Determine charge controller?

[wpmaura]

Read that you divide the solar watts by battery to determine the charge controller size. Does that mean 6 270 watt panels and epever mptt 60amp charge controller cant work with a 12v battery bank?

[Mike90250]

Read that you divide the solar watts by battery to determine the charge controller size. Does that mean 6 270 watt panels and epever mptt 60amp charge controller cant work with a 12v battery bank?

1620 watts / 12v = 135amps. You will need 2, 60A charge controllers, or run the risk of overloading a single controller. Most MPPT controllers will self limit to their rated amps, but with more than double the rated power, you are looking at a risk of damaging a single controller.

[wpmaura]

And someone else says that volts is more important. The epever says pv.input c as not exceed 150v. So panels are 30v 9 amp so run 3 in series and parelle would give me 90v 18 amps.making this possible.

[Mike90250]

If you converted to a 24V system, you could pull it off with one controller and all your panels.
Or stay at 12V, and aim your panels in 3 different directions, like Bruce does, and get a "flat" moderate harvest all day long, instead of a noontime peak

The way a MPPT controller works, is to convert the voltage above battery voltage, to more amps, sort of like a step down transformer. Yes, the 90V side only has 18A, but MPPT controllers transform high voltage 90V 18A power to 12V 135A power. MPPT controllers are rated at their Max input Voltage, and their Max Output Amps, it's a very different spec than most people come across.

[wpmaura]

Well epever says as long as both the max PV of 1200 and voc are. Ot exceeded it should be fine. As they limit the output amps to 60.

[SunEagle]

And someone else says that volts is more important. The epever says pv.input c as not exceed 150v. So panels are 30v 9 amp so run 3 in series and parelle would give me 90v 18 amps.making this possible.

No. 3 of those panels wired in series will generate 90v at 9 amps. The voltage is added when you wire the panels in series but the amps will stay at what 1 panel provides.

When you wire the panels in parallel the voltage will stay at 30v and the amps will add up to 18.

For a typical MPPT CC the max input wattage usually can be calculated by using the battery voltage times the amp rating of the CC. So a 12V battery with a 60amp CC can accept around 720watts ( 12 x 60 = 720). Some CC will allow a little more wattage to be inputed but that is because you really never get the full output of a panel or the CC can tolerate a higher wattage input.

[wpmaura]

No. 3 of those panels wired in series will generate 90v at 9 amps. The voltage is added when you wire the panels in series but the amps will stay at what 1 panel provides.

When you wire the panels in parallel the voltage will stay at 30v and the amps will add up to 18.

For a typical MPPT CC the max input wattage usually can be calculated by using the battery voltage times the amp rating of the CC. So a 12V battery with a 60amp CC can accept around 720watts ( 12 x 60 = 720). Some CC will allow a little more wattage to be inputed but that is because you really never get the full output of a panel or the CC can tolerate a higher wattage input.

I know that so I have 6 panels I set 3 in series to give me 90v 9 amps then I do the other 3 the same way. then I parrell them so when I do that I get 90volts 18amps

[SunEagle]

I know that so I have 6 panels I set 3 in series to give me 90v 9 amps then I do the other 3 the same way. then I parrell them so when I do that I get 90volts 18amps

Yes. You are correct. Now you just have to determine what the maximum amount of panel wattage your CC can handle understanding if that if you wire all 6, for a total of 1620w, then you may exceed the input rating which could either burn it up or clip the over wattage to generate power.