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Apple
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Unbalanced batteries.


Are those cheapy batteries or what?

Please expand on this topic :)
batteries become unbalanced when the individual cells of the pack discharge at a different rate. when this happens the battery can overheat, and "runaway" on you essentially getting hotter and hotter until it either explodes or "vents" and shoots flame out of the vent. That is why it is always best to "Balance charge" your batteries. The balance charger will monitor the individual cells and make sure they all charge equally and are "balanced"

typically, cheaper batteries tend to become unbalanced more easily than Name Brand or High End Battery packs, although I have had high end packs do it as well. Packs have a higher tendency to become unbalanced when run too low also. I set my cutoff point to 3.2v per cell in the speed control in my cars. You can also get a "LiPo alarm" that plugs into the balance leads of the battery pack. The alarm will sound when the battery drops to a preset level.

LiPo battery packs are rated at 3.7 volts per cell, and either wired in series "S" or in parallel "P"

So a 2S pack is rated at 7.4 volts, 3s at 11.1, and so on. a 2P pack would still be rated at 3.7 volts, and you would add together the amperage of the cells instead of the voltage.
 

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Apple
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Are these batteries in use on electric bicycles as well?
Yes. there are some that still use Lithium-Ion, and Lead Acid batteries, but more and more have changed over to LiPo, because they are lighter than Lead Acid and have a higher output rating, meaning "Burst" or "C" rating.


Note: there are two different "C" ratings: one is the charge rate, which is anywhere from 1-5 C, and there is the Burst rating, which relates to the short term high output of the battery. I have one 2S 4200mah battery that is rated at 75C, which means it can put out 315 Amps at 7.4 volts for a short period of time.
 

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If you intend on not using the lipo for several weeks/months/years, Charge the battery using the "Storage" setting on your charger (If it has such setting), then put them into a lipo bag, metal box on something metal or less prone to damage incase they catch fire. The battery still needs to be maintained even while storing them, they discharge overtime and will puff up or worse catch fire.
 

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Yes. there are some that still use Lithium-Ion, and Lead Acid batteries, but more and more have changed over to LiPo, because they are lighter than Lead Acid and have a higher output rating, meaning "Burst" or "C" rating.


Note: there are two different "C" ratings: one is the charge rate, which is anywhere from 1-5 C, and there is the Burst rating, which relates to the short term high output of the battery. I have one 2S 4200mah battery that is rated at 75C, which means it can put out 315 Amps at 7.4 volts for a short period of time.
Aren't lithium ion batteries the same as li-po aside from form factor?

I know you can get ICR and IMR chemistry li-on cells and the IMR ones are supposedly safer, is there something like that for the li-po packs?
 

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Discussion Starter #32
If you intend on not using the lipo for several weeks/months/years, Charge the battery using the "Storage" setting on your charger (If it has such setting), then put them into a lipo bag, metal box on something metal or less prone to damage incase they catch fire. The battery still needs to be maintained even while storing them, they discharge overtime and will puff up or worse catch fire.
So if not using them like you described, they must be kept charged :confused: ???
 

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The Piratenite
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How reliable are current name brand cordless tool batteries that stay on maintence chargers ?

I have several always on the charger in the garage. Would putting them in a metal container be a prudent super safety guy move ?

Fwiw.... I had a chicom flashlight burst into flames while sitting on my toolbox a few weeks ago. It was I inavertentatly left on and and placed face down.
 

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Apple
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Aren't lithium ion batteries the same as li-po aside from form factor?

I know you can get ICR and IMR chemistry li-on cells and the IMR ones are supposedly safer, is there something like that for the li-po packs?

Sort of: Lithium Ion has been around for 100 years, LiPo was invented in the 70's as an offshoot of Li-Ion. LiPo has a higher output, and more flexible form factor, sue to the construction of the density of the battery.

Losi makes a "Smart" LiPo, but the cost is about 4x what a regular LiPo costs.

Supposedly, LiFePo4, or Lithium Ferrite Phosphate, which is used in full size electric cars, is supposed to be the next thing coming. I don't know much about them though.
 

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Apple
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How reliable are current name brand cordless tool batteries that stay on maintence chargers ?

I have several always on the charger in the garage. Would putting them in a metal container be a prudent super safety guy move ?

Fwiw.... I had a chicom flashlight burst into flames while sitting on my toolbox a few weeks ago. It was I inavertentatly left on and and placed face down.
Name brand stuff like Makita, DeWalt, etc... are designed to stop charging if there are inconsistencies in the batteries, through the chargers. They also have thermal limiters that will fail before you overheat the cells.

that doesn't mean they are perfect, but they are a lot safer than standard LiPo packs we use in r/c or in the custom flashlight hobby.


Keith may disagree with that though, since his house in Lincoln burned down from a faulty DeWalt battery and/or charger.
 

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That is why it is always best to "Balance charge" your batteries. The balance charger will monitor the individual cells and make sure they all charge equally and are "balanced"
I balance packs every 5 cycles.
but I check individual cell voltages using the taps and charger before charging.

FWIW bulk charging a lipo and not balancing it will only charge it to about 90% capacity.

my shit is all oversized, so it's not a big deal, but if you want maximum performance, balance charge.

I also rarely discharge below 40% capacity, so my packs generally stay pretty well balanced.
 

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The Piratenite
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Name brand stuff like Makita, DeWalt, etc... are designed to stop charging if there are inconsistencies in the batteries, through the chargers. They also have thermal limiters that will fail before you overheat the cells.

that doesn't mean they are perfect, but they are a lot safer than standard LiPo packs we use in r/c or in the custom flashlight hobby.


Keith may disagree with that though, since his house in Lincoln burned down from a faulty DeWalt battery and/or charger.
Oh shit, is that what caused his fire ? Where does he live now ? I live in Lincoln now and think i would have seen him around if he was here :confused:

Hmm. Not digging my new Milwaukee lithium tools quite as much now. Looks like I will add fire resistant metal cabniet to my shopping list. :mad3:
 

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Name brand stuff like Makita, DeWalt, etc... are designed to stop charging if there are inconsistencies in the batteries, through the chargers. They also have thermal limiters that will fail before you overheat the cells.
... that will 'brick" your batteries.:mad3: At $80 a pop, you gotta be careful when you plug 'em into the charger. A hot Makita battery will "brick" as soon as you plug it in. A battery run to zero will do it as well.

Wish there was a way to rebuild 'em.:(
 

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Not digging my new Milwaukee lithium tools quite as much now. Looks like I will add fire resistant metal cabniet to my shopping list. :mad3:
Meh, I wouldn't worry about it.
 

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Apple
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Oh shit, is that what caused his fire ? Where does he live now ? I live in Lincoln now and think i would have seen him around if he was here :confused:

Hmm. Not digging my new Milwaukee lithium tools quite as much now. Looks like I will add fire resistant metal cabniet to my shopping list. :mad3:
I'm not sure where he is now. It was before I moved out to Tx. in 2009 so he could be anywhere by now.

FWIW, in the 20-odd years that I've worked with cordless power tools on an almost daily basis, I've only had one battery fire, and that was a nimh pack.

I've had several pack failure with my r/c cars over the years, both nimh and LiPo. There are a lot more safety measures built into power tool batteries. I would assume that is because it is a much larger industry, so there is much more money to be lost.
 
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