Which is most efficient current to recharge a battery from a gas generator?

I have a 2000 surge watt/ 1500 running watt gas generator that puts out both AC and DC power. I use this generator strictly to recharge 12 volt marine batteries on my sailboat. Currently, due to noise, I usually set the generator around 100' from the boat where ever I beach for a night, and recharge the batteries using the AC power outlet and a Minn Kota MK105P battery charger. I'm wondering if it would be more efficient to recharge my batteries off the DC outlet? And would the 100' distance from the generator to the battery make it less efficient?Which is most efficient current to recharge a battery from a gas generator?
first thing you have to consider is the DC voltage of the generator and the the voltage of your batteries. Second thing is the DC current output of your generator.



Then you need to consider the recommended charging current of you batteries. I am assuming they are deep cell batteries not regular automotive batteries and your charger has a deep cell setting.



You also need to consider that most battery chargers back off as the batteries charge up where a generator's output is since that it will continue delivering full current to the batteries even after they are charged up. That will fry your batteries. It is like using a high Amp. booster charger on your batteries even after they are charged.



As far as 100' yeah you will have a little voltage deep.



If I was you I'd keep on using the charger if it has a deep cell setting so you don't hammer your batteries with excessive charging current.



If your charger doesn't have a deep cell setting I'd recommend you get a battery that can be set for deep cell batteries.