Test/review of TenaVolts AA 2775mW (Black-blue)

HKJ · 2019-09-16T13:34:29.000Z

TenaVolts AA 2775mW (Black-blue)

Official specifications:

Product model: NF-LB1
Battery size: AA
Charge capacity: 750mAh
Energy capacity: 2775mWh
Output voltage: 1.5V
Battery weight: 18g
Cycle times: >1000
Operating temp.: 32-104°F

This is 1.5V LiIon AA batteries with build in voltage conversion for LiIon voltage to 1.5V.

I got the batteries in a nice box with specification for both the batteries and the charger.

The box contained four batteries, a charger, a USB cable and a instruction sheet for the charger.

The ring on the bottom of the cell is transparent and will emit blue light while charging, but there is only one led making the light very uneven.

These batteries maintain 1.5V until they are empty.

There is no significant difference in capacity at low currents, this means the self discharge is very low.

The batteries do not have a hard current limit, but voltage will drop when the load is too high.

The internal resistance looks smooth for a electronic regulated battery.

The output will change little when load is applied or removed.

It looks like the buck regulator runs at about 1.4MHz. The noise is less than 30mVpp, but I cannot measure lower with the current setup.

Charger TS-C1

The charger is a box with a semitransparent lid.

Power is connected to the micro USB input.

Behind the lightning symbol is a green led to show the charger is powered.

It has specifications on the bottom.

The slots are standard 2 level slots for AA/AAA batteries.

The TenaVolt are AA batteries.

The battery is charged with about 4.6V to 5V and uses an internal charge regulator, it will terminate the LiIon charge at around 50mA.

Not much difference with the other slots (The voltage varies slightly).

With four batteries the voltage is lower, this means slightly longer charge time.

But what happens if a Alkaline or NiMH battery is put into the charger? It looks like it has a PTC that will limit the current. Initially it may draw all the current the USB output can deliver but after a few seconds the current will be limited. This means a NiMH will be charged continuous with around 130mA. Alkaline will be charged with higher current!

Charger Tear-down

I could break the charger open with a spudger.

There is two small circuit boards inside the charger and no electronic on this side.

On this side is 5 resistors and one LED, as the test shows above four of the resistors (R2..R5) are PTC’s and the last resistor (R1: 10kOhm) is for the LED.

Conclusion

These batteries has less capacity than normal NiMH, but run at a higher voltage, making the energy about the same. This makes them ideal for most equipment that has trouble with NiMH batteries. They also weight considerable less than NiMH, this can be significant in some circumstances. There is one disadvantage: Battery meters do not work with them.
The requirement to use a special charger is a disadvantage, but if it is damaged or disappears it is possible to modify any AA USB charger for this purpose (Requires soldering skills).

Notes and links

Batteries and charger was supplied by TenaVolt for review.

How is the test done and how to read the charts
Compare to other AA/AAA batteries: Alkaline/NiMH/Lithium

flydiver · 2019-09-16T15:31:52.000Z

Timely write-up for me. I have about a dozen of these now. Initially got them hoping they would work in an underwater strobe, then learned they would not. Oh well.
[Specifically say; （NOT FOR CAMERA FLASH USE)]. I don’t recall seeing that when I bought them. Don’t know if it was added due to feedback issues, or I simply did not register the warning.

Had a couple applications requiring 1.5v in mind for them for the first set and they worked well. Got more and tried more normal uses. Work fine. Have not tried very low draw applications like remotes. Looks like they might be fine there….until they aren’t.
The construction and finish of the batteries is quite good. Consistency seems very good.
I personally don’t have any issues with the dedicated charger.

Pete7874 · 2019-09-16T16:43:06.000Z

Thanks for the review.

HKJ:

Compare to other AA/AAA batteries: Alkaline/NiMH/Lithium

I am not seeing these Tenavolts in your comparator dropdown. Maybe you haven’t added them yet?

HKJ · 2019-09-16T19:37:28.000Z

Pete7874:

Thanks for the review.

HKJ:

Compare to other AA/AAA batteries: Alkaline/NiMH/Lithium

I am not seeing these Tenavolts in your comparator dropdown. Maybe you haven’t added them yet?

Adding is automatic, but it do not work before I upload it. It is fixed now.

Superstocker · 2019-09-16T19:48:53.000Z

Thanks HKJ!

xxo · 2019-09-16T23:53:20.000Z

Thanks much for the review!

I just got a a set of these from the amazon deal, they seem to work well.

A few things I noticed:

Running a tenavolt in a xeno xo3 on high was noticeably brighter and ran hotter than a eneloop by a good amount. After about 37 min the light shut off and I immediately checked the Voltage - it fluctuated wildly from about 0.26 to 0.60 Volts.

Running Tenavolts in a life gear AR flashlight/lantern (3 AA’s in series/direct drive) the tenavolts were noticeably brighter as well, but after 8-9 hrs of run it started to get dimmer than a identical light running on eneloops and started to flicker. It continued to flicker for an hour or so without getting super dim but I decided to shut it off and recharge the tenavolts at that point.

While the cells were charging I pulled one and put it on an xtar VP2 charger on the 4.35V setting @ 0.25A, it seemed to be charging, but since the Voltage is always around 1.52V there was no easy way for me to be sure with a quick DMM reading so I put it back in it’s proper charger.

BTW charge times I got were just about exactly 2 hours.

flydiver · 2019-09-17T00:09:51.000Z

These will charge on (some) normal Li-on charger but they will not charge correctly. There is no feedback for the charger to determine what the cell is really doing. IMO, don’t even bother trying. I did just to experiment, as some users were claiming that they could do that in [Slickdeals]. The Li-on chargers varied on whether they would even try or not. They will do nothing at all on a NiMh charger, at least not mine, and I have a bunch of different ones I tried.

If you look at the discharge graph you can see they do OK at 1A, hang in at 1.5A, and start to fall apart after that. Eneloops do better under higher draw and inherently have more capacity. These are not well suited to sustained draw much above 1.5A I think.

HKJ · 2019-09-17T06:45:33.000Z

A LiIon charger will not fully charge these batteries, they need more voltage than 4.2V and I also doubt 4.35V is enough to charge on any reasonable time.
My guess is that they uses a very small linear charge IC, this means feeding them 5V when empty will reduce charge rate because the IC gets hot.

Richwouldnt · 2020-02-28T18:10:14.000Z

Look interesting but the discharge voltage curve is such that a charge capacity left monitor will pretty obviously not work. Thinking of using in something like the Ectaco Jetbook Lite ebook reader that runs on almost any set of 4 AA batteries. It can use Alkalies, Energizer Ultimate Lithiums or NIMH rechargeable batteries. I am using the Ultimate Lithium batteries currently in mine. This reader is old technology with a monochrome LCD display but is about the only ebook reader ever made that uses AA batteries. Per one report it runs for close to 90 hours on a set of Ultimate Lithium primary cells. Still available new from Ectaco but I got mine for about $42.00 including tax and shipping from a ebay seller, less than half MSRP. Appeared to be a NOS item, apparently from a Texas school district.

Be good too in a clock as the lower voltage of NIMH rechargeable batteries does not work well in many of them per my experience.

d_t_a · 2020-08-27T12:40:35.000Z

The requirement to use a special charger is a disadvantage, but if it is damaged or disappears it is possible to modify any AA USB charger for this purpose (Requires soldering skills).

I’m curious about this, (I’m not so well-versed in electronics), the recently-released Xtar BC4 charger can charge both 1.5v Li-Ion AA and also AA/AAA NiMh. Would this mean the Xtar BC4 can detect the type of battery (1.5v Li-Ion vs 1.2v NiMh) and charge differently? Or do they charge differently?

Any idea if another brand’s 1.5v Li-Ion AA battery charger can charge other brands 1.5v Li-Ion AA battery? (eg. do you think the Xtar BC4 can charge these Tenavolts 1.5v Li-Ion AA battery? And also vice-versa: Can this Tenavolts TS-C1 charger charge other brand 1.5v Li-Ion AA batteries? Or is there no ‘standardized’ 1.5v Li-Ion AA battery cross-compatiblity and thus will require that specific brand’s charger to charge that brand’s 1.5v Li-Ion batteries?

HKJ · 2020-08-27T13:36:12.000Z

1.5V LiIon do not have a standard charge requirement, some has build in charge circuit, some not and some has a usb connector to charge…