Charger stolen

[Andy-Mat]

I'm only trying to help you.

Transistors are electronic switches. Two legs are like the in and out connections. When you apply a voltage to the third leg, it switches on. In the case of the balancing in that animation, the electonics detects that a cell has reached 4.25v, so it sends a voltage to the transistor on that channel. One side of the transistor is connected to ground and the other side is connected to a load (bleed) resistor. The other side of the resistor is connected to the top of the cell. That means that when the transistor is switched on, there's a path from the top of the cell through the resistor to ground.

The value of the resistor is normally around 100 ohms and it controls the rate at which charge bleeds to ground. Ohms law says thar the current will be 4.25/100, which is 45 miliamps. That's not very much. It would take 200 hours to drain a 9Ah cell group, which is why doing say one full charge in five isn't enough to balance your battery.

Here is a fairly standard charge equaliser, it costs around 10 US$ per unit.
https://www.alibaba.com/product-detail/10S-18650-36V-48V-25A-Lithium_60839874905.html?spm=a2700.7724857.normalList.2.4acd4ffaOgctVl&s=p
You might even like this one better, it goes for around 18US$:-
https://www.alibaba.com/product-detail/16pcs-Universal-48v-Battery-Equalizer-Products_60764438912.html?spm=a2700.7724857.normalList.7.4acd4ffaOgctVl&s=p
None of the ones I have found online are nearly 400 UK Pounds......
But what you wrote is really not what happens with all the chargers I have seen.....
What do you think happens when the charger does NOT exceed the correct full charge voltage of 4.2 volts per cell?
According to what you say, it won't work, or do you now have a better idea.....?
You are apparently fixated on 4.25 volts per cell for some reason....
The web site I posted for you, you either haven't read it fully, or it went over your head.....
I thought that it was fairly simple and clear to understand!
I myself have been active in electronics since 1955!!!
Started with valves and very early transistors and RC control of aircraft and model boats! Went onto the RN and later 5 different major US computer companies.
You are going to struggle to show me how something works when you cannot even grasp the correct terminology!!
Especially as that web link did it so well, covering all eventualities.
This is your third attempt, I believe!!
Nothing you have posted works as you think it does either!
How sad.....
Andy

 

[vfr400]

4.25v is what is in the animation. I was only using that to explain to you how the bleed resistors open. In our ebike batteries, they open at around 4.2v.

Yes, you're correct in your understanding that if the charger doesn’t reach 42v, it won't balance the cells properly. If it's much lower, no balancing will happen at all. That's why you shouldn't charge to 80%

Have you tried any of those balance things you showed in the links above? It looks to me like a normal cheapo top balancing one to me, like you find in some ebike batteries. It doesn’t say anywhere that it does active balancing because it doesn’t have it. If it did, we'd all be using active balancing and charging to 80%.

If nothing I say works, do you think I should give up my job fixing ebikes and batteries?

 

[Andy-Mat]

4.25v is what is in the animation. I was only using that to explain to you how the bleed resistors open. In our ebike batteries, they open at around 4.2v.

Yes, you're correct in your understanding that if the charger doesn’t reach 42v, it won't balance the cells properly. If it's much lower, no balancing will happen at all. That's why you shouldn't charge to 80%

Have you tried any of those balance things you showed in the links above? It looks to me like a normal cheapo top balancing one to me, like you find in some ebike batteries. It doesn’t say anywhere that it does active balancing because it doesn’t have it. If it did, we'd all be using active balancing and charging to 80%.

If nothing I say works, do you think I should give up my job fixing ebikes and batteries?

Yours is the misunderstanding, I simply asked how it would work at only up to 4.2 volts per cell. You cannot answer, even though I had given you the answer in the links where it was fully and correctly explained both for charging and discharging!!
And of course the balancing works for both charging and discharging. That you did not read, so you did not know!!
You would not understand that these units Balance Units manage to balance cells correctly, and they are cheap in relation to your 400 UK Pounds version.
The action of balancing needs some good code, but when sold in vast numbers, it works out really cheap!! They sell them in 1000s of units..Did you not notice?
Your work has obviously very little to do with true ability, and what you have shown us all here, would convince me not to seek your help in any way, shape or form....
For example, in my life I have met (sadly!) electricians who lacked even the most basic of electrical knowledge, who are actually dangerous to themselves and their customers. I recently won an argument in front of his mates with one who was of the opinion that an RCD needed an earth connection, which of course it doesn't! That was bitter!!
Plumbers that were both expensive and slow, which is why in my whole central heating system, they only got to connect the gas, required here for insurance reasons, the rest I did and it is still working as I designed it, 33 years later!!
None of these trades are difficult if you apply yourself and learn how, making sure that the how is fully understood!
Andy

 

[vfr400]

In case you didn't notice, the second link above, which I think you're referring to in your last post is a 1S active balancer. They cost $15 if you buy 300 of them. You need ten of them for a single battery, so that would cost $150, plus you still need a BMS to handle protection. Now look at all the wiring. How much do you think that would add to the cost of manufacture compared with a plug-in BMS? That's all the cost in China. If you buy in China 300 batteries with normal top balancing BMSs, you can get them for $150, so that active system will double the price of the battery, or you could have two batteries without it for the same price.

All I ask is that you show me a single ebike battery in a bike than any forum members have that has active balancing. I have about 40 ebike batteries in front of me right now. Nearly every one has a different BMS. All are normal top balancing and none have active balancing.