March 28, 20224 yr I was wondering if there is an issue when connecting solar panels with different power, for example, adding one or two 540w panels to a string of 300w panels. I know that the 540w panels will be "pulled down" to the level of the 300w panels but supposing i dont care about the efficiency loss, is there any danger in doing it?
March 28, 20224 yr Basically the efficiency of your panels will be reduced. I'll recomend you use an inverter with dual MPPTs and connect same size panels to their own charger. Or you can buy a separate charge controller for the new panels
March 30, 20224 yr On 2022/03/28 at 7:48 PM, phoenix752 said: Basically the efficiency of your panels will be reduced. I'll recomend you use an inverter with dual MPPTs and connect same size panels to their own charger. Or you can buy a separate charge controller for the new panels Most common inverters accept the Victron has the charge controller in the inverter so not that easy to use a separate charge controller for the extra panels. One need the voltage and current to work out how much you going to loose as well as the series/parallel connection of the strings. Make and model of inverter also comes into play to get a better answer. Edited March 30, 20224 yr by Scorp007
March 30, 20224 yr 1 hour ago, Scorp007 said: Most common inverters accept the Victron has the charge controller in the inverter so not that easy to use a separate charge controller for the extra panels. One need the voltage and current to work out how much you going to loose as well as the series/parallel connection of the strings. Make and model of inverter also comes into play to get a better answer. What would happen if the different panels were to go through a combiner box and the output to the one MPPT, would that not sort out the problem?
April 2, 20224 yr On 2022/03/30 at 7:34 PM, Moffat said: What would happen if the different panels were to go through a combiner box and the output to the one MPPT, would that not sort out the problem? The combiner box will still series and parallel panels. The easy way out is to provide what size panels with their Imp and Vmp and how they are connected then it can be calculated. A simple example. Series a 200 and 270W panel and both are Imp=5.5A with Vmp=36 and 49V the output will about Vmp=85V at I=mp=5.5A is 467W Parallel these 2 panels and the output Vmp=36V Imp=2x5.5=11A for 396W For parallel keep the Vmp very close to each other. For series keep the Imp very close to each other. The above is the estimated actual power being provided to the MPPT I stand to be corrected on the above.
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