The voc of my 3 x 245w panels is 159v, would I be right in thinking i can connect my panels in parallel and use a 150/70 charge controller? I'm running a 12v system.
Thanks in advance.
asked
Solar charger sizing query.
Please clarify, Is it 159Voc per panel or all three in series?
159v voc would be all three connected in series.
Negative; the 150v input rating is a HARD LIMIT and must not be exceeded under any circumstances. You could, however, wire two in series and keep the third in parallel and -depending on the other specs of your panels- be fine.
I realise the voltage shouldn't be exceeded, I was under the impression that if I connected all three panels in parallel that I'd be well under the limit and able to use a smaller less expensive controller, the 150/70.
Well your statement was that VOC on your 3 panels connected in series is 159v, which is more than 150v, so I was using your calculation. Did I miss something?
Ahhhhh I see now... your calculation of your three panels in series led me to overlook that you were asking about them in parallel. It would be easier if you'd just post the specs of a single panel, perhaps?
Panasnic hit's?
3 parallel on a 100/50 will be ok for a 12v battery system. You will need string fuses though.
Yes hits, thanks for the reply, do you have the calculation for working out the fuse size? I'm new to this so I'm still finding my feet and there's so much conflicting information.
Use the recommended "series fuse rating" from the spec sheet. https://zerohomebills.com/wp-content/uploads/Panasonic-HIT-solar-panel-N250-245W-Datasheet-EN.pdf
2 fuses for each panel.
Justin, Can you explain a little more about 2S 1P config. I did not realise that was possible, it may open up module upgrade for my current MPPT. Are there any drawbacks?
I would also like to know, from what I heard if you have 3 panels, you should never connect 2P 1S or 2S 1P and that S and P strings should always be equal numbers like 4 panels 2P 2S or 6 panels 3P 2S etc.
Hi Frosty. Agree that paralleled into 12V batts would be fine.
Just adding that you wouldn't need a 150/ mppt in that case, and I'd actually suggest you consider a 100/50, which would rarely (if ever) clip at the A-limit into typical charge voltages. Might save you some coin..
I wondered if that would be the case, appreciate the reply, cheers.
