Recently I made the change from lead acid cells to LifePo4. I rushed in and as a result made some mistakes from lack of research. I bought 8 12v LifePo4 batteries with the ideal of putting 4 in series with 2 parallel strings. This arrangement gave me 350 amps @ 48 volts, which is a little more than half the capacity than I had before. After reading about how critical that the cells were in need of having a balanced charge, I decided that since all the BMS's could not communicate with each other I would need to balance the voltage between batteries. Enter Victron's Battery Balancer. These are a real life saver and get the job done. The Balancers come with an alarm relay which close when the voltage difference between 12v batteries get to a critical level. Victron leaves the option of what to do with the relay contacts up to the customer. After giving a bit of thought, I decided to connect my 3 balancers up to the 3 individual channels of the digital inputs of my Venus GX. I also connected the remote switch of my BlueSolar MPPT 150/85's up to the Venus GX alarm relay contacts (NC). While this works, I found that the Balancers were going into alarm very often. I decided to install the Venus OS Large firmware, and have a play with Node Red to see if I could smooth out the alarm cycling. I was able to do this to some extent, but still it is not the perfect solution by any measure. Last night I had the thought that if Victron could get the Balancer to interact with the charge cycle, it would be able to limit the charge voltage to a level that would keep the voltage difference between batteries to an acceptable level. This might make the batteries take longer to charge but it would give them a smother charge cycle. What do you think?
