[Review] Sofirn SP33 V3 - XHP50.2 3V eSwitch 26650

[d_t_a]

@Tom E

<p>I have a couple old SP33’s that have the 6V XHP50.2, but unmarked version. Think your V2’s were unmarked. Was wondering if mine were V1 or V2. Maybe V1 was an entirely different LED?</p>

<p>Btw, the 3500 lumens rating is pretty honest. Use a 30T or 40T and you get a little better. Bypasses on the springs would probably do even better.</p>

The original SP33 v1 "2500" lumens (XHP50.2 6volt LED) will have a tailcap current of 6 Amps on Turbo, no higher. <= this will be a good identifier for the older SP33.

The SP33 v2 (XHP50.2 "3000" lumens) will have around 8-10 Amps on Turbo (tail current from what I remember, will find my notes...)

The SP33 v3 (XHP50.2 "3500" lumens) will have higher than 10 Amps (probably 12-13+) tailcap current on Turbo, based on my measurements with a fully-charged 26650 battery (UT210E clamp meter) (tail current from what I remember, will find my notes)

Also, using the Zak.Wilson's "CeilingBounce" app and measuring the "ceiling bounce" (sorry I don't have a light integrating device as this time), gives the following graphs, which show different thermal control.

[Tom_E]

Ah, ok. They were all XHP50.2's. Thanx! I had been planning to swap in 3 channel drivers that CK designed here: https://budgetlightforum.com/t/-/55051, but never got around to it.

I believe these boards will work on all SP33 models, appears nothing changed in the basic driver layout, though not sure, haven't confirmed.

[icpart]

Guys, how do you remove stainless steel bezel of SP33? It will be interesting to be modded with Narsim/Anduril based driver.

[Tom_E]

Didn't try yet - maybe can try this eve.

[phouton]

@icpart

Guys, how do you remove stainless steel bezel of SP33?

It simply unscrews from the body. I used an elastic band on the bezel for better grip.

[Unheard]

Pressing the bezel against the sole of a shoe while unscrewing should also work. Takes a little force but will come off.

[Tom_E]

I removed the bezel easily with my sticky gloves.

Interesting fyi, I added 22 AWG wire bypasses on the springs (short ones in the center of the spring), and got ~ 25% boost in lumens and candela.

Measuring amps at the tail, on a charged up 40T the amps went up from 14.7A to 16.5A, but that's only seeing the bump of the bypass on the driver side because my amp measurements are with the tailcap off. I did the before/after tests with both a 40T cell and a red Dolidada 5500 26650 and saw about the same percent bump. These springs are not high performance, accept maybe for their thickness but they are not low resistance.

"nnnn-nnnn" below is "at start - at 30 secs"

Before After

Sam 40T 4390-3890, 32.5 kcd 5340-4790, 40 kcd

Dolidada 3530-3270, 27 kcd 4450-4180, 35.5 kcd

[gchart]

25% bump from bypasses? Wowsers!

[Tom_E]

We've been get'n spoiled on the high qual springs and double springs in our lights as of late - these are standard springs. I'd be worried about melting them with a good cell without bypasses.

[oweban]

Confirmed - went from 2200 lm in kit spec (kit 26650 and everything out of the box) to 2820 lm with bypass (2x 22awg twisted ends, soldered to spring).

40T was getting 2635; up to 2965 w that bypass.

[Unheard]

Anyone took a picture of the driver spring? I’m not sure where to solder.

[oweban]

I took the spring out before soldering it; just gotta “compress” it sideways at the bottom to do so.

And yes that’s two wires

[Unheard]

Thanks a lot!

But I meant the Spring on the driver PCB

[oweban]

Oh! Oops!

I’d probably do something similar - gotta desolder the wires to the MCPCB first to get the driver out though; they’re quite short.

[Unheard]

Ok, you only bridged the tailcap spring and that is already very successful. Good to know, I’ll try this

[Tom_E]

I solder the bypasses inside the spring - if the solder joint breaks, you don't want that wire touching something it shouldn't on the driver side.

Though the outer bypass has advantages - the spring can completely collapse down if a battery fits tight.

[oweban]

On the driver side I’d do my best to do it on the inside (would spend more time on it than I did), but for the tailcap side, it’s all one slab of metal so I figured it was fine for the outside.

It’s unfortunate that “3500” ended up being 2200, though.

[Unheard]

@Tom E

I solder the bypasses inside the spring - if the solder joint breaks, you don’t want that wire touching something it shouldn’t on the driver side.

Though the outer bypass has advantages - the spring can completely collapse down if a battery fits tight.

Yes, this is my concern. I have a 20700 for the SP33. Maybe I need to go back to the 26650. Or leaving the spring on the driver side untouched.

[Tom_E]

@oweban

On the driver side I’d do my best to do it on the inside (would spend more time on it than I did), but for the tailcap side, it’s all one slab of metal so I figured it was fine for the outside. It’s unfortunate that “3500” ended up being 2200, though.

2200 is much lower than mine before the bypasses. By out of the box, do you mean the battery out of the box as well, not fully charged?

[oweban]

Sorry, no - fully charged, but the kit battery. Have tested in both a lumen tube and sphere, both calibrated with lights from Maukka.

Also some crazy thermals.