[KindOfBlue]

A DC genset has a spec of 200A at 12V. What does this mean with respect to charging my batteries?

For instance if I have 600AH house bank and I run down to 50%, how long will I need to run the generator to top off my bank? Is it 1.5 hours or is there a 3 stage regulator needed to charge, accept and float my batteries back to 100%?

 

[mitiempo]

If your batteriers are lead/acid their acceptance rate is about 25% meaning that the max they will accept is 150 amps. This is called bulk charge. This will continue until they are about 80% charged and then it slows down for acceptance. At about 95% it changes to a float charge. So the first stage is fast and the last 20% will take hours with any charger. If your batteries are AGM they will accept a greater charge in bulk mode. This is why when offshore and charging with engine only people seldon get past 80% capacity and use between 50% and 80%. Wind generator and solar can of course change this.
Brian

 

[KindOfBlue]

That totally makes sense. Thanks!

 

[k1vsk]

That makes sense only if the voltage is sufficient to charge, regardless of current rating. As an example, my DC generator output is around 13V. As the voltage is insufficient to charge, it could produce a thousand amps and NEVEr charge the batteries quickly.

Without knowing it's output voltage, you can't draw any conclusion.

If you mean what you said literally, i.e., 200 amps at 12V, it will not charge anything.

 

[mitiempo]

That's true. Charging voltage is about 14.2 and 12 is a battery with about 40% charge remaining.
Brian