Nimh charger question ?

[tvtech]

Hi kiria

Please read the PDF from Duracell in my post above yours. NiMH is great. And a huge improvement over NiCAD cells. They however, still need to treated be well too.

And UNDERSTOOD. Any rechargeable battery has issues if not charged/discharged properly.

You have all the best chargers kiria.....but in actual use, the battery has to do the job. And be treated well while on the job too..with not a charger in sight.

OK. Duracell "recommend" totally discharging the battery every 19 cycles or so to just above 7.0 Volts That will stop the "memory effect" of NiMH.

Think about it kiria.

Cheers

 

[kiriakos-gr]

Hi kiria

Please read the PDF from Duracell ..........Think about it kiria.

Cheers

Hello friend I have read lots of Ansmann PDF,
and every battery model that they have,
it has it own special characteristics.

Even the Ansmann AA 2850mAh (old version) is totally different from the latest AA 2850mAh Digital ( Digital = model logo ) .
Their charge and discharge currents are lots higher.

Duracell does not lead the pack about new products with special characteristics.
Ansmann and Sanyo does that.

 

[kiriakos-gr]

I just got an email reply from Ansmann, about the technical document,
for their latest AAA 1100mAh ..
( I have full collection of their most technical documents)

I have also two sets of those AAA, and I use them on my latest DMM Agilent U1272A,
I use the rechargeable ones for long lasting data logging sessions.

They are the most high power AAA on the market today.
Check their document.

 

[tvtech]

Kiria, I have always respected Ansmann quality and all they do to stay at the top of their game/field. Please see my post no 2 in this thread where I say Ansmanns guide for PP3 rechargeables is my favourite.

I have actually agreed with you all along

No need to prove anything to me. I just raised the Duracell opinion on NiMH because they also make lots of rechargeable NiMH batteries.

Cheers

 

[kiriakos-gr]

About the NiMH 9V PP3, it is the only battery that I do not own,
and I need one, because I have an portable calibrator for DMM,
and I need it as auxiliary battery when I run uA or mA tests.

Unfortunately the pricing stops me mostly from getting one.
And the point is that just one, its not a wise choice,
you must have at list two, so to instantly exchange the empty with the charged one.

I would choose NiMH 9V PP3 Sanyo Eneloop, if they had made any.
( slower self-discharge time )

 

[tvtech]

About the NiMH 9V PP3, it is the only battery that I do not own

I suggest you buy/use one. And learn to charge it

Seven cells in one tiny package. A beaut if you understand it.

Cheers

 

[kiriakos-gr]

Well from the Duracell document I got an useful tip,
like when a cell looks to have stability issues ( prematurely looses the charge level when is connected with others in line),
the advise is to use it in high current applications.
Well I have a powerful Olympus digital flash unit ( 40GN), it can make any AA to start dancing ( high current application).
But for the AAA I do not have any high current application.

Did any one see on ebay high quality AAA to AA converters ?
Not that cheap nylon ones.

 

[curry87]

Ok i did some tests i discharged 4 x aaa 1.2v 700mah nimh cells down to 4.06v then i put in the charger for 19hours like it suggested.It charges them at 50-55mA for R03/AAA took them out at 19hours waited an hour then tested with two different multimeters both read around 1.49v is this charger busy overcharging my cells and reducing their lifespan even though ive followed their charging instructions to the letter ?

 

[audioguru]

Why don't you look at the detailed datasheet to see that a Ni-MH cell that is charged at 1/10th its C will be about 1.5V? Energizer recommends a trickle-charge current of only 1/40th C.
Here is a voltage graph from Energizer:

 

[kiriakos-gr]

Ok i did some tests i discharged 4 x aaa 1.2v 700mah nimh cells down to 4.06v then i put in the charger for 19hours like it suggested.It charges them at 50-55mA for R03/AAA took them out at 19hours waited an hour then tested with two different multimeters both read around 1.49v is this charger busy overcharging my cells and reducing their lifespan even though ive followed their charging instructions to the letter ?

Yes your charger works out of specs, you should get 1.36 or 1.38V the most,
after the 1-2 hours of cool down period.

Even if it has very low charging current, it does overcharge the batteries by topping them that high. (1.49v)

 

[tvtech]

Yes your charger works out of specs, you should get 1.36 or 1.38V the most,
after the 1-2 hours of cool down period.

Even if it has very low charging current, it does overcharge the batteries by topping them that high. (1.49v)

As always, I only comment on PP3...which I know well.
Funny thing though, all NiMH use the same cell structure...always 1.2V X amount of cells. For given voltage from cells. And total from batttery.

Ansmann and others like to keep full charge voltage below 10.15 Volts on a PP3 for longevity. I agree with them.

Voltage control means no overcharging ever. Heck, what do I know.

Cheers

 

[audioguru]

I don't know if Duracell makes any rechargeable batteries. Energizer 9V Ni-MH batteries are made for them in Germany.
Energizer AAA and AA Ni-MH cells are made for them in Japan (maybe by Sanyo?)

 

[tvtech]

I don't know if Duracell makes any rechargeable batteries. Energizer 9V Ni-MH batteries are made for them in Germany.
Energizer AAA and AA Ni-MH cells are made for them in Japan (maybe by Sanyo?)

Apparently ...AG...Duracell does make rechargeables. Never seen one though

Cheers

 

[audioguru]

Recently I saw some Duracell "precharged" AA Ni-MH cells on sale at a drugstore. I didn't buy them because they were old with a capacity of only 2100mAh. Energizer "precharged" AA Ni-MH cells are 2300mAh.

 

[kiriakos-gr]

About nominal capacity and true capacity, currently I do run some tests.
Before a year ago, I got some no name AAA 900mAh.
I have one small LED desk lamp, that needs 40mA to operate.
The fake 900mAh did not last more than four hours = 400mAh

Currently I do the same test with the Ansmann AAA 1100, I have also one digital timer with alarm,
and notifies me every 60 minutes, currently are running for a second hour.

Soon I will have some true proofs about " Real capacity "

 

[tvtech]

About nominal capacity and true capacity, currently I do run some tests.
Before a year ago, I got some no name AAA 900mAh.
I have one small LED desk lamp, that needs 40mA to operate.
The fake 900mAh did not last more than four hours = 400mAh

Currently I do the same test with the Ansmann AAA 1100, I have also one digital timer with alarm,
and notifies me every 60 minutes, currently are running for a second hour.

Soon I will have some true proofs about " Real capacity "

OK. How are your findings?? Enough time I believe.

Please share.

Cheers