Working on my truck today got asked a question which I struggled with a little from the guy parked next to me. He has : 4 x 245watt/37v VOC/8.04A panels and wants to use a VE BS100/50 SCC that has 700watt solar limit on a 4 x 100Ah lead acid battery bank. My initial comment was that he will probably need 2 x SCC to handle the 980watt potential to kick off but then I started asking myself how using 2 x SCC's can you get over charging protection for the battery bank on lead acid...?? Can anyone give me a quick overview of his system with reference to what he already has in place ie: solar panels and battery and come up with a which/what type of SCC setup would be best..?? My head is only geared for LiFePo4 at present, forgot all about LA......
Victron BS 100/50 with lead acid....???
- Thread starter MezzBatt
- Start date
The Victron solar charge controller will work with lead acid as well as LiFePO4. The solar panel configuration could be 2s2p to ensure it doesn't exceed the 100v max PV input limit. Yes, it will be overpaneled, but the controller will simply not put out more amps than it's rated for. Two controllers could get you more than 50 amps of charge, and that's a good reason to go with two.
the_colorist
"Move over... let me fix it" Installer/Engineer
I'm assuming this is 12v?
To @HRTKD 's point, the max PV short circuit current on the 100/50 is 60A so yeah you're good with 980W.
With using 2 controllers, the absorption phase by nature will limit the current of each controller as they reach the target voltage, assuming they are both set the same. A person can set the absorption target on one controller X.X1V or so lower than the other to prevent oscillation.
For proper coordination though, it's quite simple with Victron. The SmartSolar controllers can coordinate via Bluetooth VE.Smart networking. A better solution however might be to use Bluesolar 100/50 controllers with a GX device and VE.Direct cables. A SmartShunt would be recommended as well. Just connect both controllers and the SmartShunt to the GX. The software will need to be programmed appropriately but using Distributed Voltage Current Control (DVCC), the GX will coordinate charging and use the SmartShunt input to help achieve a more precise charge. Plus you'll have the SOC advantage that the SmartShunt provides allowing you to see the SOC based on storage instead of voltage.
Depending on the GX used, one device might need to use a USB -> VE.Direct cable.
That said, that to fully charge 400AH @12V a person really wants over 1000W of installed PV. Closer to 1200w to keep em healthy (EQ etc). The NOCT on those panels is likely around 180-200W meaning the real average power output for 4x 245W is closer to 800W-850W. I understand though space might be an issue in a mobile application.
To @HRTKD 's point, the max PV short circuit current on the 100/50 is 60A so yeah you're good with 980W.
With using 2 controllers, the absorption phase by nature will limit the current of each controller as they reach the target voltage, assuming they are both set the same. A person can set the absorption target on one controller X.X1V or so lower than the other to prevent oscillation.
For proper coordination though, it's quite simple with Victron. The SmartSolar controllers can coordinate via Bluetooth VE.Smart networking. A better solution however might be to use Bluesolar 100/50 controllers with a GX device and VE.Direct cables. A SmartShunt would be recommended as well. Just connect both controllers and the SmartShunt to the GX. The software will need to be programmed appropriately but using Distributed Voltage Current Control (DVCC), the GX will coordinate charging and use the SmartShunt input to help achieve a more precise charge. Plus you'll have the SOC advantage that the SmartShunt provides allowing you to see the SOC based on storage instead of voltage.
Depending on the GX used, one device might need to use a USB -> VE.Direct cable.
That said, that to fully charge 400AH @12V a person really wants over 1000W of installed PV. Closer to 1200w to keep em healthy (EQ etc). The NOCT on those panels is likely around 180-200W meaning the real average power output for 4x 245W is closer to 800W-850W. I understand though space might be an issue in a mobile application.
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