Not all cells are created equal...

Hi, just thought I'd share a somewhat surprising occurrence.
In the process of moving I stumbled across an old radio receiver, long since forgotten.
In it were four really old GP2700 cells. They had been sat there for years.
I thought, what the heck, why not give them a go in my C9000, expecting nothing more than a compete fail and dead cells all over.

What happened surprised me.

Started a break in cycle. No high warning, but at the same time nothing else either.
Voltage was around 0.05, 0.1 on all four.
5 minutes passed, still nothing, 0 mah on the display. Then the first one came to life, started crawling up slowly, accepting the charge, the other three followed.

About 10 minutes they all clicked, and jumped up to 1.40 V, roughly.

After two additional break in cycles they all deliver just over 2200 mah, back from beyond the grave.

Seriously lucky, or something to be expected? I for one did not expect it, based on experience from other cells.

Just thought I'd share.

/Dennis

Too true. Just never expected this and I believe these four are the only GP2700 I've had so was also a tad bit curious to hear if others have experienced the same.

SweD said:

Too true. Just never expected this and I believe these four are the only GP2700 I've had so was also a tad bit curious to hear if others have experienced the same.

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When you first put them into the C9000 on 'charge,' what is the reading you get in volts, for the I.R. check?

I'd be curious to see. The fact that they're charging tells me that you're probably under 2.10v for the I.R. on that charger.

Chris

1.88, 1.67, 1.76, and 1.96, in no particular order.

Do you know how long the cells have been sitting in the radio?

Hello Dennis,

I have had that happen a few times, but usually my starting voltage is a little higher.

You may want to keep an eye on them for a couple of charge/discharge cycles but it looks like they survived quite well.

Tom

Kurt_Woloch said:

Do you know how long the cells have been sitting in the radio?

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Not to the day, but for sure at least 3 years, if not 4.

That's pretty amazing. Most of my older cells just crap out, give me high IR, low capacity though they were constantly overdischarged too so that may be what happened.

MidnightDistortions said:

That's pretty amazing. Most of my older cells just crap out, give me high IR, low capacity though they were constantly overdischarged too so that may be what happened.

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That's exactly my pervious experience as well, and what I expected would be the case with these four GPs of mine.

Spoke too soon. A few recharges later, two of them just crapped out, high reading on my c9000. The other two are still going strong though.

They may have grown dendrites when fully discharged. The risk here is not so much capacity but elevated self-discharge. Check to see if they relax 90 min post-charging below 4.15v and how they hold up 72 hours after that.

Mike