Hello everyone,
I have a friend that currently has an array of 5S - 2P 100w panels wired to a Kid cc in a 48v system. I've used the sizing too & everything is within spec. He would like to add 5 additional larger 160w panels to his system. The new panels are the same style (both poly) and all the spec's are within 10% of each other. Except the ones related to the difference in amps.
watts, Imp, Isc
100/160, 5.29/7.92, 5.75/8.37
Is it ok to add an additional series of 5 x 160w panels to his system without adding an additional Kid? I know the additional panels will slightly over panel the Kid, this isn't a concern.
My question is, are these additional panels compatible with his existing system? Or does he need to buy another Kid & associated breakers,boxes,conduit, etc. The biggest headache is that the array is over 200 feet away and an additional Kid would require a new buried line from the panels to the power room.
Below are the specs for the existing and proposed new panels.
Thanks,
Ed
Max Power = 100w
Vmp = 18.9v
Imp = 5.29
Voc = 22.5
Isc = 5.75
Max power = 160w
Vmp = 20.2
Imp = 7.92
Voc = 22.9
Isc = 8.37
Have you looked at the possibility of replacing the Kid with a Classic ?
You would not only get more amp capacity but also get much better monitoring abilities.
Larry
Hi UpNorthMan,
Am too lazy ... err busy, to run your numbers through the KID String Sizer, but, using envelope-back estimates, looks like your proposed configuration should be OK.
Like to use the 5%/10% rule for strings in parallel, or PVs in series. The two different PV's Vmps are within 5% of each other. This considered to be ideal enough -- when adding PV strings in parallel, having STC String Vmps within 5% is good, and the rule says about 10% maximum difference twix them is OK. Imps come into play when adding different PVs in series in one string.
The total STC power is 1800 W, and if the system would see 80% of that at solar peak, the KID would not quite see its maximum output current of 30 A. This should be OK.
The STC string Vmp would be about 97.5 V, which is a bit high, but, still within the OK range.
The string Voc is probably OK, even on the coldest times at the location of this system. The string sizer should show the max Voc for your coldest possible weather.
IMO, FWIW, you may still want to run the KID sizer to confirm. Vic
Thanks for the replys. I have run the numbers on the 100w panels in the past. They were OK to - 72f or something like that. My friend lives close to my house and the coldest I've recorded at my house is about - 46f or about - 43c. I've had a weather station at my house for about 20 years now. I've been posting on line for most of them.
We went with slightly higher voltage so on cloudier days we could guarantee at least some production. And with the long run from the panels to the battery room, we were concerned about the voltage drop. 4 series brings us closer to the minimum voltage for the Kid to work.
I was thinking that all the panels would be compatible, just wanted to confirm my thoughts.
I will let him know about the benefits of a different CC. He will have to decide what to do.
Thanks again,
Ed