combination series, and parralell solar pnels

[robtribble]

I have a number of mixed panels see attachment, that i want to install in a way that maximizes my M60 unit. So the question is fairly complex, what is the maximum amount of amps than can pass through a single panel, NOT what is generates, but also pass through. see the picture attachment. Is this crazy or not, did I do the calc proper ????

[Sunking]

Current is limited to the lowest value in the series string. In your drawing the calculated output will be 99 volts @ 12 amps = 1188 watts. Far from the 1850 you are expecting.

[robtribble]

do you suggest an alternative.

do you have an alternataive, I do have 3 MX60 and could do the three type as individual string ?

[Sunking]

Actually I do have a good solution as you mentioned make 3 separate systems with each having its own CC all serving a common 24 volt battery as that is the common denominator voltage. The CC will have to be MPPT types with a communication bus to load share correctly.

[robtribble]

try again

the bateries are 48 volts, and what is the load sharing ? bus thing ? as long as all the CC have the same prferences, whats up ??

[robtribble]

what if

ok, so i need more parralel units

[Sunking]

the bateries are 48 volts, and what is the load sharing ? bus thing ? as long as all the CC have the same prferences, whats up ??

Load sharing is just a signal link between the controllers to apply an equal amount of charge to the batteries.

As for 48 volt battery, well you will not be able to all of your KCT panels as there is no combination to arrange them. You need four them in series which leave you with 2 unused panels.

[greenHouse]

Load sharing is just a signal link between the controllers to apply an equal amount of charge to the batteries.

As for 48 volt battery, well you will not be able to all of your KCT panels as there is no combination to arrange them. You need four them in series which leave you with 2 unused panels.

He needs no such thing as a "signal link". The charge controllers communicate through the battery voltage, and that's all that's needed.

[Mike90250]

Without a "signal link", the different charge controllers will shut off or switch stages, at different times, with a small effect (<30 minutes) of the time to totally full charge.

[greenHouse]

Without a "signal link", the different charge controllers will shut off or switch stages, at different times, with a small effect (<30 minutes) of the time to totally full charge.

That's correct, which is why the volt meters need to be properly calibrated, or the voltage set-points compensated for the differences.

The problem you mentioned only happens on the Bulk -> Absorb and Absorb -> Float transitions. Neither of which much matter because they are both low-power states. The only time it "matters" is run time, and that also doesn't matter because all the numbers for absorb and float time are rough approximations anyway.

I know some people make a big deal about it, but it's much more a miscalibrated voltage problem, not a lack of some signal-link. It's also a way to claim that Brand A is better (or worse) than Brand B.

[greenHouse]

I have a number of mixed panels see attachment, that i want to install in a way that maximizes my M60 unit. So the question is fairly complex, what is the maximum amount of amps than can pass through a single panel, NOT what is generates, but also pass through. see the picture attachment. Is this crazy or not, did I do the calc proper ????

Put 5 of the KCT 85's in series. Voc is 5 x 22 or 110, before temperature correction. Kyoceras go about -0.35% / *K.

[Mike90250]

...
I know some people make a big deal about it, but it's much more a miscalibrated voltage problem, not a lack of some signal-link. It's also a way to claim that Brand A is better (or worse) than Brand B.

It's not even mis-calibration, it's anytime you have 2 gizmo's set to trip at 14.85 V, one will go before the other. Never will be able to calibrate to have both switch at same time. So the interlink cable and several hundred dollars of interface hardware solves a little problem.

Not to scare the original poster, it's a subtle difference, won't hurt anything, but might increase charge time half an hour or so. All brands are affected.

[greenHouse]

It's not even mis-calibration, it's anytime you have 2 gizmo's set to trip at 14.85 V, one will go before the other. Never will be able to calibrate to have both switch at same time. So the interlink cable and several hundred dollars of interface hardware solves a little problem.

Not to scare the original poster, it's a subtle difference, won't hurt anything, but might increase charge time half an hour or so. All brands are affected.

Right, but the real question is -- is it a difference that makes a difference? The problems happen at the Bulk/Absorb and Absorb/Float transitions. In neither of those instances is the system required to produce 100% of rated power -- that only happens in "Bulk".

The bigger problem is the use of time for controlling absorption and float charging stages, rather than battery state of charge. Three hours for absorb is great, if that's what it takes to get to 100% and then some. But if some days you get there after 45 minutes, and other days you don't reach float, a communications link isn't going to help.

[Mike90250]

very imformative

See, this is what will get you moderated and tossed out. Pointless post replies, just to build post #'s

[sarah]

Thanks Mike.
Appreciate you thinking my reply was pointless.