Nitecore i4

[wolfdog1226]

@ledoman

Don’t know anything about TK75, but if it has regulated driver on turbo assuming constant power you can get situation when those Panasonic cells are not the best choice. Sanyo or better yet some hi amperage cells would be better. In the process of draining you are getting lower and lower voltage. To maintaine constant power, driver pulls more current. When it pulls more current voltage drops even more. When driver detect some voltage limit it steps down. Simple as that. Hope you understand. I’ve experienced similar situation with some regulated drivers before, particular with THIS one.

Compare battery curves of Sanyo and NCR18650B with HKJ comparator. You’ll see Sanyo has higher curve at second half. In general higher curve cells are better for your situation. Also notice the protected cells have lower voltage curve. You should also compare curves at constant 10W power. You will notice down to 3.4V Sanyo 2600 can run 10 min. longer than protected NCR18650B regardless of capacity.

I see what you are saying. That concept is TRUE foe some of my Vinh lights that demand more amps to sustain max power. Those IMR cells[Sony VTC4/5, Samsung 20R] and NCR 18650PF will work better than a genuine Panasonic cell.

However, for my TK75,Panasonic cells have worked fine for the last 17 months!

OP’s issue is weak cell[s] or a charger that does not charge them well enough. I would be surprised if it were the torch.My guess would be the CELL[S] .

[dazed1]

I tried 2 different chargers, i4 & LUC V4.

The runtime is around 45 min, on turbo, or 50 max, before the light start to drop to high mode, after few minutes (1/2) or even 30 seconds later on. Do you have 2900lm version? could that make the difference?

3/4 times from the time i own this batteries, i used them hard to the point the light would give low voltage warning, could this damage the cells? or shorten the life? they are around 1.5 years old but i think 14 months or so is the correct age. And maximum of 50 recharge cycles i would say even less.

[wolfdog1226]

@dazed1

I tried 2 different chargers, i4 & LUC V4.

The runtime is around 45 min, on turbo, or 50 max, before the light start to drop to high mode, after few minutes (1/2) or even 30 seconds later on. Do you have 2900lm version? could that make the difference?

3/4 times from the time i own this batteries, i used them hard to the ppint the light would give low voltage warrning, could this damage the cells? they are around 1.5 years old but i think 14 months or so is the correct age.

I have the ORIGNAL version,yes, that could make a difference. I heard the 2900 version steps down after 15 minutes and your total run time on turbo may be less!!!

IS YOURS THE 2900 [NEW] Version??? If so, there may be nothing wrong with your batteries,you just get less run time w/ that version.
I RE READ YOUR POST!!! IF your batteries are about 1.5 years old[like mine] there is NOTHING wrong,you run your torch hard like mine and the batteries are getting older!!!

[dazed1]

Yes 2900lm version. So 45 mins is fine for 2900 lumen version on turbo? aren’t the XM-L2 more efficient so the runtime would be generally the same?

[wolfdog1226]

@dazed1

Yes 2900lm version. So 45 mins is fine for 2900 lumen version on turbo? aren’t the XM-L2 more efficient so the runtime would be generally the same?

I do NOT have the 2900 version!!! Even so your batteries are 14 to 18 months old!!! There is your answer!!

If your concerned about getting more run time get an extension like me[I hardly use it!(])!

You will more than Double the run time[I got 2H 54MIN.] because using 8 batteries puts less stress on each battery making them more efficient!

[dazed1]

Thanks for your help!

But i never use my light hard, i just wanted to test to see if anything is wrong or not, having read your answer, i think i get like 15% less runtime then i should but i guess its ok.

I just cant understand how Fenix is getting 75 mins runtime on turbo with 2600 mah cells, and i can’t get more then 50 with 3400 mah….

[wolfdog1226]

@dazed1

Thanks for your help!

But i never use my light hard, i just wanted to test to see if anything is wrong or not, having read your answer, i think i get like 15% less runtime then i should but i guess its ok.

I just cant understand how Fenix is getting 75 mins runtime on turbo with 2600 mah cells, and i can’t get more then 50 with 3400 mah….

Your welcome.

There numbers are not always right!! The most I ever got w/ brand new 3400mah Orbtronic was a combined 65/67 minutes of turbo

[FMcamaroZ28]

Keep in mind that the 2600 (im guessing they use the sanyos) are able to hold a higher voltage longer than the Panasonics, even though they have less mah.

Perhaps that has something to do with it? Doesn’t explain why its such a large difference in time however.

[dazed1]

@wolfdog1226

@dazed1

Thanks for your help!

But i never use my light hard, i just wanted to test to see if anything is wrong or not, having read your answer, i think i get like 15% less runtime then i should but i guess its ok.

I just cant understand how Fenix is getting 75 mins runtime on turbo with 2600 mah cells, and i can’t get more then 50 with 3400 mah….

Your welcome.

There numbers are not always right!! The most I ever got w/ brand new 3400mah Orbtronic was a combined 65/67 minutes of turbo

So in short, you get 2x runtime compared to me! you got protected cells? was told now that the turbo on 2900 lumen is 15 mins, so the runtime on turbo is even less ~35 mins! that’s terrible!

[dazed1]

@FMcamaroZ28

Keep in mind that the 2600 (im guessing they use the sanyos) are able to hold a higher voltage longer than the Panasonics, even though they have less mah.

Perhaps that has something to do with it? Doesn’t explain why its such a large difference in time however.

Could be but the difference is still very big. They use Bak cells not Sanyo afaik.

[wolfdog1226]

@dazed1

@wolfdog1226

@dazed1

Thanks for your help!

But i never use my light hard, i just wanted to test to see if anything is wrong or not, having read your answer, i think i get like 15% less runtime then i should but i guess its ok.

I just cant understand how Fenix is getting 75 mins runtime on turbo with 2600 mah cells, and i can’t get more then 50 with 3400 mah….

Your welcome.

There numbers are not always right!! The most I ever got w/ brand new 3400mah Orbtronic was a combined 65/67 minutes of turbo

So in short, you get 2x runtime compared to me! you got protected cells? was told now that the turbo on 2900 lumen is 15 mins, so the runtime on turbo is even less ~35 mins! that’s terrible!

My cells are Protected,Orbtronic 3400mAh 18650 Button Top

[dazed1]

Its very disappointing to know that my cells are probably gone bad. If anyone can test with fully charged Panas 3400 mah protected 20 mins or 15 mins on turbo, wait 5 mins and then measure the voltage i would be very grateful!