Packs in parallel can connect the balance leads "across" so one balancer handles them all at once. If the only connection is at the pack-level voltage main power leads then you get unbalanced current flows causing uneven wear shorter lifespan. But **cells** paralleled at the 1S level, then...
I have never claimed that isolating the cells from a floating charge source is required for any reason to do with safety nor "damage" in the usual sense. My point is simply that LI charge cycles should be terminated at or before the specified endAmps / desired trailing current is reached w...
Battery Medics… ALL the passive dischargers/balancers listed above ARE rebadged BM's. That's very interesting and valuable insight if true. But I posted lots of powered units, and came across hundreds of others googling just in case some readers do not realise the distinction. So long as the "...
this PSU=charger nonsense should be condemned everywhere it's reposted I agree > A PSU does not have the safeties a charger has I agree. > using one to directly charge a pack is inherently unsafe I disagree, **if** the charging is always attended by a knowledgeable and attentive "compos mentis...
My statements here apply to the general principles, not a specific type of gear or any particular usage. The vendor data sheets for batteries create "cultural norms" for specific industries, that then get slavishly followed by the designers of charge source regulation circuits. That does n...
The most straightforward cheapest backbone for short distances of DC transmission is 12V that should always be your default starting point. Are your DC loads spread out over a large area? If you were buying a small inverter, cheap as you can get away with for each AC device, all spread around a big ...
Note that 4.15V or even 4.05V can still get to the same definition of 100% Full as using a 4.2V or even 4.35V charge setpoint. Not of course if you are using a Bulk / CC-only "charge to X and stop" profile, which works just fine and in fact is what I recommend for normal daily-usage cyclin...
So if your system is 24V, and the batteries are currently 20Ah each at 12V which are tiny capacity take the above as questions, the most basic information you should know before thinking about making changes! Then you will be putting eight LFP chemistry cells in to get to 24V, best to get the larges...
BMSs are usually designed to maintain balance, but you need to be able monitor their work, cell/group level voltages keep the delta from getting so great that it takes days of float charging to give them time to finish. A full volt shows extreme neglect, usually 30-60mV requires a rebalance session....
Fancy version with bulb protection https://www.rcgroups.com/forums/showthread.php?1901849-Best-yet-Auto-Disconnector-for-LiPo-Storage-Discharge/page20#post29745666 This will be more accurate, general coulometer and voltage monitor http://www.isdt.co/bg-8s.html _______ Fancier tester, charger + dummy...
Yes many think that once a pack is "balanced" that means the differences in voltage go away at all SoC% points Or even worse that it is possible to balance at more than one SoC% point. I mean it "is possible", but counterproductive; balancing say at 3.65V "undoes" your ...
Your controller/ESC will ask the battery for whatever the controller is rated for. If your controller/ESC is 48V 20A the controller will try to pull 20A no matter what your battery is, depending on your throttle position No, it is the throttle + **motor** that pulls current. The function of the con...
Proper balancing only pertains to the chosen balancing point. That's why I used "unevenness" for away from the chosen balancing point. Imbalance at any other point is not actionable or even meaningful data, the cells are **supposed** to be uneven there. Only midpoint balancing minimises th...
If you connect a cell @ 4.2V to a charger (voltage source) @ 4.2V, no current flows. It's exactly like connecting a cell @ 4.2V to another cell (voltage source) @ 4.2V, no current flows. By definition, when no current flows, NOTHING IS HAPPENING. This is sort of pedantic. Two equal cells in paralle...
What we call "a BMS" is really just a collection of functionalities certainly just a subset of what would be needed for fully automated protection usually several key factors are just ignored. Especially true for a BMS costing under $100, compared to one costing $5000, the latter will offe...
The spot in the SoC% curve where you choose to balance the cells, is the only spot where they will match precisely. The manufacturer usually IME delivers them balanced at the midpoint, close to the (rounded) nameplate nominal voltage. In that case (IMO ideally left that way) there will be imbalances...
Someone with experience with these specific models may (hopefully) come along and contradict me. You are supposed to buy a big enough ampacity so that in normal operation including unreasonably continuous WOT going up a hill with a heavy load and a headwind your controller will not ask for more than...