I am a virtual newbie when it comes to solar though I have built a teardrop trailer with all victron components that works very well thanks to the Will Prowse videos. I have designed and purchased the following for my off grid barn. EG4 6000xp scc/inverter, EG4 LL-S 48v 100ah battery x 2, and 10 Canadian Solar CS6R395 panels. I am in NW Arkansas and concerned about my understanding of the solar panel output in winter. By my calculations these panels have a Voc temp coefficient of -0.26°C which gives me a 10s string Voc of 504.348 Vdc at -28°C (-18.4°F) which is clearly over the MPPT spec. At -25°C (-13°F) I’m ok at 475.8 Vdc but just barely. With climate change a fact, imho, I’m concerned that even at -25°C I’m risking the health and welfare of the 6000xp.
So the questions: 1. Are my numbers shown reasonable? 2. Is there a low temp cutoff in the 6000xp that I can set to turn off charging at say 1°C? To be honest I’ve read the 6000xp manual but not the LL-S battery manual which I’m sure can shut itself down at a specified temp. 3. Would a temp monitoring circuit with a suitable DC rated relay be prudent to cut off the PV string at 1°C so there is zero chance of charging below freezing? It would be an overkill processor wise but a Raspberry Pi could easily do the temp sensing and relay control. 4. Anyone have a better approach to protecting the 6000XP from over-voltage AND protecting the LiFePO4 batteries from charging below freezing without cutting out any panels? Thank you for the wealth of information found in this forum.
So the questions: 1. Are my numbers shown reasonable? 2. Is there a low temp cutoff in the 6000xp that I can set to turn off charging at say 1°C? To be honest I’ve read the 6000xp manual but not the LL-S battery manual which I’m sure can shut itself down at a specified temp. 3. Would a temp monitoring circuit with a suitable DC rated relay be prudent to cut off the PV string at 1°C so there is zero chance of charging below freezing? It would be an overkill processor wise but a Raspberry Pi could easily do the temp sensing and relay control. 4. Anyone have a better approach to protecting the 6000XP from over-voltage AND protecting the LiFePO4 batteries from charging below freezing without cutting out any panels? Thank you for the wealth of information found in this forum.
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