I have a 24v system and six 175 watt panels (1050 watts)- three parallel strings of two per string. The panels have a Vpmax of 35.4v and Ipmax of 4.95v, delivering a max of 70.8v @ 15 amps to my current Outback mppt solar charge controller (Voc=44.4V, Isc=5.4A, or 88.8V @ 16.2A). Seems to me the Victron 100/50 would be fine. Why would Victron recommend the 150/35? Is there some reason the 100/50 wouldn't work for me? Thank you so much for taking the time to enlighten me! Eric
The spec sheet lists voc at a moderate temperature You need to look at the voc at minimum temperature where it is the highest.
Good point! I looked at the Sharp spec sheet and it says "under normal conditions, a PV module may produce more current and/or voltage than reported at Standard Test Conditions. Accordingly, the values of Isc and Voc marked on UL 1703 listed modules should be multiplied by a factor of 1.25 when determining component voltage ratings, conductor ampacities, fuse sizes and size of controls connected to the module output." So 1.25 x 88.8 Voc = 111 Voc, and 1.25 x 16.2 Isc = 20.25 Isc So, assuming this is a "worst case" scenario, such as sub-zero freezing temperature, the MPPT 100/50 wouldn't be able to handle the higher voltage. Thus the Sizing calculator's recommendation of 150/35. Thank you for the enlightenment, Kevin!
I think the 35A limit of the recommended controller will throttle your panels a bit. You're going to run close to max current as well, which means the controller may get warm and cut the charge to protect itself.
You may need to split the panels between two controllers.
