Niwalker BK-FA02S --WARNING: a direct short waiting to happen in the batt carrier

If your carrier is the old type one , without the switch means that can be put in , disregard witch side going in (double sided) !

BUT... in a review done here , on BLF, I do not remmember by who , has been noticed that inside the body that hold the carrier is a spring that COULD short the center (+) of the carrier with the heads of the screws (-) . I've noticed that on mine , so , using a long nose plier I insulated the spring up to the first turn with silicone insulation (was a 18 size or so...). Maybe is your case , I'm just saying...

Good luck !

Yes, the carrier that arrived with the light looks like that.

Warning: A direct short waiting to happen in the battery-carrier of this light…see the op.

the same thing happened to me in the original model. i thought i put the batteries in wrong. when the light wouldn’t come on i opened it up and the batteries fell out because the springs shrunk. i put in protected button tops because flattops wouldn’t fit any more. used the light a few minutes and it was fine but the next time i turned it on it wouldn’t work. i inspected the battery carrier and found a trace on the battery carrier’s circuit board melted. i believed it was caused by the wide anode on the flat top making contact with the trace. of course i didn’t figure that out until i paid $30 for the repair

I will be contacting Niwalker about this, for IMO, this design is not only faulty, but extremely dangerous. :person_facepalming:

In the meantime, I wonder what safe remedy can be done to the battery carrier? (Please read the op)

I hope some of our more experienced members here have a thing or two on this matter.

Thanks in advance.

You reminded me BTU shocker modding days.

Hmmmm, these are my thoughts on the subject.

  • If there are any of those raised rectangular solder blobs left, shrink them down a bit. Either re-solder, file, or Dremmel to make them lower.
  • Then insulate anything that could possibly cause a short.

Thanks for taking time to analyze…l have thought about this approach but it still can be a little too risky for 2 reasons:

  1. The positive protrusion in the carrier is just high enough for a flat top to make contact
  2. The original and my replacement springs are quite stiff.

lt will be just practically be a few mm away from another short, but filing the rectangular solder blob then covering it with an insulating material might just raise it nearly as tall as the positive contact, and still be too close for comfort.

My pleasure to try to help. I hear what your saying too.
You could try ‘button tops’, they would give you some extra room.
But even with the flat tops, it seems to me if you have the problem spots insulated well that should solve it. ???

Should be fixed under warranty I wouldn’t say you soldered new springs on and tried again. As that is 99% sure to void the warranty and if damage was done to the light they have grounds to not have to fix it. Id tell them I tried to turn the light on and two of the springs melted. And say there is a solder blob protruding by a positive contact on further inspection. And you would like to send the carrier and light back for inspection. That the manual says the carrier can be inserted eaither way but mine has only one direction it can be inserted it has a switch on the other side. I believe I was sent the wrong battery carrier for this light and if their is any damage to this light from a wrong battery carriee or short from no fault of my own I want it fixed especially for the price I paid

I totally agree, ‘Speed4goal’ has the best solution for sure. :+1:

Still awaiting news from Niwalker after the CNY celebration.

Fast forward to Mar. 20, 2017:

Today I received the supposedly “new, improved” battery-carrier from Niwalker.

In the photo below, while the solder blob that caused the electrical short in the original carrier is now smaller and shorter in the new carrier (right), it is still well within ‘striking distance’ as to rub and tear off the cell’s insulator (as has happened in the original carrier) and create another direct electrical short.

Photo below shows even while the cell is still not properly seated and still at angle inside the carrier (not straight up yet), the cell’s negative casing is still dangerously close to rubbing and tearing its insulator when it hits the ‘smaller’ solder blob of the the new carrier if seated properly. I did not attempt to seat the cell straight up because of two reasons: the solder blob is just microns away, and the springs of the carrier are too stiff for comfort. In fact, I even ground away some of the solder blog to make it shorter.

Well, another result of the ‘too stiff’ springs:
I tried to put in cells in the carrier’s side where there is no solder blob, but when I removed the cells, due to the extreme force exerted by the springs, it forces the cell’s insulator to ‘plow’ into the brass protruding positive ends that it deforms, if not tear, the insulation. Remember, I even use the shortest cells around.

Solved ?

Are you kidding? Haha, I don’t know if Niwalker is willing to completely redesign the carrier to make it safe.

I.Don’t.Like.This.

Really, it seems that the carrier of only this light is super tight. Why did Niwalker change the dimensions of the carrier?

If you mean the dimensions of the carrier that came with the light and the supposedly ‘new and improved’ one, no, the dimensions are the same, also with the springs’ tension. They did made the offending rectangular solder blob smaller and shorter in the new carrier, yet it was still dangerously close to the cell’s edge insulator that, as you can see in the one of the pics with the cell slightly at an angle, if I continue to put in the cell straight up and put in the cell where it should be, the insulation will again touch the solder blob (as seen on the bottom of the carrier in the pic) chances are almost 100% the solder blob will again tear off the insulation and create a direct short like what happened to the first carrier.

No I mean for example with the MM25MB. I have not heard about a tight carrier in that light…

I’m sure Niwalker engineers have tested the battery carrier with batteries but I really wonder how can they not notice that even with the shortest cell, because of the extreme stiffness of the springs, the cells are plowed forcefully not only into the positive brass ends but also into the protruding solder blob that will scrap the insulator.

I would suggest they do away with the solder blob and put in ‘medium’ strength springs, and the problem will be solved.