Charging batteries with a small generator

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.

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.

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.

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.

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

You will be very close on capacity with that gen.

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.

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.

OP here.

If while the generator is running, I turn off the fridge (pulling the fuse if need be) would that give me a better charge?

Swimmer,
You have a wonderful collection of inadequate information for your responses.
First problem: Lead Acid Flooded batteries can be charged to about 90% State of Charge (SOC) in a couple of hours depending on the battery temperature. That last 10% takes most of five hours and can't happen faster without the heat damaging the battery.
Second problem: That 1000w generator is about 60 amps at 13.5V (for a 12V system). Your electric refrigeration is probably about 120W (about 10 amps) on a duty cycle that is related to temperature and use. So, it will suffice and larger generator won't get you any advantage.
Third problem: Will you be able to run the generator all the time you need where you are going? Many places have quiet hours.

My guess based on my experience is that if you run the generator at least 12 hours a day, you should be able to survive.
You gave us no clue what the reefer is or what your house bank is, and it does not make a huge difference.

If you know more, come back and we can probably get you a better answer.