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I'm new and I have problems with an active capacitor balancer

pat_k

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Jan 1, 2022
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Hi all, I am Pat, new guy. Quick background: BSME from U of Arizona. Mostly have a handle on the electronics stuff, but I ain't exactly Will Prowse.
This is not exactly a solar question, but I figure someone here will know.
I built three LTO packs, with some sort of knockoff Yingling 40 Ah 2.3V LTO cells (Hedway type?). Actually, it is 16S3P, which is why I built 3 packs; these batteries are pretty big. I put them I'm our golf cart, which is a 36V
Anyway, I got 3 active capacitor balancers, Heltecs, for 16S batteries. I installed the first Heltec balancer, works great. Balances those cells to within 10mV after a day.I put the second one in, and it fried. Same with the third one (I may have jumped the gun putting the third one in where the second one was. I believe that is the classic definition of foolishness).

Anyone got any ideas why it fried? Maybe I just got lucky with the first balancer? Maybe the balancers need some sort of attention prior to install. I took the second of the 3P's apart, rewired everything, and will try this again. But, this trial and error thing does get expensive.
 

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BTW, new wiring is getting new leads with a T so I can plug in the BMS to the same wires as the active balancer.
 
I read your post and I don't have anything to add regarding why the balancer failed. I wanted to suggest you maybe try a JK BMS Brand Bluetooth active balancer. The 1A and 2A versions are available on ebay and Aliexpress. The company makes a 5A and even a 10A version of their active balancer (at least they did in the past, I have one of each 5A & 10A) You most likely only need the 2A version. According to the published specifications, the Bluetooth balancer will accept 1V to 5V cells so LTO should be no problem.
 
Some of the different capacitor boards have different wiring and turning on and off procedures . I have one that will fry when disconnecting the cells , if you don't turn it off first.
 
Hi all, I am Pat, new guy. Quick background: BSME from U of Arizona. Mostly have a handle on the electronics stuff, but I ain't exactly Will Prowse.
This is not exactly a solar question, but I figure someone here will know.
I built three LTO packs, with some sort of knockoff Yingling 40 Ah 2.3V LTO cells (Hedway type?). Actually, it is 16S3P, which is why I built 3 packs; these batteries are pretty big. I put them I'm our golf cart, which is a 36V
Anyway, I got 3 active capacitor balancers, Heltecs, for 16S batteries. I installed the first Heltec balancer, works great. Balances those cells to within 10mV after a day.I put the second one in, and it fried. Same with the third one (I may have jumped the gun putting the third one in where the second one was. I believe that is the classic definition of foolishness).

Anyone got any ideas why it fried? Maybe I just got lucky with the first balancer? Maybe the balancers need some sort of attention prior to install. I took the second of the 3P's apart, rewired everything, and will try this again. But, this trial and error thing does get expensive.
Hey Pat - Welcome to the forum.

I assume you are using the Heltec capacitive active balancer. Looks like it in the photo. I know wiring it wrong (i.e. not getting the right lead to the right cell) will fry the board. Other than wiring it wrong, there's not much to make it go wrong immediately.

I also had one fail after using it for several months. It didn't fail in a good way either, as it got very hot and took one of my cells completely out of balance, way lower than the others. It also was generating a ton of EM static, as it was making it nearly impossible for my phone to connect via Bluetooth to the BMS. I decided to connect a toggle switch to it on the "Run" terminals to turn it ON and OFF. That way I can have it going only when I'm around to keep an eye on it.

I've had four of these (2 8S and 2 4S) and I've only seen that one fail. That's still not a good percentage, so it may be these are just not that good in terms of quality. I've no experience with the JK BMS that @BentleyJ mentioned, but there are lots of people here that seem to be going that way.
 
Hey Pat - Welcome to the forum.

I assume you are using the Heltec capacitive active balancer. Looks like it in the photo. I know wiring it wrong (i.e. not getting the right lead to the right cell) will fry the board. Other than wiring it wrong, there's not much to make it go wrong immediately.

I also had one fail after using it for several months. It didn't fail in a good way either, as it got very hot and took one of my cells completely out of balance, way lower than the others. It also was generating a ton of EM static, as it was making it nearly impossible for my phone to connect via Bluetooth to the BMS. I decided to connect a toggle switch to it on the "Run" terminals to turn it ON and OFF. That way I can have it going only when I'm around to keep an eye on it.

I've had four of these (2 8S and 2 4S) and I've only seen that one fail. That's still not a good percentage, so it may be these are just not that good in terms of quality. I've no experience with the JK BMS that @BentleyJ mentioned, but there are lots of people here that seem to be going that way.
The Heltec you need to be very careful with the exposed board on the back also. Those things should have a case. If the back gets touched by metal the whole thing will fry. Don't ask me how I know.
 
The components of any bare PCB could short out when touching any kind of conductor unless it had a good conformal coating. Most PCB's have mounting holes that can accept either nylon standoffs or Brass standoffs so they can be affixed properly inside the battery enclosure.
 
The components of any bare PCB could short out when touching any kind of conductor unless it had a good conformal coating. Most PCB's have mounting holes that can accept either nylon standoffs or Brass standoffs so they can be affixed properly inside the battery enclosure.
Yes. that is clearly the way to go.
 
And, I had put that pad electricians use to bug wires on the back. But two out of three failed. That's pretty bad. I got two replacements; not Heltec, but identical. I have to unsolder and resolder the jumper for LTO. And, I have 3 BMS coming also, on a slow boat from China.
 
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