Is this a sign of a bad pack?

[Lessen]

So I have an Intellect 4200 7.2v pack that I've had issues getting to take a charge with my old intellipeak charger. I just got my new electronics all setup and my Hyperion is telling me this pack is at 9+ volts. I take it this thing is shot? I tried discharging at 1.0A and it clicked off right away. However, it takes a charge at .5C. How does this make any sense? I havnt changed the delta setting at all. I think it's probably past saving... Any input?

 

[Racer 1966]

Does your charger work fine for other batteries of the same type? I had one charger that did that on my 3000 pack for my roto start. Turns out the charger was starting to go bad. I have charged and used the battery with no problem on a different charger.

 

[Lessen]

Yep. I have two brand new Hyperion chargers and I have them cycling a couple 5000 Intellect packs now and all is good. Readout is normal for them at the moment, I just started the discharge and one is at 6.389 and the other at 6.547. I'm really enjoying having a quality battery charger that actually gives me feedback about my packs. It's very comforting.

 

[hamz9561]

It's probably time to recycle that pack, Josh. I had a pack that behaved like that for a ham radio that caught fire on the charger. These were NiCad cells not LiPo.

 

[Lessen]

Yeah, that's what I've been trying to do Hamz. Having a readout is new to me so I'm seeing numbers during the process that I'm not used to seeing. I cycled my two 6-cell Intellect packs and the numbers looked kinda normal but now I'm doing my two 7-cell Intellect packs and they are saying 10.3 and 10.5v. Would it be better to cycle these packs at less than 1c or does it not really matter. I've set these to discharge at .75A.

 

[Lessen]

OK, I think it might be ok at this point. I did realize that I made an error when I setup the cycle as I input the discharge as 7.2v since it's a 6-cell pack but what I was SUPPOSED to input was the discharge cutoff. I've always read .9v per cell so I put in 5.4v. I got it on now and it's reading just over 7v as it's discharging.

 

[hamz9561]

Good to hear.

 

[Lessen]

So I'm trying to understand the basics of this batteries and I'm finding myself comparing a battery with a gas cylinder because that just happens to be what I do for a living. I've read electricity explained relative to plumbing before. This pack is now charging at 2.1A and it's actually taking a charge for.... 40 minutes now. It's showing 9.358 volts but when I started the cycle it should have been charged and it was reading only 7.0 or something like that. It seems like the pack will read standad voltage when at rest but higher than that when under stress. I see this at work when blowing down or filling cylinders. They cool and heat up pretty dramatically upon those conditions and pressure required varies due these temperature changes. Is this a fair comparison? This questionable pack has taken 1700mAh in the past 50 minutes @ 2.1A and it's reading 9.4xx volts.

 

[hamz9561]

You've got the right idea on your comparison.

 

[Lessen]

yeah, I noticed when it's finished with it's charge and the charger turns to trickle (or if it's not set to trickle) the voltage slowly drops from above nominal toward it's generalized voltage. That pack took 2100mAh in 61 minutes so it's taking a charge properly at .5C (4200mAh pack)