Battery recommendation

As I mentioned in my first thread regarding advice on 18650 flashlights I ended up ordering a number of flashlights. Specifically, I ordered (in various tints):

2x AstroLux S1
1x AstroLux S41
3x Conway S2+
(and also 2 AstroLux A01 AAA lights)

I understand the IMR/INR/Hybride type batteries have safer chemistry but would have thought that it might still be a good idea to add a PCB to it. However it looks like that combination does not exist?

This ones was recommended to me by

KeepPower 18650 2900mAh - 10A (protected)
edit: link to review may not be the same battery (maybe it’s an older version?)

but I’m wondering what chemistry it uses. It is a plain old LiCo? I didn’t think those could deliver 10A? Also I know that KeepPower has a separate ‘IMR’ range so this can’t be it, or can it?

Given the lights I will be using it with, should I go for this one? Or would I be better off, in terms of overall safety, with an IMR type battery?

Also as for safety, I will be getting a good, reliable charger. More on that after I figure out what battery to use :slight_smile: .

Basically, I’m looking for a battery with the following criteria:

  1. Should fit in all flashlights mentioned and max them out (without any mods to the flashlight, not gonna do that)
  2. One type for all flashlights, I do not want to use multiple types
    # As safe as possible
  3. Of course highest possible capacity but not at the expense of safety
  4. Low self-discharge would be nice as some of these lights will probably be sitting unused for long stretches (months to a year)
  5. Would prefer to order locally from but if there’s a better/safer choice available from a reliable seller elsewhere I will definitely consider it
  6. Price is secondary to everything else

I’ve been going through pages and pages of batteries and battery reviews but it’s hard to draw conclusions with so many choices so if there is a specific battery that satisfies the above requirements (and perhaps other more important ones that I didn’t think of) that someone could recommend I would be very grateful.

Hi Arjan. You are asking a lot of questions and it seems to me you would like the answer to point to one battery. Sadly that is not possible. The S41 for instance is a 18350 light that reaches a tailcurrent of 7.6A with the purple Efest’s I bought from Arjan Kon (NKON for me is a trusted seller). The tailcurrent with a unprotected 18650 Samsung 30Q IMR goes even byond 11A (no mod’s, and it gets very hot very quick). The suggested Keeppower test dates back to 2012 and is barely capable of doing 5A. I think there might be some miscommunication between the two Arjan’s.

I’m sure the error is all mine. I didn’t get the HKJ review link from, I looked it up myself and hadnt noticed it was from 2012. I guess the KeepPower on is not the same one but an updated version. I’ll have to look into this.

I also ordered the 18650 extension tube for the S41 btw so I’m still hoping I will be able to run all these lights using only one battery type (not sure if that will be possible regardles, need to digest what you wrote about max currents first).


Let me see if I understand this correctly. The maximum current draw of that the lights I ordered is:

Conway S2+ 8x7135 drivers= 8x350= 2.8A
AstroLux S1 (on turbo): 5.9A
S41 (on turbo): 7.6a and up to 11A and beyond?

The Conway is fully regulated so any battery that can deliver 2.8A (and they all should be capable of doing that) should do, right?

The S1 and S41 on turbo however are basically unregulated directly drive. The 219BT (not sure if that is the correct one) datasheet specifies an Absolute Maximum Rating forward current of 1500mA so with 4 of those the permissible tail currrent for the S41 would be 6A? So if you put it on turbo with a 18650 Samsung 30Q IMR you would be frying the poor things?

The Cree XP-L datasheet specifies a Maximum Drive Current of 3000mA so again at 5.9A you would be frying it?

Am I missing something here? Should I be looking for batteries that max out at 6A for the S41 and 3A for the S1 to ensure emitter longevity?

No need for the protection circuit, these lights have low voltage protection and will shut off before damaging a cell.

Protection circuits can be nice in a series light, especially one taking 3 or more cells in series, but for a single cell light the new chemistry of a Samsung 30Q or Efest 35A or LG HE-4 or Sony VTC5 or or or… there’s a lot of em out there and they’re safe while being very capable.

I recently got a light in from one of Sinner’s customers that he couldn’t get to work. Even after getting battery recommendations from Sinner on what to use in the Titanium 18650 triple he went out and bought an $11 Nuon from Battery +, the protection circuit kicks out on the Turbo every time. Simply can’t run the triple in Direct Drive mode.

So, if you’re looking at any light that has a Direct Drive FET or FET+1 driver, unprotected flat top all the way. Any light with low current requirements will run on virtually any cell you choose.

Hi DB Custom,

Thank you for your reply.

Any particular reason for the flat top recommendation? Did a quick Google on pros and const of flat vs button top but could not find anything definitive, other than that some lights/devices might not make contact with a flat top. As one poster commented I kinda like having a button top to remind me where the + is on the battery. Is a flat top likely to make a better electrical connection perhaps (provided it connects at all)?

As an example of what cell choice can do, here is a list of unprotected cells in a Direct Drive Lucky Sun D80. Simply choose your performance level…

Ok, although I suppose that in your example of the D80 a tail current of 4.65A is going to shorten the lifespan of the emitter significantly as its specified maximum current is only 3A?

In the case of the 219B, if the graph below is somewhat similar to that of the 219B, it would seem that more current from a more capable battery does not result in more lumens (unless this is due to insufficient heat dissipation as the graph mentions alumimum which may not be ideal):

(from Cree, Luminus, Seoul Semiconductor, and Nichia LED comparison)

so even if it will tolerate the higher current provided by, say, a Samsung 30Q in direct drive, that might not be the best choice as it will have reduced runtime with no increased output? Although I suppose the capacity of a non-high-drain current battery might also not be achieved if you drain it close or at it’s max current?

That’s on an Aluminum star. Change to a copper direct thermal path mcpcb and the game is entirely different.

Shorten the life of the emitter? Possibly, but how does it matter? Are you wanting an heirloom flashlight your great grandchildren can use or do you want to kill some darkness? Most emitters are rated at 50,000 hours of operation, even 100,000. How many years would you have to use a flashlight to get even 1/10th of that expected life? And even at that, a new emitter is what, $6? (If you used a flashlight 6 hours a night, every night of the year, it would take 2 years and 3 months to reach 5,000 hours of operation, 1/10th of the expected emitter life)

People will pay the cost of an emitter for a cup of coffee. Gotta have a Starbucks or 3 every day, but heaven forbid a light bulb burns out! Relevancy. I’m a perspective nut.

I put 4 Nichia 219C emitters in a Titanium X6 to see what their lower Vf would do, the light makes 4500+ lumens and pulls 21.1A from an LG HE-2 cell.

I figured that might be the case.

I was slightly ‘worried’ that at these currents the emitter life might be measured in just a few hours or even less as some components will burn up pretty much instantly if you put 3x their rated max current through them. Apparently these emitters are a bit more forgiving.

Of course with 45 second bursts and the thing getting hot as hell a lifespan measured in mere hours may still not be that much of an issue. But if can be expected to survive for a few hundred hours at least I’m fine with that as most of the time it will not be on turbo anyway.

So bottomline, I’m going to get me some bad ass high-drain IMR batteries. Thanks for all the help.

Still wondering about that, presumably, rather specific flat-top recommendation, hope you can shed some light on that.

Virtually all Li-ion cells are made as flat tops. The button top is added by aftermarket people. The button top adds length and they usually just add a layer of wrap to hold it on so it makes the cell fatter as well.

I always figured the button top is a steel button, with some additional resistance. So I prefer flat tops for the most I can get from a cell. The Samsung 30Q is among the highest, but the 35A or the newer dark purple 3000mAh Efest as well as the LG cells all perform very well and an individual light can have a preference for one or the other. Some lights have reverse polarity as a mechanical feature, as such, they require a button top to make contact. Can’t do a lot about those without a driver change.

Djozz has shown that the Cree emitters top out well over the max 3A number, we drive the XP-G2 to around 5.5A with a Buck driver for max throw and it’s got a 1.5A rating. I haven’t heard of one burning out yet from these levels.

Before Cree changed the XM-L2, the top end was around 8A. Surge up there was the big problem, turning the light on could cause that Poof! and smoke, but it was usually a driver that surged that caused that, a voltage spike at start up. Cree changed things and now the XM-L2 doesn’t really do 5A in most cases, although the XP-L will still do over 6A.

When I first got the Nichia 219C, I found they’d do over 7A and at around 10-11A mine started going blue, about to fry, so I simply used a lesser cell in that single emitter direct drive light then eventually replaced the emitter so I wouldn’t have to remember what cell to use.

Thank you Dale!

Is it safe to assume that genuine brand name (IMR/INR) batteries are guaranteed to contain passive safety measures such as PTC (Positive Temperature Coefficient Resistor) and CID (Current Interrupt Device)?

It’s just that I read HKJ’s Disassembly of cheap 18650 battery (bold mine) and apparently not all batteries have these and as I’m a bit of a stickler for safety…