Sizing generator to charge batteries

A 1kw generator will take care of pretty much any battery charging duties, but bang for the buck just get a 2kw. Then you can use it for most anything short of running air conditioners.

1. You do not want to charge the batteries TOO fast. It will boil all the water out. That is why I do not connect my generator 12 volt output directly to the batteries. I connect the 110 Volt output to my RV and let the RV charge the battery.

2. The "charger" (DC power Converter) in the RV should limit the charge rate. If it is an expensive one it is programed to adjust the charge rate so the batteries do not charge too fast.

3. My 750 watt small generator will recharge my batteries in about 2 hours (a tank of gas) it I run it every day I am off the grid.

Hi,

Why does the sun not shine?

It is an overcast day and the solar system is pumping 8 amps into the battery bank.

have to agree with Grit, get a 2000 and then you will also have it for power outages or other needs.

Pianotuna and I agree....solar. Yes I carry a Westinghouse 2200/1800 inverter generator as backup for the TT and at home but in over a year have not needed it. And don't worry...the sun will come out tomorrow...tomorrow.

800w should power a 30 amp converter
But it will take about 6 hours to recharge the batteries
Because the batteries are constantly tapering the charge
It won't be 30 amps for 4 hours
In many cases, with only two 6v
It won't be 30 amps for even one hour
In 3 hours you will get back to about 80 percent charge
You will return roughly 70 amp hrs, not 115
If your down 115, it will take approx 130 to get to full charge
From the converter,
some of the power is lost to the The rechargeg process
You can feel it, in the battery warning up
It is electro chemistry, and it is PITA

If you have a WFCO converter a bit of research will show that most people (myself included) find it inadequate for quick charging off a generator. Off-grid campers get upgraded to either an IOTA or Progressive Dynamics converter.
My current setup is an IOTA-55 converter mounted in the pass-through (short cable run) and powered by a Honda 2000i generator.

Skelshy wrote:
I have to charge 115 AH ... what does a typical charger in an RV charge at? 30A?

Why guess? Post your converter model number and you can get the right stuff from the start.

+1 to consider solar but for most it is a big leap of faith. Generator is just an easy and familiar solution.

pianotuna wrote:
Hi,

Why does the sun not shine?

It is an overcast day and the solar system is pumping 8 amps into the battery bank.

We're upgrading trailers soon. That, and solar isn't very cost effective.

As to why we had the worst winter in recorded history, I do not know.

time2roll wrote:

Skelshy wrote:
I have to charge 115 AH ... what does a typical charger in an RV charge at? 30A?

Why guess? Post your converter model number and you can get the right stuff from the start.

I would not know what to look for or where. My guess it's behind a panel below the fridge, that's where we hear a fan come on when first connecting to shore power. I'll look next time I am out there.