LI-po battery safety

[Texas Torpedo]

What is the average Joe supposed to do to prevent overcharging other than follow manufacturer's recommendations for charging time? Take the pack apart and check each individual cell on a meter every 10 minutes? How do we make it safe and at least somewhat convenient at the same time? Having a timer to control each outlet seemed like a reasonable approach, and was ok when I discussed the idea with Corey at LM.

Demand that the manufacturers include balance plugs and a proper charger. Then the chargers can properly charge the cells and cut off the charge when the correct balance and voltage has been achieved.
I'd hazard a guess that they have not done so yet because they are concerned that someone might mistakenly set the charge rate above what the battery is spec'd for and possibly blow it..
LiPo's have taken over in the remote control car, airplane and helicopter market, with millions of them in service, charged by kids and adults alike..
I think technically oriented (and other) divers would have no problem safely charging these batteries given simple instructions.

[TobinGeorge]

Demand that the manufacturers include balance plugs and a proper charger. Then the chargers can properly charge the cells and cut off the charge when the correct balance and voltage has been achieved.

Proper active balancing of large capacity packs is extremely hard to do, and most if not all of the "canned" solutions are ineffective.

We use an entirely different approach using passive balancing that keeps the cells from becoming unbalanced vs trying to correct an out of balance condition.

I'd hazard a guess that they have not done so yet because they are concerned that someone might mistakenly set the charge rate above what the battery is spec'd for and possibly blow it..

?? Not too difficult to "fix" the charge current on most chargers.

LiPo's have taken over in the remote control car, airplane and helicopter market, with millions of them in service, charged by kids and adults alike..

And this a the source of many of the failures, abuse by RC hobbyists of Li-Po battery packs.

I think technically oriented (and other) divers would have no problem safely charging these batteries given simple instructions.

You don't really understand this market very well......

Tobin

[Atom]

Tobin, what's your personal procedure when you charge your scooter batteries? In the house? In the garage? In a shed? Do you watch them all the time? Do you just leave them in the open or in a fireproof box?

[TobinGeorge]

Tobin, what's your personal procedure when you charge your scooter batteries? In the house? In the garage? In a shed? Do you watch them all the time? Do you just leave them in the open or in a fireproof box?

During the first few cycles of newly assembled pack we take reasonable precautions, mostly because we need to verify both the on board electronics in the battery perform as expected, and that the charger performs as expected.

After that I still recommend that our scooter batteries and *ANY OTHER* high capacity rechargeable battery be charged in an open free from combustibles.

If you short circuit a car battery (Pb wet cell) it too can catch fire and explode, all batteries need be treated with respect.

Tobin

[Texas Torpedo]

Proper active balancing of large capacity packs is extremely hard to do, and most if not all of the "canned" solutions are ineffective.
We use an entirely different approach using passive balancing that keeps the cells from becoming unbalanced vs trying to correct an out of balance condition.

That's understandable with the size packs you are producing for scooters, but not for the packs in lights, etc. My focus here is on the smaller stuff.. Say, under 10S 10k mAh..

?? Not too difficult to "fix" the charge current on most chargers.

What are most chargers? The majority of chargers I own and see (at least in the RC market) are highly variable in both chemistry and charge rate due to the fact that we deal with so many different battery sizes and types.
I have no doubt that a company offering equipment powered by LiPo packs could put together a balancing charger with a fixed rate, however I'd just assume use my own and not have multiple chargers for different battery packs.
Actually, I'd be happy to see them with balance plugs for starters for the option.

And this a the source of many of the failures, abuse by RC hobbyists of Li-Po battery packs.

Considering there are more LiPo packs in use by people in this hobby than any other that I am aware of by a large margin, wouldn't that make sense? If you call abuse crashing a plane / heli and reputing a pack, so be it, however accidents due to improper charging methods are far less now that the right chargers are available and the industry started educating the consumers. The majority of fires you see on Youtube (etc) are all intentionally created, not real accidents.

You don't really understand this market very well......
Tobin

Well Tobin, please explain it to me. As I see it, we have companies starting to utilize LiPo's but not the ideal chargers to go with them.
Again, I'm not talking about scooter batteries.

David

[TobinGeorge]

That's understandable with the size packs you are producing for scooters, but not for the packs in lights, etc. My focus here is on the smaller stuff.. Say, under 10S 10k mAh..

Do you have idea how much power must be switched and dissipated for 10ah pack?

What are most chargers? The majority of chargers I own and see (at least in the RC market) are highly variable in both chemistry and charge rate due to the fact that we deal with so many different battery sizes and types.

Using "Universal" Hobbyist chargers that claim to be able to charge 3-4 different chemistry's and multiple different cell counts and batteries of widely variant capacity is just begging for a problem IMO.

I have no doubt that a company offering equipment powered by LiPo packs could put together a balancing charger with a fixed rate, however I'd just assume use my own and not have multiple chargers for different battery packs.
Actually, I'd be happy to see them with balance plugs for starters for the option.

Great idea really. Now a battery will need 3-4-5 more leads. Of course leads on can light batteries are never a problem in the real world. Connectors never get pulled off, broken, corroded, etc.

Balancing Circuits, if used, and properly sized, need to be built into the battery pack. Selling a battery that is dependent on some external balancing circuit is again begging for a problem. What happens when Joe Diver decides to use some other charger 'cuz he forgot to bring his, dropped his overboard, ass ummed all chargers are the same etc. etc. etc.?

Considering there are more LiPo packs in use by people in this hobby than any other that I am aware of by a large margin, wouldn't that make sense?

Of course it makes sense. I never said otherwise. My other company has built and sold high end rechargeable bike lights. I've sold ~150,000 ~$200-400 bike lights. After making my living designing and selling rechargeable devices for the past 25+ years I shudder every time a customer seeking help opens with "well I used to race RC cars/boats/ airplanes, so I know everything about every battery ever made."

The level of myth, misunderstanding, market hype and outright pure nonsense associated with RC anything and batteries cannot be overstated. For starters the vast majority of RC apps involve very short very high current discharges, and often rapid recharging.
This is simply not true for bike lights, dive lights or scooters. These typically feature long slow discharges and long slow recharges. Layer on a few heaping helpings of market hype and top it off with a generous dollop silly myths and you have an RC battery "expert"

The majority of fires you see on Youtube (etc) are all intentionally created, not real accidents.

True, just like CBS and the exploding F150's, manufactured "news"

Well Tobin, please explain it to me. As I see it, we have companies starting to utilize LiPo's but not the ideal chargers to go with them.

The correct approach is robust internal BSM's that function transparently to the user. That makes the charger a simple dumb current source.

Reliability is never enhanced by requiring the user to make more choices. The best charger is one where the user can plug in the battery turn it on do nothing more until the charge is complete.

Tobin

[kwinter]

The best charger is one where the user can plug in the battery turn it on do nothing more until the charge is complete.

Tobin

And then what? Nope, the best charger is one where the user can plug in the battery, turn it on and then walk away for a day, or a week, or longer. I know that sounds stupid to you, but this is the real world.

[TobinGeorge]

And then what? Nope, the best charger is one where the user can plug in the battery, turn it on and then walk away for a day, or a week, or longer. I know that sounds stupid to you, but this is the real world.

Sure in a perfect world, but try to get off your anti Lithium Jihad long enough to understand that all rechargeable batteries carry some risk.

There is no 100% fail safe charger for any chemistry, *NO* external device can reduce to zero the chance of an internal fault within a cell.

Good pack design, and good charger design, like all other gear choices can reduce the risks, but never make them zero.

I can say that external timers, GFI outlets and thin metal containment stations do nothing, IMO, to reduce the risks.

If you demand 100% fail safe, sell the dive gear, stay home, close the drapes and hum whatever tune makes you happy.

Tobin

[kwinter]

Sure in a perfect world, but try to get off your anti Lithium Jihad long enough to understand that all rechargeable batteries carry some risk.

There is no 100% fail safe charger for any chemistry, *NO* external device can reduce to zero the chance of an internal fault within a cell.

Good pack design, and good charger design, like all other gear choices can reduce the risks, but never make them zero.

I can say that external timers, GFI outlets and thin metal containment stations do nothing, IMO, to reduce the risks.

If you demand 100% fail safe, sell the dive gear, stay home, close the drapes and hum whatever tune makes you happy.

Tobin

Don't misunderstand, Tobin. I am not looking for zero risk. Just an acceptable level of risk. And so far I'm not convinced that lithium batteries have reached my comfort level. I know it will get there, and you will undoubtedly be at the forefront. But as of right now, I don't think even you would argue that the risk is higher with lithium cells than with NiMH cells. And as long as I'm willing to live with the shortcomings and lower power of nickel cells, that's the way I choose to go until such time as my safety comfort level is reached. No jihad intended. Just a personal choice.

Ken

[TobinGeorge]

Don't misunderstand, Tobin. I am not looking for zero risk. Just an acceptable level of risk. And so far I'm not convinced that lithium batteries have reached my comfort level. I know it will get there, and you will undoubtedly be at the forefront. But as of right now, I don't think even you would argue that the risk is higher with lithium cells than with NiMH cells. And as long as I'm willing to live with the shortcomings and lower power of nickel cells, that's the way I choose to go until such time as my safety comfort level is reached. No jihad intended. Just a personal choice.

Ken

If you think NiMh cells can't runaway, catch fire and burn down your house during charge think again.

Tobin