wwu123
New Member
Hi all, I have some new LG 435W panels with 48 Voc, that I would like to run 2-3 parallel strings of 3S = 144V. I'm not against quality SCC's like Victron, but their 150/35 and 150/45 leave very little buffer with 150 Voc max, even though temps don't get below freezing in my area. They seem to no longer make 200V models, so the next step up to 250 V is a very pricey upgrade, basically 2X the price. Similarly some of the other reasonable but decent quality brands like Ampinvt also have a 150 Voc max.
I noticed a number of the cheap but at least branded mfrs like PowMr and Easun advertise Voc of 160V, even 190 Voc (a few say they can only handle this for a short while, otherwise 160V). 160V provides a solid buffer vs 150V for my particular panels, so that's why I'm interested in these. Now I read that many of these tend to overheat when pushed to their rate max power, so I would probably only have one 3S string (=1305W) on each controller, and run multiple of these in parallel to a 48V 100ah server rack battery.
Now one of the other knocks against these I read is some people complain they've seen output voltage spikes up to 20V above the settings, which can be harmful to the 48V battery, or possibly trip overvoltage protections in place on the load. My question is - if one has multiple of these controllers in parallel, and only one throws out a voltage spike, will the other units in parallel still putting out the proper set charging voltage (around 55V) mitigate the voltage spike from actually occurring from the misbehaving unit, since they're all wired in parallel on the output to a common bus bar? If the other parallel units don't mitigate the spike, so the voltage on the bus bar is brought up to say 75V by the misbehaving one, does that cause any potential damage to the other units putting out 55V? Does it kill the output from the ones trying to still put out power at 55V while the voltage is spiked to 75V?
I noticed a number of the cheap but at least branded mfrs like PowMr and Easun advertise Voc of 160V, even 190 Voc (a few say they can only handle this for a short while, otherwise 160V). 160V provides a solid buffer vs 150V for my particular panels, so that's why I'm interested in these. Now I read that many of these tend to overheat when pushed to their rate max power, so I would probably only have one 3S string (=1305W) on each controller, and run multiple of these in parallel to a 48V 100ah server rack battery.
Now one of the other knocks against these I read is some people complain they've seen output voltage spikes up to 20V above the settings, which can be harmful to the 48V battery, or possibly trip overvoltage protections in place on the load. My question is - if one has multiple of these controllers in parallel, and only one throws out a voltage spike, will the other units in parallel still putting out the proper set charging voltage (around 55V) mitigate the voltage spike from actually occurring from the misbehaving unit, since they're all wired in parallel on the output to a common bus bar? If the other parallel units don't mitigate the spike, so the voltage on the bus bar is brought up to say 75V by the misbehaving one, does that cause any potential damage to the other units putting out 55V? Does it kill the output from the ones trying to still put out power at 55V while the voltage is spiked to 75V?