B90 battery questions

Whats up with the battery pack for the 8X?
The B90 is it? I see that when one pushes on the switch one is moving the entire battery up against the lamp.

The current does not flow through the torch's barrel, I can light the lamp just by pushing it onto the lamp springs outside the barrel.

Are these batteries special? How does the negative terminal get up to the top of the battery? Is there some kind of metal strip running up the side? Why does the top of the battery look like that?

Am I missing something here? Can aftermarket batteries be used to build a pack?

So many questions....

Gman if you look at the LA you will see 2 springs the big outer spring connects with the outer ring on the top of the battery and I assume that is the negative contact. The smaller inner spring connects with the nipple and that is the positive contact. I thought was a pretty ingenious design.

Hope this helps.

Yeah, thats obvious but how does that negative contact get up to the top of the battery?

It has to be the negative from the *bottom* battery because they are all in series.

There must be a strip running under the shrink wrap or something, thats what I didn't understand.

Not typically how it's done. Usually the outer lamp spring contacts the barrel and the switch connects the bottom battery's negative to the barrel and the barrel carries the current.

In this case the barrel is not used at all.
Guess I'll have to autopsy it after it dies.

Gman now I understand what you were asking. I don't know how it is done either but am not willing to autopsy a battery as they are less then 2 weeks old.

I'm not familiar with the 8X's layout... Does it use a tailcap switch? Must be twist ON, right?

You're saying the battery pack has its negative end completely sealed up? And the top of the pack has 2 contacts, + and - ?

Then, yes, there's a thin metal strip that run up the side from the last cell. I've seen this done on lots of battery packs for cell phones that do NOT have the small 2 pin connector. A couple of my phones have that style where the battery just drops in and makes contact usung 2 metal pads on the battery and 2 contacts on the phone.

Old battery for the 8#X series is the B92. *Current* battery is the B90.

The 8AX and 8NX have the same switch action, push the tailcap for momentary, turn the head for constant. Both methods in effect, push the battery forward to the LA.

The B90 has a blue plastic wrapping, over a "cardboard" tube. (Since it's a SureFire, it's probably "Tactical cardboard" ...... ).

The charger cradle uses the uncovered metal base and the button at the top to recharge tne B90. I think that the whole outer case, the metal under the cardboard, is the negative contact. At the top of the B90, the positive button is separated from the outer negative ring by an insulator.
Inside the metal case, each of the 5? cells must be individually isolated from the casing, except for the bottom cell. (Operating voltage is ~4.27+ to ~3.75.)

So the top cell has the positive contact, through the button, and the bottom cell's negative must be conducted through the B90's metal case to the outer ring at the top.

lightlover

Yep, thats a good description my British friend, thanx for the details.

I didn't realize there was cardboard under the blue covering but I now see the thin metal strips running up either side to bring that negative up to the top ring.

As you said, the bottom is left exposed so that charging can be done. The only thing I dislike about this setup is you *are* pushing the entire battery up, overcoming both springs in the LA.

As the single spring in "normal" tail cap switches are smaller, weaker and the mass moved is less (no battery movement), it seems to takes more of an effort to turn the 8X on using one's thumb. I'll just tweak the head in until it's easier.

Quite a different design than the E and P series but less complicated than the monkey motion that goes on in the rear end of a 9N.

Still, I like the 8X, it's a nice torch.

(Hey, if Brits call a flashlight a torch, what do you call a torch?)

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Gman:
... I didn't realize there was cardboard under the blue covering but I now see the thin metal strips running up either side to bring that negative up to the top ring....

(Hey, if Brits call a flashlight a torch, what do you call a torch?)

<HR></BLOCKQUOTE>

"A flashlight by any other name would be as sweet"

Gman, are there metal strips under the cardboard ? I thought it was the whole metal case, and the individual cells were insulated away from that internally ??

lightlover

There *seems* to be two thin strips running up on either side but I can't be sure without autopsying it.

You may well be correct and I suspect you are.

I have an older 9N Surefire, and the B90 battery that came with it definitely has a metal strip running up the side of the battery to the top. I don't really know what this is for as I have made a battery pack out of individual cells with the top cell having a 9-volt battery terminal (don't know what else to call the button on the top cell) on it and this battery charges within the flashlight and the flashlight works perfectly. I know about the metal strip from accidentally shorting the B90 pack and the strip burning through the shrink wrap.

Jerry