A lab bench power supply? I read they are pretty easy to DIY with boost/buck converters… I’m trying to do this with solar…
I use a boost converter for adjustable voltage/amperage that I plan on connecting to a large battery bank charged by a 100W solar panel. Basically with enough energy from recycled batteries to charge my board + some, wired to a solar panel that will stay outside, maybe a display so I don’t have to probe when changing volts/amps, and some nice little dials instead of pots on the boost converter PCB in a 3D printed box.
Yeah thanks for sharing that info. Casually drops in sailing round the bahamas for 8 months while we are all slogging it out working in our various countries.
I’m living 8 months a year in snow and cold weather. Don’t need a solar panel to keep my beers cold. Hah yeah that’s right! Living the dream right here!!!
I bought the big version of these, with 2A balance current and bluetooth control/monitoring. I have some thoughts.
We’re normally top balancing (balancing cells when charging, when they are full).
I believe the balance function on these is always on, looking for deltas and kicking in the balancer. Balancing when the cells are not close to full is probably a waste of energy and cycle life. The effect might be negligible though. I’m thinking if you discharge down to cutoff, the cell voltages will probably have big differences, which we don’t care about unless one of the cells is below the healthy cutoff voltage.
Also, the balancing current is hardwired at 1A, until it reaches the voltage threshold, then stop, right? This is not cc/cv. Just cv. There’s a bunch of subtle behaviors here, but maybe no worse than the typical balancing via discharge. If you just do cv to 4.2v, when you remove charge voltage, the cell voltage will drop a bit. If you’re not doing the CC part of the charge the same way for every cell, SOC for each cell may differ. Etc.
The bluetooth one has a global on/off via app, but it’s a lot more money and relatively huge.
If the unit could be turned on or off on demand, to deal with passive drain and to only balance when you tell it to, perhaps every 10 charges, I think it might be good.
Also bring the balance pins out to a connector and connecting on demand seems workable.
BTW the bluetooth one discharges from the highest cell into a supercapacitor, then charges the lowest cell. You’d think 1A or 2A would be way way faster, but I since it can only do one thing on one cell at a time it may not be dramatically faster.
I was thinking a way to balance a 12s8p every 6 months or so…BMS only charge, so it will stop when the highest cell voltage of one cell it is higher than the other, therefore it will be unbalance in the near future, and will aggravate through time.
I you guys have a simple or better way to deal with this, please share.
I do not know if this is in the right topic. (hope so)
Yeah that’s the one I was talking about above. It’ll do what you want (balance the pack every 6 months or so). The app is nice, gives very good feedback as to what’s happening.
I personally wouldn’t use this active balancer for day-to-day maintenance of a pack unless it was maybe a hundred Ah. It’s just not warranted once everything is all matched up the first time, a normal BMS with bleed resistors can keep on top of things from there.
As such, I wouldn’t install this in a board. I’d use it once to get everything happy, then use a regular BMS (With more protection features and less quiescent current) for actual use.
This kind of balancer would probably be fantastic for homemade powerwalls and the like, where unmatched (salvaged) cells can cause significant drift over time and the capacity is large enough to make passive balancing impractical.
For most of the night the bottom 4 were lit. Now it just has 4-5 lit. I’ve tried removing the plug and reconnecting to see if resetting it will help. No luck.
The only thing odd I noticed was a spark at the connector when I connected it. It wasn’t large and I just assumed it was from connecting 50v with no antispark.
If it’s not a faulty board then all I can think is maybe some bad pins on the connector