HM 65R - 3.6 vs 3.7 volts not working

jp_over

Newly Enlightened
Joined
Feb 13, 2008
Messages
61
Location
TX
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
 
Last edited:

alpg88

Flashlight Enthusiast
Joined
Apr 19, 2005
Messages
5,329
Are those all protected batteries? have you tried unprotected cell?
 

jp_over

Newly Enlightened
Joined
Feb 13, 2008
Messages
61
Location
TX
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.
 
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