Need advice regarding lithium/nimh batteries (Brunton L5 / Silva LX)

[TTT]

This headlamp uses 5-cell rechargable NIMH batteries as standard.

I want to use lithium batteries for less self discharge.

Two 18650 batteries would produce 3,7Vx2= 7,4 volts.

I do not thing the headlamp is regulated, but it probably has a driver that gives the LED the proper voltage.

In this lamp there is an K2 led, driven at (my calc) 1350 ma. (K2 rated max is 1500 ma). I think heatsinking could handle some extra power, but I am worried about how much it will increase.

Also, is there a way to use this with some kind of container so I can exchange the cells for charging or use in flashlights? I know that there exist 4xAA housings, but I have not found any for 18650. As far as I understand this will charge the cells better as well?

Thanks in advance for any advice!

 

[Edog006]

Great question, I own a Brunton L5 as well and would like to know if such a conversion is possible and how beneficial can it be.

-Eric

 

[Szemhazai]

5xNiMH's gives you maximum 7,25V after charge - I think that there should be no problem in using 2x18650 or 2x(2x18650) battery pack - the only issue here is that there is no housings for 18650 cells. So you will have to insulate them with the heat shrinking foil on yourself - look at Silvas battery packs – or buy these kind of pack in shop - all-bateries/litemania etc.

 

[TTT]

I got a mail from Silva today, claiming that it will be possible, but it voids warranty.

How are they going to prove that the unit overheatet due to excessive voltage - Perhaps I was using it daytime in Sahara :nana:

 

[TTT]

Great question, I own a Brunton L5 as well and would like to know if such a conversion is possible and how beneficial can it be.

-Eric

The K2 is running at 1350 ma (as far as I know), with at 1500 ma max rated input I do not think much gain will be visible.

I am going to try a a 7,4 lipo pack just to see, and take beamshots with set exposure so that comparisons can be made.

 

[Szemhazai]

LOL, it depends... in L1 they use buck regulator that maximal voltage taken from datasheet is 5,5V and it is getting 6,2V from 4 new alkalines so if they use the same chip in L5 it is possible that it may not survive this experiment

 

[TTT]

Only one way to find out. With the insane consumer rights in Norway, I do not see the risk unless i admit to it in the shop when complaining

 

[Edog006]

Good luck guys, I dont think im brave enough to change batteries or add the Seoul LED upgrade. I dont have faith in my ability to modify this headlamp, its already great but the idea that it could be better is tempting. Good luck, if the voltage dosent get to high and fry I might consider this upgrade, but I fear disassembling the light will be a catastophe because it would be my first and likely not go as planned. I will keep checking in to see how everyone is doing with the battery and mods of the Brunton/Silva lights