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Old 03-25-2009, 01:13 PM   #1
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Default losi lipos puffed ***CRAP*** ?

Hey guys,

I have a friend who just got two losi packs, the 14.8v hardcase packs. He charged them with the balance connected and they seemed good. He puts it in his DB8 and starts testing it out in his yard and driveway. he has the teckno rc conversion, and MMM 2600 system in there. he is geared at the stock spur which i think is 48 and a 18 pinion.

He got done with the first pack, and when he pulls it out its puffed. The cells, or one of the cells, has gone bad after one use. he said the temps were only at around 140 i think, and the fan on the ESC was on, but when he took the body off it stopped (went below 150). (how can you get accurate battery temps with a hardcase pack)

He plugs the next battery in to charge that, and after less than a minute of being on the charger it reads 0.00 volts! and the blue cable on the balance plug is busted out of the soldering job.
He spent over $400 on these batts and they are both pretty much shot, both are now puffed, and we were at the LHS having the guy call LOSI to see about a refund or exchange

i told him that maybe his gearing was a bit high and he should have been about 16t on the pinion.


he was using some proline tires and stock spur, which i think he said was 48, and 18t pinion. he said he didnt want to use a smaller one because it already pulled wheelies on a start, and was "scary fast." he was absolutely amazed at the power this thing had, before the battery crapped out.

Any experience with these batts or gearing on this setup would be appreciated!

-MJ
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Old 03-25-2009, 01:21 PM   #2
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Since this happened to two brand new batteries, I'd say it was user error.

Either he didn't have the lipo cut-off turned on, or he was charging on the wrong settings. This seems more likely to me.
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Old 03-25-2009, 01:28 PM   #3
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he was using a MMM. so im not sure if you can turn that off... if you can, i wouldn't expect it to come from the factory like that. most ESC i know come with lipo safe mode on.

it very well could have been user error, but i was thinking it was because of the over sized pinion, and not charging errors.

i also don't know of any way to charge it at the wrong setting with the charger he was using. you put in the MAH of the battery and it automatically adjust the amps for charging. 5 amps for 5000mah.

the blue wire not even being attached to the battery... when it comes out of the box like that, how is it user error?

i am sorry if the post came out like a losi hater thread. it was not meant to be at all. i am trying to see if anyone else has some experience here.

thanks!
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Old 03-25-2009, 01:36 PM   #4
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i am sorry if the post came out like a losi hater thread. it was not meant to be at all. thanks!
It didn't come across as a losi hater thread. I'd be pist if that happened to me.

But I wouldn't buy batteries from Losi. It's like buying a car stereo from Toyota. Losi knows how to make good RC's as Toyota knows how to make good cars. But Losi simply contracts out their batts just like Toyota contracts out their stereo's. If you're going to buy a good car stereo, get it from a company that specializes in stereos like Kenwood or Pioneer. If you're going to buy a Lipo, buy from a company that specializes in lipos (SMC, Maxamps, Thunderpower, etc.). Just my two cents.

But yea, definitely try to get a refund on those, even if it was your friend that goofed up.
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Old 03-25-2009, 01:40 PM   #5
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Losi/Horizon is usually pretty good about returning/replacing things, but there's only one way to find out.

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Old 03-25-2009, 01:40 PM   #6
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well the LHS is helping out with that, he ordered through the hobby shop. so its money out of their pocket too if he just returns them. he is looking the get them replaced at least, and money back at the best.

then he will get some better packs after that,

hes gotta get some hardcase packs though because the track mandates you have hardcase packs.
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Old 03-25-2009, 01:41 PM   #7
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You have to set the cutoff in the MMM, I believe it is off by default. Sounds like user error or faulty equipment other than the batteries. The odds of getting two bad batteries is slim to none.
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Old 03-25-2009, 01:43 PM   #8
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hmmm, maybe ill have to get some more info from him as well, i dont want to put words in his mouth that arent his.

he was pissed though, two packs at 200 each, and both dont work, and both puffed. he never even put on in the truck.

i will ask him about the cutoff, lets hope he had that on.
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Old 03-25-2009, 01:46 PM   #9
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You have to set the cutoff in the MMM, I believe it is off by default. Sounds like user error or faulty equipment other than the batteries. The odds of getting two bad batteries is slim to none.
That is what I was thinking. I believe you have to set the voltage on the MMM based on the number of cells you are running.
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Old 03-25-2009, 01:50 PM   #10
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You have to set the cutoff in the MMM, I believe it is off by default. Sounds like user error or faulty equipment other than the batteries. The odds of getting two bad batteries is slim to none.
You're right. Now that I think about it, I remember the first time I programmed my MMM, the lipo cutoff was off by default. I remember thinking how dumb that was. Luckily I never ran the car long enough to get the batts low before finally installing the software and programming it. I guess they figure you'll program it before you run it.
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Old 03-25-2009, 01:51 PM   #11
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Definitely sounds like he didn't have the low voltage cutoff on. Packs usually only puff if the voltage gets too low or the cells are damaged after hard usage over time. Given the packs are new, I think we can rule out hard usage.

It doesn't sound like he is very experienced using lipo batteries as this is a totally preventable and potentially expensive error on his part.
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Old 03-25-2009, 01:54 PM   #12
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Originally Posted by Edumakated View Post
Definitely sounds like he didn't have the low voltage cutoff on. Packs usually only puff if the voltage gets too low or the cells are damaged after hard usage over time. Given the packs are new, I think we can rule out hard usage.

It doesn't sound like he is very experienced using lipo batteries as this is a totally preventable and potentially expensive error on his part.
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Old 03-25-2009, 02:24 PM   #13
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As far as I know, all CC speed controls are defaulted to the LiPo cut-off disabled... Actually, I don't know of any that ship with it enabled as when you run NiMh batteries, it's going to trip the cut-off a lot, and that's what a lot of people still run...

Still, for the 2600, he should gear down a couple teeth, I think.
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Old 03-25-2009, 02:34 PM   #14
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My friend runs the Losi 2100 with a 45/13 ratio. Stock was 45/16 and it was really fast for the track we run at. If your friend is running a 48/18 with a faster motor, he is probably drawing a ton of current. Just by the motor numbers, the equivalent speed for your friends car compared to my friends would require the use of an 11.2 tooth pinion. So 11 or 12 teeth.
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Old 03-25-2009, 02:36 PM   #15
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Quote:
Originally Posted by SQC049 View Post
Since this happened to two brand new batteries, I'd say it was user error.

Either he didn't have the lipo cut-off turned on, or he was charging on the wrong settings. This seems more likely to me.
It is quite common for Lipo's to poof up, this seems to happen when they are pushed extremely hard, however too much puffing can decrease the lifespan of your Lipo, this is why LiFe batteries are far better.

I'd get the largest spur and a 17t pinion.
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