MPP solar outside of MPPT voltage range? And overpaneling a LV2424?

[SajgZi]

Hey everyone, I have a MPP LV2424 that has been working well on 2x310W panels. Looking to expand the solar array. I found a good deal on some 250W panels. The manual says recommended is 2S4P, which seems reasonable but needs some big wires for the expected 34A (my solar array and inverter won't be too close, maybe 150').

So I'm looking at 3S2P as an alternative (maybe 3P, just looked into the overpaneling resource, guess that's a separate question), which would be V_oc of 112.2V at STC. I'm in Colorado where it gets cold. The MPP LV2424 manual states the MPPT range is 30-115V. What happens over that range? Calculated voltage would be 121.7 at 0C, 125.6V at -10C and so on. Would the inverter just pull whatever it can from the current voltage? Would that then pull the voltage down into the MPPT range?

Can the MPP inverters handle overpaneling? That would be sizing the solar array for more than the rated amps and the controller just uses up to maximum amps?

 

[sunshine_eggo]

I'm assuming MPPT Voc limit of 145V. These can accommodate 2S 72 cell panels and 3S 60 cell panels in all but Antarctic conditions.

3S Voc of 112V is fine (sounds like 60 cell panels). Panels operate at Vmp, not Voc, so when providing power, they will be closer to 85-95V, which is in the MPPT range and what you need to use for your voltage drop calculations.

Most MPP inverters can handle overpaneling on the power/current side, not voltage.

If 80A MPPT, keep PV Isc under 80A 37. Assuming your panels put out about 11A each, you could go 3S7P for 5250W on a 4000W capable controller.

 

[iamrich]

Hey everyone, I have a MPP LV2424 that has been working well on 2x310W panels. Looking to expand the solar array. I found a good deal on some 250W panels. The manual says recommended is 2S4P, which seems reasonable but needs some big wires for the expected 34A (my solar array and inverter won't be too close, maybe 150').

So I'm looking at 3S2P as an alternative (maybe 3P, just looked into the overpaneling resource, guess that's a separate question), which would be V_oc of 112.2V at STC. I'm in Colorado where it gets cold. The MPP LV2424 manual states the MPPT range is 30-115V. What happens over that range? Calculated voltage would be 121.7 at 0C, 125.6V at -10C and so on. Would the inverter just pull whatever it can from the current voltage? Would that then pull the voltage down into the MPPT range?

Can the MPP inverters handle overpaneling? That would be sizing the solar array for more than the rated amps and the controller just uses up to maximum amps?

I am a little late to the party, but I am using 250w panels with my Hybrid LV2424 3S3P. It comes out to 2250w, but I rarely see above 1800w with the way my panels are mounted and the direction they are facing. I think 3S3P is a better arrangement than 2S4P because the working voltage will be higher (105v vs 70v) and the number of runs will be less (3 vs 4). My system usually maxes out at 105v and 18A, because the batteries top off before I get full sun. Highest voltage I have seen is 114v. LV2424 has a max volage of 145vdc, so just stay well below that. You will never get close to the 80a limit unless you run 9 single panels in parallel.

 

[SajgZi]

I am a little late to the party, but I am using 250w panels with my Hybrid LV2424 3S3P. It comes out to 2250w, but I rarely see above 1800w with the way my panels are mounted and the direction they are facing. I think 3S3P is a better arrangement than 2S4P because the working voltage will be higher (105v vs 70v) and the number of runs will be less (3 vs 4). My system usually maxes out at 105v and 18A, because the batteries top off before I get full sun. Highest voltage I have seen is 114v. LV2424 has a max volage of 145vdc, so just stay well below that. You will never get close to the 80a limit unless you run 9 single panels in parallel.

Thanks for validating my thoughts with your setup. I did decide to do a 3S3P setup with 250W panels. Seems pretty reasonable. Another $1000 worth of used solar panels will do a lot more than $1000 worth of batteries.

 

[Scoutmaster]

I found these panels and curious how many I can run on a lv2424
How would I configure them?
Looks like 6 panels gets me to 1900w

 

[iamrich]

I found these panels and curious how many I can run on a lv2424
How would I configure them?
Looks like 6 panels gets me to 1900w

3 in series, 2 strings would get you 1890w at ~120vdc and ~19a, well within the LV2424 specs.