Charging batteries with a small generator

[swimmer_spe]

I have been given a 1000w generator for free. If I am boondocking on 1 or 2 12v batteries how long should I run the generator? The trailer has n electric only fridge.

[valhalla360]

pianotuna wrote:
1 or 2 batteries is minimal for boondocking. I started with 7.

If only boondocking for a night or two at a time, silly to spend the money and drag around a huge battery bank.

We have two and for an overnight, we run the fridge and a big of furnace and the next morning we are typically at 12.5-12.6v.

[valhalla360]

Boon Docker wrote:
Until the batteries are fully charged. :B

With that small genny and electric fridge plus other power usage, I would say the genny needs to run most of the day.

If you want the battery truly at 100%, yeah you will need to run it all day but really a waste of time and gas. As lead acid batteries near full, they will accept fewer and fewer amps, so the last 10-15% takes many hours. Pretty much no one boondocking will use a generator to get to 100%. Just get it up to 80-90% and call it good.

Getting up to 80-90% should only take 2-3hours if putting in 30-40amps in the bulk charge phase.

If you really want to try for 100%, get something like a 100w solar panel. Run the generator for 2-3 hours in the morning and then let the solar slowly top up the batteries over the rest of the day.

[ScottG]

You will be very close on capacity with that gen.

[pianotuna]

1 or 2 batteries is minimal for boondocking. I started with 7.

[theoldwizard1]

Boon Docker wrote:
Until the batteries are fully charged. :B

With that small genny and electric fridge plus other power usage, I would say the genny needs to run most of the day.

Some small generators have a 12V DC output. DO NOT USE IT !! Use a standard AC powered charger.

The original question is too vague. Too many variables.

[time2roll]

I would not count on more than 30 to 35 amps into the battery from a 1000w generator.

Minimum three hour run time. Possibly twice a day.

Post the existing charging system for best answers.

[enblethen]

Need to determine the charge rate of your converter. Many have converters rated around 35 ampere output. This in many cases is not sufficient. Adding a separate battery charger isn't going to help much as the normal safe charge is around 10 amperes.
While boondocking refer should be set on auto. When genset is running, the refer would run off 120-volts AC.
1000-watt generator maybe a little small.
My thinking changing the converter to say a 50-ampere output would help.

[Boon_Docker]

Until the batteries are fully charged. :B

With that small genny and electric fridge plus other power usage, I would say the genny needs to run most of the day.