Victron MPPT 100/50 help

[CL1981]

Hi all

I have a Victron MPPT 100/50 which I believe maxes out at 700 watts of solar input. I had originally installed 5x175 watt panels in series but then disconnected one of the panels because it exceeded the 700watts. I’ve been using this system now for almost a year and I have yet to be in a situation where we’re getting the full 700watts from the four panels and often we’re getting quiet a bit lower (400-500 watts).

My question is, can I safely hook the fifth panel back in to the series to increase my solar potential?

 

[HRTKD]

The 700 watt "limit" is the nominal wattage, not a hard limit. The hard limit that you never want to exceed is the Max PV Input Voltage. If your five panels in series have a Voc that exceeds 100 volts then you do NOT want to use all five panels. Keep in mind that cold temperatures raise the voltage.

Use the online Victron MPPT calculator to know for sure if your panels are a good fit or not:

MPPT Calculator - Victron Energy

MPPT Calculator - Victron Energy

www.victronenergy.com

 

[MichaelK]

HRTKD is very correct about the Voc limit. I searched for some generic 175W panels and found Voc ratings of 20.1 to 21.6Voc, so the Voc for the 5 would be 100.5Voc to 108. As he suggests, use the MPPT calculator to know exactly.

500W out of 700W worth of panels though is rather low. 500W/700W = 71%. How closely oriented towards the sun are they? Are they laying flat on a camper roof?

Here is another option you could do to increase power. Buy one more identical panel and wire the six panels in a 3S2P configuration. That works out to be {(175W X 6 panels)/13Vcharging} X 71% = 57A. Around noon the 7 extra amps gets clipped off, but for the rest of the day your arrays would be putting out lots more power. Your working voltage at 3S is only going to be around 54V or so, so it will be very safely below 100Voc.

50A though is going to be a lot of current going into a battery, maybe too much. What is the size/chemistry of your storage battery?