Still looking for a simple way of balancing , not using a bms ( low input 0.5A)
My lipo charger does better at 1.2A
But I still need to do balancing again the next day something to achieve a perfect numbers …
But I came across this :
What do you think ?
The only problem is that you need to plug it and leave it a bit …
Interesting product. Looks great.
You need to balance that much??
Very nice product. Does it mean that for a 14s12p battery, you need to be able to disconnect your 12 parallel lines from one another before each charge ? That would require some battery design methods we’re not familiar with.
Price: from 6x 23.04 = 13 x 19.84 = 138usd for twice a two-hour charge
to 12 x 23.04 = 276usd for a single two-hour charge
Well last year I was pulling hard on a 12s8p 30q , I noticed after fast charge and balancing , the next day it was a little off
1,5A is not that much for a 12 or 14P : 0,1A/ cell can take sometimes
No just need one
Plug in the pack and it discharged the highest voltage row to the lowest …
Some lipo charger do that but at very low amp , it took me all night for a small 5A lipo
I think we don’t need to balance charge every time , fast charge can be use and every 5-10 time a very fine balancing and check IR
Onewheel does these ( a least the first one ) , fine balancing that take a day or two
Get rid of the BMS is my vote!
No BMS. Use a hobby charger to balance charge every time you recharge. Voltage alarm during use. That’s my system. Works good.
When I recharge the amp hours each cell group takes to charge are always within 0.1-0.2Ah of each other. 14s14p 30Qs. That’s pretty good for 42 amp hour groups to be within 0.2Ah.
Monitoring voltage is important for safety so you never go below 2.5v or above 4.2v. But, voltage is not a very accurate way to tell the battery state of charge. Which is what matters when you’re talking about balancing. Amp hours is much more accurate. With big cell groups (42Ah) the balance wire voltages readings will often be off by 0.02v-0.1v. but, when I cycle the battery and record the amp hours they are always spot on (within 0.2ah) which is only 00.47% out of balance. (0.2÷42=0.0047×100=00.47%)
Less then half a percent out of balance is pretty good. As long as I’m within 2-3% amp hour balance I’m happy. If a cell group is ever more then 5% off on amp hours I know I have a problem. Bad cell, or broken cell level fuse wire.
On lipo charger I use a lot IR of the cell
4.2-2.5v … I would say more like 4.1-3.2v
I will do a review soon on 30q , I use them also them on my e-cigarette , at least one charge and discharge / day on several cells from more then 1 year
I already notice a really big difference between old cells ( 350-400 cycles) and new one which tell me to go for 40T next battery
years ago I always was balancing my 18s lipo pack from my ebike, trying to get all cells at 4,15 or so. But I agree with Flightjunkie, don’t stare to much at a little difference in end voltage.
A normal ebike pack with 48v 13s that a customer is using for years with a bms is also one cell 4,18 and the other 4,20. It will charge and balance but after sitting for a few hours there is always some difference, normally you just don’t know it because nobody can measure.
But the balancer can be handy for building new packs, replace some cells, or after bulkcharging for many times.
40T is larger cell type I believe. That would be a challenge. I think I’ll stick with 18650 cells for now.
The Samsung 40T is not rated to have more cycles then the 30Q. They are both said to be around 250 cycle life. But, many users report 400-500 cycles.
All of these high current cells have relatively short cycle life. It’s not untill you get to the cell types that Tesla uses that you see +3,000 cycle life. But, my understanding is those cells are rated for less then 2A max draw per cell. They just use lots of cells in parallel in their cars and power walls…
Everything is a trade off.