smart BMS - balance charging at partial charges?

deetoau

1 µW
Joined
Dec 8, 2013
Messages
4
hey,
long time lurker, first time posting for a loong time.

Are there BMS systems which enable balance charging at partial charge? Or is this only possible when used in conjunction with a smart charger?

Most of the charging systems I see, have a fixed charge voltage with the battery management system (fitted internally to the battery pack) only balance charging once some of the batteries reach fully charged voltage.

I like the smart charger from lunacycle. Haven't seen similar options from other suppliers. (suggestions welcome)

I'm hoping to configure my bikes (importing a few for family and friends, currently finalising configuration options) for maximum battery cycle life. Other than choosing low wattage chargers and oversizing the battery packs (plus educating riders not to discharge their battery packs fully), I'm not sure what other easy options are worth using.

[have worked through a lot of elimination with suppliers to pick good parts, currently finalising battery construction quality issues.]
 
The Chargery.com BMS can be configured to balance on Charge, Discharge, or both. It is a nice BMS.
-YS
 
You can also get a dumb balancer.

It simply daisy chains all cells, detects the highest cell and lowest cell, and sends power between them. Rinse, repeat, until all cells are balanced. Unfortunately, it will do that regardless of the cell voltage, so if left completely unattended, can kill batteries. Good for packs which are recharged every single day though.
 
Or smart dumb balancers.
Work with any chemistry. 2-5 volts.
Charges all low cells from all high cells. Up to several amps.
Dumb, no setup required. Put one across each cell in any order.
Smart, shuts down at 10mv dif.

Sunder may be correct. Might kill a small pack.
Expensive at $25 per cell. Best for 100ah +.

HTB1LZrdQFXXXXXmapXXq6xXFXXXb.jpg
 
FWIW, lets just say you balanced them at 3.8v for lithium cobalt. This would "balance" them at somewhere between 60-80%. So uhh,, in the middle, you can't balance them by voltage at all. Now way possible to get them within 1%, using 3.8v as your balancing voltage. Only at the very top do you get a true balance, at full, or at the very least, 98% full.

But NOTHING wrong with the idea of not balancing them every charge. Pick a voltage you like for whatever reason, and bulk charge to that. If its not staying balanced, its cuz you are discharging deep enough to drive them out of balance. So reset your charger to bulk charge a bit higher. This assumes you are not beating your pack to dogshit, with too high c rate discharges, or at least spikes too high amps.

Think about it,,, do you need to balance when the pack is balanced? No. So use the thing sensibly, and you will find you only need to balance about 4 times a year. Top balance then.
 
I find the "smart chargers" to be problems. Displays give out, fans quit, and they sometimes overheat. Also found I like having different voltage batteries and have several bikes, Making the Grin Cycle Satiator the cat's meow! I can charge my 12V. 24V, 36v, 48v and 52V. Variable percentages including winter storage 50%, not just 80,90, and 100. ANY percentage and multiple Amp charge rates. Also a better warranty than any charger out there. Best tool I own!
 
Back
Top