October 1, 20223 yr Hi have a Mecer/Axpert Sol-I-AX-3VP 3kw unit. Max VoC=80v and Operating Voltage Range of 30-32v. Its a PWM model). Currently running 4 x panels in parallel. (370w / Voc-48.7v / VmP-39.4v) I want to add more 4 more panels also in parallel ( 540w / VoC-49.6v / VmP-41.64v). Will these extra panels with the different VoC and VmP work ok? Thanks Ian
October 1, 20223 yr 1 hour ago, IanDee said: Max VoC=80v and Operating Voltage Range of 30-32v. your existing panels already exceed this voltage... I'm not so sure you should try this, what aught to happen is that the existing panel may clamp the voltage to their level, which means the new panels will produce less power than they could... what may happen, based on the 30-32V range is that the inverter's solar input side will wave the white flag of surrender by way of letting go of some magic smoke... it may be a better idea to add panels to another MPPT charge controller that connects to your, presumtuous battery as well, then the inverter if needing more power can get from the battery, by way of the extra panels and charge controller...
October 1, 20223 yr Author Thanks for the info. Might be easier to sell the 3000w and get a 5000w with an MPPT controller built in. A shame as the 3000w is only 6 months old.
October 8, 20223 yr On 2022/10/01 at 12:58 PM, Kalahari Meerkat said: your existing panels already exceed this voltage... If this was not an issue, ie large inverter with charge controller that can handle the voltage, can one then safely mix panels on one string? Anything in particular to watch out for?
October 8, 20223 yr 1 hour ago, hannesvn said: If this was not an issue, ie large inverter with charge controller that can handle the voltage, can one then safely mix panels on one string? Anything in particular to watch out for? The low voltage 5kW inverters can have 145V or so on the solar MPPT end, so you could have 2 panels in series and lots of those, in parallel, then again the high voltage 5kW inverters can have up to, let's say 400V on the MPPT end, thus you could probably have 8 panels in series without too much of a problem... if you have a mixed bag of panels with different ratings, it becomes a problem unless you have panels with similar voltages or similar current ratings, then one can still try and get them to work together... On 2022/10/01 at 11:44 AM, IanDee said: Operating Voltage Range of 30-32v is really the problem with your current inverter, your existing panels are 39.4Vmp, thus above where the MPPT would work comfortably, and then new panels you are looking at are close, so could be connected, but, since the 30-32V range for the MPPT is already being exceeded, not sure how well this work in the long run, before things start smoking 🙂
October 8, 20223 yr On 2022/10/01 at 11:44 AM, IanDee said: Hi have a Mecer/Axpert Sol-I-AX-3VP 3kw unit. Max VoC=80v and Operating Voltage Range of 30-32v. Its a PWM model). Currently running 4 x panels in parallel. (370w / Voc-48.7v / VmP-39.4v) I want to add more 4 more panels also in parallel ( 540w / VoC-49.6v / VmP-41.64v). Will these extra panels with the different VoC and VmP work ok? Thanks Ian There is no problem running these panels together. The difference in voltage of 1 volt is no problem. I would use them together any day. In Gauteng we already get 20% less than STC so to loose 2-4% is no train smash. It depends if you see 2V or 2000mV difference. 😄 Seeing that the higher voltage than MPPT sweet spot has been working fine it is no problem. I am running panels via an external MPPT on a Axpert clone 3kVA and it just works fine. Using such external MPPT will in any case extract far more power than the current PWM controller. A bigger problem might be the high current being pumped to the PWM controller. Refer to the spec. Your choice to improve your system or upgrade.
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