Sanyo Eneloop cells experience?

[POF]

I'm not sure if this is the right place to ask but the answer might be depending on the application.

For my F3J/B gliders with current hungry servos I have been using Sanyo 2500/2700 mAh AA cells. But some of them seems to start failing after only 1-1½ years.

So I look for something else. I would like to stay with AA cells because otherwise I have to make changes to my gliders.
I noticed the new cells http://www.eneloop.info/ but would like to ask if anybody has any experience in this application?

http://candlepowerforums.com/vb/showthread.php?t=149804

[Guz]

I personally haven't tried them, but I would love to! They sound like great batteries. If you go to the Batteries and Chargers (http://www.rcgroups.com/batteries-and-chargers-129/) forum, you'll find a thread or two on them.

I really think they would would do real well for power hungry servos and for transmitters.

[POF]

After some reading it seems like my Sanyo 2700 mAh problems is selfdischarge so I think I'll try the new Eneloop stuff...

[Andy W]

Personally, a new $20 Rx pack once a year for my $1000+ models is a small investment worth making.
..a

[POF]

Personally, a new $20 Rx pack once a year for my $1000+ models is a small investment worth making.
..a
Even if it's a small investment I would like to make the best choice.

[Bro]

Howdy;
I have been trying the Eneloop cells now for 3 months.
Steve made me a demo pack, after issues with some of the 2700's.
So far, excellent! The cost is a bit higher, but they do not have the self discharge problems the 2700's do.
The current issue is they are only in consumer packs, no bulk.
Another good way is the old 1650's. These are in about 12 of my personal airfames, and some are 3 years+ and going strong. fwiw...

Happy landings!
Bob

[Guz]

After some reading it seems like my Sanyo 2700 mAh problems is selfdischarge so I think I'll try the new Eneloop stuff...

Wow, what a coincidence, I'm using Sanyo 2700 mAh batteries too. Hate them because of the self discharge issues. Have them as Rx and Tx batteries.

I just haven't had the time to price shop for Eneloop's.

[ThermalBuster]

I have been using 2700mah cells in my transmitter for a couple months now. Since I finished forming them I have only charged them maybe twice. I haven't noticed any self discharge issues. Its pretty nice only having to charge once a month and not have to worry about running out of power while setting up airplanes.

Are you guys forming your 2700mah cells before throwing them on the peak charger?

[Curare]

I've had one pack go funny on me, and completely shut down. Luckily for me I did my preflight check and saw that it was really slow and then just got worse and worse within about 6 seconds.


I'm wary of them, and now like others here, throw out packs like that within a year or two.

[Guz]

Are you guys forming your 2700mah cells before throwing them on the peak charger?

Actually I keep my Rx and Tx packs in dry cell holders (yes... I trust them, but that's besides the point), and I pull the cells and put them in a charger that charges each cell individually. Still get self-discharge.

[POF]

I've had one pack go funny on me, and completely shut down. Luckily for me I did my preflight check and saw that it was really slow and then just got worse and worse within about 6 seconds.


Eneloop? After how long use did they fail?

Got mine now - have to test a lot before use.

[ThermalBuster]

Actually I keep my Rx and Tx packs in dry cell holders (yes... I trust them, but that's besides the point), and I pull the cells and put them in a charger that charges each cell individually. Still get self-discharge.
Its still a peak charger. You need to give the cells a long slow charge when you first get them in order to prepare them for future fast charges. If you don't the cells are likely never to come up to capacity and will have early failures. A peak charger will often false peak with new cells because the charge is not diffusing (non-technical description) throughout the chemistry.

[Guz]

Oh, I've done "trickle" charges after the peak. They still have issues.

[ThermalBuster]

Ok.

[jofo1]

I charged all the cells individually; peaked-discharged-peaked until they held to capacity consistently. In my TX I put them into a cell holder. If a cell goes bad I can pop it out. No problems with this method after a year or so but it does take some time to condition the cells. jwf

[Guz]

I guess I'm just being picky. I always try to plan to go flying on the weekends, so when I come home I charge up the batteries so they will be ready for the next weekend. But sometimes I can't go flying the next weekend (work sucks), so the batteries sit for a week or two (or three). By the time I can go flying I have to remember to charge the batteries the night before going out (which I sometimes forget) and end up at the field with dead batteries.

I went back to the stock NiCad's on my Optic 6. Oddly enough, they are holding their charge nicely, and I'm getting really decent run times (2-3 hours of true on time).

But I just want to charge, store, fly, store, fly, store, fly, charge (repeat), without going to Lipo for the Tx and Rx.

(man this thread should be in the batteries forum).

[Curare]

I charge the night or the morning before.

I just feel safer that way.

[FrogChief]

I charge the night or the morning before.

I just feel safer that way.

Ditto... I would NEVER fly my plane without a fully topped-off pack.

[Guz]

Ok, I know it's wishful thinking on my last post.

How about this chain.
Fly, charge, store, fly, charge, store, ...

I would be really happy with that.

[Curare]

I just don't trust my batteries to hold charge over an extended storage period.
If it were over a weekend or about 3 or four days I'd probably be ok with but I expect self discharge so I allow for it by flying when they're topped up.

[hbielich]

It's kind of hard to know which batteries you guys are referring to - eneloope or 2700's.
I have been getting false charges on my 2700 packs lately and have had to get them a bit warmed up a bit before they can get a full charge.
I just bought eneloops at Costco and will see how they do...

[hbielich]

Bro,
Are you using 4 or 5 cell packs of eneloop batteries? How are they doing now after using them for a few more months since your last post here?
Howard

[Curare]

Sorry I was talking about the 2700mAh's, not the eneloops.

They're pretty good from what I hear

[arukum17]

I am using them currently in my Paragon and they are superb...
Although my other Vapextech batteries were up to the job as well, the fact that Eneloops hold their charge longer is just a little bit more reassurance. Everything about these batteries including the packaging exudes quality

Sanyos are really the way to go with batteries

[guy mckenzie]

I am using them currently in my Paragon and they are superb...
Although my other Vapextech batteries were up to the job as well, the fact that Eneloops hold their charge longer is just a little bit more reassurance. Everything about these batteries including the packaging exudes quality

Sanyos are really the way to go with batteries

Where do you buy them in the UK arukum17?

I have a 2100 mA Instant Vapextech Tx pack and it'd done great for 7 months. I bought an 800 mA AA Rx pack from Vapextech and I struggle to get 600 mA in the pack and rarely more than 450 mA out when I cycle it. They want me to return it before they replace it. By that time shipping costs will have exceeded 50% of the cost of the pack. I'm voting on this one with my feet....

[POF]

I have used them now in 3 gliders this summer. No problems:O)

[arukum17]

Guy I bought them from some UK online site (can't remember)...but I don't think they were any cheaper than this site £7.99 delivered for 4x 2000Mah AAs:

http://cgi.ebay.co.uk/4x-Sanyo-AA-ENELOOP-2000mAh-Rechargeable-batteries-UK_W0QQitemZ300149010450QQihZ020QQcategoryZ43445QQ ssPageNameZWDVWQQrdZ1QQcmdZViewItem

Like others I always charge the night before...crashes due to trees, wind, radio glitches, orientation issues, bad wood glue joints, I can handle but if I ever lost a plane from loss of RX battery power :eek: I would be scarred for life

[jsmillett]

If you look at the Specs for these, it says that they are Twicell batteries.
The original Twicell batteries were introduced about 1990.

http://www.eneloop.info/

http://www.eneloop.info/209.html

AA specs:
http://www.eneloop.info/uploads/media/Datasheet_-_HR-3UTG_01.pdf

AAA specs:
http://www.eneloop.info/uploads/media/Datasheet_-_HR-4UTG_01.pdf

Jerry

[seanpcola]

Hi all,

I decided to bump this thread instead of starting over in hopes some of you will report back in. Also, prefer to hear from fellow glider guys/gals as to their particular experiences as it will be more applicable to my situation

I have been thinking a lot lately about Eneloops and since I need a new TX and several Rx packs I went to Circuit City today and bought 2 packs of eight each AA2000 cells. First point is that the cost was $16.00 per pack of 8 ($2.00 per cell). Apparently the price is dropping from a few months ago. I thought that was a deal!

From reading over the eneloop threads in the Battery section it seems that everyone is pleased with them for Tx use but some questioned their suitability for Rx use. From what I gathered there seemed to be a concern about high draw. Then I later read where 2 A charge (1C), as I would have assumed is the norm. :confused:

Most of my planes are 6 servo (usually digitals) in 3-4M gliders and the most I have is 8 digis in a larger scale job.

What are your thoughts on this?

[schrederman]

I've been reading and these are the same as the Sanyo Eneloops. Currently have an Rx pack in one sailplane and they've been good so far.

Jack

[seanpcola]

Thanks Jack ;) .

How are they priced?


PS: Your old bird is still lookin good! ;)

Sean

[schrederman]

They were $8.99 for 4 AA cells...

Was looking through pictures of that ship yesterday. Glad it's in good hands. I enjoyed the build.

Jack

[tknuutti]

I've had eneloops in my Perfect and a couple other fullhouse-ships (all digital servos) for around 6 months now, no problems at all and capacity is holding up fine. Couple club-members are using them as well and haven't had any issues.

For a bigger scale-ship I would use dual-packs just for peace of mind. Batteries are cheap compared to value of airframe and scalies need the noseweight anyway. Amazon now sells an 8-pack of Eneloops for $14.96.

-Tauno

[EricSoar]

I have been changing all my models over to AA Eneloops. They hold their charge very well as advertised. I have LED volt monitors in all my models. I also use a lost model alarm with low voltage alarm. I no longer top off the Rx pack before flying. There is no need.

If I do top off eneloops, the lost model alarm thinks that the 4 cell pack is a near discharged 5 cell pack (5 beeps on power up) and then alarms that the voltage is low! After lots of servo movement for a few minutes I can get it down to 4 beeps on power up.

I find that AAA non-eneloop packs self discharge quite a bit in a day or two. I have not yet tried AAA Eneloops. Actually I have moved away from AAA packs on my 6 servo electric thermal models because they limit me to 45 minutes of on time (hence the voltage monitor).

[seanpcola]

We use double Rx packs in all of our scale stuff. I use the Modelltechnik AW-2 battery backers in those. You are right about the weight. Not a consideration in the big scale jobs and most of those have 3-4000Mah C and sub-C packs, again for weight as well as redundency. I probably won't go with the eneloops in the scale stuff but was planning on changing out the smaller stuff over to them this winter if all reports were good.

Thank you to everyone for replying! ;)

Sean

[C-MIC]

Those Eneloop cells are great, hold voltage/ capacity as advertised, thou not sure if they met their advertisement of annual discharge rate is less than 5%.
Some older (6-7mths) still works great as expected (I use those LED batt checkers every where as long as space is available.)
David

[EricSoar]

I seem to recall that the specified self dis-charge of an NiMH eneloop is 20% after a year. The self discharge is fastest after the day of the charge and then slows down.

Lithiums also self dis-charge 20% after a year although in this case it is not just self dis-charge but also loss of capability to store charge. That's why you throw away your cell phone battery after about three years, even when you don't use it much.

[serpnt_flyer]

Just picked up a set from Costco 8 aa, 4 aaa, 2 c cell adaptors, 2 d cell adaptors, and slim wall charger. All for $25.99. Thought I'd try them in a digital camera see how well they hold up.

[Ian Roach]

Although I have never had a complete failure in service of a pack of AA size NiMH cells in transmitter or receiver service I have never been really happy with them.

Their self discharge rates are high.

Their capacity is often much less than specified.

They need frequent cycling to maintain capacity.

The result of the above is lack of confidence, and even more frequent cycling.

I was in the process of changing back to NiCd packs when I heard of the Sanyo Eneloop and decided to give them a try. So far the results are very impressive.

They need to be broken in with a few C/10 charges, preferably with a charger that does not have automatic cut-off. Just charge them until they are warm at 200 to 250 mA, then discharge to 1V per cell at 300 mA. In my experience they achieve the specified minimum capacity on the first charge, and the nominal capacity, or close enough to it, on the second or third cycle. This is far better than any other AA size NiMH cells I have used, and indeed better than many NiCd cells.

Charging at the C/3 rate still achieved around 1900 mAh capacity (nominal is 2000, specified minimum is 1900).

Capacity was still better than 95% after a little under a month.

I have not been using these cells long enough to comment on their useful life.

I expect you could charge these cells and fly a couple of weeks, or even more, later quite safely, but I have no intention of doing this. I will still charge soon before flying, for example on Friday night for a Sunday flying session. It is the consistency and reliability of these cells that I like.

[mwhitman]

I've read through this thread and other sources online and there are lots of positive observations about capacity and slow discharge rates for Eneloop cells. However, I could not find any test data for a 4-cell pack under load. Today, I tested two different 4-cell Eneloop packs and found that the voltage drop is significant when you go from a 0.5A load to 1.0 amp and over. At 0.5 amps, the pack voltage stays above 4.8V. At 1.0 amp, the voltage drops to 4.1V and at 1.3 amps, the voltage drops to 3.6V. Although that type of load would me momentary, it seems too close to the cutoff voltage of a receiver for my comfort if I were to use them with digital servos.

Am I missing something here?

Mike

UPDATE 1/3/08:
I rechecked the batteries and found that the battery holder I was using to test cells was faulty. The cells test out just fine now.

[tknuutti]

Eneloops tested under load from here;
http://www.rcgroups.com/forums/showpost.php?p=8423894&postcount=26
They hold voltage fine on this test. Voltage from several packs I've tested with a 0.5A-load battery-checker seem to agree well with these numbers.

[onethermal]

Tauno
How do you think these cells are going to hold up to the winter cold on our slope.
(quick discharge) ???

Clarence

[tknuutti]

Hey Clarence,

They should be ok even in colder weather, at least better than nimhs.
But approach with caution just in case!

Here's a graph borrowed from a german website (http://www.stromflug.de/eflug/eneloop.htm)
Eneloops and twicell-nimhs discharged at -24 deg C, that's -11 deg F, pretty darn cold. Eneloops do pretty good, allthough usable capacity drops to ~1400 mah.
Twicell-nimhs on the other hand die a quick death..

-Tauno

[onethermal]

That is not a bad cold discharge rate. I can live with that....Thanks Tauno
Below zero for Salt Lake Tonight...