Using external charger on generator?

[MikeyInNY]

New to boondocking but experienced camper. Reading about generator use and battery charging: I have a portable 3500 KW generator (not the quiet inverter type) and it has a built-in 30A RV receptacle. If I want to run my generator the shortest amount of time just to charge my batteries, do I plug the camper into the generator or use an external battery charger directly to the batteries? I don't know how efficient the installed converter is as a battery charger. I have two 12V batteries in parallel, I'm guessing I should charge them one at a time with the external charger, is that correct? If I use the installed converter, should I let both batteries charge at the same time?

[Siamese]

Generally, the best way is to plug your trailer's shore cord directly into the generator and let it use the onboard charger.

However, on a lot of Jaycos, and others, the standard converter/charger isn't the greatest. Like on my 26BH, it had the WFCO charger, and they are known for not going into bulk mode (more voltage), when the batteries are down.

What a lot of people do, me included, is to visit the Progressive Dynamics web page and see what they have for a direct replacement for the crummy WFCO unit. They produce better chargers that fit right in the old WFCO enclosure, and go into bulk mode when needed. If you're at all handy, it's DIY.

Figure maybe a couple hours of charging instead of ten or more. There has been plenty written on this, so do a little search and you'll have plenty of info.

If you get the Pro Dy unit, their instructions are fairly good, and you can find videos on youtube that make it even easier.

If you were to use an external charger, and I wouldn't, you'd treat your two 12v batteries in parallel as just one big battery. The charger doesn't know the difference.

[MikeyInNY]

How did you determine the exact replacement?

[Siamese]

Take a look at the converter/charger that's on your RV. If it's a WFCO, then find a model number on it. It'll be there, somewhere.

Then, you can go to the Progressive Dynamics website and see if they have a direct replacement for it by model number. If so, their electronics will fit right into your existing WFCO enclosure.

I'm a slow DIY'er, so it took me about 3 hours to do the entire job. Works great.

Our strategy is: We're usually hooked to shorepower, so batteries aren't much of an issue, but when we travel, we'll often stay over at a Walmart, etc., and have to rely on our two, 6v batteries wired in series. We keep a 2200 watt generator in the back of the pickup. If we're off the grid, and figure on using a fair amount of 12v, like the furnace fan, we'll open the door on the pickup's topper, hook up the generator to shorepower, and give the cord a tug. It's quiet, and while it's charging, it's a good time to use the microwave, or anything that uses 120v AC. We'll let it run a couple hours.

In a nutshell:
Progressive Dynamics Converter charger
2- Duracell 6v golf car batts in series
small (2200 watt) generator
Extra can of gasoline (stabilizer added)
voltmeter and hydrometer and distilled water for batteries

That takes care of all our power needs. We aren't able to run air conditioning off our generator (not big enough), but if it's hot, we're on our sailboat. We do our trailering in the winter in Alabama, Mississippi, and Louisiana, etc. so temps are moderate.

[Rustic Eagle]

Here's a recent JOF thread on the same subject that may be helpful (contains links):

https://www.jaycoowners.com/forums/f...wap-65815.html

The following link is the Progressive Dynamics direct replacement unit I installed in place of my 2018 WFCO 8955 PEC Converter/Charger:

http://www.bestconverter.com/PD-4655...l#.XL0Myi3Mw1I

Bob