Bought a c9000 and test old batteries

[Eugene]

I have some Sanyo 1650mAh AA's from Feb 2001 that have been charged in crappy Ray-o-vac chargers, used in everything from a digicam to kid toys so I thought I'd test them. One of them tested at 136mAh
The other three are still going at 650, 590, and 790mAh so far. I thought the numbers were interesting after seven years. One bad out of 4 so far.
So whats the proper charge rate for eneloop's

 

[matrixshaman]

You might be surprised at what the Maha can do for those old batteries if you run the full break in mode. Or at least the analyze and charge. Eneloops in AA size are normally charged at 1000ma I believe. I think the usual rule of thumb for best life is to charge them at 1/2 the milliamp rating on the battery so Eneloop AA 2000ma batteries charge at 1000ma.

 

[Turak]

You might be surprised at how some of those older 1600-1850mA cells will spring back to life...which I go with about 75-80% of original or stated capacity as the end of life cutoff point where I throw them out.

Run 2 or 3 Refresh and Analyze cycles on them and then run a Discharge cycle and see what you get.

If that doesn't do it...

Make sure they are fully discharged by running a Discharge cycle on them, then run a Break-In cycle on them. Now, run a Discharge cycle and see where they are at. If still not within 75-80% of original capacity, run 1 more Break-In cycle on them, then a Discharge cycle again to see what they end up at.

If they don't spring back to life after that, then they are just too far gone to spend the time on.

As for the charging rates....do some searching and you'll find ALOT of debates.

Generally speaking, go with .5C -1C charge rate

For the Refresh and Analyze cycles, you will be fine using the default 1A charge rate and for the 1650mA cells, I would go with a 300mA discharge rate. The reason for the 300mA discharge rate is so that you can somewhat accurately compare your results to the manufacturers.

For the Discharge cycle where you are measuring the capacity, also go with the IEC standard of .2C which would be 330mA (i.e. .2C x 1650mA = 330mA) in your case, but you will have to go with 300mA (can't select 330mA) to measure it as closely as possible to the manufacturers stated capacity.

 

[SilverFox]

Hello Eugene,

While I basically agree with Turak, I would suggest starting with the Break-In cycle first. Discharge at 1000 mA, then discharge again at 500 mA, then discharge one more time at 200 mA, then run your Break-In cycle.

Tom

 

[VidPro]

Hello Eugene,

While I basically agree with Turak, I would suggest starting with the Break-In cycle first. Discharge at 1000 mA, then discharge again at 500 mA, then discharge one more time at 200 mA, then run your Break-In cycle.

Tom

yup when you have a cutoff voltage (.9-1v) on the discharge cycle discharging slower will discharge the cell "more" and therfore that set of chemicals will also get cycled, with only a fast discharge, the discharge wont be as "deep".
call it "forming" or just call it getting a deeper fuller cycle.

 

[Eugene]

As for the charging rates....do some searching and you'll find ALOT of debates.

Thats why I put the smily, I read all the debate threads. I'm tempted to pick a couple different charging rates and charge a few of each battery at them for a few years and see which one works best. But I have different devices so they wont all get used the same and by then there will be a different technology anyway.

I can see I'm going to be busy playng with testing batteries now.

I have some brand new eneloops now dated 6/2006 does anyone want an analyze of nearly two years in storage?

 

[Mr Happy]

I have some brand new eneloops now dated 6/2006 does anyone want an analyze of nearly two years in storage?

Sure, go ahead. Extra data points are always good. If you discharge them on the C9000 at 500 mA I predict they will read about 1350 mAh.

 

[Eugene]

Hmm, the old 1650mAh ones are still running the discharge part of the break in cycle and three are reading 2100mAh while the 4th is at 500mAh, that doesn't sound right.

 

[Turak]

Careful with the 9000 about 'when' you are reading your display. One of the 9000's 'quirks' is that during certain times it does not update its display immediately. Search around and you can get more details about this particular 'feature'....hehe.

From the numbers you indicate.....I would say that;

The slots that are displaying 2100mA have not updated yet and are actually displaying the total charge that was put in to the batteries during the charge cycle.

The total accumulated charge during the Break-In cycle is actually about 120-130% of the batteries stated capacity. It does this due to various losses that are incurred during the charge cycle. With your batts....2100mA / 1650mA x 100= 127% so that's about right.

Not sure about the slot displaying 500mA. What part of the Break-in cycle is it in...charge or discharge. I would bet that it finished the discharge cycle...is that slot indicating 'Done'?

I almost guarantee that it will take at least a couple of Break-In cycles and/or a few Refresh/Analyze cycles to get those poor old batteries up to their current maximum capacities. By the way....I'd toss them at about 1300mA or less.

If they had sat quite a bit for some extended periods of time, I would have recommended the Break-In cycles first, followed by a Refresh/Analyze or two.

Since you had indicated that the batteries were basically used in a variety of devices and charged on ummmm 'questionable' chargers... that is why I recommended the 2-3 Refresh/Analyze cycles first, followed by a Break-In or two.

The logic being....

The first method (Break-In cycles followed by Refresh/Analyze cycles) seems to work 'best' on batteries that have sat unused for extended periods of time. The long, slow overcharge of the Break-In cycle helps redistribute the electolyte and insure the reactive materials are as energized as possible.

The second method (2-5 Refresh/Analyze cycles followed by a Break-In cycle or two) seems to work best on batteries that have been in use, maybe suffered through a few incomplete charge discharge cycles, charged before being fully discharged, etc. In this scenerio, the Refresh/Analyze cycles help to push the battery through some 'complete' charge discharge cycles, thus helping insure that when a Break-In cycle is applied, it will more readily accept the overcharge of the Break-In cycle.

As I always say...see what works best for you...

Test the above 2 methods on some known batteries (i.e. batteries that have been used regularly but not fully discharged versus batteries that have sat for 6 months or more in a drawer. I think you will find the logic above generally to be sound.

 

[Eugene]

Ok, it was doing the discharge cycle and started another charge. the 4th slot was the one that initially tested at 130mAh while the rest tested over 1000mAh so thats probably going to end up being a bad one.

 

[Turak]

Keep running them through cycles till you don't see anymore improvement.

Break-In <-> Refresh/Analyze <-> Refresh/Analyze, repeat, repeat until there is no further improvement.

Who knows...you may save a couple of them, but it will take awhile. Hey, now you have an excuse to order a couple more...:twothumbs

 

[clintb]

Hello Eugene,

While I basically agree with Turak, I would suggest starting with the Break-In cycle first. Discharge at 1000 mA, then discharge again at 500 mA, then discharge one more time at 200 mA, then run your Break-In cycle.

Tom

Hello Tom,

So, you're saying to:
- Run the break-in
- Discharge at 1000mA
- Discharge at 500mA
- Discharge at 200mA
- Break-in
* At no point between the first break-in and discharges is there a charge cycle, correct?

 

[SilverFox]

Hello Clintb,

No. That is not what I suggested..

Start with a discharge at 1000 mA,
Then do another discharge at 500 mA,
Then do another discharge at 200 mA,

Now you can run the Break-In.

Tom

 

[Eugene]

How long does the break in go for, its been going since last night.

 

[Mr Happy]

How long does the break in go for, its been going since last night.

It takes about 40 hours. There is a 16 hour charge, a rest, a 5 hour discharge, a rest, and another 16 hour charge.

 

[Eugene]

I had already started the break-in before getting all the advice here and it finally finished. The four I tested all came out between 1300-1500mAh which is pretty good for seven year old 1650mAh batteries.
I bought them in Feb 2001 from mouser http://www.mouser.com/catalog/633/1974.pdf for $2.88 each, they were the highest capacity available then, Radio Shack was selling a pair of 1200mAh ones for $9.99.
I have about 24 old NiMH cells, if all of them recover then that 24 less ~$2 per cell I have to replace so the c9000 will have almost paid for itsself already. They range from 1999 to 2004, it was around 2005 that I gave up on re-chargeable due to the self discharge and my walmart quality "smart" charger not fully charging them. I went back to re-chargeables in 2007 with my firt couple packs of eneloop and not have 64 of them.

 

[SilverFox]

Hello Eugene,

I generally suggest recycling batteries that drop below 80% of their initial capacity. 80% of 1650 mAh works out to 1320 mAh.

Also, keep in mind that charging and discharging at higher rates will result in lower "usable" capacity.

Now that you know where you stand with these batteries, the next step is to check them for high rates of self discharge. Charge them up and set them aside for 7 days. Now run a discharge and see how much capacity is left. Good cells will retain around 95% of their initial capacity after 7 days of self discharge.

Tom

 

[Eugene]

the first 4 came out as
1 1525mAh
2 1353mAh
3 1407mAh
4 1315mAh

what do you think % wise for a non critical app. Since I've replaced them with eneloop's in my stuff these are going in toys for a 2 year old. so they are not critical, if his fire truck stops running, he'll just bring it to me and say 'open' or reach in the kitchen drawer and get the screwdriver and try himself.

 

[Vikas Sontakke]

Which "crappy" Rayovac charger you had? Was it timer based or the intelligent charger?

- Vikas

 

[Eugene]

I had the PS4, it was supposed to be a smart charger but turned out to be not as smart as it should have been.