overcharger lipo battery grrrrr

[auto2]

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.

[Arct1k]

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.

[BrianG]

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.

[Arct1k]

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.

[auto2]

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.....

[bl-is-future]

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.

[What's_nitro?]

Originally Posted by Arct1k

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.

Originally Posted by auto2

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.....

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 Thank you for using a lipo sack instead of your car!

[bl-is-future]

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

[What's_nitro?]

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.

[bl-is-future]

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

[bl-is-future]

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

[What's_nitro?]

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.

[bl-is-future]

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).

[BrianG]

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.