overcharger lipo battery grrrrr
 

i had 2 2s batterys and by accident i hooked up the balancer tap from one battery and the deans from the other to my charger. i now have 4.5 volts in each cell. the battery is not hot and not swollen..... what to do.? is it junk? the charger has a heat attack if i try to hook up the right tap cause it is overcharged now.

You probably have shortened the life of the cells but I would put in a car and gently run it back down to 3.7v under supervision (in a safe place) and balance charge again properly.

How the heck did that happen? The pack with the Deans plug attached to the charger was the one that took a charge. So, if the cells are too high, it sounds like the charger was set up wrong. The balance connector usually just discharging high cells.

What happens if a battery is inadvertently overcharged? lithium-ion is designed to operate safely within their normal operating voltage but become unstable if charged to higher voltages. When charging above 4.30V, the cell causes plating of metallic lithium on the anode; the cathode material becomes an oxidizing agent, loses stability and releases oxygen. Overcharging causes the cell to heat up. If left unattended, the cell could vent with flame.

Much attention is focused to avoid over-charging and over-discharging. Commercial lithium ion packs contain a protection circuits that limit the charge voltage to 4.30V/cell, 0.10 volts higher than the voltage threshold of the charger. Temperature sensing disconnects the charge if the cell temperature approaches 90°C (194°F), and a mechanical pressure switch on many cells permanently interrupt the current path if a safe pressure threshold is exceeded. Exceptions are made on some spinel (manganese) packs containing one or two small cells.

hyperion charger . totally my fault. i was charging one pack and had balance tap hooked up to a different pack that was 1/2 charged. pack never got hot or even warm and i am dishcharging it slowley with a test light inside a lipo sack. doen to 3.8 volts.....

oh i see so the charger only seen the half charged pack so it would have kept going even more but you caught it, correct?? Just take it donw to normal voltage and you should be okay, just do it in a safe place JUST IN CASE.

Arkt1k: Whoa whoa whoa- why would you suggest putting an overcharged lipo in a car to discharge it? That is not a good idea. So what if the car is in a safe place...sure noBODY will get hurt but your car could be burned to a crisp!

auto2: So the charger was set for the wrong cell count?? 0o :oh: Thank you for using a lipo sack instead of your car!

to my understanding he was charging the battery but the actual balancing tap on the charger was connected to an entirely different battery.

I know, but the battery still wouldn't overcharge unless the cell count was incorrect on the charger. I don't see how the charger can see the voltage from one battery while charging another... If it's possible to hook it up in that way then that is a very poor design if you ask me.

well i guess the question would be does the charger measure the cutoff voltage from the balance lead or the main leads. I agree it is a poor design if i measures the cutoff from the balance tap. it should measure cell voltage from each cell and match them and the main lead should cut the charge off at 4.2v per cell.

IMO the dangers of lipos are greatly over stated I have been using lipos for about 4 yrs now and the only time I have had an issue with a lipo was due to an error on my part,I kept it connected while in storage for about a month, it puffed and I disposed of it. I have charged lipos using Hyperion 0610i using only the output leads and balanced afterwards and had no problems so I would say it was voltage setup...The Hyperions are about fool proof as a charger can get...I have my diffent lipo packs already programmed into the chargers memory and I will always double check the parameters before charging

yep every lipo danger i've seen was due to operator error. Including one myself.

I agree that OE plays a part in every accident. I still think that being able to hook up one battery to the charge leads and another to the balance leads is a bad design. This is only true of chargers which have the balancer built-in. I always use a stand-alone balancer, which makes it extremely apparent whether the battery I'm charging is also the one I'm balancing/referencing. And yes, the charger should use the main leads as a cut-off voltage reference. It's obvious that in this case it didn't. The balance tap reference is more accurate, but the charger should still recognize that the battery is being overcharged from the voltage at the main leads! UNLESS the cell count is wrong.

yep valid point there. I too use a separate balancer. Besides keeps less heat from the charger. Only has to focus on one thing (charging).

Well, lipo manufacturers could simply integrate charging circuits into each pack so all you do is apply 12v to it and it does the rest. That would surely eliminate OE - of course we won't talk about cost. :sarcastic:

I have a 606i at home and will test the theory on this tonight - The bigger issue is really that the charger won't have swapped between CC/CV mode when it hit the cutover point.

This may have caused more damage - Time will tell if you have trashed the pack - Hopefully it was not too expensive.

Best of luck

That is what all LiIon cordless drills have. Protection circuitry built into the pack. I can't imagine how many accidents there would be if the general public had to balance their batteries manually. I think that's also why we don't see LiPo batteries in drills. The risks outweigh the performance gains. It would cost a lot more to have the circuitry, but it would be pretty nice just to be able to put it on the charger and come back in an hour.

How do you think your cellphone or laptop battery works - They all have this protection circuitry built in and in the case of a laptop a balancer...

Just open your cell phone up and chances are the battery will be rated at 3.7v i.e. 1s...

Lipo packs are everywhere!

Yeah even the little stuff has protection built-in. With smaller cells, IE phones, PDAs, etc. they usually don't charge anywhere near a 1C rate. Most of them are 1s so they don't even require balancing, just over-voltage protection. The larger ones like laptop batteries charge more quickly and are multicellular. In fact there have been several instances with laptops going "poof". Most recently a batch of Sony batteries.

Also, these are all Lithium-Ion batteries. Not Lithium-Polymer.

Sony failure was due to small metal particles that had contaminated Lithium-Ion battery cells. In a few cases this caused batteries to fail and, in some cases, overheat.

Sony then made changes to its manufacturing process to minimize the presence and size of the particles in its batteries.

The recall was for batteries made during the impacted time.

FYI:

Lithium-Ion batteries are constructed with coated anode and cathode foils separated by thin layers of polymer material.

It looks like a jelly roll. You get a high surface area with thin layers. The thinner they go with the separators, the more room there is for the active material.

The coated layers are wound up on machines to create the individual Li-ion cell, and it’s at that stage that contaminants, such as metallic particles, can get embedded in the battery cell. The metallic particles such as happened to Sony may have been cast off by those commercial machines.

Generally, the polymer separator is very thin — less than 25 micron (one millionth of a meter) thick. If that is punctured by an electrically conductive material, like a metal particle, the battery cell’s anode and cathode short circuit.

There is nothing you can do to control this. In contrast, manufacturers have a variety of measures to guard the battery contents from external threats, like ambient heat.

Sony strengthened and reinforced the protective barriers and lining of their battery cells to address the danger of metal particles piercing the lining of the cell.

One of my former step-kids had a portable DVD player that use actual lipos. And the power/charge jack was directly connected to the battery, the actual charger was in the PS brick (I know this because I checked). Good thing the ex (and her hell spawn) aren't there anymore - I can just imagine what's gonna happen when they can't find the real charger and just plug in whatever will fit...

wow that would not be good for the portable player. Could cause a major problem, but again that comes down to OE. (use the charger made for it) We take for granted what we know on this stuff. something that simple could cause the uninformed some problems with the safety of themselves or others. It all just comes down to paying attention. Doesn't matter what the issue is. Could be charging lipos, or driving to the store. i don't know how many accidents so to speak i have seen where the person involved was not paying attention. There are poor designs but if you pay attention you can catch it. Now i am even guilty of this. I do not pay attention sometimes and it will come back to bite me.

And no matter how "idiot-proof" you make something, a bigger idiot will come along... :sarcastic:

Now isn't that the truth. I believe it is vintage that has a sig of taking all the warning labels off everything and lets see what happens.

They're constructed in the same manner as electrolytic/PIO/film capacitors. With capacitors, the rated voltage depends mainly on the thickness of the electrolyte-separating layers. I'm sure if a piece of metal found it's way into a capacitor of sufficient size it could do some real damage as well.

BrianG: Do you know what brand of DVD player it was? Do they still make them with the LiPo cells? That's definitely an accident waiting to happen with all of the charging/protection circuitry in the PS. Was there even a proprietary connector on the charging port?

Tell me about it! Do not turn off the traction control on BMW Z3's on wet bendy mountain roads!

Oh to be young and foolish!

Oh no, was it totalled? Poor thing...

I'm living proof. :tongue:

I slid perfectly sideways into a dry stone wall but didn't roll into the field - wheels were half on and half of the wall.

Two new wheels and tires
New front and rear bumper
New panels down one side
Bent a rear suspension component

No air bags or anything dramatic and no sheep escaped... Car was 6 months old so repaired like new...

But I've never touched that button again on any of my cars even on my 4wd TT...

PS Caution : Bags of Planters Peanuts might contain traces of nuts!

Can't remember the brand, but it wasn't your typical brand. And no, the connector was just your typical center pin and sleeve type...

That has to be illegal!

the charger was set to 2s 4000. correct for the battery. is is th 606i and it never stopped charging cause the balance tap when hooked up must be the deciding factor on end voltage.
battery "looks" fine. i hooked it to a 12v test light bulb for gesh 2 hours? more? and it still has 8.7 volts in it. Oh and the thoought of putting it in a $1000 truggy to drive around was :-)
yea only a $70 pack i use in my started box that i dont use anymore cause i run BRUSHLESS!... i had 2 of them and taped them togeather to make a 4s pack as a practice pack and was charging them at work in a rush . ( dumb)