Help me fit Fluke pack in 2D Mag

[killforfood]

I acquired this battery pack to replace what I thought was a faulty one in my Fluke oscilloscope but it turned out that the problem was an open solder joint at the power input plug that was keeping the old battery from charging so now I have this battery in need of a home.:twothumbs

I figure the perfect home will be a 2D Maglite driving a R2 or P7.

The problem is that it's just a hair to big in diameter and the tube will need three grooves ground out of the inside.

There is one other problem that I haven't quite figured out yet and I'm hoping one of you electronic brainiacs can sort it out for me.
The pack has four leads and I really don't want to tear apart the pack to sort out why
I get exactly 7.7V when I connect my Fluke meter to the red lead and any of the other three leads.

Forgive me for all the pictures but for me pictures carry much clearer meaning.
Switching my meter to resistance I find that the two black negative leads only have 0.4ohms resistance between them so I think it's safe to say that I can bond them into a single negative lead.

But if I check between either of the black negatives and the white lead I get over 10kohms?
What's up with that.:thinking:

I called Fluke tech support for help but they were unsure of why there would be four leads and suggested that maybe the white lead went to a thermister to monitor temp while charging.
Battery space offers a direct replacement battery for the Fluke Oscilloscope but after looking at the picture on their web site and talking to them on the phone I discovered that their version only has two leads and they had no clue why Fluke would need 4 leads.
So much for direct replacement.

http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=3293

I suppose if worse comes to worse I can tear the pack apart and rewire it but I was hoping to avoid that.

Any body have the lowdown on how this pack is wired?

 

[cheetokhan]

All of my rechargeable cordless tool batteries have the thermister built in and have 4 separate contacts on the batteries. The charger monitors the thermister to regulate the charge rate. Just ignore the white black pair to the thermister and use the red black pair.

 

[gswitter]

Tri-boring the tube for 3x ~17mm cells is no problem. If you don't have the equiptment, there are a few members here who offer the service.

However, if you're going to keep the stock switch in place, I suspect that pack will be slightly too long for a Mag 2D.

 

[killforfood]

Gswitter,

You're correct about the battery being a bit long. With the tail cap screwed in I only have room for a 132mm long battery MAX! This battery is a tad long at 134.4mm

I think I can gain some space though by shaving the bottom of the switch housing.
I also have the option of removing a couple threads from the tail cap.


cheetokhan,

Thanks for the info. That makes things simple.

My brave side says I should rewire this pack in parallel and DD a P7.
Do you all think this would be a good choice to direct drive a P7?
From the reviews I read it's not just the color lottery we need to worry about but I see guys complaining about getting J bins when they ordered I's.
It's tough to plan a project when you don't know what vf you'll actually receive.

 

[gswitter]

I think I can gain some space though by shaving the bottom of the switch housing. I also have the option of removing a couple threads from the tail cap.

You may be able to move the switch up a mm or two and still use the stock switch cover hole, as well. Some models have retaining rings above the switch, and I can't remember if the current Mag D cells are among them or not.

You could also use a spacer similar to download's MagRingD to save a few threads. It would be easier than shaving the tailcap anyway.

There's always possibilities.