Generator Charging

[devo]

I've been reading lots of threads about various backup generator setups and have yet to find anything that will work in my particular situation. Thought someone might be able to point me in the right direction.

We've got a bunch of off-grid sites that run on solar/wind. Everything is controlled by classics & clippers. I think we have around 20 controllers in total. For the most part everything works great.

Sometimes things break. Solar panels get covered in heavy snow. Wind turbines fly off towers in high winds. Animals find ways to destroy things. We need a good backup system.

Right now we're using AC generators, remote started by a Magnum AGS with the output fed into various brands of battery chargers. All the systems are 48V. The problem is that these setups charge really, really slow. I think the largest charger we have is 18 amps at 48v. Our solar/wind setups can nearly triple that at some sites when things are humming along. The battery banks are all surrette AGM's that want to be charged at around 40 amps.

Does anyone have a suggestion for a better backup battery charging system? I've looked at dozens of telecom grade 48V backup generators, but they're very pricey and we would need a lot of them.

Would I be crazy to consider building a 48V battery charger with a gas/propane engine and an alternator? What would be the best way of controlling the output of something like that? I'd rather not burn down the building or destroy the batteries.

Any suggestions would be appreciated!

[Highflyer]

Devo,
If you want to whip this problem, and I mean whip it good, tell us about your setup.  Are you all DC?  Or do you use inverters as well to run your loads?  If there is AC being used, the newer hybrid inverter/charge controllers is where I would be looking. 

All that said, I am no expert, But I am interested in hearing the advise of the experts that do chime in.

[devo]

Highflyer, we're all DC.

We don't have any AC at the sites whatsoever. I do pack a small inverter to charge a laptop while I'm onsite.

[ClassicCrazy]

My Outback 48v inverter is rated to charge batteries at 45amps DC .
Of course it is going to cut back on that once it goes to Absorb  just like the Classic does.

Larry

[devo]

Larry,

I'm not sure using a $600 generator to power a $2500 inverter to charge the batteries is the most economical way to go .

Ran across this site on the web: http://arduinoalternatorregulator.blogspot.ca/

Seems interesting. Any thoughts on building a DC generator with an alternator & this regulator? I'm sure lots of people have tried something similar.

[ClassicCrazy]

One of the local renewable energy resident  out this way has a Lister diesel engine that has a home made generator - like the kind you put in homebrew wind turbine . It cranks out a huge amount of DC power.  That would do the job for you .
http://www.windsine.org/2017/02/07/listeroid-backup-generator/

Larry

[Ron Swanson]

Good day folks.

Late to this party, to the OP or somebody, reply and let me know you saw this.

Have you considered the Kohler 6VSG?

Made for this application with low cost parts.  Or is it still too expensive?

I assume your other options have been Polar Power and the like.