MPPT Volts to Current Conversion

jodeb720 wrote:
My buddy picked up 6 300 watt panels today - because he wants to be able to feed his ravenous Starlink - without running the generator.
The starlink uses 190 watts of power at 120v - it's a pig for power.

The panels have an open voltage of about 30 volts - and are rated at about 8 amps.

When the output is run through an MPPT controller - whats the conversion of higher voltage to output in amps?

One would assume that it would drop the voltage to 14.4 or 14.6 for bulk charging - but the amps would be higher than the panels rating of 8.

He's got two sets of 6 volt batteries (I think they are 100 amp Golf Cart batteries). if what i've read here is correct, he can only put 25% of the total battery capacity (lead acid) in per hour to recharge them.

I'm a bit concerned that the Controller could easily drive over that 25% amount and wipe out his batteries prematurely. Now before you tell me we can control the total amps on the controller (which we can), I'm just curious how many amps he should expect per panel assuming full sun - 30 volts and rated at 8 amps.

Thanks in advance!

josh

if they are 100amp gc batteries they are very small. most are around 200AH which means you can charge at 50 amps if you go by that. a good mppt controller will also have a profile for charging so it will only put out the max charging in bulk then it will switch to adsorption and the amps taper off as the battery becomes more charged. if you are going to be running that kind of load I would even consider adding two more batteries to the mix for more capacity.

if there rated at 8 amps and he has 6 panels then your looking at a max of what 48 amps? but 8 amps seams low for a 300watt panel. if it is a 24V panel then I could see 9 amps if it is at over a 30v output but I guess that all depends on the efficiency of the panel and equipment.