Parallel holder for 3 x 26500 cells - High current

[greencardigan]

Hi All,

For my 3D SST-90 Maglite Mod I needed a parallel holder for 3 x 26500 cells capable of supplying 10A to a SST-90 LED.

I dont believe there's anything available off the shelf so I went ahead with a DIY version.

First I got some PVC tube the same diameter as the C cells and cut it lengthways. The cut is not quite down the centre so it springs around the cells and holds them in place.

Two slots were cut in the back for the battery connections to come through.

I made the battery contacts from some copper pipe brackets.

Here's the contacts added to the holder. The copper is soldered onto disks of circuit board.

The arrangement of the contacts on the back.

The completed holder.

The holder and batteries fit nicely into D cell sized PVC tube.

And fits nicely into 3D maglite.

Thanks for looking. :twothumbs

Hope this helps someone.

 

[Lumencraft (Matt)]

I really like that, the idea of using bits of circuit board for the pads in between is creative.

 

[mash.m]

wow, one of the usable mod´s i ever seen. i will take this in the back of my mind cause i think i will use this in the near future.

thanks for sharing,

markus

 

[Hill]

Very nice custom work! If you can make more, I'm sure there would be many buyers here. I think a holder for 2 x 25500 in a cutdown 1.5D would be a great DD SST-50 or SST-90 solution.

 

[kramer5150]

wow... nice.
Very impressive

 

[Mettee]

that is for sure a great idea...nice work with the high current paths

 

[Techjunkie]

That is a real masterpiece. I'll bet if you shortened the outer, D-sized tube, you could probably squeeze your 3-cell holder into a Mag 2D, with the last cell sticking into the D tailcap.

Very, very nice!

 

[^Gurthang]

Like the Guiness ads say:

BRILLIANT!!!!!

Your solution is elegant and VERY useful for beacoup parallel DD mods. Take a bow sir!

 

[holdthat1]

Im a little lost. How does this setup provide 10a's

 

[aurum]

great idea ... hope 9A driver will be released soon.

 

[greencardigan]

That is a real masterpiece. I'll bet if you shortened the outer, D-sized tube, you could probably squeeze your 3-cell holder into a Mag 2D, with the last cell sticking into the D tailcap.

Very, very nice!

I was originally going to put my driver stack below the switch. That's why I went with a 3D mag.

And if I change to a buck driver, I will try to squeeze 4 x 26500 in series into the 3D. Do you think that will fit?

 

[greencardigan]

Im a little lost. How does this setup provide 10a's

Low resistance and large effective battery capacity (about 7Ah).

 

[irv_usc]

Low resistance and large effective battery capacity (about 7Ah).

If i remember correctly, the IMR26500s can provide upto 20A?

As such this custom holder is for increased capacity?

 

[Techjunkie]

I was originally going to put my driver stack below the switch. That's why I went with a 3D mag.

And if I change to a buck driver, I will try to squeeze 4 x 26500 in series into the 3D. Do you think that will fit?

Yes, 4 50mm cells in series with nothing between them should fit in place of 3 60mm (D) cells and a tailspring.

If i remember correctly, the IMR26500s can provide upto 20A?

As such this custom holder is for increased capacity?

It increases capacity (AH), and because the cells are run in parallel, the current drawn is divided amongst the cells. Instead of 9A, each cell only has to deliver 3A of current load. If the contacts are beefy enough, the threoretical sustained max current is 3x what one cell alone can provide.

 

[HarryN]

Nice work. Do you happen to remember the pipe sizes that fit?

Thanks

HarryN

 

[Raoul_Duke]

Looks like it will be a good solid performer, but can the large copper strips move with a shock/ bang?

It looks like they are soldered to the circuit board so look unlikley they will shift...I'd hate to think of them touching/ shorting!!!

I once shorted 8 Emoli in series with thin wires. I was using the wires to measure V bulb on a 250W hotwire ( the +ve V lamp bare wire made contact through the flashlight anodizing (the wires were bare as the heat from the lamp melted any insulated wires quick) The wire went V bright for a millisecond and then vaporised...oo:

If it was me I'd glue/ insulate/ tape or something the copper strips individually on the outside for peace of mind if it was dropped from a height or something.

Still looks good...Looking forward to what you power with it.

 

[greencardigan]

Yes, the copper strips are soldered to the circuit boards and the whole setup is quite strong. But I might insulate and epoxy the strips to the PVC for insurance.

It's already being used in my sst90 mag build.

 

[bstrickler]

You could also put heatshrink on the copper, to help with drop resistance, too. It should also help protect against corrosion, as well.

~Brian