How to puff a lipo

Batteries, Chargers, and Battery Management Systems.
User avatar
dogman dan   100 GW

100 GW
Posts: 34420
Joined: May 17 2008 12:53pm
Location: Las Cruces New Mexico USA

How to puff a lipo

Post by dogman dan » Sep 17 2010 2:48pm

Simple, Hook up two 5ah packs paralell, and use a paralell adaptor that has one of the andersons pushed back inside. Then go run 8 ah out of the pack. :oops: I was concerned about this, so all my connectors were taped together to prevent an oops disconnect. But one bad anderson in the rig caused the same thing.

They really swell up when you try to discharge 8 ah from a 5 ah pack. :lol: Reads 0v now. Fortunately I only lost one 4s pack.
puffy 4s 1.JPG
puffy 4s 1.JPG (223.23 KiB) Viewed 843 times
puffy 4s 2.JPG
puffy 4s 2.JPG (227.28 KiB) Viewed 843 times

User avatar
number1cruncher   1 kW

1 kW
Posts: 415
Joined: Sep 13 2009 1:52pm
Location: Alexandria, Virginia

Re: How to puff a lipo

Post by number1cruncher » Sep 17 2010 2:54pm

Good CuggaMugga! You almost became the HotDogMan! Glad all is well.
Go to http://www.ebike.ca and buy stuff to support the rEVolution!

Electra Townie 700c Euro 8i - 20s2p Zippy LiPo - Rear 9c clone
Performance x201 - 18s2p - Rear 9c 8x8

All things lead to the path of least resistance.

"Political correctness is tyranny with manners." ~Charleton Heston

User avatar
philf   1 kW

1 kW
Posts: 328
Joined: May 28 2008 5:15am
Location: Burlington, ON (Canada)

Re: How to puff a lipo

Post by philf » Sep 17 2010 3:23pm

Wow. Impressive. And such an easy thing to have happen - yikes!

texaspyro   100 kW

100 kW
Posts: 1408
Joined: May 12 2010 6:53pm

Re: How to puff a lipo

Post by texaspyro » Sep 17 2010 3:31pm

philf wrote:And such an easy thing to have happen - yikes!
And a easy thing to avoid and detect with a per-parallel-cell-group LVC monitor... any battery worth having on a bike is worth at least a minimal BMS.

User avatar
number1cruncher   1 kW

1 kW
Posts: 415
Joined: Sep 13 2009 1:52pm
Location: Alexandria, Virginia

Re: How to puff a lipo

Post by number1cruncher » Sep 17 2010 3:42pm

Dogman,

You may also want to reconsider paralleling the balance taps. I've had an anderson come apart on a parallel group, but the group maintained a decent voltage because the cells were also paralleled. Not sure it would hold up long under high discharge currents, but it would help for a while, as mine did.
texaspyro wrote:
philf wrote:And such an easy thing to have happen - yikes!
And a easy thing to avoid and detect with a per-parallel-cell-group LVC monitor... any battery worth having on a bike is worth at least a minimal BMS.
Go to http://www.ebike.ca and buy stuff to support the rEVolution!

Electra Townie 700c Euro 8i - 20s2p Zippy LiPo - Rear 9c clone
Performance x201 - 18s2p - Rear 9c 8x8

All things lead to the path of least resistance.

"Political correctness is tyranny with manners." ~Charleton Heston

User avatar
dogman dan   100 GW

100 GW
Posts: 34420
Joined: May 17 2008 12:53pm
Location: Las Cruces New Mexico USA

Re: How to puff a lipo

Post by dogman dan » Sep 17 2010 5:09pm

Good point. I've been toying with the idea of paralelling the balance taps, with 16g wire perhaps. then splice on the skinny wire. I got no respect at all for cheeze jst plugs. But that would be a chore. I dunno, you want to keep the pack flexible and easy to swap out stuff for racing, but you need to permanently paralell stuff. Or at least be sure nothing can come undone. Maybe I'll just hot glue the andersons into the housings after double checking that they are in and clicked. I just want the stuff to be able to swap out in seconds in case something goes bad minuites before a race.

Fortunately the fireworks would happen when I try to charge that puffy. But I'm not going to, it's in the dumpster.

The paralelled packs were sharing a lvc alarm. On the pack that wasn't connected. So no beeps from the pack happily sitting there not discharging. That can be fixed by moving the lvc to the other pack. I'm using a different method to paralell most of the pack, but used a seperate adaptor for the added 4s packs. Lack of proper planning, and eagerness to go burn some turns.
Last edited by dogman dan on Sep 17 2010 5:14pm, edited 1 time in total.

tostino   10 kW

10 kW
Posts: 970
Joined: Mar 24 2008 4:12pm
Location: New Port Richey, FL

Re: How to puff a lipo

Post by tostino » Sep 17 2010 5:11pm

I can imagine some crispy balance leads if that happened :lol:. Like you said though, it probably would have helped a lot. If it wasn't at a high C rate, you may have not even noticed.

User avatar
dogman dan   100 GW

100 GW
Posts: 34420
Joined: May 17 2008 12:53pm
Location: Las Cruces New Mexico USA

Re: How to puff a lipo

Post by dogman dan » Sep 17 2010 5:18pm

Yeah. Can those things take 25 amps? I doubt it. That's why I was thinking, the only proper way to paralell the balance leads would be with thick wire, that could hack 10-20 amps for 15 min.

The more I think about it, taping the connectors is good enough to prevent accidental disconnect. And glueing the wire into the housing should prevent any backed out contacts. Sometimes a bent contact will click, but not really hold permanent. Gold bullets wouldn't back out of housings either.

User avatar
knoxie   10 MW

10 MW
Posts: 2430
Joined: Jan 03 2007 5:54pm
Location: UK
Contact:

Re: How to puff a lipo

Post by knoxie » Sep 17 2010 7:01pm

Lipo buzzer on each pack would have saved the Bacon here! I finally got them to stop blowing on me, each pack has one so even if the Andersons werent making it would beep, folks will pitch in about how its better to solder them in parallel and what not but like you I like the flexibility of running different voltages on the fly no problems here with buzzers and BM6 on each pack, pretty much fool proof and with the BM6 on each one its cell level on each pack, they stay well in balance so far.

Glad you only lost 1 pack and no fires
Electric KMX 72V Lipo, USPD drive unit. BMX 72V, Puma BMC,
Raleigh 26 inch MTB Puma 50V Turnigy 25C Lipo 10AH, Trek MTB, X5 48V NIMH. Electric BMX
http://tinyurl.com/4vrmc8 http://tinyurl.com/3umm4n

User avatar
dogman dan   100 GW

100 GW
Posts: 34420
Joined: May 17 2008 12:53pm
Location: Las Cruces New Mexico USA

Re: How to puff a lipo

Post by dogman dan » Sep 17 2010 7:18pm

I'm going to redo my packs so the buzzer is on the pack that makes the final connection. The way I wired em, if one of them disconnects, the buzzer will be on the pack that is still providing power. Right now, it's the opposite, so the buzzer would be on the disconnected pack.

Are your buzzers permanently connected? that's the other issue, you're counting on some plug for that right? I'm currently connecting with wire nuts to the buzzers. If the buzzer plug is flakey the buzzer is useless too. Seems like they make a bit of heat, so I haven't hooked em up permanent.

texaspyro   100 kW

100 kW
Posts: 1408
Joined: May 12 2010 6:53pm

Re: How to puff a lipo

Post by texaspyro » Sep 17 2010 7:35pm

Unfortunately the only proper way to interconnect packs in parallel is to have parallel connections at the cell level. Without those connections at the cell level, the paralleled packs cannot properly share the current. But balance leads just won't be able to handle the currents if something opens or cells get out of balance or go wonky. This is the major flaw in building bigger parallel packs out of LiPo modules and can lead to LiPo barbecues.

It would be nice if they sold those 6S1P packs as 1S6P's, etc. Then you could build up much more robust packs. And if one goes bad, you unhook it from the string and only lose 4V until you can replace it.

BIG BEAM   100 W

100 W
Posts: 175
Joined: Jul 18 2010 6:48pm

Re: How to puff a lipo

Post by BIG BEAM » Sep 17 2010 8:30pm

How come you guys don't use the 4mm connectors that come on the packs ?They even make bigger ones...5.5mm and I think 8mm.
DON

chroot   100 kW

100 kW
Posts: 1284
Joined: Nov 29 2009 4:03pm

Re: How to puff a lipo

Post by chroot » Sep 17 2010 8:42pm

Never mind, I see you mentioned run out super low below LVC. I got it clear picture. OUCH

That's why few of us mentioned rather have more than 10Ah so you have plenty ahead left the LVC line
to give you time to get home.
Thank you Justin Lemire-Elmore - You are a HERO!

Tidalforce, Yuba Mundo V4 Cargo bike, Juiced Riders ODK V1 Cargo bike
English is my secondary language - ASL (American Sign Language) is my primary.

BIG BEAM   100 W

100 W
Posts: 175
Joined: Jul 18 2010 6:48pm

Re: How to puff a lipo

Post by BIG BEAM » Sep 17 2010 8:47pm


Hillhater   100 GW

100 GW
Posts: 9321
Joined: Aug 03 2010 10:33pm
Location: Sydney ..(Hilly part !) .. Australia/ Down under !

Re: How to puff a lipo

Post by Hillhater » Sep 18 2010 12:26am

FYI .. i produced a similar "puffy" when running 2 5s packs in series.
both were balance charged ( 20.5v) with cell logs fitted and i was monitoring every few min use, as they were new packs.
dispite the checks, i noticed the power drop off suddenly ( maybe 2 mins after a 3.6v check).
One pack was puffed and hot reading 1.9v/ cell !! :shock: ( note: cell log alarm is not loud enough ! ) but the other pack was still at 3.5v ?
I pulled the puffed pack out to let it cool..then peddled home.
Luckily, after a slow ballance charge (0.5A) all cells have come back up to 4.0v within 20mA of each other.

So lesson learned. ...
Get good LVC setting and cell monitoring alarms
consider thermal monitors & alarm for each pack also !
This forum owes its existence to Justin of ebikes.ca

User avatar
knoxie   10 MW

10 MW
Posts: 2430
Joined: Jan 03 2007 5:54pm
Location: UK
Contact:

Re: How to puff a lipo

Post by knoxie » Sep 18 2010 1:46am

Hi Dog

I have my cell monitors in that blue box soldered to the 25 pin d plug, so its less likely that one can disconnect of course you would have to have 2 buzzers disconnect in 1 parallel block and that is highly unlikely you cant cover all the possibilities.

Those JST connectors wear over time I have noticed and some pins dont make a connection I see this as more of a problem, I think that if folks are going to parallel the packs at cell level and at the discharge leads they should consider soldering the balance wires and the discharge leads together I wouldnt rely on the JST connectors as you have the possibility that if 1 disconnects it will not show when you balance and that pack would never be balanced and would possibly go out of whack.

I agree if you dont want to change the pack voltages then paralleling the packs at charge and balance is the best idea but solder all connections.

Knoxie
Electric KMX 72V Lipo, USPD drive unit. BMX 72V, Puma BMC,
Raleigh 26 inch MTB Puma 50V Turnigy 25C Lipo 10AH, Trek MTB, X5 48V NIMH. Electric BMX
http://tinyurl.com/4vrmc8 http://tinyurl.com/3umm4n

curious   1 kW

1 kW
Posts: 445
Joined: Dec 29 2007 1:46pm
Location: NJ, USA

Re: How to puff a lipo

Post by curious » Sep 18 2010 1:49am

Hillhater wrote:I pulled the puffed pack out to let it cool..then peddled home. Luckily, after a slow ballance charge (0.5A) all cells have come back up to 4.0v within 20mA of each other.
Don't use the puffed lipo pack even if it seems working OK. Major fire danger ! Really not worth the risk...
bike1: hardtail frame, 5304 rear, 850wh a123 66v/33v switchable, Kelly KEB72601, proportional regen;
bike2: bikeE FX recumbent, sensored bafang front on a 16" rim, 16s a123;
bike3: work in progress (slow), long range SWB touring recumbent, >1.5kwh pack TBD, Kelly KBS72101, likely HT35 hub, proportional regen.

Hillhater   100 GW

100 GW
Posts: 9321
Joined: Aug 03 2010 10:33pm
Location: Sydney ..(Hilly part !) .. Australia/ Down under !

Re: How to puff a lipo

Post by Hillhater » Sep 18 2010 4:17am

curious wrote:
Hillhater wrote:I pulled the puffed pack out to let it cool..then peddled home. Luckily, after a slow ballance charge (0.5A) all cells have come back up to 4.0v within 20mA of each other.
Don't use the puffed lipo pack even if it seems working OK. Major fire danger ! Really not worth the risk...
Really !!
you know what worries me about that more than any actual fire etc ???..
..its the fact that this pack now appears perfectly normal, back to original size , 20.5v, all cells 4.1V balanced, etc etc..
no one other than me would know its history,
how many packs are sold after having testing "events" like this ??
.. is there no way of telling if you are using a potential incendiary pack ? :shock:
This forum owes its existence to Justin of ebikes.ca

User avatar
neptronix   100 GW

100 GW
Posts: 12947
Joined: Jun 15 2010 5:56pm
Location: California refugee living in Utah, USA
Contact:

Re: How to puff a lipo

Post by neptronix » Sep 18 2010 4:45am

Wowsa, those are zippy flightmax, yeah? I'm surprised they didn't blow!

Well, i gained confidence in mine..

I am using EC3 connectors for mine. I bought a big 20 pack. It also helps that i'm running stock voltage on my controller, so i have a LVC.. nonetheless, i suppose it's easy for this to happen anyway :/
My first major build: 8T MAC motor on a Trek 4500.
The new all-arounder: Leafmotor 1500w on a Turner O2 full suspension.

User avatar
dogman dan   100 GW

100 GW
Posts: 34420
Joined: May 17 2008 12:53pm
Location: Las Cruces New Mexico USA

Re: How to puff a lipo

Post by dogman dan » Sep 18 2010 5:18am

Re hillhater. I bet you stop at 3.6 next time. I consider 3.75 time to stop, and have noticed that if you don't, you will hit 3.5 in about a mile or less. By 3.5v they are about to go over the cliff, and with only 5 ah, the cliff gets even steeper. From 3.5 to the ovedischarged would take no time at all.

2p 3s packs would be nice! Or even 3p 2s! Be perfect for the ebikes. Paralelling packs at 5s is not ideal. I did consider buying 2s packs. But then soooo many wires to connect. I'm trying to achieve the 10 ah pack with the minimum number of connectors.

I went with andersons because I like the flexibility of em, and don't need all 30 c discharge rate. They don't have the only plugs in one way feature that bullets usually have. I've only run across a bum one once or twice now, where the connector was pushed back. Usually the only issue is one coming unplugged. I've learned to crimp good, so I don't have to solder anything.

But this incident goes to show how closely you have to look at and also see everything on your bike. How many posts have you seen, " I unplugged everything and plugged it back in and it still doesn't work" Often a backed out contact on a phase or halls wire.

User avatar
geetarboy   100 W

100 W
Posts: 266
Joined: Nov 19 2009 8:31pm
Location: Kansas City - USA

Re: How to puff a lipo

Post by geetarboy » Sep 18 2010 12:42pm

BIG BEAM wrote:How come you guys don't use the 4mm connectors that come on the packs ?They even make bigger ones...5.5mm and I think 8mm.
DON
Yeah, these are much better than andersons - my old e-bike kit battery connection was always coming loose.

User avatar
geetarboy   100 W

100 W
Posts: 266
Joined: Nov 19 2009 8:31pm
Location: Kansas City - USA

Re: How to puff a lipo

Post by geetarboy » Sep 18 2010 12:54pm

Hillhater wrote:
curious wrote:
Hillhater wrote:I pulled the puffed pack out to let it cool..then peddled home. Luckily, after a slow ballance charge (0.5A) all cells have come back up to 4.0v within 20mA of each other.
Don't use the puffed lipo pack even if it seems working OK. Major fire danger ! Really not worth the risk...
Really !!
you know what worries me about that more than any actual fire etc ???..
..its the fact that this pack now appears perfectly normal, back to original size , 20.5v, all cells 4.1V balanced, etc etc..
no one other than me would know its history,
how many packs are sold after having testing "events" like this ??
.. is there no way of telling if you are using a potential incendiary pack ? :shock:
Hey Hillhater, I have a pair of 6s packs that have done the same thing. They were only "slightly puffed" compared to Dogman's picture, the lowest cell was @ 2.1 volts. I have 15 cycles on it since and it's working fine. Maybe we caught them just in time before irreversible damage was done? Mark

User avatar
nicobie   10 MW

10 MW
Posts: 2156
Joined: Aug 07 2008 1:48pm
Location: Central Coast CA,USA

Re: How to puff a lipo

Post by nicobie » Sep 18 2010 1:24pm

I know most of you guys really like your Andersens, but I'm glad I went with Deans. Even though I use the cheap clones, I've NEVER had a problem with them getting hot. They are alot smaller and are impossible to reverse polarity when plugging in. Their only draw back is that on the male plug the prongs are exposed when disconnected. This isn't a problem if you pay attention and put the female on the power side and the male on the load side.

On my new build I'm going to try HK's new XT60 plugs. They are fully enclosed and handle 60a+ with out getting hot (so they say). They cost about $3 for 5 pair which is the equivalent of 10 Andersens.

http://www.hobbycity.com/hobbycity/stor ... oduct=9572
Image

May your tote always stay tight and your edge eversharp :wink:

my eTownie build thread: http://endless-sphere.com/forums/viewto ... =6&t=23701

User avatar
amberwolf   100 GW

100 GW
Posts: 25452
Joined: Aug 17 2009 6:43am
Location: Phoenix, AZ, USA, Earth, Sol, Local Bubble, Orion Arm, Milky Way, Local Group
Contact:

Re: How to puff a lipo

Post by amberwolf » Sep 18 2010 1:49pm

FWIW, those balance leads wouldn't need to take much current, if any, under normal use. And if they did take more than they were supposed to, perhaps the smell would alert you that there was a problem, before they actually melted enough to short together and start a fire. ;)

texaspyro   100 kW

100 kW
Posts: 1408
Joined: May 12 2010 6:53pm

Re: How to puff a lipo

Post by texaspyro » Sep 18 2010 3:37pm

Under normal "normal" use one would not need balance connectors, BMSes, etc at all. It's those pesky real-world "normal" conditions that cause all the irritating problems.

Post Reply