How can a 48 volt dc generator be used to charge 24 volt battery bank?

I would contact Kohler with the model numbers and serial numbers and ask them about converting that genset. If you don't have a manual, it would also be a chance to get one.
They would also be the best people to provide a new 24v generator to match the gas power unit, if you cannot convert what you have.

Based on the somewhat limited info you provided, my impression is that you could probably benefit by moving the entire system up to 48V. You may want to consider that option.

The other caution I will give you is that if you do not understand the automatic controls in-depth, you may want to get somebody that does. Have them look at the logic for both the genset and the controllers. Sometimes logic systems have a way of fighting each other. With more complex logic circuits, particularly from two or more vendors, the more likely a conflict is to occur.

Good luck with it.

DC voltage converters are sold inexpensively almost everywhere including www.altenergystore.com.  Have a good 1!

No, I was not aware of that Ken...Thank You.  Although a larger transformer should be available to do the converting; unfortunately with some current loss.  I agree, the solution may be to bring the whole system to 48 volt.

I have a friend with a similar scenario, only in reverse.
He has an old boat with a 6 volt generator, but
Wants to be able to use modern 12 volt electronics on the boat.
I suggested he charge two 6 V batteries in parallel, then use them in series to run the 12 V stuff.

I'm not smart enough to let technicalities get in the way of my ideas,
So,
How about using your 48V generators to charge the 24 V batteries, in blocks of two, wired in series ?

Good Idea, or am I truly Lost ?  <G>

George Patteson
Molalla, Oregon

Victor
Eric's advise is extremely bad advise, that risks severe damage to the equipment.

I don't know exactly how your unit is wired, but I believe that the DIP switches are there so the manufacturer can sell one cabinet with one set of controls and put either a 24V or a 48V unit in it. An owner could also replace the 48 with a 24 or vis versa.

The actual generators are normally a hard wired unit and the voltages cannot be changed just by flipping switches.

Hopefully, the controls are sophisticated enough to sense the problem prevent the start. Or cause an immediate shut down. If they are not, I hope no one is standing close to it.

I've still thinking about your problem. If you could describe the system config a little more, it might help.  How big is your battery bank and do you have plans to expand the storage if you change voltages ? How many watts of solar panels do you have ?  How well balanced are your loads to your current generation and are the loads going to increase ? I am under the impression that the windmills are not yet installed. Correct me if I'm wrong on that. What to you expect as far as power from the windmills ?
Ken

Ken

Victor:
I am sorry my reply to you was simplistic and incomplete. I don't think you would have tried changing the dip switches with all of your other equipment hooked up and running. I think you are smarter than others think you are. I suppose there are some people out there that would. Yes,the dip switches are there solely for changing the output voltage of the generator. Alpha makes the generator as an auxiliary power unit (APU) for powering telecom installations. They cannot build a special generator for every different application out there, so they build one that has the flexibility to cover as many as possible. Just like Onan, Caterpillar, Kohler, Marathon, Baldor, etc..., they can be changed to suite the application. Most generators are reconnectable (aka... restrapped), their output is based on too many things to go into here, but voltage regulation is controlled by field excitation, which is controlled by solid state regulators, which is controlled by the operator (you). In most cases, the turning of a very small potentiometer is all it takes. Enough about AC generators, lets get back to what you have.

The generator you have is supposed to work something like this; when utility power fails, the telecom system will operate off batteries (UPS system). As the backup battery voltage drops to a preset level, the generator will automatically start up and provide power. Once utility power is restored, the generator continues to run for a while to cool down and then shuts off and waits for the next run. The generator is a permanent magnet type, 3 phase, high frequency AC generator rectified to DC. The engine controller changes the engine speed to adjust output power. If you want to know what it is set for, call Alpha Tech at 800-863-3364, or simply test run it. Set the main switch (manual/off/auto) to manual run, let it warm up, and check the output voltage with a meter, it should be a couple volts higher than the dip switch setting of 24/36/48vdc. No external batteries attached, of course. It does need its internal 12v battery to operate. Even if it were hooked up wrong it would either not run or blow its internal fuse. The people who designed these things were not stupid, they are the safest generators I've ever worked on.

Speaking of work, I don't have much time for long-winded
technical writing like Ken does, I have machines to fix.

Good luck with the project Victor,
Eric



PS: Ken, you spelled advice wrong.

Ken It has a 48 volt dc output and it doesn,t have any ac output. It is wild ac rectified to 48 volt dc. Eric gave a good description of what it is. I read somewhere that alpha technoloies might get into the alternitive energy field. So far I havn,t seen anything on the alternitive energy web stores yet. I figured I might see it here first.
                Vic Snodgrass