- Joined Jul 19, 2018
Hi all, I have a 350 watt solar panel project that is connected to a MPPT. I'm using this to charge a 13v 200Ah LiFePO4 battery pack through a BMS. The BMS will enable charging when it senses greater than 9v at the charge pin. I use the resulting enable signal to close a relay that connects the panels to the MPPT (and more importantly disconnects them in the event of a overcharge situation) The panels will provide well over 9v even in very low light conditions (i.e: dawn), long before they produce enough current to charge the battery. I would like to somehow keep the panel voltage output low until the panels can produce enough current to effectively charge the cells. I think about a Zener diode and perhaps a resistor. The BMS apparently draws very little current when detecting charge power being available. In short I'd like to prevent the current draw of the 30 amp automotive type relay until the panels are ready to charge.