Horsefly
Solar Wizard
My QNBBM 8S active balancer arrived yesterday and I hooked it up. In my 8S pack of the little Navitas 25Ah cells, I have one that refuses to stay balanced with the others, so I was anxious to see how well the active balancer works. This pack is just for me to educate myself until I get around to buying larger cells, so although I would have hoped to have 8 good cells, I'm actually kind of glad I've got one misbehaving cell so that I can test the balancer. The Overkill BMS with passive balancing was not up to the task.
So far I'm pleased with the QNBBM. When I hooked it up the bad cell was about 170mV below the others. I did a brief discharge and then a charge (each about an hour), then left the pack alone with no charging or discharging. This morning the difference was only about 15mV.
Of course, there's no documentation for the balancer, and what I've found on-line seems to mostly be explanations of what it does for the purposes of selling more of them. If anyone has found some useful documentation, I'd love to get a link.
One thing that is a bit strange. There is a constant high-pitched tone coming from the board. It isn't really loud and so doesn't cause a problem, but I can't figure out what is causing it. At first I thought the sound might be only when it is performing energy transfers to make the pack balanced, but this morning they were well balanced, and it was still making the sound. Anyone else notice this? Any idea what the sound is from or what it means?
So far I'm pleased with the QNBBM. When I hooked it up the bad cell was about 170mV below the others. I did a brief discharge and then a charge (each about an hour), then left the pack alone with no charging or discharging. This morning the difference was only about 15mV.
Of course, there's no documentation for the balancer, and what I've found on-line seems to mostly be explanations of what it does for the purposes of selling more of them. If anyone has found some useful documentation, I'd love to get a link.
One thing that is a bit strange. There is a constant high-pitched tone coming from the board. It isn't really loud and so doesn't cause a problem, but I can't figure out what is causing it. At first I thought the sound might be only when it is performing energy transfers to make the pack balanced, but this morning they were well balanced, and it was still making the sound. Anyone else notice this? Any idea what the sound is from or what it means?