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EP 4200 blew up in my face today. >

EP 4200 blew up in my face today.

EP 4200 blew up in my face today.

Old 11-13-2007, 07:22 AM
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Originally Posted by wes95_z28
Undoubtledly, of course there will be a battery war. If it werent for competition, we wouldnt be trying to get 4300 MAH out of sub c sized cells. A battery war will insue, i have no doubt in my mind. But with there already being a saftey concern about li-po manufactuers will not release these batteries untill they believe they are safe.

It is then up to the user to again READ THE DAMN MANUFACTUERS INSTRUCTIONS AND CHARGE THEM HOW THE MANUFACTUER RECOMENDS.

Of course you know some jackass out there will think he can win a race by charging his 20c 4800 mah lipo at 37 amps or so and wind up burning a beloved track to the ground. That is why i am standing up so strong in this thread there is absolutely no point in charging a sub c at 10 amps. its stupid. I am sorry if i affending people, but i really dont care if i do, only becuase i know the ones i am offending are the jackass charging at more than 6 amps.

I have my 2 year old daughter at the track with me when i am racing and the last thing i want to happen is have a sub c or li-po pop when she is anywhere near it. I have been using li-pos for 4 years now in various minis. All brands all cell counts you name it i have done it. Except for have one burst into flame. I have even had a ESC fail and dead short the battery, the battery did swell after half an hour at that point i put it in the middle of the driveway for over 12 hours and nothing happend.

That is the only Li-po mishap i have had. I have had a Losi triple x-s burn to the ground with a NIMH battery on board. It was due to a horrible crash in which the pack took a direct hit and shorted and caught the plastic chassis on fire.

I consider both just a part of the hobby things happen sometimes. It is ridiculous however to push the limits and the manufactuers warnings on what a battery can and cannot handle.
The good thing about lipo is there really isn't any performance increase from charging at higher rates. The only 2 things you're left with to worry about is time and voltage.

Time because there's always someone trying to get a pack charged in less than the ~1 hour needed to charge a lipo. Rotating 2 packs would solve this little dilemma of course. Now Orion has stated their packs can be charged at a 2C rate. Whether the pack have been stickered that way or instructions have been updated I am not sure.

Voltage because there are some chargers (Integy comes to mind) that you can set a higher than 4.2V/cell. I had an Integy that you could set to 4.25V per cell which is, in my opinion, an absolutely crazy thing to do.
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Old 11-13-2007, 07:36 AM
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Default charging time on lipo's

Please remember that if you are running a 4000mah+ LIPO pack, there is no way you will use even 75% of that capacity in a race, unless there is something serious wrong with your car (you will probably use about 50%.) In addition, because LIPO don't heat up with discharge and are more efficient that nimh, that 4000mah pack will be more like a 5000mah nimh pack (and it's lighter too, which puts even less stress on the motor and therefore draws less power from the battery.)

Also keep in mind that unlike nimh, you can charge up a lipo the week before and run it on race day. When you top off a lipo, the longest part of the charge is the last 10% because you are in the cv phase of the cycle, and the current is dropping to 0. You can pull the pack when you see the current dropping from your original charge rate.

Plus, when everything goes brushless, the power draw of the brushless motors is much less than the brushed, so topping off will be even shorter.

In short, if you want your LIPO packs to last their longest, don't charge your batteries above about 1.4c (according to linger.) You really don't need to.

Last edited by billjacobs; 11-13-2007 at 07:57 AM.
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Old 11-13-2007, 08:59 AM
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Originally Posted by SRBMOJO
yes it was an ICE, I have two, I'm pretty sure I know what they look like. The display said charge rate 10 amps, discharge rate 10 amps.

I have had 2 since they came out. If you have two then try adjusting the charging amps to 10. You will find that you cannot. They will only be able to go to 8 just like the specs state:

http://www.duratrax.com/caraccys/dtxp4170.html

So either you were looking at a different charger(maybe the new Checkpoint/ICE 2.0) or you were seeing the discharge amps.
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Old 11-13-2007, 10:10 AM
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Originally Posted by mkdut
I have had 2 since they came out. If you have two then try adjusting the charging amps to 10. You will find that you cannot. They will only be able to go to 8 just like the specs state:

http://www.duratrax.com/caraccys/dtxp4170.html

So either you were looking at a different charger(maybe the new Checkpoint/ICE 2.0) or you were seeing the discharge amps.
Ha Ha Ha. I love the signature. Chevy Chase is one of my favorites.


My ICE will not go to 10 amps. Anyways, I'm ready for the lipos. Our track is gonna allow them now.
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Old 11-13-2007, 10:32 AM
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Originally Posted by billjacobs
In short, if you want your LIPO packs to last their longest, don't charge your batteries above about 1.4c (according to linger.) You really don't need to.
LOL...way to go...LOL...boil out all the nuance and just make up some arbitrary number. I'm 100% sure that's not what Linger said.

He said that some batteries will degrade faster when charged at rates higher than 1.5...some will degrade faster when charged at over 1c, some will perform better when charged at higher rates, most will live longer at 1 or lower, some will tolerate higher rates better than others.

The 1.5 figure Linger mentioned was nothing more than a generic figure for a point on a curve where he opined that the returns were outweighed by the cost...when it came to many of the batteries he had worked with.
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Old 11-13-2007, 11:18 AM
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Default lipo charge rates

Since linger said 1.4c as a number for many of the lipo's he tests, and I don't have the equipment he does or the cells to test, that's good enough for me.

I'll you what, buy 10 of whatever LIPO packs you want to run, send them to linger, and have him test them for you. When you get a number, please share it and the brand and model of the packs so we can all be informed.

If I don't know, instead of guessing, I take a conservative approach and listen to those who know more than me. Makes my life easier. But I guess R/C is all about reinventing the wheel, especially when it has been stated many, many times that charging at a higher rate doesn't have any benefit, but can shorten cell life.

But what do I know.

linger's quote:
Technically, you get a tiny bit more cycle life at 0.5C vs 1C charge, but the difference is so small, that it's not worth it. The cycle life degredation seems to be exponential. For example, some of the cells I tested had fantastic cycle life up to about 1.4C and then you really start noticing a dip at 1.5C and the dip becomes huge at 2C. It's highly dependent on the battery and it chemistry on how high of a charge it can accept.
Also, charging at a higher charge rate does not make it perform any better - it just takes away cycle life..
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Old 11-13-2007, 12:35 PM
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I guess some people aren't wired to see nuance. Since you seem to be one of those people, then by all means, please use "1.4C" for all occasions.

Just please don't spread it around like it really means anything to any of the rest of us who read the rest of his post.

I'm all for being cautious and I don't charge them any faster than I have to...but there isn't really anything magical that happens in every Lipo cell at 1.41C that doesn't happen at 1.39C. Somewhere between some cells living a long time at 1C and notsomuch at 2C you make your own decisions. Like he said in that post and elsewhere, SOME cells do that, some are more tolerant and some are not as tolerant. But hey...for you...1.4C is it.

Originally Posted by billjacobs
Since linger said 1.4c as a number for many of the lipo's he tests, and I don't have the equipment he does or the cells to test, that's good enough for me.
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Old 11-13-2007, 07:35 PM
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Originally Posted by 403forbidden
does anyone at Trinity have the decency to contact the original poster at least to see how he is doing?
No they still have not contacted me. I really don't know what I am supposed to do now.
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Old 11-13-2007, 07:39 PM
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Originally Posted by billjacobs
Since there are racers from many countries on this board, what's a snop?

The original intent of this thread was to shed light on the dangers of the 4200 nimh cells and in small part about the complete disregard shown by Trinity. My first and only concern is about the safety of those racers who have had nimh blow on them. Batteries are cheap and the days of nimh are numbered anyway, so I don't have any pity for IB and EP and whoever.

On to Trinity. I love how trinity starts all of the arguments in r/c to keep the old technology and then quietly releases the new technology, but because of the bad blood, people are reluctant to buy new technology with trinity's name on it. This is IRONY at its best.

Roads, has the damage from the cell blowing healed?

Thank you for redirecting people in the direction this thread was originally intended. I think the damage has healed for the most part. I still, at times, have slightly blured vision. I never went to a doctor when this happened but that is my own fault. I don't feel I will suffer any long term affects.
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Old 11-13-2007, 08:08 PM
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Originally Posted by Roads
No they still have not contacted me. I really don't know what I am supposed to do now.
That really is too bad.

It wasn't too long ago, that ErnieP (Trinity owner and CEO, Ernie Provetti) came on to these boards, to constantly bash brushless technology. He made hundreds of posts bashing it.

Yet he doesn't have any time to simply check up on a customer when one of his products blows up in the customers face?

Shame.
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Old 11-14-2007, 01:50 AM
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I hope your vision goes back to normal and sorry to hear about the injury. But I agree that we should be more careful with handling the 4200 pack regardless of them being ep or ib. I've followed the instructions of the manufactures and lately I've been having trouble with the ep cells. Often when I charge them, the cells on the ends get hotter than all of the other cells unless I put them on the discharge tray every time.

Bottom line I guess is be careful charging and handling the 4200 packs
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Old 11-17-2007, 01:47 PM
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Glad things are getting better, and hopefully trinity gets back to you. Something like this can't be just neglected...

Have cells under 4200mAh had as many problems as cells today do? There's just so many incidents with the 4200mAh batteries...
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Old 11-20-2007, 02:42 PM
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Intellect just announced IB4600s!

I can see suicide bombers with those strapped to themselves
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Old 11-20-2007, 03:44 PM
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lets get it right, they have been announced, subject to testing before release, as I think they know to well the problems they have had.
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Old 11-20-2007, 08:03 PM
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Originally Posted by drivingpro
Intellect just announced IB4600s!

I can see suicide bombers with those strapped to themselves
.......can i charge them at 100 amps dad? can i? can i? can i?...............
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