TENAVOLTS AA Lithium 1.5V rechargeable cells

Rat_Racer · 2019-09-16T15:42:58.000Z

HKJ did a review on them, and the charger: Test/review of TenaVolts AA 2775mW (Black-blue)

nibble · 2019-09-16T18:34:43.000Z

pc_light:

Lower self/shelf-discharge than LSD NiMH (?)

I don’t think any rechargeable lithium cell can get anywhere near the current Eneloop spec (70% capacity retention after 10 years).

Lightbringer · 2019-09-16T19:28:46.000Z

Pete7874:

To me the issue is primarily about compatibility/convenience. If you lose/misplace the included charger, you will not be able to recharge these cells in any other charger, unless you feed them 5V directly.

A plain ol’ AA holder with flying leads and bare usb socket is all anyone’d need to be able to charge these on the fly. 2 soldered connections is all it takes.

flydiver · 2019-09-16T23:40:25.000Z

nibble:

pc_light:

Lower self/shelf-discharge than LSD NiMH (?)

I don’t think any rechargeable lithium cell can get anywhere near the current Eneloop spec (70% capacity retention after 10 years).

I have a LOT of Eneloops. I just flat don’t believe that spec. Maybe a brand new, specially selected cell, placed in a 40* cool dry place….might……maybe….pull that off. No battery in real use will get close to that.

Lightbringer · 2019-09-17T00:52:16.000Z

Wellp, I popped one into my E03, and brightness is comparable to a new alkaleak.

Of course, it’s way brighter with a 14500, but all those levels are quite bright. M is comparable to H (ie, little discernable difference in brightness), and L is still hella bright, way too bright to use late at night.

At least with lower voltage, modes are quite evenly spaced, and L is suitable for moonlight-duty with diffusion film.

Hjeh, now that I got mum set up with an LED desk-lamp (another vipon special) instead of having to use flashlights to read, etc., I might be able to completely do away with those detestable little leaky things.

Lightbringer · 2019-09-21T23:24:45.000Z

Odd. Ran down a Tenavolt in my E03. Can’t recall running down a cell to nothing in a long time. My EBL 14500 that I had in it since I got it was used lots longer (and brighter in all modes) and after swapping it in still had/has some oomf in it. (Just checked, 3.45V, so could stand to be charged, but still…)

Anyone have observations that they run down fairly quickly?

Pete7874 · 2019-09-21T23:34:34.000Z

Lightbringer:

Anyone have observations that they run down fairly quickly?

Since they run at full 1.5V, they will spend themselves faster than other cells that run at lower voltage.

How many amps does the E03 pull?

Also, when the Tenavolt cell has no more energy to give, it may show 0V on my DMM, from what I’ve seen.

Lightbringer · 2019-09-22T00:43:58.000Z

From Illumn (and others confirming same):

Ni-mh cell:
Low: 20mA, 10 lumens, 20hrs+
Medium: 135mA, 60 lumens, 4hrs+
High: 500mA, 200 lumens, 1hr+

14500 Li-ion:
Low: 300mA, 90 lumens, 2.5hrs
Medium: 1000mA, 320 lumens 45min
High: 1560mA, 430 lumens, 30min

So figure maybe a half-amp-ish even at 1.5V vs 1.2V. Below an amp on high, at any rate.

flydiver · 2019-09-22T01:20:37.000Z

I don’t mean this as an insult, but are you sure you had a fully charged cell? It’s impossible to tell except freshly charged, or empty and dead.
I have a dozen, all tested at 1.6Ah @ 0.5v, or slightly better. Good consistency.

I don’t get the specs. How does, say a 2000mAh NiMh pulling 500mA only run for 1hr+? Math doesn’t work out. Should be near 4 hours. That much inefficiency?
I’d expect the Tenavolt to go somewhat over 3 hours on high.

Lightbringer · 2019-09-22T01:41:53.000Z

flydiver:

I don’t mean this as an insult, but are you sure you had a fully charged cell? It’s impossible to tell except freshly charged, or empty and dead.

As soon as I opened ’em, I popped out the plastic thingy, loaded ’em all up, powered up the charger, spun each cell around ’til the bright part of the ring was on top, and let ’em burn. After a half-hour or so, poop! poop! poop! poop!, all 4 lights eventually went out. Charged, I presume.

flydiver:

I don’t get the specs. How does, say a 2000mAh NiMh pulling 500mA only run for 1hr+? Math doesn’t work out. Should be near 4 hours. That much inefficiency?
I’d expect the Tenavolt to go somewhat over 3 hours on high.

NiMH is only 1.2V. It has to boost the voltage to the LED to 3.whatever. So if it boosts the voltage 3× to 3.6V, current would be 1.5A from the cell to supply 500mA to the LED, assuming 100% efficiency.

Granted, it’s the lousiest route as far as efficiency, going from 3.xV from the internal cell, down to regulated 1.5V, then back up to 3.xV to drive the LED. Still, I prefer the more evenly-spaced modes at 1.5V, even if not nearly as bright, vs all-bright directly from a 14500.

Besides, I gotta find something to use ’em in. :laughing:

flydiver · 2019-09-22T15:27:32.000Z

Got a battery powered: nose trimmer, beard trimmer, 2xAA Sonicare travel toothbrush? Really perks up devices like that, small motors that are kind of laggy, especially as the batteries get old.
The only lights I put them in are small 2XAA or 4xAA motion lights I have all over the house. Some of them that I want to keep brighter and are harder to change out seem to do a bit better with these.

A minor point, but important to me, is that the battery grip in some of those lights is damn aggressive. I can shred the top edges of the cell prying it out, or break a fingernail (ouch!). Some cells I actually need a tool which can cause even more damage. The Tenavolt are a tad smaller diameter, much nicer and harder skin/wrap than any other battery I know (including Eneloops), and slipperier. They go in and out nicely. For a permanently mounted light near the ceiling I like that a lot.
The best cells I had for those particular lights were some REALLY old RayOVac 4.0 and Eneloops. They are getting tired and need replacing anyway. They have hundreds of cycles. Those old ROV have actually been amazing. Manufactured in 08/2011, I beat the snot out of them and most of them are still OK, not great, but still buzzing along. Good enough for stuff like that.

BTW, thanks for the efficiency explanation. Didn’t think about the multiple conversions going on. That would not help out at all.

Lightbringer · 2019-09-22T16:37:44.000Z

After finding out the hard way just once, I’d stick a thread or thin string under the cell to help yank it out later if wedged-in.

But yeah, things that directly take 1.5V are what these cells are best suited for.

flydiver · 2019-09-22T16:39:16.000Z

Well, that’s a [DUH!] moment. They put those in devices. I guess I could too.

xxo · 2019-09-23T18:45:48.000Z

Pete7874:

Lightbringer:

Anyone have observations that they run down fairly quickly?

Since they run at full 1.5V, they will spend themselves faster than other cells that run at lower voltage.

How many amps does the E03 pull?

Also, when the Tenavolt cell has no more energy to give, it may show 0V on my DMM, from what I’ve seen.

The Tenavolt cell I took out of a xeno eo3 after it shut off running on high read 0.24V fluctuating wildly to about 0.60V. The tenavolt ran this light more like a 14500 than a eneloop - brighter with a lot more heat and shorter run time. In direct drive lights, the Tenevolts are great. The run at full brightness until they are almost dead when they start to dim and flicker. In most fully regulated lights, Tenavolts seem to run pretty much like standard eneloops.

Lightbringer · 2019-09-23T21:23:40.000Z

xxo:

In direct drive lights, the Tenevolts are great. The run at full brightness until they are almost dead when they start to dim and flicker. In most fully regulated lights, Tenavolts seem to run pretty much like standard eneloops.

Hmm, odd. Mine was going full tilt and then just shut off without warning. Try turning it on, nope, nothing. No flickering nor dimming.

I’d like some kind of indication, in fact. That’d at least give me some warning.

Alkaleak, lit right up. 14500, lit right up. Tenavolt, nope.

Recharged it, lit right up.

Pete7874 · 2019-09-23T23:02:44.000Z

Lightbringer:

I’d like some kind of indication, in fact. That’d at least give me some warning.

Have you not seen the completely flat discharge curves posted by HKJ?

Lightbringer · 2019-09-24T00:33:40.000Z

Oh, I’ve seen ’em, but still wish there’d be some kind of warning. It’s a bit disconcerting to be shaving your face and have the beastie just up’n’die as if you switched it off. Bad enough NiCd cells would do that over 5sec or so. Having it happen instantly is definitely a “Whoa, what happened??” moment.

xxo · 2019-09-24T19:05:53.000Z

The Xeno just shut off - I think the protection circuit kicked in.

Running tenavolts in a couple of flashlight/lanterns combos, a energizer weatheready 2AA and a life gear 3AA is where I got the dimming/flickering……thought it might have something to do with the multiple cells, but I had the same thing happen with a inova X1 which suddenly dropped from full brightness to a few lumens and soon started to flicker. I’m not sure what is going on, but this is what happened.

flydiver · 2019-09-24T19:18:03.000Z

I think there may be some variation in cut-off. I’ve got some that simply go to 0v, and others that do kind of what you are saying. But, when it’s flickering, it’s done.

Lightbringer · 2019-09-24T19:24:04.000Z

Could be chuggle. Ie, voltage under load when it’s spent drops too low, the circuit stops functioning, load drops to near-0, voltage rises, it kicks in ever so slightly for a “flicker”, then the cycle repeats ’til the cell’s so spent that it doesn’t come back on again at all.

Neighbor whose yard abuts mine has an idiotic spotlight in his yard, where the sensor must be in the beam or at least catching enough light from it. Turns on, sensor thinks, “Ooh, it’s light out!”, then shuts off 5sec or so later. Then, “Ooh, it’s dark out!” and it comes back on another 5sec or so later. And the cycle repeats.

All.

Night.

Long.

Think of the “flicker” as a very fast and thankfully very transient effect like this.