high, others are smart regulators.
    In my system, I installed what's called a DC-DC converter https://www.loveyourrv.com/renogy-40-amp-dc-dc-charger-installation-and-demo/ It provides a consistent near 40 amps of charging.
    I imagine your Class A should have a pretty beefy alternator since most charge a large lead-acid house battery bank.
  • NA8M

    Thanks for the prompt attention to my questions.

    I posed this message and its questions to Battle Born Batteries. Their quick reply echoed your thoughts. I will likely need a Battery Isolation Manager, BIM. I am struggling with exactly how the engine driven alternator is wired to the house batteries. I would need to find this circuit and "insert" either the BIM or the DC-DC converter.

    I'm glad I'm only in the planning stages. This would be worse if I had the lithium installed and Then asked this question, "How do I charge these new batteries while driving down the road?"

    Fun stuff?

    Bill, NA8M
  • Ray
    Yeah, its a little more tricky on motorhomes as the batteries and alternator are usually quite close but I imagine companies wire them in different ways with different forms of isolating. Maybe you can located a wiring diagram for your make and model.

    With the trailers, it's not much of an issue as the tow cable can only provide a limited amount of charge amperage due to its long length and small gauge. I think the only issue they have is some tow cable setups may not have an isolation relay and the trailer lithium bank having a higher resting voltage can end up charging the truck batteries when parked. But again even without a relay the small gauge, long run of wire may have so much voltage drop even that may not be much of an issue.
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