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Old 01-21-2008, 02:22 PM   #241
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this is a question for linger....if we are going to warm a battery to make it perform better, what temp would the device need to get them to and still be safe?
and would we do this before charging, during charging or both. and if we were to follow this advice it wouldnt have any negative affects on the battery life right?
please give us some more specific advice on this.
Ideally you want the ending battery temp below 150 deg F so you can start out around 100-110 deg F. Once you hit about 190 deg F, the battery electrolyte starts breaking down and you will be massivley reduced preformance. One you hit about 390-400 deg F (depends on exact chemistry) - you will have a fire.

Danny/SMC - if you were to make a battery warming sock, I would personally buy it and endorse it.
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Old 01-21-2008, 02:30 PM   #242
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Ideally you want the ending battery temp below 150 deg F so you can start out around 100-110 deg F. Once you hit about 190 deg F, the battery electrolyte starts breaking down and you will be massivley reduced preformance. One you hit about 390-400 deg F (depends on exact chemistry) - you will have a fire.

Danny/SMC - if you were to make a battery warming sock, I would personally buy it and endorse it.
How does voltage play a factor in temp and fires? If you charge a pack and it never gets over 100 degrees then it will never catch fire? I'm not asking to be a smart azz just curious as I've heard you are VERY knowledgeable on this Lipo stuff.
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Old 01-21-2008, 02:41 PM   #243
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How does voltage play a factor in temp and fires? If you charge a pack and it never gets over 100 degrees then it will never catch fire? I'm not asking to be a smart azz just curious as I've heard you are VERY knowledgeable on this Lipo stuff.
Linger put together a very good thread about LiPo fires a while back. You can read it here:

http://www.rctech.net/forum/showthread.php?t=182219

Here's what he said about overcharge:

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Originally Posted by linger
2. OVERCHARGE LiPos are extremely non tolerant to an overcharge condition. A standard charge profile is CC/CV to 4.200V. Drastically overcharging a cell just once is a sure way to send a cell into thermal runaway. Overcharging a cell slightly but repeatedly is also extremely bad for a cell. For example, it you charge a cell to 4.300V, the lithium ions start plating on the electrodes forming lithium metal. Lithium ions are not flammable, but lithium metal is. Every slight overcharge cycle will plate more and more lithium metal resulting in a battery that is very prone to igniting.

The best way to prevent overcharging is to charge through a balancer and to avoid chargers that do not charge with the standard 4.200V CC/CV charge profile. At this point in time I do not recommend passively balancing the cell (matching the voltages while the cell is not charging) I posted my reasons for this in another thread somewhere. There is an Integy charger with a 4.25V/Cell setting which allows for a slight overcharge. In my opinion, that charger should be banned.
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Old 01-21-2008, 02:49 PM   #244
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Linger put together a very good thread about LiPo fires a while back. You can read it here:

http://www.rctech.net/forum/showthread.php?t=182219

Here's what he said about overcharge:
Thank you.
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Old 01-21-2008, 05:55 PM   #245
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Thanks Danny and Tony for the Information. Its nice to see guys letting out speed secerts to the non-team drivers. I will be buying SMC Lipo when they hit the market...


Thanks,

Speed
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Old 01-21-2008, 07:21 PM   #246
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Hahaha. Yea, thanks guys! You're the greatest! Can I get a free battery?
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Old 01-21-2008, 07:26 PM   #247
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And a fire extinguisher?
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Old 01-21-2008, 07:45 PM   #248
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I hope this makes it clear why it's important that you guys as leaders in this business send the right message about safety. Because even after this entire thread, and all the talk about why this is possibly the dumbest thing you can do, you still have people coming here to thank you for the "speed secrets." Right or wrong, people look up to you guys. And now they think you're endorsing these practices. Can you really sleep at night knowing that people who don't know any better look up to you, and might get hurt by your endorsement (silent or otherwise) of what's been said here? Really? 'Cause if one person on this thread is saying it, how many more are thinking it?

This thread makes me sad, and somewhat ashamed to be involved in R/C. It's been ugly when it didn't have to be, and has obviously put the wrong idea into the heads of the weak-minded. Today, I weep for our hobby.
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Old 01-21-2008, 07:55 PM   #249
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And the daytime Emmy goes to......syndrOme!

How many times do I have to say we DON'T endorse this before you actually quit posting that we do? Are you intentionally ignoring my responses or are you just trying to be antagonistic?

Quit "weeping", wipe your eyes dry, and read my posts.
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Old 01-21-2008, 08:23 PM   #250
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Danny, et all. You probably need to have an attorney look at this thread for you. I can easily see somebody burning down a house and/or a buisness and citing the information on this thread as the reason why. I don't think any of you realize how quickly this info can find you defending your advice in court. The defense "if I told you to jump off a building would you?" does not work in court.

There is a VERY good reason that every other company that has produced thes e kinds of batteries have strict, conservative guidelines about how to handle their batteries.
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Old 01-21-2008, 08:36 PM   #251
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Jack - Is it possible to be deaf from text??...lmao.... It's hilarious that no matter how many times it's posted the same people have to take a shot.. Hmmm, maybe they are just trying to add to their r/c tech post count.... Maybe they just like seeing their screen name every 2-3 posts....lol..

Yes, I am being a smart (censored)... but seriously... COME ON!!!
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Old 01-21-2008, 08:41 PM   #252
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Originally Posted by Jack Rimer View Post
And the daytime Emmy goes to......syndrOme!

How many times do I have to say we DON'T endorse this before you actually quit posting that we do? Are you intentionally ignoring my responses or are you just trying to be antagonistic?

Quit "weeping", wipe your eyes dry, and read my posts.
Your words keep saying that you dont endorse it, but by giving the step by step instructions on how to abuse the packs and get more power out of them, your actions ARE saying it's ok. And refusing to remove it even says it louder that you think it's ok.
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Old 01-21-2008, 08:42 PM   #253
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I just thought of what this thread reminds me of...... The movie Happy Gilmore.... you know... the guy who followed Happy around the golf course yelling profanities at him each time he went to hit the ball.... Yep... I need sleep...lol..
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Old 01-21-2008, 08:46 PM   #254
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Losi boy - Neither Jack nor Danny gave instructions how to do this... Tony did... He is not a SMC rep.... Get over it...
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Old 01-21-2008, 08:47 PM   #255
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Do you guys realize since I left in the early afternoon I drove to the airport, sat on a plane while they fixed the engines and flew to Atlanta and the same people are saying the same things.

Jack has said numerous times he does not endorse overcharging and has no interest in killing our hobby, Ok fine I believe him.

A few people still want to keep saying Danny and Jack are trying to kill lipo use, Ok fine, probably not.

Josh has said as a track owner he does not endorse overcharging and will ban people from his track if he finds them (plus I will be really pissed off if one of the people I race every week is doing it, but I don't think they are), Ok fine I believe him too.

So I think everyone actually agrees.

I do think ROAR needs to make the point real strong that they don't like it either. Actually I would like to see all tracks take a stand like Josh has, perhaps ROAR and the battery companies can help with that.
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