Thrunite TN42 V2

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.

These batteries will be available on the store soon for US customers first. I just saw a FB post about them.

Since I modified the light, I do not need the thrunite batteries. It would just be a hassle having to cover the idiotic negative post on them. I can forgive Olight for their similar modification, because at least their added negative on the positive side serves a purpose with their magnetic charger and remote pressure switches. Having to add a plastic insulator in the head to prevent the unnecessary negative post shorting is just idiotic. Thrunite techs…if you read this…don’t add a negative post to batteries that does not have a functional purpose. Maybe you could have used the added savings to have better battery level indicator or smooth ramping.

no buck driver? this light is getting least interesting day after day

The SBT90.2 has a glass window in front of the LEDdie for protection, aka a lens.

Interesting….begs the question…protection from what? The led is already enclosed by the glass and reflector and the flashlight body. Seems like manufacturers would themselves remove the lens to increase the performance in such a competitive business. Are there statistics that point to much higher led failure once the lens is removed?

Eva Z. Clarification below.

Hello Robert,
sorry for my mistake
Yes, it is bipolar 21700 battery. I checked with our engineer.
the length is 76mm, with protected circuit board.

the unprotected battery may not perform safe for the high drain light, so we add the protected circuit board

Just like dedoming, there is risk of damage to the extremely delicate die leads.
Any LED failure will come from something falling on or touching the die/leads.
Manufacturers don’t like voiding warranties by modifying parts and increasing the number of failures/defects in the production line.

The true test is can you charge them in a standard desktop charger. If you can’t, they are proprietary and should be avoided.

It would be very dangerous to charge these in a normal charger, since chargers often are made for multiple sizes of cells and the positive terminal is not just a button but rather a rectangle, and if it has raised points it could contact both the positive and negative terminals of the batteries at the same time since they are on the same side, shoring the cell.

You can’t without risking shorting due to the negative on the positive side. Once I modified the modified battery with insulators I could.

Once again, that too is not exactly correct. The high current drain is not the issue requiring protected cells. The fact that these 4 batteries are in parallel with common positive and negative termination points is the issue with unprotected cells. In such a setup, an internal short in any 1 battery would cause the other 3 to overheat badly, perhaps even catch on fire, even with the light off. 4x21700 high drain batteries provide way more current that this led requires. That is not the case with an internal short of 1 battery which effectively completes the circuit with a 0 resistence load. I would not recommend even a 2 cell light having unprotected batteries, but 4 cells might burn someones house down as they sleep. With 1 cell, the protection can be in the lights PCB. I had no issue with protected batteries. The idiotic negative termination point on the positive side serving no purpose, was my issue with the design. As designed that negative only touches an insulator, so there is no reason for it to be there. I was an electrician/mechanical troubleshooter so I know electronics. The only really safe means of protecting 4 cells in the light itself would require 4 seperate termination points to the lights circuits.

Or just use a mechanical lockout, by unscrewing the tube or tail half a turn.

I feel that just had those protected cells already designed and wanted to use them rather than getting new ones made.