Fixing old Ni-Mh in my Maha C9000 and LaCrosse B700 - Your Help Please

I have some Uniross 1300 batteries that are probably about 3-4 years old, I have just purchased a Maha C9000 and also have the B700 charger too.

I ran all my Uniross 1300 batteries through break-in on the C9000 and these are the results.

1 = 1136, 1.42V
2 = 1060, 1.41
3 = 1.73v Imp Test, 770mah, 1.41
4 = 1.55v Imp Test, 1029mah, 1.41
5 = 1.66v Imp Test, 797mah, 1.42
6 = 1.6v Imp Test, 1320mah, 1.43
7 = 1.71v Imp Test, 816mah, 1.43

Is there anything now that I should be doing with these to squeeze more out of them? (apart from number 6 as that one seems ok) or should they be chucked in the bin?

I have read somewhere that I now should do several more break-in cycles on them but setting the break-in capacity of the c9000 before starting it at the capacity I have just recorded, would that be correct?

Also read about the deep discharge method to re-condition old batteries however I don't have a torch with incandescent, just a mini-mag with an LED mod on, would that work?

The C9000 appears to be an awesome charger as well as the B700, I want to try and use them hand in hand, hope I can learn quite a bit from CPF

If your batteries still have 80% of original capacity, you can consider them as good enough. That would be just over 1000mAh for 1300mAh batteries.
There isn't much you can do to bring down impedance or voltage depression.

Are you hanging on to these for a particular reason or is this more of a "project"? I'd probably toss those old cells and replace them with some shiny new Eneloops.

Not really keeping hold of them for any particular reason as these were my first rechargeable batteries that I have owned, should I chuck the ones that are lower than 80%?

I've got some Eneloops in the C9000 at the moment, going through break-in mode.

I have a big bunch of old/crappy NiMH-cells.
I test them once in a while to check up if they can get even worse or perhaps improve.
GP 2700's are garbage, at least the ones I own. Not a single cell managed to discharge to more than 2050mAh.
GP 2500's are almost the same, they discharge to 1950mAh,...
An old 750mAh Varta NiCd cell only gets to 500mAh.
I also found some untested 850mAh Memorex NiMH-cells!

For real use I have either Sanyo's, Memorex, GP Recyko's and some less known branded LSD-cells.

I too have the GP 2700s, I'll post my data for them but they are a bit rubbish.

As promised for s0lar and also everybody else my GP 2700 data

1 = Imp Test 1.67, 1988, 1.44
2 = Imp Test 1.63, 2039, 1.43
3 = Imp Test 1.58, 1866, 1.40
4 = Imp Test 1.56, 1946, 1.41

Would running any of my ageing batteries through the cycle mode improve some capacity?

Thanks for your test results of the GP 2700's.
Mine are showing similar results.

I just charged and discharged some 10y old AA Memorex 850mAh NiMH-cells:
975, 887, 929.
All of them perform better than the label specifies! Too bad that's no longer true for NiMH-cells on the market today.

I tried to cycle my GP 2700's batteries myself, but they do not seem to improve.
1:1614;1899;1833;1179(after 2weeks on the shelf);2017;1988;1728(in 30min charger);1880;1959;1862;1829
2:1654;1901;1846;(not tested);2032;2013;1715(in 30min charger);1738;1963;1887;1863

I got a small boost in capacity the next recharge after letting them rest when fully charged.

s0lar said:

I just charged and discharged some 10y old AA Memorex 850mAh NiMH-cells:
975, 887, 929.
All of them perform better than the label specifies! Too bad that's no longer true for NiMH-cells on the market today.

Click to expand...

You mean AA Memorex 850mAh NiCd I hope

No, I have some AA NiMH 850mAH batteries from Memorex!

May you post photo of those oldies?

I will post a picture later today of my low capacity NiMH batteries.

Here some pics:
https://picasaweb.google.com/hendrickx.maarten/Batteries#

KR 15/51
KR means NiCd according IEC 61951-1 2004
HR - NiMH according IEC 61951-2 2004
I haven't any 10 years old NiMH, but a lot of such NiCd without any capacity loss

Hello Mikl1984,

What about the Nickle Hydride part of the label?

Tom

Mikl1984 said:

KR 15/51
KR means NiCd according IEC 61951-1 2004
HR - NiMH according IEC 61951-2 2004
I haven't any 10 years old NiMH, but a lot of such NiCd without any capacity loss

Click to expand...

That is odd. There seems to be a discrepancy here somewhere. As I remember, when AA NMH cells came out, they were around 1200mAh in capacity. At that same time, the best NiCd AA cells were 850mAh.

It was a bit of a mix when I first got into NiMH chemistry AA cells. The 850mAh NiCd AA cells I had actually outperformed the 1200mAh NiMH cells, in devices that had a high current drain. The NiMH cells had far more voltage drop under heavy loads. This is why I still used NiCd AA's for some time, in high drain devices anyway, such as handheld transceivers and pretty much anything that used an electric motor.

Dave

SilverFox said:

Hello Mikl1984,
What about the Nickle Hydride part of the label?
Tom

Click to expand...

I don't believe in all labels
Have you any 10 years old NiMH with full capacity?

45/70 said:

That is odd. There seems to be a discrepancy here somewhere. As I remember, when AA NMH cells came out, they were around 1200mAh in capacity. At that same time, the best NiCd AA cells were 850mAh.

Click to expand...

I think so. My first NiMH was GP GP130AAHC from 2001
Some cells working till now with real capacity 813-1041mAh

Those Ni-something batteries perform very good (labelwise).
Results for each cell:
1: 975,969,915
2: 887,890,852,837
3: 929,750,894,870

Label clearly says: free of cadmium. It's odd.

s0lar said:

Label clearly says: free of cadmium. It's odd.

Click to expand...

Agreed. The only thing I can think of, is that these cells must be some of the very first commercial NiMH cells to arrive on the consumer market. Maybe you should preserve them and put them in a glass display case, rather than use them!

Dave

I still have old nimh, back to about 2000. My oldest are unmarked and I have a few unused 1400 green sanyo oem button-top cells. I chaarged 4 recently. My recollection is the breakin only showed about 20-30%, but they improved greatly with each of a few test cycles on the lacrosse. I think they reached 80-90% and charged very consistently.
I think I have been looking for the HR since about 2000.