Is exceeding the maximum PV input voltage by a little bit okay?

[Hedges]

Of course, you may get away with it, if temperatures aren't too cold, PV panel Voc runs a bit low, SCC has margin above spec.

To be safer, you could get another SCC, use it with a single panel and use your existing SCC with two panels in series, "2s"
That also gives redundancy, in case one SCC dies for any reason.

Since dimensions are small, wiring 3p could be an alternative, if it doesn't violate max input current specs.
That might harvest more power, MPPT more efficient if voltage conversion is less.
However, in a hot environment, Vmp might drop below minimum input voltage of MPPT. I think "2s" or "2s2p" is optimum for efficiency and voltage margin (both high and low.)

 

[eXodus]

I was always told to:

Above the input Amps is fine (in a certain range 10%?) - but above the Voltage is not.

But that was a few years / decades ago.

 

[Snubber]

How much did your SCC cost?

If SCC did fail, would it simply crowbar PV panels (shorted input capacitor), or would it connect PV directly to battery (shorted FET)?
In the latter case, what did your battery cost?



Anybody for a game of Tetris?

I want to start with ( 4 ) 100AH Deep Cycle FLAs I already have. I have not purchased a SCC yet , am thinking about the EPEVER 8420AN. It has a max pv input of 200vdc.

 

[Hedges]

Epever isn't the premium brand, but here's one with 200V input.
(I think some people had issues with some models, so suggest you search this forum and others on it. Don't take this link as a recommendation by me.)

Epever 8420AN 80A MPPT Solar Charge Controller - SanTan Solar Store

Buy our Epever 8420AN 80A MPPT Solar Charge Controller for only $380. Click the link to start shopping today!

store.santansolar.com

I have noticed that higher voltage SCC cost more per watt than lower voltage ones.

 

[12VoltInstalls]

some people had issues with some models

My 50A 150V epever appears to be cutting out during equalization if that’s what you mean.

 

[Snubber]

Epever isn't the premium brand, but here's one with 200V input.
(I think some people had issues with some models, so suggest you search this forum and others on it. Don't take this link as a recommendation by me.)

Epever 8420AN 80A MPPT Solar Charge Controller - SanTan Solar Store

Buy our Epever 8420AN 80A MPPT Solar Charge Controller for only $380. Click the link to start shopping today!

store.santansolar.com

I have noticed that higher voltage SCC cost more per watt than lower voltage ones.

What are thoughts on using branch connectors and running 2 smaller SCCs?

 

[Hedges]

What are thoughts on using branch connectors and running 2 smaller SCCs?

Two smaller SCCs works.

Earlier I mentioned that single panel one MPPT SCC might not have high enough Vmp on a hot day (panel runs hotter than ambient) so evaluate that. I think 2s of that panel is ideal for 24V battery. If one panel is too low a voltage, my best suggestions are either one more same/similar panel so 2s2p into one 150V SCC, or a 200V SCC with 3s panels.

A PWM SCC would have sufficient voltage from one panel (except in very hot weather), but will harvest less power in some conditions. Output voltage pulses may or may not be confusing for other electronics. I think PWM is OK for lead-acid but might be a problem for lithium especially near fully charged. Look carefully at voltage requirements for MPPT SCC; some don't need as much headroom.

What do you mean "branch connectors", what for?
PV feeding two SCC would be isolated from each other

Output of two SCC would be paralleled somewhere on the way to battery. Best to minimize the length of shared wire between them, and shared with inverter, because voltage variations driven by any one device might affect other device's measurement of battery voltage. Star connection from battery negative and from main battery fuse on positive might be best in this regard. That could be one main fuse able to carry inverter current right at battery (+), then smaller fuses on wires to SCC.

 

[Snubber]

Two smaller SCCs works.

Earlier I mentioned that single panel one MPPT SCC might not have high enough Vmp on a hot day (panel runs hotter than ambient) so evaluate that. I think 2s of that panel is ideal for 24V battery. If one panel is too low a voltage, my best suggestions are either one more same/similar panel so 2s2p into one 150V SCC, or a 200V SCC with 3s panels.

A PWM SCC would have sufficient voltage from one panel (except in very hot weather), but will harvest less power in some conditions. Output voltage pulses may or may not be confusing for other electronics. I think PWM is OK for lead-acid but might be a problem for lithium especially near fully charged. Look carefully at voltage requirements for MPPT SCC; some don't need as much headroom.

What do you mean "branch connectors", what for?
PV feeding two SCC would be isolated from each other

Output of two SCC would be paralleled somewhere on the way to battery. Best to minimize the length of shared wire between them, and shared with inverter, because voltage variations driven by any one device might affect other device's measurement of battery voltage. Star connection from battery negative and from main battery fuse on positive might be best in this regard. That could be one main fuse able to carry inverter current right at battery (+), then smaller fuses on wires to SCC.

By Branch Connectors I was thinking of splitting each wire from the ( already series connected array ) just before and after the twin SCCs. Then just running the + & - on to the battery bank as usual.

 

[MisterSandals]

By Branch Connectors I was thinking of splitting each wire from the ( already series connected array ) just before and after the twin SCCs.

You cannot branch a panel/array to different SCCs simultaneously. You would need to dedicate specific panel(s) to each SCC.
The primary issue is that the SCCs will slam dance as they each try to adjust the array while seeking MPPT optimisation.

 

[Snubber]

You cannot branch a panel/array to different SCCs simultaneously. You would need to dedicate specific panel(s) to each SCC.
The primary issue is that the SCCs will slam dance as they each try to adjust the array while seeking MPPT optimisation.

Ahhh. Didn't know that. Makes sense.