Thrunite TN42 V2

Thanks…Yes I saw that on the website.Was hoping to get better pics of an actual battery…pics like I took of the 26650.

Look at the positive end, you can clearly see the metal ring that is a negative terminal.

In case you’ve never seen them before, many proprietary Li-ION cells do this to have both the + and - contacts on the same side.
It’s not that rare.

I can’t figure out how to copy a picture from my laptop…copy and paste does not work.

No it is not that rare, but none of the three similar proprietary batteries in these 3 pictures would work due to shorter center button. I think if I remove the pastic insulator held by 3 phillips screws and add insulators to the button side of these idiotic thrunite batteries both the thrunite and orbtronic protected cell might work. The plastic insulator ring is maybe a mm taller than the brass ring conductor. Therefore the button needs to be about a mm taller than the rest of the battery on that side. Otherwise the plastic insulator ring prevents the button from touching the brass conductor.

Update…removed the three screws that hold the insulator in the head and removed the insulator. Screws must be re-inserted because they also hold the PCB. Next I used plastic sticker insulators like those used for 18650 button top batteries when re-wrapping them, to totally cover the problematic negative washer on the positive side of the Thrunite batteries. With that simple mod of both the light and the battery, I can now use the thrunite batteries I further modified, or the orbtronic protected button top 21700 batteries. It is quite a simple mod if you have the right size battery end insulators. Both the Thrunite and Orbtronic batteries can also be charged in the light, or in a charger that charges 21700 protected batteries. Easy fix, but for a problem that should never have existed.

I wasn’t talking about these being replacements for the stock batteries, I was explaining how the negative terminal on the positive side can be obviously seen from the product picture.

This is what the head looks like…finally figured a way to post pics. The black is a plastic ring that is thicker than the brass.

This was the four batteries in the base carrier

This final picture is how the head and batteries look after I removed the insulator in the head and added insulators to the batteries.

Ah, thanx!

That makes sense and removing the ring looks like an easy fix to use other cells!


I can 100% verify that at least orbtronic batteries now work. The white plastic 18650 end insulators are super cheap and sticker on 1 side…bought from for 99 cents for a 20 insulator sheet. I have a bunch because I re-wrap batteries if damaged. Re-wraps are also available there. Having vaped for years, I have become super educated on all forms of batteries. The orbtronic batteries are likely samsung 50E re-wraps with orbtronics adding the protection circuits. Take my word for it, never ever use unprotected batteries in this or any light that has common positive and negative termination points. Doing so is very dangerous. If just one cell shorts internally, it can cause thermal runaway on the other 3 cells even while the light is off. A short becomes a 0 ohm resistance load and will draw dangerously high amps from all remaining batteries once that short completes the circuit. Watch a video to see what these batteries do when vented….it is scary!!!

Now that photos are available, it looks like this whole MUST USE PROPRIETARY BATTERIES thing was overblown and pitchforks were brought out too early. All this light needs are button top 21700s and the black plastic ring removed. If normal 21700s are too short, then a set of matching protected ones from anywhere should work.

Yes the light needs a mod to take all button top 21700s. No, removing and replacing three philips head screws is not difficult

While I agree the mod is simple, it is still a negative that it was designed to only use the Thrunite modified batteries. There was no good reason for having both positive and negative posts on the button side of the battery, which necessitated the insulator ring in the first place. I do not think the fact that I could fix an issue that thrunite created in their ill advised design should negate the fact that it was a bad design as shipped. I fixed the issue, I posted the photos, so exactly how was the proprietary battery issue overblown? I suppose you can credit Thrunite in not glueing the insulator ring in to make the mod more difficult. They could however have used normal button top 21700 batteries without the insulator ring to begin with. Since the negative terminal on the positive battery side only contacts the insulator, it has no reason to be there. The only reason I can come up with is to cause most consumers to buy replacement batteries from them at inflated prices. The majority of consumers will never see my fix, so the light as shipped is using proprietary batteries. Not every purchaser of these flashlights are on this forum.

Also take note…the 4 batteries all contact the brass ring with the button top, and the negative terminals are all common as well. If you use unprotected batteries in such a light, an internal short in 1 battery could cause a fire and burn your house down. The internal short would complete the circuit, even with the switch off. That is the reason multiple batteries in a light use protected batteries. Any protection circuit in the light itself can’t protect against an internal battery short circuit.

Eva Z. From Thrunite responded.She said the batteries are NOT custom.They are 76mm Protected 21700.

Also said they are working on getting the batteries in their store. No doubt will be at least double the price of a Standard Unprotected 30T,40T or P42A.

If Eva Z. said that she is sadly mistaken. My Fluke meter does not lie, and there is a negative post on the positive side. If that is not considered custom, neither are the Olight batteries. In fact, I can’t think of any 21700 batteries that are custom, if those are not. They are the only 21700 batteries I have checked that will work in this light without modification or magnets…that is the definition of proprietary batteries. To be fair…all 21700 button top batteries or protected batteries are modified. The factories only make them flat top, and unprotected. The protection circuits, button tops, and negative terminals on the positive side are all 3rd party modifications.

I will add that all unmodified 21700 batteries are 21mm diamater and 70 mm in length…that is where the 21 700 comes from. 18650 batteries are 18mm diamater and 65mm length. These are closer to 22760 batteries. The added length is due to the button top and protection circuit and negative post. I suspect the added diamater is perhaps double wrapped. What can’t be said truthfully is that they are not modified, and with the negative post on the positive side they are heavily modified, and as shipped, proprietary.

So I just saw that Vinh @ Sky lumen has this posted for sale & mods. Vinh has this light listed @ 1.2mcd! And 2190 meters throw, listed as de lensed only. There is no stating any other mod beside de lense and his driver for one option, but he says the performance is the same with his driver and stock driver…

I don’t know Sarge if you have a way of measuring throw with a lux meter? Or if you even care to, but honestly if this light really throws 2190 meters or close to that with just a delense to the led (which we know only adds approximately 5% throw - so maybe 90 meters to claimed 1800m) then I would deal with the stupid batteries, because the head size is really a nice medium between MF02s v2 and k75, but 2190 is really good for the 105mm head size

I hope when someone else gets this they can confirm it throws even within 5% of 2190 meters? Because that is about 21% more throw then the claimed 1800 meters, and would make this light a REALLY great performer. That is the same throw as the mf04 with xhp35, but with a 30mm smaller head! And twice the lumens!

What is de lensed? I have heard of de domed, but this has no dome that I can see. I doubt seriously this light could throw 2190 meters. The reflector is not as deep as the TN42, which is why it only out throws the TN42 by about 300 meters. It is a wider, brighter center spot though, and I think it has more spill. I wish they had just put the same emmitter in the TN42 body. The deeper reflector would likely reach that higher throw with the TN42 reflector. I also have the mf04, and it out throws this light by a good bit…I actually compared them last night. I do not have a lux meter, so can’t measure candella.