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RICHARD's avatar

One of the biggest enemies of a battery that sits unused for long periods of time is sulfation. A battery maintainer that also has a desulfation mode, will prolong the life of a lead acid battery immensely. I have used these chargers for years. The one I use is sold by Northern Tool for about $35.00. They call it BatteryMINDer. Item # 167981-2556

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Dave Meekhof's avatar

I have a fleet of 12 rental motorhomes in Michigan, all with lead-acid batteries. I leave the batteries in the motorhomes year-round, plugged into shore power. Some RVs have 4-stage converters... but most do not. I have each motorhome plugged into "Christmas Light timers", set to turn on at dusk for 2 hours. Just enough to keep the batteries topped off, without boiling. Ever since I started doing this, I've never had a problem with the batteries... and rarely have to top off the water levels anymore.

All the motorhomes have a factory "boost" relay, which (in factory configuration) only turns on when the engine and alternator are running to charge the camper battery. I replace this relay with a smart, voltage-controlled battery Isolator relay, which is bi-directional. So now I'm charging the engine battery whenever the RV is plugged in.

https://www.amazon.com/dp/B0B9RT971X

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Doug Modlin's avatar

I use a smart switch as a timer for the charger I leave connected to a truck that I use rarely. I charge it for only 1 hour per day. I believe it’s a 3 stage 8 A charger but it works great. Battery maintainers are great too but they charge very slowly unless you pay more for them. The base model Battery Tenders I have are only rated to charge at .75A. When you have a vehicle or RV that you use occasionally and you run the battery down a battery down a bit while using it, it’s nice to have a charger with enough current capacity to charge it up in a reasonable time. Plus using a timer you can sometimes use an older charger safely in a pinch.

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Marco Moreno's avatar

Two questions:

1 - Why the need to maintain electrolyte levels in lead acid batteries? Cars have had sealed maintenance free batteries for decades. Why aren't RV batteries also maintenance free?

2 - How can I tell whether my converter is a 2 stage or 3 stage?

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Michael D Brown's avatar

If the RV is stored outside, a small solar-powered trickle charger can be a great solution.

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Mike Sokol's avatar

Yes, in fact Battery Tender (and others) make a solar powered float charger that would work great for this application.

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LOU FRANKLIN's avatar

Considering LiFePO4 batteries have dropped in price so much, they are now "the better bang for the buck" considering lifespan, minimal maintenance, and usage (don't have to fully recharge after each use).

FLAs are (should be) a dying breed in the RV business.

AND you can use their full capacity and don't need to pull them for Winter.

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Mike Sokol's avatar

Don’t forget that they also weigh a lot less!

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