Test / Review: Efest IMR10440 V1 350mAh (Black)

Efest IMR10440 V1 350mAh (Black)

Official specifications:

  • Brand /model: Efest IMR 10440 350mAh 3.7V
  • spec: LiMn 10440 350mAh 3.7V
  • Material: IMR(LiMn)

Internal resistance is calculated from 1A to 2A.

I got a pile of batteries in one envelope, not the best way to ship batteries, even when they are shrink wrapped. Efest have changed their packing.

1A is handled very well, but even 3A is possible with these IMR cells.

Thse IMR batteries handles a high load for their size.


These IMR batteries have very good performance at high loads, but the capacity is, of course, not that high.
At the current time I can only rate them acceptable, because Efest is a new company, and the batteries is not from one of the big brands.

Notes and links

How is the test done and how to read the charts
How is a protected LiIon battery constructed
More about button top and flat top batteries
Comparison to other LiIon batteries

Thanks for the test. I have a pair of these waiting for light(s) in which to use them.

Thanks for the review!!

I like 10440's :)

Any chance of 5 amp loads?

I do not believe there is any point in a 5A test, look at the difference between 2A and 3A, the difference between 3A and 5A is going to be larger.

HKJ, do you have any suggestions for a IMR battery (18650) that could supply 20+ amps and still have enough of a voltage to power an XM-L?

lol scaru, you are cheap! I ordered 5 different IMRs (2pc of each) to get them tested. :P

The only 18650 I have tested at 20A is the AW IMR 18650 (Except A123, but they are lower in voltage).

Well, when I am already paying for 7 XM-Ls I need to save some money. ;) And you don't need that much power, you only need 12 amps. ;)

For 10A you can use this chart:

And then also check my protection test that goes to 15A.

I am going to add some Efest IMR cells to the chart soon.

You know nothing about my needs! :D

Triple MTG-2? :evil:

Great idea, but I want my lights to be useful. I'm no multicell guy.. did I say useful? :D

Do it right… dump’em and use XML2’s…

Thanks very much! Frontpage’d and Sticky’d.

A few low current chargers for 10440s: XTAR XP1 (250mA), Micro Lipo mcp73831 (100mA / 500mA, default 100mA), LipoNano (100mA / 500mA, default 500mA). Lipo nano / mcp73831 test. You can even connect an AAA battery holder to the micro lipo without soldering (twist & tape).

Modding a $1.50 tp4056 charger board would be the least expensive option. A 5.1k resistor gives 250mA, 10k for 130mA. A through hole resistor works or a 0805 resistor. Original resistor is 0603 but 0805 does fit on the pads. FT $1.56 0805 3.9K-62K Resistor pack 270-Piece

With efest10440 250mA is 0.81C, 150mA is 0.49C. LiMn might be able to tolerate more but don’t want to risk losing any capacity from charging too quick.

So is the 250ma option good for these batteries?

Yes, 250mA charge current is fine for 10440

Thanks! :slight_smile:

i see that in the protection test, you run the batteries
down to below 2 volts and sometimes below 1.75 volts.

these batteries have no protection circuit.

Is this safe to do with this chemistry.?
can i run these without protection until dead
and then recharge ?

thanks for the great info