Victron Charge controller

[Webbee]

The specs say in the manual for a Victron Charge Controller 150/45
12volts PV nominal 650watts
24volts PV nominal 1300watts
36volts PV nominal 1950watts
48volts PV nominal 2600watts
My question is, what difference does the PV wattage make if you are under all the other specs? Meaning you are not maxing out voltage or amperage.
I can't seem to get an answer for this.
Maybe this is a stupid question but I just don't get it...

 

[snoobler]

It's a 45A controller. 45A is the battery CHARGE current.

45A at different voltages delivers different power.

1*14.4V*45A = 650W
2*14.4V*45A = 1300W
3*14.4V*45A = 1950W
4*14.4V*45A = 2600W


You can actually exceed the wattage listed, but the charger won't use anything beyond the peak. Array must stay below PV Voc input limits (150V) and the PV input current limit (listed in the data sheet).

 

[Rocketman]

If you have under those amounts - For example you have a 24v system - the SCC (Solar Charge Controller) can handle 1300W - But you only have 1000W of solar panels, then the power will be limited by how much power the panels can produce. That is the case even if you go over. For example on my RV I have 800 watts of power and a Victron SCC 100/50. The SCC has a limit of 700 watts - (which is 50 amps at 14.4 volts). So like Snoobler says if my panels ever produce more than 700 watts - they will be clipped. I have only noticed that happening once - where I was at 700 watts. For that to happen you need a really bright day - clean panels - sun directly overhead of panels and a battery that can handle the full charge. My current Lead-acid batteries can only handle the full charge during the bulk stage - when I change to Lithium's - they will handle the full charge whenever charging.

If you are way over paneled or way under paneled that is probably not ideal. But a bit over or under is just fine.

 

[Webbee]

Ok, my PV Voc is 21.7 volts and I have 4 paired series strings in parallel (hope I wrote that right) which should be around 87. volts. So I should be ok, right?

 

[Rocketman]

What are the full specs on those panels?
Yes you will be OK for voltage 87 volts is way below the 150 volts. I am assuming these eight panels are 100 watt panels and you are on a 12v system - correct?

Your panels can produce 800 watts - that SCC will clip at 650 watts. If panels are flat mounted with Lead-acid batteries - that will be fine. If lithium and tilted panels you may want to move up a size on your SCC.

 

[cinergi]

Ok, my PV Voc is 21.7 volts and I have 4 paired series strings in parallel (hope I wrote that right) which should be around 87. volts. So I should be ok, right?

Short answer: yes. If you were closer to 120 voc then I'd ask what your coldest temperatures are because temperatures affect voc and you have to factor in your worst-case cold temperatures when calculating your max voc.

 

[Webbee]

Ya my panels are 100watt, sorry I guess I should have put in all spec. Yes I am a 12volt system as well.

Thanks for clearing this up, it is helpful to understand these things.

 

[cinergi]

It takes a little getting used to the Victron model number meaning. 150 = max VoC it can ever see. It typically won't operate any higher than this value minus 5 (145 in this case). The 45 = max charging amperage. A wattage rating is somewhat misleading for SCC's so that's why using these numbers is more accurate. As long as your panel array voltage isn't too high, you're OK. As long as you're OK with the maximum amperage to the battery, you're OK. If you want to make sure you're making the most use of the SCC, do some math on the amperage * battery charging voltage and that's the maximum wattage the SCC can output. If you have more watts' worth of panels (Pmax), that's OK -- you'll just "throw out" that energy whenever you're maxing out your output (charge) amperage.

The other panel specs like Vmp, Imp and Isc are more about sizing your wiring and breakers/fuses for the most part (in this situation).

 

[Webbee]

Thanks guys for clearing this up for me. This was very helpful!