P60 drop-in question

LED Flashlights – General Info
1

I have a P60 drop-in. It’s a 3 mode XP-G driven at 1.4A.
2.8-6volts.

It will function perfectly on all 3 levels for a certain amount of time, but after some time(3-10min), it will flicker and revert to low mode or dimmer and flash every 1.5 seconds.

The light has barely warmed up by the time it starts to flicker, so its not overheating, and i have tried it in 2 hosts and with different cells.
Any ideas?

Cheers
Matt

2

Well, it’s almost certainly a driver issue of some sort, as the behaviour you’ve described is similar to the programmed behaviour of some driver circuits in response to low voltages.

Give us as much information as you possibly can about the drop-in and your batteries.

3

Thanks for the reply.

The part of the drop in where the positive spring is soldered(driver?) has ‘NANJG’ and ‘101-AK-A1’ printed on it.
I have tried it in a surefire C2 and a Solarforce L2M that arrived today.

I have tried 2x cr123 cells and 1x Senybor 3100mAh 18650 and 1x Panasonic GCR18650CH.

Cheers
Matt

EDIT: This seems to be the driver here http://www.intl-outdoor.com/amc71354-5mode-circuit-board-nanjg-101aka1-p-254.html
It has a low voltage protection that makes the light revert to low mode and flicker like you suggested.
Do you think its possible to remove the low voltage protection out of the circuit?

4

Have a look here: http://www.intl-outdoor.com/amc71354-5mode-circuit-board-nanjg-101aka1-p-254.html

So it’s definitely the low voltage protection kicking in, which is supposed to happen at 2.9-3.0 volts, and given that you’ve tried an array of different batteries, it sounds like it’s kicking in when it shouldn’t.

Just for the sake of completely ruling everything out however (no matter how unlikely some things may be), have you measured the resting voltage of all the batteries you’re using? What are they?

If they are all fine, then it sounds like a faulty driver, in which case you can purchase a new one for a few bucks and replace it if you’re handy with soldering iron (and have a fine enough tip).

5

You beat me to it :smiley: I just edited my post above with the driver link.
Sounds like your right about the faulty driver.
I measured the 18650’s at 4.18volts, so they should be fine.

Cheers
Matt

6

There’s a way to bypass the Atmel chip, but then you’d end up with only one mode (high). I’ve seen instructions somewhere on how to do this (you basically just jumper past it), but I don’t remember where.

There are a number of people around here who have much more experience with drivers like this than I do, so hopefully one of them will chime in at some point.

7

Ok, thanks for your help.
I think the drop-in is thermally potted. I’m trying to remove the driver at the moment(i’ve removed the solder), but it seems to be stuck in place.

Cheers
Matt

8

You can bypass the chip by running a jumper here but I am not sure if that will solve your problem.

9

Thanks for the reply.

Unfortunately, because its potted with epoxy, the driver won’t come out in one piece. But in the process of trying to see about removing the driver, i removed 2 strips of solder between driver and pill. I then put new solder on to make the drop-in function again, and touch wood, its worked perfectly since.

I’m must be near the end of this 18650 now, then i’ll try another just to be sure.

Cheers
Matt

10

Can it be some way of thermal protection from the driver?
If so, you may fix it with aluminium foil around the drop-in, so the heat can be transferred from the drop-in to the body much better.

11

I thought at first it might have been thermal, but then realised the light hadn’t even had a chance to get hot before the fault would trigger. I managed to fix the problem by re-soldering the driver board to the brass pill, must have been a bad contact between the two.
I do have copper tape between the P60 and host now too.

Cheers
Matt

12

I did a conversion awhile ago with a 7135 2.8 driver and always had a problem with it flashing on low mode at 3 volts. I thought it was a crook earth somewhere but did not twig it was the driver as it was pressed into a copper sleeve which it was soldered to and the sleeve was pressed into the aluminium pill. After reading you fix i put a bit of acid on the aluminium and dropped a bit of solder onto it and the copper sleeve. You ripper. Problem solved. Thanks.

13

That’s great news that you got it fixed :slight_smile:

Cheers
Matt