As the regulars here know I purchase / test / use a lot of batteries many of which just happen to be AA consumer grade cells.

While at Wal-Mart exchanging my $15 merchandise coupon from Energizer I ran across these new cells.
Now Sanyo,Tititium and many others are all coming out with a new generation of NiMH cells which are designed to have a greatly reduced self discharge rate.
These RAYOVACs come charged ready to use and the claim is that after 6 months storage they still have 80% remaining capacity.

Well it turns out that most of these new and improved cells are also only 2100 mAh and it has been my experience that the 2100 capacity cells have a much lower self discharge rate than the 2500 or 2700 mAh cells anyway.
Perhaps they all could be improved by reducing their capacity back to 1600-2100.

Hybrids purchased on 11-02-06 . Test discharge at 500 mA to 0.9V ,1800 mAh.
charged and discharged at 500 mA rate
940 mAh discharged 1.18 volts
1800 mAh discharged ,1.13 volts
2070 mAh discharged 1.0 volts.
Test stopped

Cell recharged and stored at room temp. for 8 days.

Discharged on BC-900 at 500 mA rate
Start no load 1.36 / 500 mA load 1.28

250 mAh discharged 1.22 volts
500 mAh discharged 1.22 volts
835 mAh discharged 1.22 volts

900 mAh discharged 1.21 volts ( 1:45 minutes under a 500 mA load)

1300 mAh discharged ,1.18 volts
1450 discharged ,1.17 volts
1565 discharged ,1.15 ( approx. 6-8 Hrs. transmitter on time)
(this is the point where many RC Transmitters and other consumer electronic devices have a low voltage alarm or stop working).

1825 discharged at 0.99 volts test stopped.


2070-1825=245 capacity lose(difference) after 8 days of storage which is approx. 12%. Now the max capacity lose with NiMH cells is normally during the first 24 hours after charging. It will be interesting to see if these come nearly their claimed retained 80% capacity after 6 month storage. At this stage I find it very doubtful.

Update 01-23-07
82 Day test

01-23-07
OCV 1.29

LaCrosse at 500 mA discharge rate.
Start 1.22V
1.18V / 30 min. / 250mAh
1.18V / 60 min. /500 mAh
1.18V / 90 min. / 750 mAh
1.17V / 120min. /1000 mAh( equal to approx. 4 Hrs.of RC Transmitter useage.
1.16V / 150min / 1250 mAh
1.12V /180min. / 1500 mAh
1.03V / 210min. / 1750mAh
1.0V / 1780 mAh prior stop point used and 80mAh more than cell tested at 38 days.

0.9V / 1814 mAh End of test.
Charles

Cell charged on 11-02-06

discharge at 500 mA rate on LaCrosse BC-900

Discharged capacity / volts

1000 / 1.21
1200 / 1.19
1350 / 1.17
1500 / 1.15
load reduced to 250 mA volts 1.16
increased back to 500 mA and
1700 / 1.0
stoped test.

From post above .Fresh from charger

2070 mAh discharged 1.0 volts.


1700 this test or 300 mAh less capacity at 500 mAh discharge rate after 38 days storage at room temp.

Not bad but makes one doubt the claimed 80% remaining capacity after 6 months of storage.



Charles

Charles, I saw these at a local store last week and wondered about them. An internet search revealed precious little information. I like the idea of being able to use rechargeables in things like TV remote controls rather than filling the trash with spent alkalines. But I don't like the idea of having to recharge remote control cells every 60-90 days. So I was hoping these new cells would hold a charge in something like a TV remote control for up to a year. I really don't see much benefit in them for RC use, but will be interested in how your testing shows they might work in non-RC devices such as TV remote controls.

Originally Posted by Dave Hederich

Charles, I saw these at a local store last week and wondered about them. An internet search revealed precious little information. I like the idea of being able to use rechargeables in things like TV remote controls rather than filling the trash with spent alkalines. But I don't like the idea of having to recharge remote control cells every 60-90 days. So I was hoping these new cells would hold a charge in something like a TV remote control for up to a year. I really don't see much benefit in them for RC use, but will be interested in how your testing shows they might work in non-RC devices such as TV remote controls.

in addition to the low performance,
the rayovac cells also leak as cink batteries!

i had 4 of them, they lasted about 5 cycles with decreasing capacitance (they had 2100mAh written on them, this was less than 750mAh discharged <0.5C after 5 cycles...), then
2 of them blew while charging, so i woke up for a big bang!

Originally Posted by z-matrix

in addition to the low performance,
the rayovac cells also leak as cink batteries!

i had 4 of them, they lasted about 5 cycles with decreasing capacitance (they had 2100mAh written on them, this was less than 750mAh discharged <0.5C after 5 cycles...), then
2 of them blew while charging, so i woke up for a big bang!

Charged at what rate on which charger?

Charged to the point of a Big Bang suggest to me that it was a charging rate and / or a charger problem.

IMO, very often the problems experienced by users of high capacity consumer grade AA NiMh cells comes from trying to charge them at to high of a rate. Most of these cells can not be charged at 1C as many suggest. These cells have high IR and as such do not take kindly to fast charge / discharge rates.

I am not saying this was the case here but there have been cases of fast chargers which were made for use with very specific cells being used with other cells and cells made for a specific charger being used with other chargers.



Charles

Originally Posted by Dave Hederich

Charles, I saw these at a local store last week and wondered about them. An internet search revealed precious little information. I like the idea of being able to use rechargeables in things like TV remote controls rather than filling the trash with spent alkalines. But I don't like the idea of having to recharge remote control cells every 60-90 days. So I was hoping these new cells would hold a charge in something like a TV remote control for up to a year. I really don't see much benefit in them for RC use, but will be interested in how your testing shows they might work in non-RC devices such as TV remote controls.

There are several of these low self dsicharge rate cells coming to market.

These Sanyo cells look promising however I have been disapointer with the 2700s from Sanyo.I know apples and oranges.

http://www.rcgroups.com/forums/showp...&postcount=121

I have used AA NiMH cells in TV remotes, programmable temp. contollers and many consumer electronic devices for many years.
I have often stated that high quality NiMH cells do not self-discharge nearly as fast as most seem to believe.

One of my test with Sanyo 2500 green sleeved cells resulted in over 6 hours of operation time in a HiTec Eclispe Transmitter after storage for 58 days at room temp..

More recently I have had excellent results with ENERGY 2300s.
I just checked the voltage of a cell still sealed in package purchase on 8-2-06( just over 4 months ago) stored at room temp. ,1.26V. Yes it is true that open voltage is not a good capacity test but I know from experience that a cell at 1.26 volts no-load is far from being mostly discharged.Well perhaps I should qualify that by adding that it depends on the load which will be placed on them.


TENERGY 2300s purchased 8-2-06 last charged (toped off) on 8-18-06
measured voltage of 8 cells 1.27-1.28

Placed 4 cellls in BC-900 at 500 mA discharge rate.
After 5 min. holding at 1.12-1.14 volts.

Discharge rate changed to 100 mA and voltage holding at 1.22 volts per cell..

So in an application where the drain would be minor such as a Remote or Memory backup even after close to 4 months these cells are still performing fine.

Placed two cells that were holding at 1.22 in a universal TV remote and with continuous on cell measured 1.25V.



RAYOVAC HYBRID 2100 mAh NiMH AA
which was last charged / disharged on 11-2-06 under a 500 mAh load down to 0.9V and yeilded 1800 mAh placed under an 500 mAh load and after 7 minutes is holding a steady 1.23 volts. This cell has been through approx. 5 full charge / discharge cycles.

Charles

I totaly agree on charger problems.

I have a Hi-Tec #CG-320 charger. Works fine, IF, you are carefull as hell.
It does not state on it that it is only for NICAD & NIMH. Has a mode #1 that lets you charge a 4.8volt NIMH at 900 ma. Fine.
If you or some one else looks at the switch positions and slides it to 10.8 and mode #3, you are now charging at 1.8 amps. Nicad, OK. Nimh not to good.
Still looks like a 900 ma. setup.

That is why a in line Amp. meter is really required for SAFE charging.

I also put a Volt meter across the battery to check the voltage also.

They are only machines, not people.
They can not tell when they are wrong and stop.

Charles,
I too bought some of the Ray-o-Vac cells and have been very happy with them.

A single cell tested . Last charged on 11-02-06 and has been stored at room temp. for 9 weeks (63 days).


Tested in LaCrosse at 500 mA discharge rate. 1.24 volts after 2 minutes.

After 150 min. (2:30) and 1270 mAh 1.17 volt.
1500 mAh / 1.15 volts. This is equal to approx. 6 hrs. Transmitter on time.
I reduced load to 250 mAh (typ. Trans. load) and volts holding at 1.16 after an addational 30 minutes.

Perhaps they are not as bad as I first thought.


Charles

Originally Posted by Dave Hederich

Charles, I saw these at a local store last week and wondered about them. An internet search revealed precious little information. I like the idea of being able to use rechargeables in things like TV remote controls rather than filling the trash with spent alkalines. But I don't like the idea of having to recharge remote control cells every 60-90 days. So I was hoping these new cells would hold a charge in something like a TV remote control for up to a year. I really don't see much benefit in them for RC use, but will be interested in how your testing shows they might work in non-RC devices such as TV remote controls.

For low drain devices like remotes, rechargable alkaline batteries work well. I've been using a brand sold here called Pure Energy. (Data sheets here: http://www.pureenergybattery.com/oem.html.)
They have characteristics like lead-acid batteries. I.E. they hold a charge very, very well (they claim up to 7 years) but don't like to be deep discharged (if you do deep discharge them you'll only get a few cycles out of them before they really start to loose capacity.)

I can't tell you how long they will last in a remote. I've been using the same pair for ~5 years now and they've probably only been charged about 5 times. At this rate, I expect they'll last a long time.

Finally, while they are great for low drain devices like remotes, they suck for high drain devices and NIMH's are better in those applications.

I made a pack of 2500for mynTx glider ans so far some glider Tx's and so far so good.

BOSS

Stored at room temp. for 113 days since charging.
Discharged on LaCrosse BC 900.

Open cell voltage 1.28
Load 500 mAh
start 1.19
1 hour- 500 mAh - 1.17
2 hours -1000 mAh - 1.16 ( equal to 4 hrs. plus with most RC transmitters)
3 -1/2 hours + - 1761 -0.90
-------------------------------------

From A prior post : 82 Day test results

0.9V / 1814 mAh
All things considered not bad results IMO.



Charles

It's been a year since that last post and it looks like there hasn't been much excitement about these cells since then. Why not?

Have there been any new developments? Has the capacity of the AA cells increased since then?

Are these cells the way to go for transmitter and receiver packs, particularly for folks who want their gear ready to fly even after long storage?

Are they a better choice for folks who like to use LiPo cells in their transmitters?

Originally Posted by Miami Mike

It's been a year since that last post and it looks like there hasn't been much excitement about these cells since then. Why not?

Have there been any new developments? Has the capacity of the AA cells increased since then?

Are these cells the way to go for transmitter and receiver packs, particularly for folks who want their gear ready to fly even after long storage?

Are they a better choice for folks who like to use LiPo cells in their transmitters?

Quite simply.... yes! I've been using the similar Sanyo Eneloop 2000 mAH cells in my TX for at least 6 months... great shelf life and perfect for TX's. Biggest issue is they are harder to solder up in a pack, but I was able to fit a battery holder in my TX, so no soldering needed.

Ray-O-Vac Hybrids in a Spektrum DX7 Tansmitter.

I purchased these cells 14 months ago. They were used lightly a few times and then placed in DX7 approx.4 months ago. They get charged overnight with 110 mA OEM charger approx. once a week and provide approx. 12 Hrs. of Transmitter useage between charges.



http://www.rcgroups.com/forums/showp...44&postcount=1


A snip from one of my Ray-O-Vac Hybrids / DX7 test.

10-31-07 Evening 10 days , 12 Hrs. & 55 min. and Low battery Alarm at 9.0 volts. Time to recharge.

Interesting DX7 Transmitter Data ?

I have read many conflicting reports of how much current these Transmitters use but 190 mA seems to be the one stated most. Well upon recharging this Ray O Vac Hybrid 2100 mAh pack my Triton displayed 1,902 mA . 1902 mAh / 13 Hrs = 146 mA used per hourand that is if there was no selfdischrge during 10 day and the charge was 100% effecient. Guess I will have to check Trans. load myself if I want to have a correct figure..
Seems like DX7 uses just over 130 mA

Charles