Anything's possible

[Commander Kinsey]

Old phone, battery expanded to triple thickness, looked like an imminent explosion, using it as a quad core CPU only, so let's use a AAA battery.

[invalid unparseable]

I have seen quite a few bulging LiPo batteries in my lifetime.

LiPo batteries will bulge if overcharged for prolong period of time. Newer charging circuits will completely stop charging before reaching peak capacity. LiPo batteries should never be trickle-charged.

Unlike lead-acid, NiCd and NiMH batteries, the terminal voltage of LiPo batteries is a function of the remaining capacity. Therefore, a well designed charging circuit can determine when to stop charging by monitoring the terminal voltage.

Newer cellphones and laptops can give you an option, in the setup menu, of charging up to 80% instead of 100% capacity. That will prevent bulging and extend battery life.

[Commander Kinsey]

I wonder what the solid cylindrical ones do, like the AAA in the photo? Do they have a release valve like an electrolytic capacitor?

Actually PP3 NiCads used to bulge when getting old, not sure what was happening in the cylindrical ones.

Lead Acids also bulge.

No idea if it's LiPo or not, I treat them as just another Lithium. Just a slightly newer better version that's all.

Actually Lead Acid is the same, but you have to rest it open circuit for a bit first. Lithium probably doesn't need so long a rest.

As you do with Lead Acid. To charge one I just stick 13.8V on it and it stops taking current when it's full.

I just charge Lithium batteries to 4.2V with a bench supply on a 2 hour charge, seems to work, they draw almost zero current when they get full. Like Lead Acid, they're easier to charge than Nickel, which doesn't stop taking current when it's full.

Not sure what my phones do.

[invalid unparseable]

I have opened quite a few NiCd and NiMH cylindrical batteries when they first became popular decades ago. They do have a safety vent beneath the nipple (+) terminal. That's why you haven't heard in the news about exploding AA or AAA batteries.

NiCD and NiMH use steel cylindrical shells. They have safety vent. It is almost impossible to make them bulge.

Lead-acid batteries have open vent. It is impossible to make them bulge.

Lead-acid, NiCD, and NiMH battery will maintain steady terminal voltage and nosedive near the end. Therefore, it is impossible to judge the remaining capacity of a lead-acid battery by its terminal voltage. On the contrary, Sony camcorder can tell you exactly how much remaining capacity, in terms of hours and minutes, of its Sony LiPo battery pack.

The nominal voltage of a 12V lead-acid battery is not 13.8V. It should be about 12.7V. That means your charger is trickle charging your lead-acid battery to maintain that 13.8V.

"Almost zero" is not zero. You are practically trickle-charging your lithium batteries.

I deal with LiPo batteries very often because I play with many gadgets and toys that use them. All of the chargers that came with those gadgets and toys would completely stop charging when full. Some of the high power LiPo battery packs actually have built-in circuit to refuse charging when full, and stop discharging when the terminal voltage drops too low, in order to protect the battery. The protection circuit is internal. You don't even know its there because you cannot see it.

Many of such high power LiPo battery packs for drones, for example, don't have casing in order to reduce weight. They look like long strips of putty folded into a slab.

You can see in this example of LiPo strips combined to form a LiPo slab. Visually you can only see 3 strips, but it has 3 strips on the other side that you cannot see. So the whole battery pack is 6 strips of LiPo. A simple math: 6 x 3.7V = 22.2V (that is exactly what it advertised)

22.2V LiPo Battery 3300mAh, Lipo 6S Battery 50C

[Commander Kinsey]

Is that where the white powder comes from when they get old?

PP3 do, every single one when they age. You do know what a PP3 is? The 9V rectangular ones.

Liar, I have one right here. I use it as a weight. The ends have bulged.

Utter bullshit. Lead Acid when at rest is 11.6 to 12.6V, linearly proportional to state of charge.

Similarly NiMH is 1.2V to 1.3V.

No. Open circuit it's 12.7V. As soon as you apply a tiny current the voltage raises significantly. The current is minute, enough to fill it in a few months. But if you don't give it that current, it will self discharge in a few months. So you're just keeping it full. Like a dripping tap counteracting evaporation from the full sink below it.

They don't care. And it's not like I leave them there for weeks on end. I plug them in then unplgug them when they're full and I happen to be around. Might be a few hours later, might be the next day.

They advertise it on the side, mind you the AAA in the photo is made by "Trustfire" - so I don't believe the lie on the side, or it's capacity.

Maths. Short for mathematics. If you're going to steal our language, don't bastardise it.

[Commander Kinsey]

Why do they not give Lithium batteries a safety vent?

[invalid unparseable]

Yes, the electrolyte leaked and dried out due to overcharging by trickle-charge.

9V are pile-batteries. The rechargeable ones are either 8.4V or 9.6V NiMH. Personally I have never seen one that bulged.

You must be talking about the single cylindrical ones. I must say it's lousy British technology and moronic users.

Knowledgeable people know that one cannot reliably tell the remaining capacity of a lead-acid by its terminal voltage. You can believe all the nonsense from the internet you want.

Trickle charging is OK for lead-acid batteries, but will kill LiPo batteries by making them bulge.

That will kill LiPo batteries by making them bulge.

I am familiar with "Trustfire". Trustfire makes cylindrical LiPo batteries, not AA or AAA format.

[invalid unparseable]

I haven't seen a rechargeable Lithium battery yet. Coin batteries are 3V Lithium, but not rechargeable.

3.7V LiPo batteries are like putty. There is no liquid electrolyte, so you see, in the link I showed you, that they are wrapped in thin plastic.

[Commander Kinsey]

What do you think the Li stands for in LiPo and LiIon?

My phone battery got three times thicker without letting gas out. Eventually I guess the plastic would rip, but rather suddenly and with toxic gas. I would rather it seeped out gradually.

[Commander Kinsey]

No, ones stored in a cupboard and hardly used do it too.

All mine did when they got old.

No, car batteries, 6 of 2V cells in a big heavy rectangle. And the "user" is the car.

There are thousands of sites with the same information, and from personal experience they are correct.

Then they're a piece of shit. They shouldn't take current when they're full.

I doubt 10mA into a full 3000mAh battery will kill it. You just get heat.

You really do know nothing at all don't you? Would you like a close up photo of it?

[invalid unparseable]

Of course I know. Lithium batteries are not rechargeable, but LiPo are. They both have lithium inside, but are different animals.

You should worry more about your phone catching fire. There are internal wiring inside the LiPo battery. The bulging will tear the insulation and short-circuit some wires. LiPo has very high discharging rate. It can start a fire.

I haven't seen bulging LiPo batteries for more than 10 years, at least. Apparently they have figured out that trickle charging is causing LiPo batteries to bulge and crack the phone casing, and cause spontaneous combustion in cellphones.

[invalid unparseable]

You really should crack open one to see for yourself. They use a metal plate to cover the vent. The metal plate will not restore itself once it has been pushed up. The battery is not sealed anymore after the safety vent has activated.

It's either lousy British technology or your misguided habit of connecting your battery to a constant voltage to recharge.

I have never seen a bulging 12V car battery. There are vents, and the casing is hard plastic. I think you are full of shit.

One moron repeating what the other moron says.

Any battery will take current if you connect it to a voltage higher than its nominal voltage. You still don't get it.

The energy you put into a battery will do work. It is supposed to charge the battery in an electro-chemical process. When the electro-chemical process is complete, the excess energy will cause other unintended electro-chemical processes. Heat is only one of the byproducts. The other unintended electro-chemical processes are causing the bulging.

I own a few of the Trustfire 3.7V batteries for my high power LED laser (10W). It is powerful enough to ignite a piece of paper just by pointing at it.

[jim.gm4dhj]

totly

[Brian Gaff]

Why do batteries expand with age, I wonder. It seems to have always been an issue way back to the old dry cells. Brian

[invalid unparseable]

Thanks for point that out. The one you posted is "not available". I did a search. There are just a few listings for 3V rechargeable. Most are

3.7V. There must be a reason 3V rechargeable is so rare. Maybe it doesn't last long. I had bought some 1.5V rechargeable alkaline AA and AAA many years ago which died after a few charging cycles, so nobody wants to buy them anymore.

It is really strange. I have never come across one. The plates are lead, and the shell is hard plastic. I can't imagine how lead can swell.

[Vir Campestris]

Lead itself can't.

But...

In the charged state the plates are made of lead and lead oxide.

As they discharge both are converted to lead sulphate.

During that conversion the plates may change shape.

Andy

[invalid unparseable]

I have toyed with lead-acid batteries in my youth, and cracked open some to investigate what's inside. Lead in the battery can only turn into powdery coating. Some will drop to the bottom. It can never push the plastic casing out.

I have done a Google image search for "12V car battery bulging". The bulging car batteries they show are "SEALED" lead acid battery, and the reason for bulging is "fast charging at high rate" and "overcharging at high rate" which cause heat and gas that soften and push out the plastic casing because "SEALED" lead acid batteries cannot vent the gas created by fast charging and over charging.

Google image search for "12V car battery bulging":

[Rod Speed]

Brian Gaff [e-mail] wrote

With lead acid batterys, sulphating of the plates with not enough space between the plates originally.

With those the body of the cell corrodes.

[Commander Kinsey]

You're being overly pedantic either for comic effect or because you're an OCD idiot.

Lithium (and presumably something else, a battery needs two chemicals doesn't it?) makes coin cells you can't recharge. Then came several variaties of rechargeable Lithiums. Your favourite is the Po, but there were many before it. There are still at least three types on sale. I hear of LiFePo for example. Reality check - when someone says "a Lithium battery" they are quite likely talking about a rechargeable one where Lithium is one of the components, it could be LiPo or any of the others. As in "my electric car runs on Lithium batteries".

So why do you love them so much? Lead Acid doesn't catch fire, it's full of water.

Well this one did. Only about 3 years old, bought new.

Sounds like a totally shit battery design to me. And as I've already said, if I were to connect a Lithium battery to a bench supply set to precisely 4.2V and leave it forever, the trickle current to a 3Ah battery would be about 10mA. I doubt that would cause damage.

Try this: Stick your phone in your back jeans pocket. Fall over onto something hard like some concrete steps outdoors and snap the phone in half. Try to get the burning phone out of your pocket before your buttock is singed. Yes it's happened, I've seen the youtube video.

[Commander Kinsey]

One possibility is the devices those go in are things like a computer motherboard for the BIOS settings which draws so little power there's no point in having a rechargeable. Or a watch where the hassle of getting it open is far more than the cost of a 10p cell so who cares if you have to buy one every 3 years.

Those don't have to be different batteries. You can buy a charger which will charge any Alkaline battery 10 times, it just does it slower, you could probably use a 16 hour NiCad charger. Maybe those "special" batteries were just normal Alkaline and you were ripped off.

The plastic swells, the lead could have buckled and pushed on it. Lead is soft and bendy.