Demonfire 10440 600mAh 3.7V High Drain Li-Ion Rechargeable Battery with Button Top (4 Pieces) D1 Charger

So far so good

I liked the price. The tech in the description looked like it was good to have, but alas, the only flashlight that I have that takes 10440's does not work with these probably because of the fancy electronics. The charger seemed decent, it just had a hard time holding the little 10440's well enough for me to know there was good contact on each end. I accredit the misfortune to my flashlight. I have an older ultratac K18 that did just fine with a truefire 10440 with the same output ratings as the demonfires. I am unable to truly test this product though so I resultingly have to cap my rating in the average range.

Made in C_ina crap. plug in and both lights are green even with no batteries inserted - put in dead batteries, lights stay green forever and batteries don't charge. tried with multiple batteries I know to work when charged. They then charged and worked with a different charger. This is a toy.

The bad news about this Demonfire D1 charger is that, like many chargers that support small and larger batteries this D1 will not mechanically hold in place the smaller AAA or 10440 batteries unless you add some shims or a "sleeve" of some sort to keep the batteries from popping out or going sideways. I fashioned my own sleeves with about three layers of cardboard from a toilet paper roll and that works - marginally if you're careful. It does seem to hold AA, 18350 and 18650 batteries well. The other bad news is that, although the D1 has an 8-12VDC input jack for use with a car adapter, it does not come with the cable so good luck finding one that fits. The good news is that this D1 does support the lower voltage Lifepo4 batteries with a switch for that purpose. But if you don't need to support Lifepo4 , the Nitecore D4 is far superior alternative, in my opinion, given that the D4 (for a few dollars more) shows much better charge status, holds 4 batteries, supports far more battery styles (except LifePo4 as stated) and comes with a DC adapter cord. By the way, the D1's DC input is different than the D4, so the D4's cable will not fit into the D1's jack. The D4 does have the same problem with retaining the smaller aaa batteries.

Tried multiple times to fit into a device that requires these batteries specifically with no success.