All I want is a Balancer!

Batteries, Chargers, and Battery Management Systems.
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All I want is a Balancer!

Post by Kingfish » May 04 2013 12:00pm

I don't give a hang about HVC and LVC; that is well handled by my Charger and by my Controller's programming.

I just want to have active balancing for a difficult to reach battery pack in the Triangle.

One of the guys here linked to a BMS on http://bestekpower.com - but it won't resolve now. The boards displayed had HVC and LVC, though it was the Balance circuit that interested me.

I know we've been round and round on HVC and LVC... though really - I just want a descent passive balancer, or if I can't get passive - then invoke balancing when the pack is not in use. The circuit would have to be embedded, in situ: I don't want to take my pack apart to reach it.

And Keep It Simple. Ideas? KF
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Re: All I want is a Balancer!

Post by friendly1uk » May 04 2013 12:20pm

Won't the $20 smart bms do you?

Yes it has voltage cut off points, but the point is it comes programmed how ever you like. You don't have to use them. However the lvc in your controller is pack level, while the bms is cell level. They are not the same. Likewise the hvc. Letting your controller do this won't help in a bad cell situation.

It's $20 so I don't see you doing a lot better.

I don't know your cell count/configuration/chemistry.
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Re: All I want is a Balancer!

Post by dnmun » May 04 2013 12:34pm

i could not talk him into offering me that D131A balancing board. he said it is part of the D131 BMS and not offered separately. people are bulk charging the lipo so i am trying to get more lipo BMS options out there before we have a bad fire. plus so many ruin good cells because there is no balancing during the charge so they get outa balance and can lead to overcharging of some cells so the pack puffs up. and then thrown away.

but i am thinking 15S or 62.2V so the pack could be used with the regular 36-48V controllers without problems. i just ordered five of the 6S turnigy so i can take them apart, repackage into two sets of 15S by splitting one of the 6S. cut off all the leads, compress each of them into one 15s block with hardboard plates on the ends, add the 15S sense wires for the BMS and then use it as a 15S lipo pack with BMS. no balancing charger, just let the BMS balance them and set the final voltage at 62.2 so it balances to 4.15V/cell.

that's the plan. then parallel that with the 48V ping pack using diodes. 5Ah from lipo, 15Ah from lifepo4. put a switch on the lipo BMS to turn it off when it reaches LVC, and combine them with the diodes on top of the lifepo4.

i am gonna use the D126 but if i could figure out how to make the display stuff work i woulda bot this for $34 instead of $19 for the D126:
http://bestekpower.com/fuelgasgauge/BMS-D141.html

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Re: All I want is a Balancer!

Post by Kingfish » May 04 2013 1:00pm

Bestech is resolving now.

Dennis, you know I have great respect for you :wink:
I am listening actively to your sage advice my friend.

@ friendly1uk, By profile is 15S LiPo as 5Sx3 (63V). I rarely let it drop to 54V because sags can take it to LVC.
The pack in question is my Commuter 15S6P 30Ah; it's two assemblies of 15S3P in Left/Right bags hanging in the Triangle.

I see that they have a Balance Board, and a 15S Protection Board (35A).

There isn't much room in the bag, although there is between the bags. I would like to parallel each bag before handing off to a circuit board.
What do you suggest?

Do you like this manufacturer? How do you purchase these boards? The links do not resolve.

Thanks, KF
* My 2WD Garden Wall
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* Primary ride: 2WD Disc 9C 2806-equiv / Dual Lyen 12FET / 20S7P LiPo.
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Re: All I want is a Balancer!

Post by velias » May 04 2013 2:01pm

Kingfish wrote:I don't give a hang about HVC and LVC; that is well handled by my Charger and by my Controller's programming.
KF
How is LVC for each cell handled by your controllers programming?

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Re: All I want is a Balancer!

Post by dnmun » May 04 2013 3:06pm

i was looking for the little ptc devices to put between parallel cells that would be able to handle the balance currents and some currents associated with difference in the internal resistance of each pouch. but if one pouch goes short, i would like to have a ptc ressettable fuse isolate that pouch off of the sense wire connection so as that pouch goes short internally it does not suck current out of the parallel pouch. i thought of making a little pcb so the ptc could be surface mounted and then the sense wires soldered on the pcb next to it. then connect that to the sense wire plug on the BMS.

and a short on the sense wire would be limited, then not much current could go to the short from the rest of the pack. less heat.

but i don't know if that is the proper use of the ptc.

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Re: All I want is a Balancer!

Post by dogman dan » May 04 2013 3:19pm

When I do balance, which is less and less all the time, I'm liking single cell charging or discharging more and more. Access to your jst plugs is really all you need. Then though tedious, you can run though the pack pretty quick with either a charge or a turn signal light bulb, one cell at a time. plugs to add or subtract some wh to a single cell are just bare male just plug prongs. Stick em in where you want to charge or discharge a single cell.

Yeah it's manual, but way quicker than waiting for RC chargers to balance a pack, let alone something like a ping bms to do it.

Towards the end of the bulk charge, catch the highest cells and start em on the light bulbs.

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Re: All I want is a Balancer!

Post by chroot » May 04 2013 4:45pm

Don't buy this balancer board sucks. Why........ Because this balancer bleeding real slow (Balancing Current
Li-ion:around 10~84mA;) and it is going VERY LONG TIME to be finally balanced all cells (30Ah).

I experiment with my 20Ah pack with new bulk charger from Cell_Man called LXE Li-Ion charger and I ran 20Ah to 3.2V got all out of balance when the Methods LVC board tripped then cut off. I went ahead bulk charging while all cells were out of balance. By time hit 50V (12S4P) and I surprised that I ran balancer watt meter and shunned 1~3mV within all cells! Absolutely no need balance..... :lol:

I love the new LXE charger from Cell_Man, This thing is much higher quality than Kingpans and I am not sure about your HRP-600 bulk charger. It should be automatically balance itself with your 30Ah without any problem. Have you inspect all cells with your balancer watt meter to see if the pack needed to be balancing?

How about get 150watt discharger/balancer watt meter with 3 halogen lamps and it helps quick balancing your all LiPo packs. Here info viewtopic.php?f=14&t=41145
Kingfish wrote: The pack in question is my Commuter 15S6P 30Ah; it's two assemblies of 15S3P in Left/Right bags hanging in the Triangle.

I see that they have a Balance Board, and a 15S Protection Board (35A).

There isn't much room in the bag, although there is between the bags. I would like to parallel each bag before handing off to a circuit board.
What do you suggest?

Do you like this manufacturer? How do you purchase these boards? The links do not resolve.

Thanks, KF
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Re: All I want is a Balancer!

Post by liveforphysics » May 04 2013 6:01pm

Be careful what you pick has a very very low quiescent current while idle.

Many cheapo BMS's Ive seen have a quiescent current that will bleed your pack down surprisingly quick if it's just left sitting for a fee months. Of those, many eventually just bleed the first 2 cells of the string dead if they are left in a passive balance mode while parked over the winter or whatever.
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Re: All I want is a Balancer!

Post by Kingfish » May 05 2013 11:13am

Many good points.

@ velias: All the batteries are from the same manufacturer, they are the same type. Not of the same lot though. So I can partly trust the charge and discharge variances are not going to be too different. If I never (or rarely) take my pack below 30% capacity (when commuting it never drops below 50%) – the cells should never see LVC. As it is I have the controller set to cut out at about 50V (@ 15S = 3.33 V/cell); well in the safety margin. There isn’t much oomph left in the pack below 3.46V/cell anyways; handful of miles so why push it.

@ dnmun on ressettable fuses: Richard got me thinking about that a while back. I went as far as buying a 5 position DP rotary switch and using a 5V 1A USB power supply (little 1x1 direct plug-in cube) to facilitate trickle charging of the low boys. But that’s back to manual balancing.

@ dogman: I like the turn signal light bulb for a bleeder idea! Perfect use for an incandescent. 8)

@ chroot: You are right; those boards do bleed frippen slow; I didn’t see it until you pointed it out. Curious about the LXE Li-Ion charger: Can you share the link?

@ Luke: Yes, I can respect that. Like leaving the controller connected to the battery pack over the winter without monitoring… been there done that; once was enough :roll: It’s why I considered having a Balance function that can be invoked as opposed to passive balance.

Good points all around.
Charging, KF
* My 2WD Garden Wall
* Kinaye MotorSports
* Primary ride: 2WD Disc 9C 2806-equiv / Dual Lyen 12FET / 20S7P LiPo.
* Epics: Going to California: 2011 8)
* 50-mph, 101, 10k-Club. 12,527 miles-to-date, 7037 as 2WD.

It is by caffeine alone I set my mind in motion.
It is by the beans of Java that thoughts acquire speed.
The hands acquire shakes, the shakes become a warning.
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Re: All I want is a Balancer!

Post by Holocene » May 06 2013 7:43am

Kingfish wrote:I just want to have active balancing for a difficult to reach battery pack in the Triangle.
And Keep It Simple. Ideas?
Hi Kingfish,

Check out this article on using a charge-pump IC for active balancing:

Battery Cell Balancing for Improved Performance in EVs - Part II: Active Balancing Technologies

Image
Figure 6: Texas Instrument’s PowerPump cell balancing technology uses a simple charge shuttling scheme to transfer energy between adjacent cells.
It uses the TI bq78PL114 master gateway battery controller as part of a complete Li-Ion control, monitoring, and safety solution designed for large series cell strings.

hth. :wink:
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Re: All I want is a Balancer!

Post by t3sla » May 06 2013 8:55am

liveforphysics wrote:Be careful what you pick has a very very low quiescent current while idle.

Many cheapo BMS's Ive seen have a quiescent current that will bleed your pack down surprisingly quick if it's just left sitting for a fee months. Of those, many eventually just bleed the first 2 cells of the string dead if they are left in a passive balance mode while parked over the winter or whatever.
+1^10!

I would say that you can plug and play your bms.
Utilize large 10/12/20s taps and plug it in when you require balancing.
You unplug that large tap and boom, problem solved.
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Re: All I want is a Balancer!

Post by Ykick » May 06 2013 9:18am

What appears to be missing in the affordable range is a cell balancer circuit powered via button battery (AAA's. 9V, etc.) so nothing is able to drain pack cells while not in use.

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Re: All I want is a Balancer!

Post by dnmun » May 06 2013 9:21am

20μA is not much current imo.

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Re: All I want is a Balancer!

Post by chroot » May 06 2013 9:50am

@Kingfish - I have a board 1A bleeding balancer made by fecther long time ago. I think I left in my storage. These sure work great fast balance involve resistor arrays and bit little hot. I will look for it, find the board balancer and see if it works for the LiPo. Maybe give it to you.

I haven't use it for ages.
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Re: All I want is a Balancer!

Post by dnmun » May 06 2013 9:54am

a lifepo4 shunt transistor balancing network will not work for lipo.

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Re: All I want is a Balancer!

Post by chroot » May 06 2013 11:00am

@dnmun I never said LiFeP04 type. fecther made was for both lifepo4 and lipo 1A bleeding board. I have is an lipo.

Anyways, Here the picture of my homemade balancing using 3 in 1 discharger/balancer/watt meter and it works. But hey dirty quick faster balancing and usually within 10~20mV avg. Better than using iCharger 3010b took forever balancing just one 5Ah brick. I also have BC168 charger thru the balance tap and I killed BC168. OH WELL! :lol: :lol: :lol:
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Re: All I want is a Balancer!

Post by Kingfish » May 08 2013 10:33am

Holocene wrote:Hi Kingfish,

Check out this article on using a charge-pump IC for active balancing:

Battery Cell Balancing for Improved Performance in EVs - Part II: Active Balancing Technologies

Image
Figure 6: Texas Instrument’s PowerPump cell balancing technology uses a simple charge shuttling scheme to transfer energy between adjacent cells.
It uses the TI bq78PL114 master gateway battery controller as part of a complete Li-Ion control, monitoring, and safety solution designed for large series cell strings.

hth. :wink:
I just wanted to comment that I have read and re-read that article several times in the past - and again recently (thanks to the prod). I understand at a high level what it is trying to do. The gating factor is that I'd have to make my own. A bit scary cos I'm not an EE.

The TI bq78PL114 offered on Digikey is inexpensive, though we'd have to purchase 2,500 units. In addition, it supports 3- to 8-series cell Battery systems, so you'd essentially need 2 or 3 to handle the lion's share of sbike needs... and I don't know if these chips can be paralleled (!EE). Upgrading to use bq78PL114S12 firmware (+ additional hardware) can extend the management limit to 12-series cells; almost there for me @ 15S. A better value might be to string two bq78PL114 together for 15/16S - though it is all speculation on my part.

2,500 units would come to an investment of 12,656.25 USD. Haven't found an alternate source - but then I didn't look very hard.

Have you seen this thread? New TI BMS chipset? They go into more meaty detail. :)

On the balance... KF
* My 2WD Garden Wall
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* Primary ride: 2WD Disc 9C 2806-equiv / Dual Lyen 12FET / 20S7P LiPo.
* Epics: Going to California: 2011 8)
* 50-mph, 101, 10k-Club. 12,527 miles-to-date, 7037 as 2WD.

It is by caffeine alone I set my mind in motion.
It is by the beans of Java that thoughts acquire speed.
The hands acquire shakes, the shakes become a warning.
It is by caffeine alone I set my mind in motion.

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Re: All I want is a Balancer!

Post by dogman dan » May 09 2013 9:33am

For quick, dirty and cheap, I'm still inclined to go manual.

All you need is a Y cable for JST plug that has two female ends instead of two male ends. Then you plug in your balancers, or a cellog, into one plug. When you see one cell getting too full, hook the bulb to that cell using that extra female plug in the Y cable. That will hurry up the one that needs discharging the most.

Yes, you have to sit there and do it, but it should only take 15 min as the bulk charge finishes. At that point, your bulk charge is low amps, so the bulb will easily keep up with the charger. What takes too long, is all that waiting for the RC charger to decide to turn back on again as it runs a balance.

I would think you could also make a rig with a bank of 5 or 6 bulbs, then switch on several at once if needed.

I tend to get the opposite, one low cell in a pack. For that I just single cell charge it some more, after the bulk charge is done .

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Re: All I want is a Balancer!

Post by docnjoj » May 09 2013 3:11pm

chroot wrote:@dnmun I never said LiFeP04 type. fecther made was for both lifepo4 and lipo 1A bleeding board. I have is an lipo.

Anyways, Here the picture of my homemade balancing using 3 in 1 discharger/balancer/watt meter and it works. But hey dirty quick faster balancing and usually within 10~20mV avg. Better than using iCharger 3010b took forever balancing just one 5Ah brick. I also have BC168 charger thru the balance tap and I killed BC168. OH WELL! :lol: :lol: :lol:
Hey chroot! Do you have those 3 balancers parallelled? That is way cool!
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Re: All I want is a Balancer!

Post by simat » May 11 2013 8:57am

I am in the same boat, but for an off grid solar power system.

After some reasearch and thought i rather like the idea of balancing the cells when the voltage difference between the cells reaches a certain level, rather than when each cell reaches a maximum voltage. This means the cells would be being balanced all the time.

The big question is whether to design something from scratch or try to use existing gear. I came accross this Turnigy 6S balancer while ordering some cell-log 8s. http://www.hobbyking.com/hobbyking/stor ... duct=26136

If it is accurate enough it should do the job. One problem is the 50ma equalisation current, i think that it may be enough for my application as i am only charging and discharging the batteries slowly and only charging to 3.45 volts/cell. If not it shouldn't be too hard to find the discharge resistors in the device and externally substitute them with a bank of optically isolated relays or transistors with suitable power resistors. If you wanted to balance more than 6 cells i think it should be possible to overlap one cell between two balancers, so 1 balancer would do 6 cells, 2 balancers would do 5+5 cells, 3 balancers would do 5+4+5 cells and so on. Are there any flaws in my logic or does anyone have any thoughts on this?

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Re: All I want is a Balancer!

Post by Kingfish » May 11 2013 3:40pm

I took the Commuter Pack apart for inspection; I do this about once/quarter... though in my case I can't quite recall the last time it was done... must have been more than 3 months. I really did expect worse, though it was not bad:

Out of Qty-18 5S1P batteries (partly charged after a ride), the lowest cell was 3.83V, and the highest was 4.09, however the average was about 3.6 to 3.89 with one odd grouping of three (they were side-by-side in a 15S unit) of 4.02 to 4.07. One of those had the +V wire disconnected from the barrel connector (cold solder joint from the looks of it) so I suspect that was the culprit - not fully discharging. I now have them all disconnected from the Main and unified through the Balance Taps, from (GND) 3.88|3.88|3.90|3.91|3.95 (+V). Overall - except for the grouping - I was very pleased to see them in relative balance. There were no puffers either, not a one :mrgreen:

Dogman, I like your idea with the light bulb as a bleeder; I'm looking through a catalog of 5V LEDs but the current rating is pretty dang low @ 10uA. There's a high-powered 5W LED that has a forward voltage of 6.84V that can pull 0.7A. Would one or two of those in parallel work? The Balance wires can easily take 2A @ 5V; they get warm but not hot.

I have a 5V 1A USB AC-DC power adapter (2A available on Amazon), and am going to put together a little breadboard where I can pick which channel to boost-charge and which to drain.

Something to keep me busy this weekend whilst we ponder more sophisticated methods of automation and option... :wink:
From the forests of Rain City, KF
* My 2WD Garden Wall
* Kinaye MotorSports
* Primary ride: 2WD Disc 9C 2806-equiv / Dual Lyen 12FET / 20S7P LiPo.
* Epics: Going to California: 2011 8)
* 50-mph, 101, 10k-Club. 12,527 miles-to-date, 7037 as 2WD.

It is by caffeine alone I set my mind in motion.
It is by the beans of Java that thoughts acquire speed.
The hands acquire shakes, the shakes become a warning.
It is by caffeine alone I set my mind in motion.

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Re: All I want is a Balancer!

Post by Kingfish » May 11 2013 6:15pm

Hehe little funny: Awhile ago I bought these Cree UltraFire WF-501B to upgrade my Cree R5 UniqueFire X8 but the parts were not compatible. Then I got to thinking about using lights for bleeders and thought what the heck, let's make an adaptation and see if it could work. Well - as it turns out these UltraFires really are 3X brighter than UniqueFires - I tested them side-by-side, so I think I'll swap out the old for the new.

In the meantime, since it's built to be a replacement, I hooked it up to the 18 batteries unified by Balance Taps, and it's doing a fine job of draining the highest cell. I know there's an idea hidden in there somewhere:

:idea: Create a circuit that runs the highest cell to the flashlight for balance while yer riding :lol:

Illuminated in a twisted sort of way, KF
* My 2WD Garden Wall
* Kinaye MotorSports
* Primary ride: 2WD Disc 9C 2806-equiv / Dual Lyen 12FET / 20S7P LiPo.
* Epics: Going to California: 2011 8)
* 50-mph, 101, 10k-Club. 12,527 miles-to-date, 7037 as 2WD.

It is by caffeine alone I set my mind in motion.
It is by the beans of Java that thoughts acquire speed.
The hands acquire shakes, the shakes become a warning.
It is by caffeine alone I set my mind in motion.

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Re: All I want is a Balancer!

Post by Holocene » May 28 2013 7:32pm

Hi Kingfish,

Have you seen this video from Linear Technologies (the makers of LTSpice ) titled "High Efficiency Bidirectional Cell Balancer Maximizes Capacity and Lifetime of Series Connected Battery Stacks"?

It looks like it'll actively balance your pack during the discharge cycle.
EDIT: Max balance current is 4 amps! :twisted:

A datasheet, journal article, and press release are also available on the Documentation page.

Cheers!
Holocene
Last edited by Holocene on May 29 2013 3:54pm, edited 1 time in total.
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Re: All I want is a Balancer!

Post by Kingfish » May 28 2013 7:58pm

Holocene wrote:Hi Kingfish,

Have you seen this video from Linear Technologies (the makers of LTSpice ) titled "High Efficiency Bidirectional Cell Balancer Maximizes Capacity and Lifetime of Series Connected Battery Stacks"?

It looks like it'll actively balance your pack during discharge :twisted:

A datasheet, journal article, and press release are also available on the Documentation page.

Cheers!
Holocene
Wow - what a cool find! Many thanks 8)

It certainly sparks thought, namely how can I adapt it to do 5-cell batteries... or perhaps not worry and just stack the components until the desired limit is reached. A question that I had was about the transformers, the small 10uH units: Is that for isolation to prevent direct short?

I'll have to file this into my future projects folder and design up a custom board for the Triangle pack :idea:

Thanks again for the lead; that's just great!
Cheers to you, KF
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