I have two sets/strings of two 12V batteries wired in series for 24V, and those two sets/strings are then wired in parallel to increase capacity. I would like to monitor the voltage of each individual 12V battery. Can I install/connect a Smart Battery Sense to each individual battery or not?
The very limited online manual for the product simply states “For banks of batteries Smart Battery Sense may be connected to any one of the individual batteries.” However, the more detailed physical manual that came with the Smart Battery Sense suggests that for parallel-wired batteries you can connect to any individual battery, but for series-wired batteries (strings) you’re to connect to the string “(positive of the first battery and negative of the last battery)” and not the individual batteries… Hence my confusion.
Better to use a smart shunt and to connect the AUX Voltage input to the mid point. Then you can read total Voltage and mid point voltage, as well as getting current and soc values.
You should be using a balancer. These ones have a display. If you want remote access with Bluetooth then a smart battery sense on ea is fine. You could look at running 2P2S instead of 2S2P so you only have to monitor 2x 12V banks.
I wired up the first string of two 12V LFP batteries to create a 24V “single battery”. I independently charged both batteries prior to connecting in series to try to ensure they’re balanced. And then I wired three of the VE SBS (Smart Battery Sense) devices to this “single battery” - one for each 12V battery and then one for the string. So far it’s working exactly as I had hoped; I can monitor the voltage and temperature of the individual batteries as well as the string as a whole.
I like that the SBS devices are very small as this application has significant space constraints, and I like that I can access the data wirelessly via Bluetooth on my phone. It would’ve been nice if the batterys’ BMS had built-in wireless monitoring via bluetooth and smartphone app, and then I would’ve only needed a single SBS for the string, but this is a small (<10Ah) battery size application and I can’t find any batteries at that capacity with built-in wireless monitoring.
Just got another three of the SBS devices in for the second string, so gonna get that wired up, and then see how well it works once both strings are connected together in parallel. Might then look into a smart shunt for between the 2S2P bank and the load, depending on if there’s space.