I'm gearing up to set up a SGR-20K30E for my off-grid project soon. I've opted for the regular LiFePo4 batteries instead of self-heating ones, but I'm a bit concerned about how they'll perform during the winter months. I plan to install them in a small shed where temperatures often dip below freezing.
The documentation is lacking, but I believe the BMS (Battery Management System) should prevent charging or discharging if the temperature falls outside specification limits. My initial thought was to just insulate and heat the entire shed with materials like fiberglass and foam. However, I'm now considering insulating just the battery rack and using tank heating pads, potentially controlled by a Raspberry Pi hooked into the RS485 loop.
On another note, if I wanted to increase capacity and the BMS stops damage from cold, could I mix in some self-heating batteries to capitalize on the waste heat for the other batteries? Has anyone had success heating Sungold 48V batteries using these methods?
3 Answers
A good option could be to get some silicone heating pads. I found some 12-watt ones that can almost boil water! A little electronic setup could easily keep the battery pack warm enough for operation. You could even place one in a container of sand for broader heating effects. Just a thought since I'm in a warmer area myself—good luck with your project!
I suggest grabbing a 48V temperature relay. It could really help manage your setup. You might consider checking out some 48V heating pads as well. This way, you can directly integrate heating into your system without a ton of additional work!
You don't have to worry about discharging LiFePo4 batteries in freezing temps; the real issue is charging them. Most good BMS will allow discharging while preventing charging if it's too cold. If your BMS has a Bluetooth feature, you might even set the temperature limits directly from your phone! Keeping it around 3-5°C is ideal. Also, many BMSs come with outputs that let you connect heating pads, so they can kick in and warm up the batteries before allowing a charge. Insulation is key here, as the better insulated your setup is, the quicker it'll warm up! Handling it all externally can be more challenging, but definitely doable.
Yeah, setting up a relay with a Raspberry Pi to monitor and control heating pads sounds smart! It could make your system super efficient. I’m thinking along the lines of a low-power heating pad or maybe using an oil-filled heater just to keep the shed warm enough. But those silicone heating pads can pack quite a punch too!