4 battery (12 volt Dec each) series connected to run a 2 hp 48 volt dc motor

harvshu

What is the best way to set up a solar charging system for this arrangement?
HELP!

mike95490

you need about 70V of solar cells (Vmp) not Voc, to provide the charge controller enough voltage to charge and equalize a 48V battery (can require almost 65V at times) .
Then you need enough PV amps, to recharge the battery in the limited sunlight hours that are usable for charging (3 hrs winter, 5 hrs summer as a rough guess) Panels only put out 80% of nameplate amps, batteries generally need 120% of what was removed from them,
That's a start.   Work all the calculations in watts & watt hours, not amp hours

oil pan 4

Need more information. How much will you run it, is it really only going to make 2 horsepower or will it be more or less?

harvshu

It is the power supply for an electric boat motor that will be used sporadically, usually on a weekend.  So, the 2hp load (from the motor nameplate) is variable depending on the "use of the day", and I don't think it can be more...

harvshu

Hi Mike, I looked at your solar: site and would like to know what would be the Voc at the output of the "combiner" for the pv arrays?

oil pan 4

You need to figure out how much power you are using to charge the batteries. I assume you have some kind of grid power charger?

The easiest way I can think of to do this is plug the battery into a kill-a-watt meter, see how much power goes into them over the course of a weekend and go from there.

mike95490

harvshu said:

Hi Mike, I looked at your solar: site and would like to know what would be the Voc at the output of the "combiner" for the pv arrays?

Can't help you there.  The Panel voltages will be on the sticker on the backside, and then as the temperature goes colder, the Voc of each panel goes up, so you go with the historical low temp for your area