TENAVOLTS AA Lithium 1.5V rechargeable cells

Batteries and Chargers Rechargeable Batteries
1

I picked these up on a whim, more out of curiosity than any particular need. This was a set of 4 cells and a charger, although I believe you can buy the cells separately as well.

These are basically 13430 3.7V 750mAh Li-Ion cells with a buck regulator that maintains constant 1.5V output throughout the entire discharge cycle, wrapped in AA shell. Such output is good for applications that have trouble with 1.2V output from a typical NiMH cell, but it’s also bad because there is no way to tell how depleted the cell is. It could be full or it could be empty or anywhere in between, and it’ll still show 1.5V when you check it with a DMM. Also, these cells are not designed to handle high current applications (about 1.5A max, I believe).

HKJ tested similar cells (different brand) recently.

Given this unique setup, it’s obviously not possible to charge them in your normal NiMH/Li-Ion battery charger. You have to use the supplied charger. It takes just under 2 hours to fully charge them. Each cell has a glow ring at the bottom that lights up during charging and turns off when charging is complete.

This is what the cell looks like disassembled (images from a youtube review of user vuaeco):

Running a discharge test on my Opus C2400 @ 500 mA discharge rate gives the following results. One of the cells shows slightly higher output voltage, but it appears to be just a bug in my charger - that particular slot always shows higher voltage for some reason. According to my DMM, that slot 1 was actually at 1.53V.

Voltage during discharge test:

Capacity (final):

Anyway, do any of you use such cells? If so, in what applications/devices?

2

This is great for my Blink XT cameras. They run on lithium AA at 1.5v and I cant run them on my rechargeables 1.2v eneloops. So I always have to spend $10 to change the batteries.

3

Will these safely recharge on a Li ion/NiMH charger? Does the charger identify them as Li ion or NiMH?

4

I mentioned that above:

5

Well, so you did. I missed it. My apologies.

6

No worries. It’s actually another drawback of these cells. If you misplace the charger, you have to get a new one.

7

The Blackube ones HKJ tested use a USB charger which is actually kinda nice.

On the off chance the two batteries share internals otherwise, I wonder if the proprietary charger is also 5V based?

8

The output on the terminals of the supplied charger appears to be 5.25V without the cell present.

Actually, it’s basically passthrough voltage from whatever USB power source you’re giving it. Looks like it’s feeding 5V to the buck regulator, which then charges the internal Li-Ion cell.

9

So each cell has a buck converter?

10

Good to know, should you find yourself in a pinch without the proprietary charger.

11

Yes.

12

I just ordered a set of these (4 with charger), on Amazon. $34.99 with a 30% clip coupon, and a coupon code (3678BX1X) I found on Slickdeals , brought the total down to $11.90. Thought they might be a descent companion to my Sorfirn SF11.

13

Yup, that’s what I paid for mine. I thought this deal was dead. Glad it’s still on. I might pick up another set.

How much current does the SF11 pull?

14

I’ve never used such batteries but after reading your review and HKJ’s on the Blackube some thoughts on the pluses of such a battery could be -

  1. No alkaleaking!
  2. Fast recharging
  3. Lower self/shelf-discharge than LSD NiMH (?)
  4. Better low temperature performance than NiMH, or alkaleak
  5. Flat 1.5V versus falling from 1.7V for primary lithium

And some minuses might include -

  1. Relatively expensive initial cost
  2. 5V charging, requiring proprietary charger; unless one has the USB version/brand of baattery
  3. Loss of efficiency when used in 1.5V boost light, after having been bucked from higher lithium voltage

One application I’d like to try might be 2S in a direct-drive driverless LED arrangement. For example, if the 2S 3v is as flat as the single 1.5v cells one could use this to mod an incan 2-AA by simply dropping in a 3V LED on a suitable heatsink pad for a flat output single mode light.

15

I just bought a set using the coupon and code.

How will these compare to running an eneloop in a single AA flashlight?

16

Which specific flashlight?

These Tenavolts cannot deliver as much current as Eneloops can.

17

If you look at the 2 Blackube reviews HKJ did the top USB charge [Gray] seems to have a bit more capacity and better amp support than that [Black]. The Tenavolt capacity is more in line with the [Gray], but the amp support more like the [Black].
People seem to have an issue with “yet another charger”. Jeez, our shelves and drawers are crawling with chargers, batteries, holders, and lights. I say, give it a rest. The charger is so small you can use it for a 4xcell holder if you want.

I do find some applications that don’t need a LOT of amp support, but do benefit from 1.5v actually do run better. I have 12 of these, and every one is in use somewhere. I like ’em. The product seems to be made well and the batteries have been consistent in all my tests.

For about $3/cell on specials (frequent), they are a reasonable buy and work pretty well. For the long haul……we are all beta testers I think.

18

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. Alas, if you order several sets of these Tenavolts, you will have multiple backups. :slight_smile:

19

Occasionally the ‘special’ allows the use of the discount code to get only the batteries for another couple $$ off. Haven’t seen that the last 2 cycles though.
For full price these are ridiculous. When they get down to Eneloop pricing they become attractive if you have the right use for them.

20

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