Power dropping issue in series connection

Hey friends I am facing power dropping issue in series connection. I have connected 340watt and 380watt solar panels in series to epever mppt controller. It show power of one panel when I disconnect solar connector and reconnect, the mppt show both Panels. It’s hard to do this every morning. It was fine in winter but now summer starting and facing this issue. Using both panels form 2 months. images attacked. I have to try both in parallel to see what mppt response. Both panels volts amps are litre different. Tesla 34.51v maxpower 33.18v. Tesla amps 11.01amps maxpower 10.29amps.

Hmm… I think that – at least under some insolations – the voltage drop across one or both of your two panels isn’t anywhere close to optimal for its production of power. When wired in series, the current will be flowing through both panels; and when wired in parallel, they’ll both have the same voltage. Indeed, it seems very unlikely that a 340W panel and a 380W panel would have similar-enough operating characteristics to be at all efficient when connected either in series or in parallel. And, since yours are from different vendors, then they might behave very differently when partially shaded. If your MPPT doesn’t have two ports, then … maybe you can find a couple of inexpensive used (or legacy) microinverters?

"… Though mixing different solar panels is not recommended, it’s not forbidden and things would be ok as long as each panel’s electrical parameters (voltage, wattage, amps) are carefully considered.

“When you intend to wire two panels produced by different vendors, the vendors actually are not the problem. The problem is in different electrical characteristics of the panels, together with different performance degradation…”

Yeah I installed mismatched panels but 380 was not available and my mppt is 40A so oversized panels could damage. Still about the limit 520watt 12v battery. And 1040watt for 24v. Today I have connected them in parallel to check wither one panel work or both. If issue remains I have to sell one panel and to buy 340 to match both.

1 Like