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All Forums >> Radios, Batteries, Clubhouse and more >> Batteries & Chargers >> LiPo degrading
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LiPo degrading - 5/28/2008 2:18:47 PM   
spiral_72



Posts: 511
Joined: 3/7/2007
From: Chesnee, SC, USA
Status: offline 		I'm new to the foamie scene. I bought my first LiPo about six weeks ago. A bunch of the guys decided to fly full-on combat. We made a couple orders with Hobbycity.com and another one and ended up with a delta wing and the gear cheap.

The LiPo I bought was supposed to be good. It's a Loong Max 1600mA 20C 3-cell with a balance plug. I bought a Triton Jr but no balancer.

I run it on a small 10A brushless, 12A ESC plane and a larger 15A brushless, 25A ESC plane. The first flights were amazing, lot's of power for 15-20 minutes.

The ESC were set for reduce power at 3.3V, I never flew the planes after that. I just landed.

Anyways, my question. After about 10 charges the output was reduced. My buddy has a balancer, so we balanced the pack for four flights I think. The balancer spent most it's time on cell 1, and then on cells 1 & 2. After every flight off the balancer, it continued to get worse.

The pack continues to degrade untill now, it only takes up to 450mA to charge and the flight time is about 4 minutes. So, it's pretty worthless.

I always charge at 1C rate.

Any ideas?
Is it something I did, or do you think it was a bad pack to begin with?
Is there anything I can do to recover the pack? With a NiCd I'd cycle the pack, but I'm told it doesn't work with LiPo's.

_____________________________

Wasn't that cool? I meant to do it.
       Post #: 1

RE: LiPo degrading - 5/28/2008 5:34:45 PM   
wswanepoel


 

Posts: 97
Joined: 6/28/2007
From: FintasKuwait, KUWAIT
Status: offline
quote:

It's a Loong Max 1600mA 20C 3-cell


I have 4 Loong Max 2250mA 20C 30cell's and don't have a problem at all. I always charge all Lipo's with a balancer. I think you just got a DUD or maybe you have hurt it before you started using the balancer. I am using Lipo's since they hit the market. In the beginning i also lost a lot before I started to use a balancer.

Since you have a charger already just get a cheap balancer. It is worth it as you will see, once you get into electrics your batteries will get bigger and more expensive.

This balancer should doo the trick:

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=6748&Product_Name=MKS_3in1_Balance/Discharger_System_6S&cda=36317

or a cheap solution is

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=6507&Product_Name=Turnigy_2-3_Cell_Lipoly_Balance/Charger&cda=36317

_____________________________

Regards Bill
Remember: Nose heavy planes flies like a dog. Tail-heavy planes only fly once.

(in reply to spiral_72)
       Post #: 2

RE: LiPo degrading - 5/28/2008 5:39:05 PM   
oldschoolracer


 

Posts: 77
Joined: 5/27/2008
From: Hobbs, NM, USA
Status: offline 		Was that 3.3v TOTAL or per cell?
Personally I never let mine drop below 3.6vpc

Some battery companies say balancers are of no use and a waste of money.

(in reply to wswanepoel)
       Post #: 3

RE: LiPo degrading - 5/28/2008 5:56:22 PM   
DARKWAV



Posts: 306
Joined: 12/5/2007
From: San Diego, CA, USA
Status: offline
quote:

ORIGINAL: oldschoolracer
Some battery companies say balancers are of no use and a waste of money.


I've seen that mentioned before...but I think it may be part of their marketing strategy supporting their product line. Basically saying they provide near perfectly matched cells in their packs which effectivley remain balance through the life of the battery. So buy their matched cell batteries and you shouldn't need a balancer.

Anyway I'm always open to new info so let me know if there's something I'm missing.





_____________________________

HPI E-Firestorm 10T / HPI E-Savage / Tamiya TamTech-Gear GB-01

(in reply to oldschoolracer)
       Post #: 4

RE: LiPo degrading - 5/28/2008 6:02:19 PM   
wswanepoel


 

Posts: 97
Joined: 6/28/2007
From: FintasKuwait, KUWAIT
Status: offline
quote:

ORIGINAL: oldschoolracer

Was that 3.3v TOTAL or per cell?
Personally I never let mine drop below 3.6vpc

Some battery companies say balancers are of no use and a waste of money.


Well I suppose it is personal choice. I will not charge my expencive lipos without a balancer. I would not even charge them with a cheap balancer. I had a cheap balancer charger combination before and when I tested the cells after a charge, they were out of balance.

_____________________________

Regards Bill
Remember: Nose heavy planes flies like a dog. Tail-heavy planes only fly once.

(in reply to oldschoolracer)
       Post #: 5

RE: LiPo degrading - 5/28/2008 7:49:58 PM   
spiral_72



Posts: 511
Joined: 3/7/2007
From: Chesnee, SC, USA
Status: offline
quote:

ORIGINAL: oldschoolracer

Was that 3.3v TOTAL or per cell?
Personally I never let mine drop below 3.6vpc

Some battery companies say balancers are of no use and a waste of money.


Um, yea that's 3.3V per cell. The speed control doesn't have a balance port on it, so that's 3.3V x 3C = 9.9V
So when the pack reduced to 9.9V total, it'll reduce power. I thought that maybe one cell lagged behind and maybe dropped below the 3.1V critical voltage, but supposedly that cell just won't charge anymore..... If that were the case I'd have a 3C pack with one dead cell..... or a 7.4V pack right? And that's not what I'm seeing... The stupid thing just won't hold a charge.

I dunno. I'll get a balancer as soon as money permits and a new battery too. It seems the common idea was a balancer is a luxury to give you maximum power/runtime, not a "you're screwed if you don't it" item.

Just doesn't make sence. Sure I knocked the foamie around a little, but there's no traumatic damage to the pack. Actually it still looks like the day I bought it. It just doesn't work!

Does anyone NOT use a balancer EVER? Never have never will? Are there any problems associated with this?

.........and of course the warranty run out 15 days ago.

_____________________________

Wasn't that cool? I meant to do it.

(in reply to oldschoolracer)
       Post #: 6

RE: LiPo degrading - 5/28/2008 10:08:49 PM   
oldschoolracer


 

Posts: 77
Joined: 5/27/2008
From: Hobbs, NM, USA
Status: offline
quote:

ORIGINAL: spiral_72
Does anyone NOT use a balancer EVER? Never have never will? Are there any problems associated with this?

.........and of course the warranty run out 15 days ago.


I haven't yet, and had no need to as I've seen no performance problems. (knock on wood)
That doesn't say I won't some day.

I'd call, most companies are going to be that tight with their warranty cut-off.

(in reply to spiral_72)
       Post #: 7

RE: LiPo degrading - 5/29/2008 3:44:31 PM   
spiral_72



Posts: 511
Joined: 3/7/2007
From: Chesnee, SC, USA
Status: offline 		Well, I'm going to get another battery and try to keep a close eye on it.

Thanks for all the input. I wish I could afford an e-flight or thunder power Lipo.

_____________________________

Wasn't that cool? I meant to do it.

(in reply to oldschoolracer)
       Post #: 8

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