While warpspeed is no longer posting here, he kindly shared the design of this balancer with me. And it's a real clever bit of work, too much electromagnetic trickery going on for me to fully understand.
But it works! Today I finally got everything ready to test it on my old 16 cell Winston battery bank (200Ah cells). Half of the cells are 10 years old and the other half 5 years old. I could never completely balance these using my Deligreen balancers when that bank was still in use.
Its been sitting around for a year or so, getting charged occasionally. I estimate there is 50% capacity left in these cells, so an extra 5KW of battery bank would be welcome to add to my 2 x 10KW banks.
You might ask by now what Warpspeed's balancer looks like, well, like something that came from the deep blue and crawled on top of my battery bank
See for yourself:
How does it perform? Very well so far at this early testing stage.
For the test there is no load connected to the bank nor any charger, it's just the battery bank powering the balancer.
Initial reading was a max cell voltage difference of 310mV.
After one hour that dropped to 160mV
After two hours it was 110mV
3 hours later it was 100mV
5 hours later it weas 70mV
It's now balancing overnight, I'm curious when it gets to perfect balance of 3.37V/cell.
After that it's going on the charger to see how that goes.
The balancer's electronics consumed 33mA at the 5 hour test, this was a little higher at start up.
The balancer is deadly quiet and nothing got warm even on this 36 degree day here in Perth.
I'm happy with it so far, it's not a cheap solution, probably similar cost than a 16 cell Deligreen balancer due to the many parts required. But it was a very interesting project, I'm grateful for warpspeed's help during the building time.
Anybody interested in more details let me know, there are a few tricks involved setting it up. Messing about on top of 200ah cells can be 'exiting' if something goes wrong.