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coolmom42's avatar
coolmom42
Explorer II
Oct 22, 2014

charging battery from generator---how long does it take?

In 2-3 years, I'm planning to convert a van to a minimalist RV, and estimate that I'll need about 100 amp-hours of power every couple of days, absolute max. (LED lighting, fan, water pump, charging electronics, maybe at some point a 12 V fridge.) So that means a 200 amp-hour battery bank at 50% or less discharge level.

I recently purchased a Honda EU1000 generator, with the intent of running home fridge/freezer in a power outage, plus the long-term intent of using it to charge a future camper battery.

My understanding is that this will require a good quality battery charger between the generator & battery bank.

Battery chargers come in different amp ratings, so how do I choose the most useful amp rating for my needs?

Is the amp rating calculated at 12 V DC output?

With the generator running at say 800 watts/12 V = 67 amps x 90% charger efficiency that gives 60 amps possibly going to a battery bank. Correct me if that's wrong, please.

So given the 60 amps possible from the generator, does the charger then become the limiting factor?

With a 20 amp charger.... does that mean it would take 5 hours to restore 100 amp-hours to the battery bank?

Just trying to figure this out. My plan is to gradually acquire smaller components and then pull the trigger on the van in 2-3 years, depending on lots of factors.

Any input appreciated!

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