Ray o Vac Hybrids won't hold charge

[Lighthouse one]

I 've bought 3 sets of AA Ray o Vac Hybrids . My first set - about 8 months old- recharged maybe 20 times- doesn't hold it's charge very long anymore. Maybe a month or 6 weeks at best. Made in China.
Anyone else have dying Ray o Vacs?
I have since ordered several sets of Eneloops.

 

[Marduke]

The possibly VERY important question is.....

What charger are you using on them?? The Hybrid charger they often come bundled with?

 

[Stress_Test]

I bought a set that came bundled with a charger, but it stated that the batteries could be used in any charger.

I haven't put mine through enough recharge cycles to give you any long term data, but for now they seem to be holding charge well.

Would you be using these in a 2-cell light with a voltage cut off too low for 2 cells? (ie Fenix cut off apx 0.8(?) so each cell ~0.4)

 

[Lighthouse one]

I have the Maha C401FS. It has two levels. I always have it set on low. I'm not sure what ma it charges at . On the back it says 1000ma x 4. So I guess 250ma per circuit? ON low?

I recently got an eneloop kit with their charger, but have not used it yet with the Ray o Vacs.

Wonder if I should use the fast charge?

Most of my use is for my camera (4 AA) during the summer, and several radios that I use at work and home. I rarely use them in flashlights.

 

[Stress_Test]

I think that means 1000mA per battery. So they should be charged in roughly 2 hours. My Rayovac charger charges for 8 hours, and the rate is something like 350mA if I remember right. In general, slower is better (gentler) on the cell. I've used a 15 minute charger several times, and it seems like you don't get good run times.

 

[Marduke]

I bought a set that came bundled with a charger, but it stated that the batteries could be used in any charger.

I haven't put mine through enough recharge cycles to give you any long term data, but for now they seem to be holding charge well.

Would you be using these in a 2-cell light with a voltage cut off too low for 2 cells? (ie Fenix cut off apx 0.8(?) so each cell ~0.4)

The bundled hybrid charger is a piece of junk. It's a dumb timed charger which will kill your cells in short order.

Lighthouse one, try putting the cells through several refresh cycles and see if that'll bring them back to life. If that doesn't work, contact Rayovac, tell them your issue, and they should give you a coupon to replace your cells in any store that sells Hybrids.

 

[Stress_Test]

The charge rate of 350mA is low enough it shouldn't hurt the cells even if they stay on a little longer than necessary.

350mA charge divided by 2100mA capacity gives a charge rate of 0.17 C. A 1/10th C (0.10) rate is almost an indefinite trickle charge.

 

[Marduke]

The charge rate of 350mA is low enough it shouldn't hurt the cells even if they stay on a little longer than necessary.

350mA charge divided by 2100mA capacity gives a charge rate of 0.17 C. A 1/10th C (0.10) rate is almost an indefinite trickle charge.

That rate will still kill cells in short order.

 

[Bones]

That rate will still kill cells in short order.

I would find it helpful to know the rationale behind this statement Marduke.

 

[Marduke]

I would find it helpful to know the rationale behind this statement Marduke.

NiCad's can tolerate a constant trickle over-charge, NiMH cannot. There is a reason that simple timed "dumb chargers" are universally advised against here in favor in independent channel "smart chargers", using at the very least delta V termination.

Edit:
Some interesting reading (even though it's a tad old)
http://www.duracell.com/OEM/Pdf/others/TECHBULL.pdf
http://data.energizer.com/PDFs/nickelmetalhydride_appman.pdf

 

[lumenal]

EDIT- double post

 

[lumenal]

Would you be using these in a 2-cell light with a voltage cut off too low for 2 cells? (ie Fenix cut off apx 0.8(?) so each cell ~0.4)

If you are running NiMH cells down to cut-off voltage in your Fenix lights, well, you'd better stick to primary cells.

On the other hand, if you run NiMH cells down to where the light falls out of regulation ( a very noticeable dimming) and then change to fresh cells, you should be fine.

My L2D falls out of regulation when one cell has a voltage of around 0.975v, and the other cell has around 1.065v.

Pretty much a complete and healthy discharge - not an over-discharge.

 

[Stress_Test]

The voltage range is info that I got from Lighthound's website. It may be stated elsewhere, but I don't think the Fenix store lists it.

Anyway, both the 1 cell and 2 cell lights use the same head, right? So a minimum led voltage input of 0.9-0.8 is fine for a single cell. But for the two cells in series, that means each cell will be at half that voltage at cutoff... too deep a discharge for NiMH cells in general. Some may be more tolerant of this than others, but I wouldn't try it myself.

Incidentally, motor controllers (speed controllers) for electric RC aircraft have a low voltage cutoff to prevent battery pack damage.

Anyway, other people have posted that their 2-cell Fenix lights have caused the NiMH batteries to vent when run all the way to light shut-off. In my view, it's a poor design if the light can cause damage to the batteries during normal use, especially if the company specifically says that NiMH is ok to use.

 

[Stress_Test]

My last reply was to the post before you edited it, btw.

 

[Marduke]

The voltage range is info that I got from Lighthound's website. It may be stated elsewhere, but I don't think the Fenix store lists it.

Anyway, both the 1 cell and 2 cell lights use the same head, right? So a minimum led voltage input of 0.9-0.8 is fine for a single cell. But for the two cells in series, that means each cell will be at half that voltage at cutoff... too deep a discharge for NiMH cells in general. Some may be more tolerant of this than others, but I wouldn't try it myself.

Incidentally, motor controllers (speed controllers) for electric RC aircraft have a low voltage cutoff to prevent battery pack damage.

Anyway, other people have posted that their 2-cell Fenix lights have caused the NiMH batteries to vent when run all the way to light shut-off. In my view, it's a poor design if the light can cause damage to the batteries during normal use, especially if the company specifically says that NiMH is ok to use.

I think you are incorrectly assuming how the Fenix lights operate. The L2D will not run NiMH down to ~.5v per cell. The reason people were having venting issues was that they were operating turbo for extended periods of time (the entire runtime in one go), which is not an issue of how far the cells were drawn down, but how fast.

The Fenix light in question also does have a voltage shutdown point, but any self-respecting flashaholic will check and charge the batteries long before this point. By the very latest as the first signs of dimming and not the voltage shutdown.

 

[lumenal]

My last reply was to the post before you edited it, btw.

Yes, I know what you mean, there was slow server issues and I thought my original post had not gone through. So I posted a slightly different thought...

Back OT, any mass produced items are bound to have a few "duds" get past quality control.

I've got Eneloops and Hybrids, and others.

I had one AA Hybrid slightly vent about 2 pin-head sized black spots of crud. Not sure when it happened, as I only noticed it when I was about to use it. It had maybe 20 cycles on it.

A call to Rayovac CS and they took care of the problem, and then some.

 

[Glasstream15]

I haven't had Hybrids or Eneloops long enough to really try them out. And I use them more for Camera equipment than lights. I have 8 AA and 6 AAA Hybrids and 24 AA and 10 AAA Eneloops. I haven't really compared runtimes on either but casual observation seems like the Eneloop AAA give slightly better runtime in my Cobra Micro-Talk Radios than the Hybrids. I have only had them about 6 weeks, but all of the batteries seem to be holding up well and maintaining a good charge. I use an Energizer Family Charger whuich has 4 "smart" bays that will each take 1 or 2 AA or AAA cells and seems to charge very well. I also carry one of the Energizer folding 4 cell chargers in my camera box to recharge if needed away from home. And none of my chargers is faster than about 4 hours, so I get a good charge and good battery life. 5 year old Panasonic 1800mAhs still going strong and a bunch of Energizer 2500s, both Japanese and Chinese, all seem to be doing well and holding their charges well.

I think ROV and Energizer and Duracell and Sanyo all have decent CS, so check with them. They just may help you out.

YMMV

 

[BlackDecker]

I use both Eneloops and Rayovac Hybrids in my Maha 9000 charger and both seem to perform about the same. The Hybrids usually charge up to a bit higher ending charge than the Eneloops do in this charger.

Not seeing any reduction in performance on the Hybrids and they have been charged/discharged over 20 times.

 

[Anders]

Hello.

A swedish study was made several years ago, they explored over charging at 0.3C. They found that at this low charge rate over charging the cell resulted in damage to it.

I think 0,17 C at extended time also overcharge the cells.

To find a proper end of charge signal from the cells it is best if your charger charge your cells between 1 to 2 hours, 0,5 - 1 C, at lower rates it is hard for the charger to detect the weak end of charge signal from the cells which can result in overcharge.

Anders