August 7, 20215 yr Just bought a new JA solar panel. - model JAM60S20 - 380 watt. Back of the panel says amperage should be around 11amps, however on my inverter its showing 19amps. Voltage is around 24. is this normal?
August 7, 20215 yr Author Just now, Tariq said: 1) What inverter do you have 2) how money panels do you have the mecer mppt 1200 one panel. I am starting to think the reading on the inverter is the mppt adjusting to best voltage and amps, and not the actual reading from the panel
August 9, 20215 yr On 2021/08/07 at 9:33 PM, sunset1 said: Back of the panel says amperage should be around 11amps, however on my inverter its showing 19amps. The 19 A is probably on the battery side, after the "DC transformer" that is a MPPT solar charge controller. If your battery is nominally 12 V, getting charged at say 14.0 V, that's 14 x 19 = 266 W, which is 70% of 380 W. That's slightly low, often you can get 75-80% in good conditions. Presumably it's winter where you are, so the panel is probably not facing the sun directly, so that's reasonable. You're probably getting something like 35 V x 7.3 A at the PV input, and 7.3 A is well under the Imppt rating for the panel. 11 A might be the Isc value, which you'll likely never see in real life.
August 21, 20215 yr I had some surprising readings too: My array of 9 335W panels (3s3p) delivered sometimes up to 3.3kW according to the Axpert MPPT readings. That is 10% more than specification despite the far from optimal exposure to the sun. There is good credibility for that reading since it is confirmed by the independent charge current readings from the batteries BMS. Another experience: In April I relocated 3 of the 9 panels to be on the same exposure as the 6 others. For ease of wiring I installed them upside down with respect to the original installation. When checking it out I got the impression that they deliver far less than the other 6 in identical position. I double checked all connections but found no problem. I decided to observe for some time. Now I just got a power reading (3.2kW) that confirms that they also deliver like they did before. Could it be that the panels need some time to burn themself in to the new main sun direction?
August 22, 20215 yr If it was a new panel it can burn in but it should make no difference. Would like to hear any reasons for the increase.
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