Bought a Convoy S2+ 7135*8 today, need battery/overall suggestions. Help with older Fenix TK15 337 max lumen I found.

First post, sorry guys I’m a little overwhelmed I just started this today. I’m going over the basics threads, there’s too much. I’m just going to ask the default recommendations and some silly questions to see if I’m understanding correctly.

Phase 1: Charger - I’m set on buying a Nitecore D4. Xtar VC4 is second choice. Any other charger recommendations or is the D4 gold like I’ve read? Is the Nitecore UMS4 for very large and good batteries?

Phase 2: Today I bought a Convoy S2+ XML2-U2 7135*8 orange reflector from banggood, not coming for a month probably.

Some stupid questions.

  1. I’m setting to buy a couple Panasonic 3400mAh 4.9A Protected Button Top 18650s. Is this overkill for such a budget first light? Would this have issues with fitting in the tube since protected is thicker?
  2. To verify my understanding of protected vs unprotected: If a Convoy S2+ accidentally turned on in your bag at max output, then the temp would soar. Would a protected battery’s fuse cut it off before it sets fire while an unprotected would just keep going and set on fire? Is this the safety issue everyone speaks of?
  3. How do you know when to recharge your batteries? Will the Convoy notify you when voltage gets too low? Or is being mindful of your 18650’s the game like manually checking it with a charger.
  4. I wanted to buy a Convoy SST40 1800 lumen for comparison to the XML2-U2 (i’m assuming it’s drivers are 7135*8). The SST40 is brighter and draws heavy. I read it’s like 6000mAh @ 1800 lumen max?? That doesn’t sound right. If it is, I think I’m understanding all this and it will be hotter than the XML2.

Phase 3: I found my old Fenix TK15, 337 lumen max Cree XP-G R5. I bought 10 years ago and never used because it was so nice and CR123A’s were so expensive. The manual says to use 2x CR123A or 1x 18650 for 1h 50m runtime on max 337 lumens. I’m going to fathom that a Panasonic 3400mah 18650 would be a complete waste on this light. If my Phase2 Question2 on understanding protected vs unprotected is right, a Samsung 20S 18650 2000mAh 30A Battery would have little issues as long as I’m mindful of the temp?
The basics threads had a chart for the Cree XP-G R5:
139-148 - 350mA 100%
260-277 - 700mA 187%
348-370 - 1000mA 250%
463-493 - 1500mA 333%
I’m reading this as 350mA produces 140 lumens and anything over 100% mean it’s operating out of normal temp tolerance. If the max lumen is 337, based on the chart 1000mAh is the max draw. A 2000mAh battery would run it for 2 hours @ max so that’s all I’d need, correct? Don’t know mAh capacity of each CR123A (i’m going to guess 800 based on the manual stating 1h 50m runtime) so if I’m reading all this correctly, running at 337 lumens would be capacity/load (1600/1000) = 1.6h runtime which fits the bill. Please let me know if I’m right or wrong.

Sorry for the lengthy post and any help would be greatly appreciated. Thanks!

Welcome to BLF.

Why buy a 4-dock charger. Planning on some bigger lights, with more batteries?

A protected battery is just what it says: built in protection FOR THE BATTERY.
NOT for the person who owns a light where the battery goes in.

If the battery goes “empty” the voltage sags. Maybe the light warns you for that.
But that depends on the driver that came with the light.

Yes, a led that draws more power (Amps) will generate more heat.
But that does not depend solely on the led itself, but also on the driver that supplies the power

The driver that usually comes with an SST-40 can deliver 5 or more Amps.
The 8*7135 driver can “only” deliver 8*350milli-Amps = 2.8Amps.
Which is enough to make you feel quite uncomfortable if switched on in your pocket.

Imo the Nitecore D4 charges too slow if 3-4 batteries are being charged. The Xtar VC4 would be my choice

Welcome! I’ll take a stab at some of your questions.

It’s never overkill to buy quality cells.

They are usually longer too. I don’t think it’s an issue in S2+ though. From Convoy store (S2+): “Required battery type: 18650 lithium (protected or unprotected)”

Not really. The safety cut off triggers on too high amp draw, and also (if I remember correctly) if voltage is too low. To my knowledge it does not trigger in temperature alone. I’ve never had a protected cell trigger.

It’s quite standard to have a low voltage warning blink of some sort, and maybe a critical voltage cut off. From Convoy store (S2+): “Low voltage protection function: when the voltage of battery is 2.9-3.1V,the flashlight flashes 2times/sec with low brightness,it’s a low voltage alarm.”

If you’re worried about a flashlight turning on inside a bag, just unscrew the tail cap a half turn to prevent an accident. Will only work on lights where the threads are anodized.

Batteries with protection protect against the following: draining the voltage down too low damaging it, short circuit, over charging, overloading with too much current.
Unprotected batteries can drain all the way to 0 volts unless the light has a low voltage cut off.
Unprotected are needed in most high lumen lights due needing more power than the protection allows.

The Convoy S2+ driver has no temperature protection so you need to monitor this yourself. For the S2+ is better to get the 4x or 6x 7135 version so it doesn’t get too hot.

Thanks for the responses guys.

The 4-port charger is for future-proofing for both torches and equipment that I should have switched over to rechargeable a while ago, especially AA/AAA. It looks like D4/VC4 are my top choices.

So protected is to protect the chemistry of the battery so it doesn’t become unstable/volatile under load or charging, not situational protection. That makes more sense.

I made mistakes in my choices for the S2+ I bought then. It will be an emergency light then.

- I’ll buy another 7135*3/4 for extended runs with a bicycle.

  • Seems biscotti firmware does the low voltage protection, don’t know what I got.

The accidental switch on was a hypothetical situation on what I thought protected meant. But I will spin that tailcap for certain situations good advice. I’ll pass on the SST40 for now, 5A sounds like a lot for such a small footprint.

Any specific suggestions on batteries? I was intending on buying two Panasonic 3400 protected for two convoys. And 2 low cap samsung unprotected, but now maybe two cheap EBL from Walmart as a beginner.

Did I read that emitter chart correctly?

Thanks the responses helped.

In my research, it looked like the Sanyo NCR18650GA 3500 and Samsung INR1865035E were the most recommended.

I haven’t tried much of Nitecore chargers (I’ve checked out the Nitecore SC4 and Nitecore F1 chargers before).
Haven’t tried reaching reviews about the Nitecore D4… but I’ve also tried the Xtar VC4 which was the first real li-ion battery charger I got — The VC4 is OK but it’s pickup with the USB power supply — a slight drop in USB voltage causes the charge current to drop. Also, the charging is a bit on the slow side these days (VC4 can charge 2x 1A, assuming a good USB power supply but will drop to lower charge current if not so good USB power supply.) I find charging 18650s at lower than 1A to take more time…

So I’ll look for a charger that can do at least 1.5A or 2A, for the times a faster charging time may be needed. (too high charging current may degrade some battery types a bit more quickly)

I think the S2+ tube fits protected 18650s just fine, at least when I tried them before. I don’t use protected 18650s 99% of the time though.

I think no, it won’t do that. (that’s likely not part of the feature of a protected battery, but I could be wrong…)

Well, my guess is it has the “old firmware” with 5/3-modes. If I recall correctly, how it behaves is that the flashlight LED will blink when battery is low — I can’t remember if it will finally shut off (I think at a really low voltage, it will). Also, the light should be noticeably dimmer when battery level is low.

(with the new Biscotti firmware, I’m more sure that when battery is low, the flashlight will shut off completely. Just can’t remember with the 5/3-modes firmware)

Convoy S2+ SST40 will get hotter than the S2+ XM-L2 when at highest brightness mode…. however, the S2+ SST40 uses a different driver with thermal control — meaning, when the flashlight (LED board) gets hot, the flashlight will automatically dim down in brightness, which will then cool down the flashlight.

On the other hand the S2+ with XM-L2 with the old firmware, doesn’t have thermal control feature — so its brightness (assuming flashlight set to max brightness level), will slightly dim as battery capacity/voltage drops. Assuming the user doesn’t adjust the brightness, I think the S2+ with XM-L2 (set to highest brightness) will become hotter than the S2+ SST40, after the SST40 version steps down in brightness due to the automatic thermal control. (again I haven’t acutally compared the 2 side-by-side in this scenario, but I’ve checked that the S2+ SST40 does dim down when it gets hot after a few minutes).

“6000mAh @ 1800 lumens max” = it’s supposed to say “6000mA @ 1800 lumens max”, not 6000mAh (mAh is a measure of capacity, while mA is a measure of how much current/power). S2+ SST40 I think is supposed to max at 5000mA only (the other Convoy with SST40 maxes at 6000mA, but the S2+ version has a slightly lower limit). I’ve measured only around 4500mA for the S2+ SST40 when set to max brightness. The “1800” claimed lumens is “claimed” and likely doesn’t hit that level (I don’t have something to measure lumens), but other reviewers put it at 1600 lumens more or less at max. Still the S2+ SST40 is defintely much brighter than the S2+ XM-L2 version.

Phase 2:

  1. No, it’s not overkill. There were a few Convoy samples with fitment issues in the past but hopefully the issue is solved now.
  2. Protected batteries protect against overdischarge, overcharge ( any good charger won’t overcharge in the first place) and shortcircuit. A 2.8A Convoy was tested to reach up to ~80C(~170F) after 20 minutes turned on on high mode IIRC. That’s very uncomfortable for your hands but probably won’t start a fire.
  3. If the battery is very low it will blink, but brightness will decrease as the battery depletes, you will notice it.
  4. The SST40 version will step down after the driver reaches 55C (131F). Many people here think that’s too conservative because the driver may heat up faster than the flashlight body, but at least it’s an useful safety measure when lending it to people. The 4.9A protected battery could have issues with the 5A load, I would rather buy a protected LG MJ1 or Sanyo GA.

Phase 3)
No, it wouldn’t be a waste unless you never use it. More capacity rarely is a waste. A Samsung 20S, if you already have a spare one e.g. for vaping, should work well on both flashlights, but the current rating is overkill, buying one would indeed be a waste.

The XP-G is rated for 1500mA max, the % you see are relative outputs compared to 350mA. 1000mA shouldn’t heat up much.

You can use the medium mode. I’m pretty sure you got the 3/5 version.

Avoid EBL, they are actually only ~2200mAh instead of the 3000mAh they claim and their quality is suspect. If you intent to buy two protected and two unprotected, for the unprotected I would recommend the LG MJ1 from LiionWholesale while the discount lasts (out of stock now), either the button top Samsung 30Q for futureproofing (or the flat top) or the flat top LG M36 for its capacity if your flashlights support flat tops, and for protected either the LG F1L (has pretty much the same performance as the NCR18650B while being typically cheaper), or the protected LG MJ1 (better than the NCR18650B and still cheaper than the GA).

Regarding flat top or button top for unprotected cells, flashlights with a spring on the positive side like the Convoys will support both, otherwise button top cells are more compatible, but some compact flashlights like the FW3A require flat top cells.

The S2+ you ordered is a good light that ships in many colors with a few different emitters from $9.99 up.

The S2+ that I would recommend is the one with the SST40 1800lm 5A.It has both springs bypassed,the driver is secured with a locking ring.

The 8*7135 has the driver soldered in and a pita to desolder and remove.

I recommend flat top unprotected cells for the S2+

For cells I suggest the Samsung 30Q or Sony VTC6

I you want more capacity but lower amps the Sanyo/Panasonic NCR18650GA 10A is worth looking into as is the Samsung 36G.

Some battery sellers offer lower prices but when you calculate the shipping they may not be the best deal.

BTW,I own 7 S2+,they're good bang for the buck