Sofirn SP31v2; is this normal?

Hello and Happy New Year.

I just posted this on Sofirn Flashlights group on Facebook, but want to know opinion from this forum too as I’m about to purchase a new light and Sofirn is one of my choices (SP10v3).

I have both LH351D & XP-L HI versions. They randomly blink on High/Turbo mode and the side switch illuminate red. It’s been randomly happening since purchases (LH351D from Sofirn’s site, XP-L HI from Sofirn’s AliExpress Store). This happens with both Sofirn (button top) & Samsung 30Q (flat top) batteries. At first happens even batteries are fully charged or above 85%.

I got this answer from Sofirn through e-mail contact in Dec’20 - “High/Turbo Mode drains battery very quickly, so the chip tells battery is running out of power soon. After changing to lower mode, the battery works longer, so the indicator is green.”.
Is that true? I just don’t see it happens regularly.

I attach a video to demonstrate the issue. This is the latest (and the most severe?) happening on my LH351D version since last night. I just swapped batteries with my XP-L version and the issue disappeared from both of my SP31v2’s.

Update: Thx for all comments. I just had a quick cleaning at the light/battery contacts and recharged batteries (both were at around 70–88 from the charger display). Now the lights are working well but not sure for how long, hopefully forever :smiley: .

sounds broken to me, it should flash red obvious when battery volt is low obvious, but not when battery is fully charged. it looks to me faulty and they should treat it so.

Did you try cleaning up all the contact points? My experience with boost/buck drivers has been they are very sensitive to voltage drops due to weak batteries or dirty contacts. That said, I have not seen that happen with my SP31s.

It looks so to me as well. When I sent the video and received that reply, I decided to gave up the argument even I wasn’t 100% convinced.

SP31v2’s are my first and only high power (18650) flashlights as I heard a lot of good things about Sofirn. I thought the first one was defective but after I bought the second one I doubt their quality/design. I like that they have many products and some have hit my needs (SP10v3 is really tempting). But with this experience, I’m just afraid to buy more of their products.

Not yet, but will try :slight_smile: .

Seems that you discovered the reason—why would anyone say the light is defective after this?

Sorry, what reason you mean? This is likely a temporary fix because I saw this issue happens a few times, randomly on my SP31 (both versions) since I purchased around 1 year ago. I’d be happy to know the reason or if there’s any permanent fix. There are couple lights from Sofirn in my wish list :slight_smile: .

The fault was caused by the batteries—does that not appear to be the case.

Sorry my post maybe not clear. It happens with whatever battery I use (I have 30Q and Sofirn batteries). Last night it happened again (with another battery from XP-L HI one). I guess I’ll need to find replacement for SP31vs LH351D soon.

Get some mild abrasive, scrub the contact parts of the driver- and tailswitch springs. Wipe down later with IPA or similar to get the “shavings” off.

Test the light.

Also, do the same and scrub the edges of the head, tail, and tube, to make sure they’re all clean and make good contact. Ie, both edges of the battery tube, and where those edges make contact with the head- and tail parts.

Test the light again.

Also, if you can, loosen the retaining ring on the driver, jiggle it, snug it up good and tight.

Test again.

While you did say it affects multiple cells, do the same with the cells’ contact area. I mean, why not?

Yeah, test again.

Basically, it sounds like there’s a bad connection somewhere, that at higher currents, creates a big enough voltage drop to let the µC think the battery’s running low. Even if the power path is pretty good, raising the ground level of the driver by, eg, 1.0V, might make the µC think the cell voltage is 2.8V instead of 3.8V.

Do. Not. Take. Shortcuts.

I’ll try those. Hopefully it will work cuz my search for new flashlights often end up with Sofirn products. It will be difficult to cut the brand out of my list. :partying_face:

It looks like you are trying to go up to Turbo over and over again, after the light steps down. That is not good user behavior. Do not use Turbo over and over again.

It looks like the red light is telling you Not to go up to Turbo over and over again. So, do not expect Turbo to work over and over again. Use a lower output.

here is a review that tells us not to use Turbo over and over again:

“I performed a runtime on turbo, and reset the light to turbo once during the run. Turbo falls off quickly, from around 920 lumens to 840ish at 2 minutes. Not too bad. But very soon, the light steps down very hard, to the High setting. Turbo can be reset, but the output doesn’t reach the initial output. “

Wanting to use Turbo after step down is not correct Operator Expectation.

Hey, thanks for the warning and sorry it may seems like that. But, AFAIK, this light can go to lower modes only by cycling through Eco>L>M>H>T>Eco>… . Is there any other way to skip H>T modes? I don’t have much knowledge with this to be honest.

In addition, I couldn’t think of any other way to demonstrate the blink in Turbo mode that I found without going to Turbo mode. Unfortunately the light just stuck in High mode during the record and could eventually go to Eco after a few multiple clicks. That was also the first time I experienced this behavior. Before that I could easily cycle to Eco when the light blinked/indicated Red, in Turbo.

For your reference, I’ve never seriously used High/Turbo mode until step down yet (never reach 10 sec I’d say, no situation where I need to). When the light blinked in Turbo/indicated Red, I just cycled to Low. And all the time the issue happens, the light is completely cool from a long resting, battery is within 70–90 range. I should not expect a reasonable step down, should I?