Ultrafire 602A low voltage start up cured with SX0H luxeon1

Finally got around to putting the SX0H luxeon 1 into the ultrafire. Before the mod it would not light on voltages 1.2v or lower. It would stay lit as the battery went to those voltages, but turning off then on resulted in darkness.

Now it will light on 1.06v recharable alkaline (and imediatly dims down as the cell is dead).


I measured a variety of luxeons hooked up to the circuit and no matter what Vf, the circuit always delivered 250ma to the led's. So I'd say it's safe to declare it 250ma CC flat regulated circuit. I guess the stock clone Vf was high enough that the circuit could not stay in regulation at 1.2v, and refused to fire up.

Now it fires up just fine, and is brighter than my fenix. Also the beam is wider on the ultra fire too with some corona around the hotspot. It's not double bright, but I can tell a difference.

Runtime seems to go on forever using amondotech 2600mah NiMH. I don't want to say yet, but I'm going to guess at least 2 hours flat output. Yes flat, this doesn't dim like my Fenix L1P. Of course that's becuse of the CC circuit.

These lights aren't bad once modded, but you need a premium low Vf luxeon to make the CC circuit worthwhile. Stock, the circuit isn't a good choice.

I may send this off to someone who can graph it. It's suprising me.

Nice work!

I hope this light wil work well with a cree XR-E as well.
Hope to be able to test that soon .
If not I may invest in a SX0H as well....

I'll try to explain why this mod helps it turn on with lower voltage.

CC circuit, so if you have a lower Vf emitter, that's less power out. Less power out means less power in. Less power in means it won't hit the circuits max input current limit so fast, therefor allowing it to run on less voltage in as now it has room for extra current draw to convert lower voltage in to current.

It defeats the purpose of a cheaper clone having to modify it to have it work well, but at the same time, you can open it up, and you know what luxeon you have. S flux @350ma (it's getting 250ma) and low Vf, nice X0 tint. Also instead of a comprimise of a semi regulated or voltage boost circuit that will run on low voltage, now you have a constant current circuit that gets impressive runtime.

I'm charging up my two 2600mah titaniums and I'm going to compare this with my Fenix head to head and see what the runtime is by eye. I will turn on/off each light ever so often to make sure I haven't exceeded the turn on threshold for either light. (as both will run a battery down till damage).

knoefz, it was very easy to mod. I even shimmed behind the rubber boot cap with some thin packaging cardboard as mine had too much give before the switch enganged. I also took the time to sand both ends of the battery tube to shine it up, and then cleaned it with rubbing alcohol so there is as little resistance as possible. I measured over an amp draw on NiMH.

If you do mod this for a cree, you'll have to remove the top emitter board PCB ring, and then file/grind down the center heatsink as it's got a centering depression for the luxeon, and the cree will need something flat. I'm thinking of modding an Ultrafire 602D instead for a cree, since it's smaller and I'll make it an EDC. I'll use a modded IMS17mm as others have done.

Did a runtime test by eyeball with my Fenix L1P next to it. 2600mah cells.

Both lights started out about the same.
After 20mins the Fenix was dimmer to the eyes.
Fenix continued to get dimmer to about half as bright until:
1hr 30mins they both seemed as bright as eachother.
1hr 55mins the ultrafire was really dim, and the NiMH was 1.02 volts.
2hr 23min the Fenix was really dim, and the cell was .9xx volts.


So the Ultrafire is rock steady until about 1.5 hrs. Then it has 30mins of declining output. The Fenix declines the whole time and that gives it about 30mins more of light.

Thats the best I can do with my eyes as I have no graphing software and lightmeter!

Nice work, Isaac! I wonder what happens with the updated ones...

So something like $25 for a good, solid, light with decent runtime. Much cheaper than the Fenix, though not quite as nice.

Thanks,
Kevin

We seem to be on the same line of thoughts for modding Isac

I know how easy the 602A was (remember my red badwing mod from a while ago in this light?) and I've been thinking about a 602D /XR-E combi as wel. But what keeps me off is that I's need to invest in some rechargable 123's and a charger as well as 123's are hella expensive here. AA clicky lights have something that attracts me.

I still have a super cheap (and not so nice) "MX POWER" light that originally had a Nichia led (now carries the red batwing, but has a plastic reflector. That one will be easier to grind down for the XR-E and I won't be bummed if I mess it up by grinding too much.

I re-charged the batts and the UF is defiantly brighter than the fenix starting out. They are not the same brightness. BIG difference in light on the UF. The fenix does have about 30mins more of light, but the UF has almost 2hrs of steady brightness. It sure does get hot/warm!!!

Knoefz: I think I'll be modding the 602a again to cree as well. I already ordered the 602d in HA/TypeIII, a DSD charger, and 2 unprotected rcr123a's from fifthunit. The price was not bad, I even ordered a few other items and it was under the cost of a new Fenix P1. The 602d being so small and having a li-ion in it will be a screamer with the XRE. I do however want to mod the 602a and put an cmg infinity clip on it to make it EDC perhaps instead. I will do both and see which I like best. Small, short runtime, super bright, or bright, AA with longer runtime, and a little bigger.

BTW I see the happy tree friends guy in your avatar.

Happytreefriends rock! lol

About the 602D (great buy!)... I'm still hoping Ultrafire will come up with a 123 clicky... sort of an Arc LS clone instead of a P1 clone.