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I have 2 x 330 watt panasonic HIT solar panels with a maximum 50 volts fitted to a narrowboat which is powered by a 48 volt electric motor. I have 2 banks of 48v gel batteries with 230ah from each. I will be looking to move to lithium in the future when the prices drop. Looking for advise on the most suitable charge controller
Hi AJ. Into 48V, you don't need much A, so a '100/20_48' is for you. Not to be confused with a standard 100/20, which can't do 48V. https://www.victronenergy.com/upload/documents/Datasheet-BlueSolar-and-SmartSolar-charge-controller-overview-EN.pdf
But the panels must suit. My google suggests those Panas are quite high V, like well over 50V. In the case of a 100/ mppt, this is critical, and I'd urge you to recheck the Voc and Vmp of them.
JohnC
Being a complete novice the specification of the panel is below
Specifications:
Peak power Wp 330W
Voltage at peak power Vmp: 58.0V
Max open circuit voltage Voc: 69.7V
Current at peak power Imp: 5.7A
Max short circuit current Isc: 6.07A
Please advise
Yeh, those V's are where google led me. That would be ok, but strictly wired in parallel into a 100/ mppt. For better low-light performance they could be seriesed into a 150/35 mppt, but that's a stepup in price and capacity. The capacity is no issue, just a few more $$.
Those panels aren't especially natively suited to your application, and there may be others more easily dealt with, but if that's what you want, it's certainly doable. And further expansion possible just by adding in more matched panels if you went with the 150/35.
JohnC
I take it that the 2 panels can be wired into the 1 MPPT unit
Yes, (and answering your other comment too) Series wired for best results. The 150/35 is what I'd do too, and if it makes you feel any better about having overcapacity, my own 48V system can only use about 35A, but I put in a 150/100. We do what we do, ha. Lambs vs Rams, hey? :)
JohnC
I am lead to believe that when in series if 1 panel is in shade then the other panel is affected. On a boat on the canal it is likely that many times I will get shade so parallel should be the better option. As you know far more than me, can you advise why series is better
Yeh, the issue that doesn't show on the panel spec sheets is that those quoted V's don't happen in poor light/sunup/sundown. They may go as low as half that, and won't charge at all. If you had 12V batts you'd see no problem with parallel, but 48V (I use too) needs that extra V to operate. And that's why I would choose the 150/, and indeed why the 150 actually exists, aside from simpler wiring.
Shading, and especially 'mottled' shading, comes a lowly second for consideration. It becomes partial/reduction vs no power. And the panels you're proposing might actually handle series very well under shade.
If you get a Smart unit you could monitor the seriesed panel V, halve it, and if you can't see (say) >3V difference between Vbat and Vpanel, then you'd likely have no production at all from paralleled units. By all means experiment, it's only wiring to change.
