I have a Victron 100/50 MPPT controller and I am a bit confused about the voltage I am seeing when the batteries are fully charged. I have two identical panels hooked in series and the panel specs I was given was the following
Rated Maximum Power (Pmax): 275 W
Open Circuit Voltage (Voc): 24.88 V
Maximum Power Voltage (Vmp): 21.24 V
Short Circuit Current (Isc): 13.58 A
Maximum Power Current (Imp): 12.94 A
Module Efficiency: 20.4%
What confuses me is why I see the SmartSolar MPPT in the Victron UI showing voltages of 80-90V, how is this possible? Have I done something wrong?
Not sure why you would see that high of voltage. It should be around 42 V on the solar side. I am sure others will chime in. You ought to post your settings and a screen shot of the UI.
You are sure your panels Vmp is 24.88? Either way they are working and within the boundaries of the controller. It will handle up to 100V.
In bulk stage the battery side voltage should climb and current stay relatively constant until you reach absorption. The screenshot you posted looks like its working correctly. From that point the voltage should climb to 14.2 then go to absorption.
Attached is an image from the sticker on the back of one of the panels. I tested them individually in the late afternoon sun and both measure over 40V output.
Great sleuthing @Radunre That is crazy that the factory sticker is completely incorrect. I haven’t been able to find the data sheet on the perlight website, but I did see a few solar businesses selling the same model with specs in-line with the Victron MPPT calculator. Thanks again
I am considering changing from series to parallel for this setup so both amps and volts are well under the MPPT max input values. I previously had some renogy 3-1 connectors for this but there were some connectivity issues. To make things more solid my thought was to bring all 4 lines into the van and connect to positive and negative bus bars and then to the MPPT. I also have inline 15A fuses to add to each positive line at the busbar. Does this sound like a good idea? Or would I be better off mounting fuse holders on a DIN rail? In the future I may add one, possibly two more panels but never more than 4 total.
I understand with any more panels I will probably need either a second controller or a larger spec’d controller as series will put me over the max volts and parallel would put me over max watts
I am a fan of simple. I would leave it as it is. If you want to add panels in the future you can just add another controller. On another note you should have circuit protection on the PV side. Anything over 40 V is considered dangerous. There are high voltage circuit breakers that would work for this.
The output shown on the charge controller is what I would expect to see on a 275 watt panels in normal daylight. I say the label has the wrong numbers for voltage and current rating
I guess I am missing something. Your screenshot shows 81V which is well within the specs of a 100/50 controller even if temperatures are low and the voltage climbs. @Radunre posted the Victron MPPT calculator for your panels showing the 100/30 being sufficient.
There is no “issue” per se, aside from the numbers being output by the panels not matching what is being advertised on the panels. I was unsure if I was doing something wrong. Now that I know the panels are mislabelled, I know that I am better off changing to parallel so I can plan for a third panel in the future if/when needed. With this setup being on a van, I have to be pretty careful with my planning for the future so I don’t have to rip everything apart to re-organize, drill holes, etc.
According to the calculator is hovering at 98V at -10° and this is assuming that the ~3% variance they can have doesn’t swing to more than bargained for.
