Hi, this is my first post, as I just found this company as a reseller of REC BMS.
I'm building a new battery system for my double-split-phase Sunny Island backup power system.
The battery will consist of 24 blocks in series, where each block consists of 18 LTO pouch cells having a capacity of 55 AHr per pouch (nominal). So to the BMS this looks like 24 series cells @ 2.2V nominal per cell and about 1,000 AHr capacity.
Most of the REC BMS models seem to have a limit of 16 cells max, being designed for higher-voltage lithium chemistries.
What would be the appropriate model, or master-slave combination of models, to work for this battery?
[I'm not sure I'll make use of the balancing resistors, because at 2.2 VPC the balancing current would be pretty low for a 1000-AHr pack. Instead I'm considering a separate active balancer, such as the Neey 24S15EB (up to 15 amps balancing current).]
As far as precharge control, I've already designed and built a precharge system that uses DC vacuum contactors, a main and a pre-charge with a power resistor, for each SI inverter (each inverter also has its own 250A DC breaker in series with the contactors). This system accepts a relay closure signal to turn on all four inverters, which can also turn them off when there is an out-of-spec condition at the battery. Then there is a separate contactor with relay closure input signal that can interrupt the current from the DC charge controller when necessary. So this means I'd like a pair of hardware signals from the BMS that represent "overcharged" and "overdischarged" error conditions.
Finally, what are the options for controlling and monitoring the BMS? I see there is a WiFi option, but is there an Ethernet option? I could use either, but prefer wired networking.
