Charging batteries with a generator

[DC8Captain]

Hello everyone,

I bought a small 1000/800 watt generator specifically to charge the batteries when boondocking. Would it be advantageous to run the generator at full throttle while doing that or would the converter draw the max amount still if the genset was run in ECO mode?

Dale

[norty1]

I just did mine yesterday. I left it on eco and it ran for 6-8 hours while we were running fans, fridge and water heater. Batts were fully charged and I was there all night. Boondocking, so to speak in a rest area.

[northwindone]

Yep, you have the right idea, the converter draw, as well as anything else running, will determine how much power the generator needs to put out, so if the converter is only drawing 5 amps for example the generator will respond accordingly in eco-mode and set the throttle to put out the correct amps turning at the lowest RPM and using the least amount of gas.


Running in standard mode will simply make the generator RPMs (and noise) go up without any benefit as the converter will still only draw the same amps. You generator will simply be noisier and burn more gas.


However, running at full power is beneficial if you need to power something which draws a sudden large amount of amps such as a large motor (AC is a good example, but not the only one). The reason for this being is that it takes the generator a moment to increase the throttle and meet the demand for this large draw and if the current demands are too high it may not be able meet the demand quickly enough.


As the only large motor in an RV is usually only the AC and it has a large capacitor, you are usually okay running the generator(s) in eco mode even when using AC. Though I realize this isn’t an issue with your generator as you will not be running AC with a 1000/800 watt generator. This is probably a perfect size though to charge your batteries, which is all I usually use my 2000/1700 for as well, though I’ll usually use the opportunity to let my girls watch a movie while it’s running. We can use the inverter, but a little extra draw while it’s already running seems like “free” power.


EDIT: Sorry, probably way more information than you needed.

[RPreeb]

Originally Posted by fdhealy4

Hello everyone,

I bought a small 1000/800 watt generator specifically to charge the batteries when boondocking. Would it be advantageous to run the generator at full throttle while doing that or would the converter draw the max amount still if the genset was run in ECO mode?

Dale

I run my Powerhorse 2000 in Eco mode. Since it won't run the AC, and everything else works fine in Eco, that's where I leave it. I try to keep my battery charged to at least 12.5 - just ran the generator for an hour in the morning and an hour again in the afternoon. I only have a single 85 ah 12v battery. That's one of my planned upgrades this next winter, to get at least a group 31 AGM 12v with 120 ah.

[mike837go]

We also boondock and carry a small (900W) genset.

Running the little bugger for 45 minutes per day (with the fridge and water heater set on propane) charges the battery more than sufficiently to last another 24 hours.

[sennister]

Keep in mind that the converter will charge the batteries but will do so very slow. You may be better getting a battery charger and using that to charge the battery rather than the converter. It very well could be a faster charge meaning less time running the generator and less fuel burned.

[mike837go]

Originally Posted by sennister

Keep in mind that the converter will charge the batteries but will do so very slow. You may be better getting a battery charger and using that to charge the battery rather than the converter. It very well could be a faster charge meaning less time running the generator and less fuel burned.

The OP has a modern RV. Most probably equipped with a 3-stage charger.

The days of the trickle-only battery charger are long gone.

Each hour of 500W being available to the converter/charger will put close to 50Ah back in the battery. Adjust run time as needed.

[RAurand]

Originally Posted by RPreeb

I run my Powerhorse 2000 in Eco mode. Since it won't run the AC, and everything else works fine in Eco, that's where I leave it. I try to keep my battery charged to at least 12.5 - just ran the generator for an hour in the morning and an hour again in the afternoon. I only have a single 85 ah 12v battery. That's one of my planned upgrades this next winter, to get at least a group 31 AGM 12v with 120 ah.

If you get a Micro-Air Easy Start you will be able to run your AC on that 2000 Watt generator.

https://www.microair.net/collections...-soft-starters

We boondock and I run my 15K on my 2000 Watt Yamaha generator.