How to balance a highly unbalanced Lipo

[Mechdude]

Hi all. In my first foray into ebikes I have bought 6x 6S 5000Mah nanotech batteries. However things have not gone to plan, including exploding batteries (Long story).
However I now find myself with several batteries which are significantly unbalanced.
The battery in front of me has voltages:
3.736
3.727
3.742
4.128
4.166
4.186
(This is indicative of about 4 of the batteries)
The charger I have is a Turnigy Accucel-8 150.
If I use the balance mode, it pushes all the cells up rather than balancing, and I find myself exceeding the 4.2 limit.
After a short charge the other nite, I came back to find #6 cell at 4.32 and cells 1,2,3 only just on 4.0. (Quickly turned it off!)
Have also tried the discharge mode and a similar thing happens in that it drains all the cell down, still unbalanced, and the first time I tried discharging it dragged one cell down to 2.8 until the cell dropped out on error. Grrh. Unfortunately the charger does not have the ability to change upper charge limit (4.20) or lower discharge limits (3.0).
Growing to dislike Lipo's!!
I read somewhere about balancing cells on a cell by cell basis, however I can't figure that one out with the charger I have. The lowest charging level it will let me select is 2S which I assume is too high for a single cell.
I find it incredible that Hobbyking sell items that are so sensitive to incorrect use with no instructions.
I can only assume that this unbalance has come from over draining (I bought the cell meters after the fact)
The batteries have probably only seem 3 or 4 cycles.
But I am also hopping that if I can re-balance them that I can get them back to a working state.
Appreciate your assistance, cause I want to get out riding!!
Howard

 

[itchynackers]

You need to make a single cell charger. Using the main red/black leads from the charger, make an extension that connects to it. On the other end will be a jst-xh connector with all but 2 pins pulled out. This way, you can charge/discharge 1s into any cell that is off.

Edit: Also, to be safer, use the LiIo setting, not the Lipo setting on the charger. This will only charge the cells to 4.1V/cell.

 

[izeman]

correct. you will need a charging adapter with goes into the charger on one side, and has two pins adjacent to each other. then charge one single cell after the other with not more than 1-1.5A through the balance plug, until it reaches the voltage of the "good" cells. do this for all low cells, and you're done.
you could also buy a battery medic which (if you have some days time) will lower all high cells to a predefined level.
eg. http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=10328
i don't know your charger, but setting cell count is only necessary if you charge multiple cells. you obviously don't need to set cell count if you only charge a single cell at least this is how my icharger handles that.

 

[neptronix]

You have a super crappy charger. No balancing charger would allow that situation to happen. I can't believe they designed the charger that way, it seems to act more like a battery disbalancer.

Perhaps it's been part of your troubles, and you should insert it into the garbage can and get something like an iCharger or Hyperion.

 

[izeman]

+1 for the icharger
but as is said: you should be able to charge single cells through the balance tab.
one silly question: did you really chose "balance charge"? or did you use "charge". this of course would explain the problem you see.

edit: "After a short charge the other nite" = BIG failure. NEVER leave your charger and battery unattended while charging. especially NOT now that you know there are troubles.

 

[wesnewell]

The HK-010 and it's many clones for under $20 does a much better and faster job of balancing as it uses the higher voltage cells to bring up the lower ones into balance, rather than just bleeding the higher voltage cells down as most chargers do.
http://www.ebay.com/itm/Digital-60V-100A-Balance-Voltage-Power-Analyzer-Watt-Meter-Balancer-RC-Charger-/170844773177

 

[TheBeastie]

Hi all. In my first foray into ebikes I have bought 6x 6S 5000Mah nanotech batteries. However things have not gone to plan, including exploding batteries (Long story).
However I now find myself with several batteries which are significantly unbalanced.
The battery in front of me has voltages:
3.736
3.727
3.742
4.128
4.166
4.186
Howard

Get a bc168 balance charger, it charges at 8amps into each individual cell,
more info here http://endless-sphere.com/forums/viewtopic.php?f=31&t=41107
http://endless-sphere.com/forums/viewtopic.php?f=31&t=41107&start=15#p601267
I got a 1000w power supply with the expectaton I would want a faster bulk charger but it hasn't happened yet.
You can get them for $70 on eBay or some people prefer dx.com.
http://www.ebay.com/sch/i.html?_odkw=BC168&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313&_nkw=BC168+charger&_sacat=0
Only rule of thumb to remember with parallel balance charging is you can't charge them if there connected in serial, no big deal really I just unplug the serial cable so the battery is essentially split in two halfs while charging.

 

[neptronix]

Actually the balance wires are meant for about 2-3 amps, tops. 8A is too much. That bc168 is a bad idea.

You can get a Hyperion 14S 550W charger for not much more ( ~$130 USD shipped ), and it won't make a bunch of waste heat and low efficiency when charging.

If you are running 14S or under, then this is perfect because you can bulk charge without connecting the thin & flimsy balance taps every time.

 

[izeman]

The HK-010 and it's many clones for under $20 does a much better and faster job of balancing as it uses the higher voltage cells to bring up the lower ones into balance, rather than just bleeding the higher voltage cells down as most chargers do.
http://www.ebay.com/itm/Digital-60V-100A-Balance-Voltage-Power-Analyzer-Watt-Meter-Balancer-RC-Charger-/170844773177

do you know the balancing current between cells? i found the manual but it says nothing about it.
is it in the 1-2a range? or is it another super low super slow mA balancer?

 

[wesnewell]

Don't know the current, but it's a lot faster than my Hyperion 1420i which only bleeds the higher cells down without charging the lower cells at the same time.

 

[izeman]

now i'm confused
so how does it work? it's a balancer only with no external power supply needed.
edit: i'm missing a post just before my one. it said something like it's not transfering from higher to lower cells.

 

[wesnewell]

Watch this.
http://www.youtube.com/watch?v=-6mvm3osjPw

 

[Mechdude]

Wow, thanks for all the advise. What a great forum!
Yep, I had pretty much come to the point of ordering a new charger.
Hadn't looked at the Hyperion one though.
The idea of having a combined charger power supply is attractive to me, so I was considering this:
http://www.leaderhobby.com/product.asp?ID=9394001226905

But I'm now thinking that quality is more important that convenience.

I was also looking at the Thunder 1220 http://www.hobbypartz.com/75p-1220-charger.html due to it's ability to bulk charge my complete 12S 3P without breaking it down.

Would the Hyperion 14S be the better path?

Anyway enough questions. Thought I's post some pics:

 

[wesnewell]

If I didn't already have the Hyperion 1420i I'd get the Thunder 1220.

 

[briangv99]

Actually the balance wires are meant for about 2-3 amps, tops. 8A is too much. That bc168 is a bad idea.

Bear in mind the current is adjustable from 0.1A to 8.0A. Side by side between the BC168 and the Hyperion 1420, the BC168 will restore and out of balance pack into balance in a fraction of the time the Hyperion will. They can be had for ~$80 on Ebay

 

[izeman]

I was also looking at the Thunder 1220 http://www.hobbypartz.com/75p-1220-charger.html due to it's ability to bulk charge my complete 12S 3P without breaking it down.

the 1220 surely is a nice charger which should be able to do all you need. especially not having to seperate the pack is a big plus. just take care to buy a big enough power supply to unleish the power of the charger. for charging you will need 300w+. those chinese ps are not known for delivering high amps @ low voltage output. the 1220 takes 15v max, so you better take a 500w ps. better take one with 2 power outlets - you may be suprised how often you will need them.#

edit: if you order all a one shop: http://www.hobbypartz.com/77p-g350-powersupply.html that one surely is not bad, but on the lowest end. at least you can reduce charging current in case you connect 2 chargers. for the price you can even take two ps

 

[icecube57]

Why are you against the BC 168 Nept. I had it in my hands and it aided in lipo recovery and balancing pack from HK that had a horrible misbalance. This charger ran circles around my Icharger when it came to balancing imbalanced packs.My icharge i would have to pull up the cells individually. The bc168 does this without having to create a special harnes or use pins and alligator clips. Its a dangerous situation. What is this scare with the balance taps. They barely get warm if you even call it that no where near hot or burning or melting or anything I will charge at 8A all day every day through the balance taps. The only time i wouldnt is when you try to rescue lipo from below 3v which you need obvious caution.. I like the way the charger back offs the charge current takes a reading and continues charging it does this very constantly. This pulsation is one of the reasons why it probably doesnt heat up the balance taps like you think it would. Basic point is It may seem like a bad idea and defies all logic but until you have it in your hands and seen first hand what it can do.... it is only a 200w charger and its only sole purpose is to balance unbalanced packs but when you have spent alot of money on a big boy charger and this cheapy runs circles around it when it comes to balancing its a no brainer. If I had a small pack 2-4 turnigy packs I would use the bc168. If i had a large pack this charger on a 1kw+ pack is like pissing in the wind...

 

[dogman dan]

Back to square one, I have two of the same charger you have and have noticed it's ability to balance to great accuracy does suck. I never saw any cells taken above the no go, now you ruined a cell level, but it will take forever if you have a really unbalanced pack as you do, or did have.

I'm flummoxed that you can't select 1s charging. Both mine will, and both my B6 chargers will allow 1s charging. That's the method I've been preaching for faster balancing when you are dealing with a cell more than .2v or so off. WT heck yours won't do 1s? One solution would be to buy a very cheap charger, such as a B6 for your 1s charging. 50w is plenty, since you'd selcet no more than 2 amps of current anyway.

Connect to the charger at the main wires by making an adapter. The battery end of your wires is just two bare prongs from a male jst plug, usually you can just pull two prongs out of a jst extension wire. If they won't just pull out, heat em a bit and they will slide out easy.

Find the low cell on the jst plug on the battery with a voltmeter or cellog 8, then plug in the two bare jst prongs to single cell charge just that cell.

Another approach you might try, using your current charger. Set the charger to lilo charging, so it will balance them at 4.1v per cell. That way if they go over .1v you are still no higher than 4.2v charged.

I can't recall the exact sequence to change to lilo charging, so if you can't figure it out post another reply here asking for it, and I'll go play with mine and get back to you.

 

[dogman dan]

On slightly different topic, you might just have another pack that should be retired. But hopefully you can get it to balance and stay that way.

If not, stop wasting your time with it, put it in a safe storage place till you can get around to scavenging the remaining good cells from that pack.

Discharge the bad cells to 0v, slow and safe with a light bulb, or fast and fun, your choice. Then they can go in the trash or recycle bin.

 

[izeman]

@icecube: you didn't ask me, but i don't recommend the bc168 either. it may work great, but i does abuse the balance leads. neither the plugs nor the cables are specified for such a high current. of course: if you know the risk you can get that charger. but there is a lot a garbage out there. balance plugs that are very poor quality, balance leads that are thinner than they should be, and then you run 8amps through them - and see you plug melt. not funny.

 

[TheBeastie]

I could easily argue that the 8amps option is only when you charge through a bunch parallel balance leads so if you had more then one pack you would only charge at 4amps to each balance cable.
Also when you first use the bc168 it defaults to 1amp, and again it's very easy to set it to charge as low as 0.1 amps per cell if you want.
Only choosing to talk about this charger at 8amps is like saying a Ferrari is a no good car/shouldn't buy a Ferrari because it too dangerous since it can go 300km/h. I could still very much use and appreciate a Ferrari at more modest speeds.

 

[izeman]

... is like saying a Ferrari is a no good car/shouldn't buy a Ferrari because it too dangerous since it can go 300km/h. I could still very much use and appreciate a Ferrari at more modest speeds.

the comparison is flawed, as the ferrari was built to go 300km/h. balance leads/tabs are NOT built for that current.
see linked pdf. current limit as per design is 3A.
http://www.jst-mfg.com/product/pdf/eng/eXH.pdf

but as you said, and i said as well: if you know what you do, then go for it. but don't blame anyone if your tabs melt

 

[Mechdude]

Thanks Dogman, my mistake. I was assuming that this cell balancing would be done in balance mod, which only offers min 2s. Makes sense that you can't balance a 1S.
Normal charge has 1s option. Will give it a go.
Cheers

 

[chroot]

@nep I have the bcm 168 charger, and they are rocks! I tested it at 5A on single lipo 4s 5000mAh and I felt the jst wires like warm and of course I always keep checking the temperature all the time.

I used the iCharger 3010B fast up to 4.1v then I switch to the bcm 168 balance to 4.17v. I can't live without it and lipo battery balanced within 4mv. Can't complain :-D

 

[TheBeastie]

... is like saying a Ferrari is a no good car/shouldn't buy a Ferrari because it too dangerous since it can go 300km/h. I could still very much use and appreciate a Ferrari at more modest speeds.

the comparison is flawed, as the ferrari was built to go 300km/h. balance leads/tabs are NOT built for that current.
see linked pdf. current limit as per design is 3A.
http://www.jst-mfg.com/product/pdf/eng/eXH.pdf

but as you said, and i said as well: if you know what you do, then go for it. but don't blame anyone if your tabs melt

Flawed? Not really, because i can argue that roads are "built/designed" to go at a max speed of around 100km/60mph yet Ferraris which can drive on these roads can still do over 300km/h, again just because I have something that goes that fast doesn't mean I am going to drive it that fast which is what all of the anti bc168 / "8amps" posts start with, I like it just as much at 1amp which is nice and very useful and handy.