New Haikelite MT40 Problems or Battery?

Hi to all the respected, experienced members

I was hoping to ask some advice please.

I just received my new Haikelite MT 40 from Banggood.

I struggled to source button top 4 x 18650 batteries within a reasonable time frame (one local seller had Nitecore, but only 2 batteries).

I ended up buying SDNMY 4800

and then subsequently Jeff51 and the other members enlightened me, so I placed the order for the Panasonic batteries, but they both arrived at the same time.

Then I ended up with a totally flat punctured tyre in the dead of the night in the bush in darkness.

I had a head lamp I bought with me that claimed to be 12000 lumens at a cheap price with 2x 18650 button top no name brands included and a charging cable included, BUT this was useless in the bush even though bright inside the house (could not have been 12000lumens).

Then I noticed that the Panasonic batteries that I bought for the Haikelte MT 40 did not have any label on it that it was Panasonic. It stated : "cell and IC made in Japan, assembled in China", but the MT40 did not work and flashed orange indicating these 4 so called Panasonic batteries were already flat. Is it worth giving it a charge with the battery charger that came with the flashlight OR must I kick up a fuss with the seller and return them?

Then I inserted the SDNMY 4800 batteries and this worked but only for half and hour, BUT here is the problem (I am not sure if it is the MT40 or the battery).

First the activating switch works and then does not work. It goes blue sometimes and other times not,

Then when I unscrew the flashlight as if wanting to take out the batteries, but I dont take them out, then the activating button functions again.

When I can't get the flashlight to work, then I have to double click the button, but then the turbo extreme brightness goes on. So I could not get the other lower modes.

At other times when I press the button, nothing happens.

When it does go on, then the light in itself is as bright as daylight, but the flashlight is not functioning properly.

When one is in a corner in the dead of the night in the bush along the road with a flat tyre, then it leaves you in the lurch.

Do the experienced members think the problem is with the batteries or is it with the MT 40 flashlight?

I am not sure how much time Banggood gives to return the flashlight, plus how open they are to returns and then there is the inconvenience of having to pay to ship something back again abroad.

Now I connected the flashlight to the charger that came with it. Its been going for 6 hours, but the flashlight is still totally dead. So I took 2 of the 4 batteries out of the flashlight and I placed them in the so called "12000 lumen" headlamp and attached the charging cable that came with the headlamp, now I have to see what happens with the charging mechanism of this headlamp.

May I ask what the experienced audience thinks (I spent some money on my first "modern, powerful" flashlight with an interface and this is my negative experience with it. I was accustomed to just a manual button to press on and off and in between, as they used to be in the past, not an interface with one button that does multiple things, including locking it, and the user manual which is just 2 pages does not even tell you how to unlock it. I had to search on youtube how to operate this flashlight).

Thank you again to everyone



I’ll leave your issue up to someone who has experience with Haikelite. My concern is that you even attempted to use dodgy batteries in the MT40. I’ve seen the aftermath of torches exploding, blowing out windows from batteries exploding inside.

Banggood usually give 30 days. They told me 6 months but very unlikely

I wouldn’t of purchased 18650’s with a protection circuit for this torch, you need unprotected button top.

Did other members tell you to buy that exact one or did you just give you a model and you found it yourself? Maybe they meant the unprotected version

That’s normal in some protected batteries brands. You need to give us a link and/or photograph of what you purchased. Unprotected would have been better, no chance of the overcurrent/shortcircuit protection tripping, also cheaper. Are unprotected button tops nonexistent in SA? Can you purchase 18650 cells from overseas?

Li-ion batteries arrive at most 25% charged for safety reasons, your post is rather confusing, did you charge them first? I’m not sure what’s the maximum battery length for the MT40, maybe they are too long and the flashlight doesn’t close correctly.

I’m not sure whether the turbo mode would trip the overcurrent protection, but being NCR18650B rather than GA the CDR is only about 5A, current limit in protected batteries often is lower than the CDR. Given the output I guess you would need at least 6-8A in turbo mode.

Maybe you could use the contact link in and ask for clear instructions on how to use flat tops if high drain button tops are so hard to get in SA.

Also see this useful review Haikelite MT40 (CW) Flashlight Review! - YouTube

stay away from that brand, really bad quality and it shows, sadly they have not improved in this matter….

Hi Funtastic and ggf31416

Thank you to you both for the help and advice.

I bought button top batteries. I was under the impression button top means protected.

BUT purely by chance I discovered these so called Panasonic batteries 3400mAH (without the label from Panasonic) are slightly bigger than the SDNMY 4800mAh.

The battery charger of the Haikelite is extremely slow when you charging the flashlight with 4 SDNMY batteries, so I took 2 out and put them in the apparent 12000 lumen headlamp’s battery compartment and attached the charging cable it came with. In just under 2 hours it was charged - a much faster charger than the Haikelite charger, then I charged the other 2 SDNMY batteries (was also quick).

But the so called Panasonic batteries would not fit in the battery compartment of this headlamp to charge them, then I compared their sizes. The “Panasonic” blue batteries are slightly taller, and I think perhaps you are right that this might be why the flashlight was functioning erratically (or because it was flat, but now you are saying it is normal to hold only 25% charge when new).

The flashlight seems to be working with the smaller SDNMY batteries, but I struggling to figure out how to use this flashlight. It saves the most recent mode, and I do not know how to stop this from happening. It is a very dangerous device in terms of the extreme brightness if it inadvertently catches your eyes because of experimenting and suddenly the turbo goes on.

The button top “Panasonic” batteries has a label that says “Protected”

Funtastic are you saying a protected battery is dangerous?

I thought a protected battery is the safer option.

I am not sure how an explosion can occur, but I know the flashlight can become hot.

The instructions said buy button top (and besides the external appearance being different to flat top, I do not know what the difference is).

Are you saying that we can regard these batteries as genuine Panasonic batteries even if the label does not state they are Panasonic? These were not wrapped up, They were lose batteries in brown paper bag, indicating that the seller probably has a big stash of these and took out 4 to sell me.

When I press the button on the Haikelite MT40, then the button becomes blue, but the flashlight does not go on. Does anyone know if this is normal?

Then 5 minutes later I did the same and this time the flashlight went on. I still do not even know how to switch on the strobe when getting stuck at night along the road with a flat tyre.

For the life of me, I could not figure out how to upload a picture here of these batteries.

Thank you to Funtastic and ggf31416 for your excellent advice and help with this matter (I think I am goint to try to fully charge these “Panasonic batteries using the Haikelite charger to see if it makes a different, but I feel terribly bad sending a bad email to the seller now that you say it is normal for these batteries to be at only 25% when they are new).

Can you or anyone recommend a cheap device I can buy to measure the strength of these batteries and 12 volt batteries - to measure voltage and amps and perhaps a solar charge controller that also performs these functions at the same time. I am literally a newbie, but I have a portable solar system of 100 Watts that only weighs 5 pounds with DC 18 volts and 2 USB ports, but I do not want to dammage anything.

Thank you again to Funtastic and ggf31416 and all the other experienced, helpful members here.



The forum doesn’t have the bandwidth to store images on its own, it would be too expensive. You need to use an image hosting service: How to Post Images on BLF

Unprotected cells are either flat tops or button top, vapers almost always use flat tops, some flashlights require button tops, other flat tops, many can handle both. Protected batteries typically are button top, but I think there are a few rare flat tops protected batteries, they are the exception that proves the rule. Protected batteries are longer, they are a standard 65mm 18650 + protection + button top, the protection circuit adds 2-4mm. There are no 18600 cells that would allow a protected battery to measure 65mm.

BTW in theory a sole unprotected cell, 18650 or AA/AAA, should not be called a battery but nobody agrees on the terminology. I’m not sure if a protected cell should be called a battery, some say the protection circuit is enough to call it a battery, others say a batteries requires multiple cells. In practice everyone calls cells batteries even if a single one.

Funtastic says that the SDNMY are probably dangerous. Their capacity is a lie (member dno36 tested them at ~2000mA in 2015, but I repeat, anything over 3600mAh is a lie), likely they are low quality cells so you don’t know how much current is safe. If the flashlight ask for too much current the cells may overheat and in extreme cases explode. High quality cells have some protection features (not a circuit) built in in the battery that need to fail before extreme incidents happen, low quality cells may not have such features. Given how easy is to get high quality 18650s in USA the ‘standard procedure’ in the forum is treat all 18650s with fake specs as timebombs, the actual risk is somewhat overstated, there has been some really bad incidents but they are no dynamite sticks guaranteed to explode, regardless it doesn’t mean they are safe.

I have a Haikelite and affirm that they can be a bit squirrely. Nothing a tailcap power-cut won’t normally fix.

Do you have a decent stand-alone charger? Spend $20 or so to get a basic, reliable charger though I admit that is extra cost if the built-in charging worked properly. You will likely find it useful as you collect more lights.

In my professional experience, the “battery” refers to one or more cells - generally packaged together as a single unit. In this case, a single cell for actual use typically comprises a battery as well, though they can also be components in more complex batteries. A good example of a cell that’s not a battery might be the common experiment in which something like a lemon or potato is used with zinc and copper contacts to form a cell. Another case where the distinction is clear is 12v lead acid batteries (6 cells within each 12v battery, and the individual cells are definitely not batteries) or something like the common alkaline 9V battery.

I would also argue that in many cases, it’s useful to distinguish “cell” and “battery” further than their definitions, so that it can be clear that “battery” always means the entire pack and “cell” means just the one cell: saying you “had a bad battery” on your electric bike build might be ambiguous if this were not already established (whereas “bad cell” is always clear). But in cases where there is no battery pack involved, there’s not much problem using the terms interchangeably.

If I had to bet, I would say that the problem with the SDNMY is that they are very long, and therefore make bad contact, have you tried to use a lot of force when screwing? I say this because I have a protected Samsung 35E from Banggood, and when I use it on the MT40 instead of the 30Q, I have to use a lot of force when screwing in for the flashlight to work, but then I have no problem. Those SDNMY batteries are likely to be even longer and that’s where the problems come from, not to mention that they are absolutely poor quality batteries, none 18650 that advertises more than 3600mah can be a good battery.

The SDNMY aren’t the issue with length, the Panasonic’s he purchased are protected.

He said the MT40 works with those cheap cells but not with the Panasonic’s.

These were the batteries that you were told to purchase in your other thread - Samsung 30Q Button Top Battery - 18650 3000mAh 15A | INR18650-30Q