HM 65R - 3.6 vs 3.7 volts not working

[jp_over]

Hi,

I ordered a Fenix HM65R Headlamp in Nov 2021 which came with a Fenix 3400 mAh 18650 3.6 volt 12.24 Wh rechargeable Li-ion battery. Unfortunately, the light will not run my preferred KeepPower 3500 mAh 3.7 volt 12.95 Wh protected cells. It won't power up or show battery status. If I drain the cell a bit, then it works. Also, it works fine with the factory/Fenix battery.

Anyone experience this? Are this year's Fenix 18650 headlamps limited to 3.6 volt/Fenix brand batteries? I've also reached out to Fenix and will post an update when available.

I assume there is a protection circuit in the light but confused as to why I can't run a standard 18650 at full charge. I've tried a few different cells (same specs - 3.7 volt KeepPower) but still no luck unless the batterie has been drained down a bit.

Many thanks,

JP

 

[alpg88]

Are those all protected batteries? have you tried unprotected cell?

 

[jp_over]

Are those all protected batteries? have you tried unprotected cell?

The cells are protected (both Fenix & KeepPower 18650). I haven't tried unprotected cells.

I heard back from Fenix and the light should run both cells so I'll check on getting a warranty inspection/repair.

 

[sirpetr]

The cells are protected (both Fenix & KeepPower 18650). I haven't tried unprotected cells.

I heard back from Fenix and the light should run both cells so I'll check on getting a warranty inspection/repair.

I cannot see any reason why the other cell doesnt work. 3.6V and 3.7V means that nominal (=average) voltage is different, sometimes just a result of math rounding. Max charging voltage is same so both cells should work.

 

[jp_over]

Thanks for the replies. As a long term update, I gave up on using non-Fenix batteries with this headlamp after Fenix looked at the headlamp (twice) and said all is good/working as it should.