I have modified a Petzl Myo XP Gen. 1 to work as a bicycle light. This means that I use the light for about 2 hours and then charge the NiMH batteries between the bicycle rides. I use NiMH batteries since the light is unregulated and I want to have fresh batteries for every ride to get as much light output as possible during the 2 hours.
The problem is that the light is dimmer with 3 NiMH than with 3 alkaline batteries, due to the lower voltage of the NiMH I would guess. I was therefore wondering if I couldn’t use 4 NiMH instead to get the light as bright as (or even brighter than) the light running on alkalines. The problem is that i don’t know if the slightly higher voltage 4,8 V with 4 NiMH batteries compared to 4.5 volts with 3 alkaline batteries would damage the light.
1. Do you know if using 4 NiMH (4,8 V) instead of 3 alkalines (4,5 V) would damage the light?
2. If yes, is there a way to avoid damaging the light by adding a resistor or something like that?
I know that you’re not supposed to use NiMH batteries in the Myo XP, but I’ve done that almost daily for more than a year without any problems.
that should be fine, although if you want to test it first, use some partially discharged NiMh cells and see if the light copes ok. Another option would be to add a 18650 holder on the back (or get a lipo cell to fit the battery compartment) and wire it into the light. I did that to my old headlamp as I got tired of constantly replacing the 3xAAA alkalines (NiMh just didn’t work well). Looks kinda kludgy but it worked perfectly that way for years. It’s now with a friend while I build myself a new one
I’ve used my Myo XP on a dark trail it was ok because my eyes were night adjusted, but under the city lights was totally useless to see any add’l road hazards.
