# Battery holder source?



## mntn-biker (Sep 12, 2010)

I am on a hunt for a 4 place battery holder to hold and run 4 - 18650 cells running parallel (1S4P). Radio Shack has something similar to what I am looking for but it is setup to run AA series and the 18650 cells are quite a bit longer so cannabilizing this holder is not an option.

4 AA Battery Holder : Battery Holders | RadioShack.com

TurboFerret was making exactly what I am looking for at one point but he has dropped out of the running for personal reasons. Below is what he was making. Does anyone know of a source that makes something similar to this or the Radio Shack style for 18650 cells?


----------



## KBARK (Aug 7, 2007)

You could get the double ones from digikey and glue them back to back...


----------



## mntn-biker (Sep 12, 2010)

KBARK said:


> You could get the double ones from digikey and glue them back to back...


I suppose I could. It's just the $3.80 each that I am struggling with. I like the Radio Shack price of $2.19 a lot better 

If I went the digikey route, I would need to bend the tabs up out of the way which would actually be beneficial for soldering.

http://www.memoryprotectiondevices.com/datasheets/BK-18650-PC4-datasheet.pdf


----------



## KBARK (Aug 7, 2007)

BTW, those contacts are removable, so you can run the wire inside the holder or outside the holder.


----------



## mattthemuppet (Jul 16, 2004)

digikey 4 cell 18650 holder $5 + postage isn't all that much money


----------



## mntn-biker (Sep 12, 2010)

mattthemuppet said:


> digikey 4 cell 18650 holder $5 + postage isn't all that much money


I like the square setup better so that it will fit in the Magicshine battery bag I ordered this morning on ebay.


----------



## KBARK (Aug 7, 2007)

You could also use the single holders to make a square setup. Kinda like this, http://forums.mtbr.com/6372852-post31.html


----------



## mntn-biker (Sep 12, 2010)

KBARK said:


> You could also use the single holders to make a square setup. Kinda like this, http://forums.mtbr.com/6372852-post31.html


That's probably my last resort but still a viable and cheapest option (if I buy off Ebay)...


----------



## xyz-saft (Sep 23, 2010)

If you aren't in a hurry one option could be to pick up some of these from DX.


----------



## mntn-biker (Sep 12, 2010)

xyz-saft said:


> If you aren't in a hurry one option could be to pick up some of these from DX.


The problem with those, and I have seen plenty of them on Ebay for pretty cheap too, is they are setup in series, not parallel. I need a setup for parallel.

2x18650 in parallel = 3.7V
2x18650 in series = 7.4V


----------



## CathastrophiX (Sep 28, 2008)

DX has three different 18650 battery olders:
DealExtreme New Products: the Latest and Coolest Gadgets - DealExtreme]


----------



## Vancbiker (May 25, 2005)

My experience with holders is the ones with spring clips like on the Digikey or Turboferret style are better at keeping a solid connection than ones that use a coil spring. Here is a place that shows holders similar to turboferret's.

Luminous DIY - High performance "Build It Yourself" Light Kits

He used to post in this forum regularly but has been gone for a while. See if he is still selling maybe.


----------



## Vancbiker (May 25, 2005)

Looks like Luminousdiy is no longer making holders. A couple years ago you could not find 18650 holders, so many made their own. A few saw an opportunity and did small runs to sell. Now that you can buy them for next to nothing from several sources I am sure that the demand for an expensive, "handmade" holder is pretty much dead.


----------



## mntn-biker (Sep 12, 2010)

Vancbiker said:


> Looks like Luminousdiy is no longer making holders. A couple years ago you could not find 18650 holders, so many made their own. A few saw an opportunity and did small runs to sell. Now that you can buy them for next to nothing from several sources I am sure that the demand for an expensive, "handmade" holder is pretty much dead.


The only 4 place ones that i have found so far (in a parallel series) are the 4 side by side, not a quad style. The 1pc quad holders look really nice with all of the rounded corners. I may wind up making my own using the same method like the other guys have....


----------



## KBARK (Aug 7, 2007)

The one cell ones from digikey hold the cells really tight! No way u could bounce them out.


----------



## Vancbiker (May 25, 2005)

Before 18650 holders became easily available, I made my own. First was a stack type using 3/4" ID rigid plastic tube with spring contacts salvaged fom a flashlight. Didn't work to well as the batteries would bounce and break the circuit momentarily. Next I made a couple round 5 cell holders. They worked well but pretty time consuming to build. Then the Digikey holders became available. I have done a 3 cell with integrated LED driver, a 4 cell, and an 8 cell with them. They are super easy to build with. If you have a fair selection of tools you could put a 4 cell square holder together in an hour.


----------



## mntn-biker (Sep 12, 2010)

Vancbiker said:


> Before 18650 holders became easily available, I made my own. First was a stack type using 3/4" ID rigid plastic tube with spring contacts salvaged fom a flashlight. Didn't work to well as the batteries would bounce and break the circuit momentarily. Next I made a couple round 5 cell holders. They worked well but pretty time consuming to build. Then the Digikey holders became available. I have done a 3 cell with integrated LED driver, a 4 cell, and an 8 cell with them. They are super easy to build with. If you have a fair selection of tools you could put a 4 cell square holder together in an hour.


I actually have 4 of these single cell holders on order since I am putting together a LED upgrade for my newer style Marwi light in the next week or 2 and will need a way to retain my 18650's so we'll give that a whirl but the singles were not exactly cheap from Digikey.$11 for 4 of them plus $5 shipping. Sure I could have ordered them from DX for $2 each or Ebay for $6 both free shipping but they you get to wait 3 weeks or so and then you have to glue them together. I will say that they look like they will hold the cells in place really well with the 4 curved tabs that look to hug the cell when inserted.


----------



## Guest (Oct 16, 2011)

Check this out....

1x 2S2P 7.4V 18650 Holder Case Battery w/ Li-ion PCM Protection Circuit Module | eBay


----------



## mntn-biker (Sep 12, 2010)

nattyboh74 said:


> Check this out....
> 
> 1x 2S2P 7.4V 18650 Holder Case Battery w/ Li-ion PCM Protection Circuit Module | eBay


I saw those in all different types of configurations. 1x 2x 3x 4x. Still not a "square" type like the top image and quote: "Delivery:	
Estimated between Wed. Nov. 2 and Wed. Nov. 16" Really??? Not waiting that long when I can buy it (w/o the pcm) on this side of the pond and get it in less than a week.


----------



## mntn-biker (Sep 12, 2010)

I might start making these since I can't find a sexy looking holder that fits a MagicShine battery bag so it would be a 4x18650 holder in a "square" type pattern like turboferret used to make. I'm getting some quotes on my pattern and checking pricing on mold materials and resin for the parts. Not even sure how much interest would be out there for these anymore so I may just be making some of these for myself and my close friends that convert to LED lighting.


----------



## Guest (Oct 17, 2011)

Well if you do make them I'll take one or two.


----------



## Ofroad'bent (Jul 10, 2010)

I bet FMA Battery can build you one of these in 1S4P configuration:
eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices

They've done others for me, 1S2P holders and protected battery packs. The included connector can be adapted to Magicshine or Trailtech males with 2 layers of heat-shrink tubing and makes a nice water-resistant connection.


----------



## mntn-biker (Sep 12, 2010)

Ofroad'bent said:


> I bet FMA Battery can build you one of these in 1S4P configuration:
> eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices
> 
> They've done others for me, 1S2P holders and protected battery packs. The included connector can be adapted to Magicshine or Trailtech males with 2 layers of heat-shrink tubing and makes a nice water-resistant connection.


Again, "Delivery: Estimated between Wed. Nov. 2 and Wed. Nov. 16".

I'd much rather buy something on this side of the pond and _patronize_ a stateside company (within reason when talking $) if possible (I realize that everything comes from across the pond but at least some of the $ stay here when I buy "local"). Granted, DX has the best deal on 18650's that I have found so in that case, I will go that route but the delivery still seems like an eternity.


----------



## mntn-biker (Sep 12, 2010)

nattyboh74 said:


> Well if you do make them I'll take one or two.


Thanks! I will keep you in the loop....

Not sure what Luminous was selling his 4x compact for but I know TF was selling his for about $16 and I've seen these holders below (see link) all over the web for sale for about $16 as well (just not the compact type setup):

Battery holder: Li-Ion 18650 Battery Holder (1S4P) With 2.6" long 20AWG & PCB

So I'm hoping to be comparable in price. Maybe I will sell cheaper with just the holder and the battery clips and the DIY's can wire up their own configuration and decide how and if they want to waterproof their setup. I'm still undecided on what I plan to do with my waterproofing. Who knows, maybe I mold up some small round waterproof "bottles" that the holder fits into and then a waterproof "gland" thru a removable cap for easy access to the cells. A bottle and cap would be pretty easy to resin mold I would think...


----------



## phburns (Sep 30, 2008)

I've been working on my own setup for about a year, this is what I've come up with. A modular one cell holder that has channels for running wires and flat surfaces for glueing them together to make whatever size pack I need. I could be talked into making a few extra for the right price, not sure what that would be though. (not trying to hi-jack your thread) I've been wiring my packs so that all the positives line up towards the exit of the wire out, so I can load my packs in the dark if needed, that's why so many wire channels are needed.


----------



## Vancbiker (May 25, 2005)

mntn-biker said:


> I might start making these since I can't find a sexy looking holder that fits a MagicShine battery bag so it would be a 4x18650 holder in a "square" type pattern like turboferret used to make. I'm getting some quotes on my pattern and checking pricing on mold materials and resin for the parts. Not even sure how much interest would be out there for these anymore so I may just be making some of these for myself and my close friends that convert to LED lighting.


When I made my holders, I used machined plastic parts. It was easier for me as I have access to machinery and not much knowledge of molding.


----------



## Guest (Oct 17, 2011)

Vancbiker that's what I was thinking about doing with lexan .. can you give a few more detailed shots without the batteries?


----------



## Ofroad'bent (Jul 10, 2010)

Ofroad'bent said:


> I bet FMA Battery can build you one of these in 1S4P configuration:
> eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices
> 
> They've done others for me, 1S2P holders and protected battery packs. The included connector can be adapted to Magicshine or Trailtech males with 2 layers of heat-shrink tubing and makes a nice water-resistant connection.


I have to say these guys have been pretty quick on the delivery for me, faster than Dx.
I'd love to buy made-in-North America products, but even the local guys use cells and parts made overseas I suspect.


----------



## Vancbiker (May 25, 2005)

nattyboh74 said:


> Vancbiker that's what I was thinking about doing with lexan .. can you give a few more detailed shots without the batteries?


I don't have any pics of it without batteries installed. This thread details the build...

http://forums.mtbr.com/lights-diy-do-yourself/5-cell-18650-holder-501179.html


----------



## Guest (Oct 17, 2011)

Thanks man.


----------



## mntn-biker (Sep 12, 2010)

I pulled the trigger on getting my silicone mold pattern made so once I receive it, I will start playing with the silicone mold creation and then finally starting the trial and error process on resin casting these parts. I'll probably start a new thread showing the progress of these.


----------



## phburns (Sep 30, 2008)

When developing the mold, think lots of sprues. Anything that looks like it will trap air will. I don't have a vacuum box, and I've had some pretty good success with smooth-sil 935, and even better success with Mold Star ® 15, from Smooth-On, mold star doesn't need a vacuum chamber. The small trial sizes don't last long enough.


----------



## mntn-biker (Sep 12, 2010)

phburns said:


> When developing the mold, think lots of sprues. Anything that looks like it will trap air will. I don't have a vacuum box, and I've had some pretty good success with smooth-sil 935, and even better success with Mold Star ® 15, from Smooth-On, mold star doesn't need a vacuum chamber. The small trial sizes don't last long enough.


Thanks for the tips. I am going to try the Alumilite brand silicone for the mold and some type of their resin since it is manufactured locally and a local hobby shop retails it (so I could save on shipping). The Alumilite Silicone Rubber QuickSet does not need to be vacuum degassed. Plus, the guy I talked to at the hobby shop is big into molding stuff so he said to bring my pattern by and we can discuss casting tips and tricks. :thumbsup:


----------



## tv-kid (Jan 15, 2010)

I bought 5 of these from ebay / hongkong

5 Battery Box Holder Case 2 x 18650 with 6'' Leads | eBay









They are wired in 2S config (which would suit you?). I have rewired them so they are 2P, and also stuck another on the back to make it up to 4P if I want longer runtime. - creates the nice block shape, rather than "4 in a bed".

Only prob is that I had to cut the spring down so a protected cell will fit. - no problem now.

for £6.50 I have 2x 4P packs, and 1x 2P pack. Even got a great strain relief using a cable tie. probably £10 with magicshine extension cables.... worth a punt

can provide pics if you want.


----------



## mntn-biker (Sep 12, 2010)

I have a couple different pairs of 2x18650 holders (with clips only no wires) "free samples" coming from Keystone Electronics to see how they fit/work. I'm still leaning towards the round style and have plans to make a somewhat waterproof "cartridge" and cap system with a waterproof cable gland in the cap. The issue will be to make it compact enough to fit a MagicShine battery bag.


----------



## Ofroad'bent (Jul 10, 2010)

tv-kid said:


> I bought 5 of these from ebay / hongkong
> 
> 5 Battery Box Holder Case 2 x 18650 with 6'' Leads | eBay
> 
> ...


I got some similar to this, but I doubled up the wires as they're pretty thin.


----------



## phburns (Sep 30, 2008)

What cad package are you using?

I've modeled the keystone #209 clips in Inventor, I can e-mail if you want it.



mntn-biker said:


> I have a couple different pairs of 2x18650 holders (with clips only no wires) "free samples" coming from Keystone Electronics to see how they fit/work. I'm still leaning towards the round style and have plans to make a somewhat waterproof "cartridge" and cap system with a waterproof cable gland in the cap. The issue will be to make it compact enough to fit a MagicShine battery bag.


----------



## mntn-biker (Sep 12, 2010)

phburns said:


> What cad package are you using?
> 
> I've modeled the keystone #209 clips in Inventor, I can e-mail if you want it.


I'm using Catia.

I actually have a request into my contact at Keystone and he is getting me a step file of that clip. I will message you if that falls thru but I've signed and e-mailed a non-disclosure agreement from them already on it so I'm thinking I will be getting it from them.

Here's my latest revision with a watertight cordlock in place:


----------



## Andy13 (Nov 21, 2006)

I have a question on these battery holders. There seems to be two choices. A battery holder w/ attached pcb protection circuit and use unprotected 18650's, or a battery holder w/o attached pcb protection circuit and use protected 18650's. Any advantages/disadvantages to either?
I plan on using w/ a taskled L flex so the batteries will have low voltage protection w/ the driver and the protection circuits on the individual cells should protect against overcharging. It seems like making a holder like Vancbiker's design and using protected cells would be OK. Any thoughts? Not trying to hijack the thread, just wanted to be clear.
TIA 
Andy


----------



## mattthemuppet (Jul 16, 2004)

protected 18650s are usually more expensive, but that's about it. Built in pack PCBs make more sense when you're charging the pack as one unit as they can balance the cells, protect from overcharge/ discharge. But if you're taking the cells out to charge them, there's not really much in it. I don't use protected cells or PCBs at all, as I rely on the taskled drivers and my hobby charger (although it probably wouldn't hurt to have a PCB in there for redundancy I guess).


----------



## mattthemuppet (Jul 16, 2004)

mntn-biker said:


> I actually have 4 of these single cell holders on order since I am putting together a LED upgrade for my newer style Marwi light in the next week or 2 and will need a way to retain my 18650's so we'll give that a whirl but the singles were not exactly cheap from Digikey.$11 for 4 of them plus $5 shipping. Sure I could have ordered them from DX for $2 each or Ebay for $6 both free shipping but they you get to wait 3 weeks or so and then you have to glue them together. I will say that they look like they will hold the cells in place really well with the 4 curved tabs that look to hug the cell when inserted.


I'm surprised the shipping is so high, all the small Digikey orders I've received have been around $2.50. I'm also not sure why you didn't buy 2 2cell holders for $7.60?

Either way, $16 is lot cheaper than making molds and buying resin (I use those for another hobby) unless you need to make 5 or 10 or more of them. It's a neat idea to make them to sell on here, but I'd caution that TF and Luminous stopped making 18650 holders around the time Digikey started selling them. I know as I was looking into a Luminous holder(s) but the ~$20 price plus postage lost out to $4 from Digikey (I don't even use them anymore).


----------



## mntn-biker (Sep 12, 2010)

mattthemuppet said:


> I'm surprised the shipping is so high, all the small Digikey orders I've received have been around $2.50. I'm also not sure why you didn't buy 2 2cell holders for $7.60?


I went with the single place holders since they had the little curvy looking battery retention tabs (the 2 place holders did not):










I did find out that Keystone makes these 2 place holders as well but WITH the battery retention tabs:

[URL="https://www.alliedelec.com/Images/Products/Datasheets/BM/KEYSTONE_ELECTRONICS/839-1384.PDF"}KEYSTONE_ELECTRONICS/839-1384.PDF[/URL]

I am pursuing the molding option so that I can encase these in a round waterproof "cartridge" (see above) and still be able to remove the single cells for charging, replacing, etc. so if on a long night ride, my batteries die out on my, I can have some spare cells in my pocket to get me out of the woods.

BTW - Here is a picture my 3d printer sent me this morning (you can't see the part since I guess all that other stuff is support structure that he removes manually after printing):


----------



## Andy13 (Nov 21, 2006)

Matt,
Do you use packs made of unprotected cells? Or do you charge cells individually w/ your hobby charger? I bought the charger you recommended last year and it has been great for all the different batteries, but I don't use it for individual 18650's, only packs. Just wondering......
Thanks,
Andy


----------



## mattthemuppet (Jul 16, 2004)

mntn-biker said:


> I went with the single place holders since they had the little curvy looking battery retention tabs (the 2 place holders did not):


to be honest, those curved retention tabs are a complete pain in the butt - I have to use a screwdriver or butter knife to get a cell out of that holder. I have one glued to the back of a head torch (got tired of buying AAAs) and it's almost easier to charge it in the holder with some crocodile clips. That reminds me actually, I've been meaning to cut them off for ages now.

I used a 2 cell (commuter) and a 3 cell (mtb) holder back before I bought a hobby charger and I never had a problem with cells coming out, they're in there pretty snugly with the clips.


----------



## mattthemuppet (Jul 16, 2004)

Andy13 said:


> Matt,
> Do you use packs made of unprotected cells? Or do you charge cells individually w/ your hobby charger? I bought the charger you recommended last year and it has been great for all the different batteries, but I don't use it for individual 18650's, only packs. Just wondering......
> Thanks,
> Andy


I use 2S and 3S (1P and 2P) packs, first with unprotected Ultrafires, now with Panasonic somethingorothers, all with balance taps. They're wrapped in marine tape and plastidipped so that they're reasonably water resistant and I balance charge them with that hobby charger I recommended to you. I should probably use a PCB in those packs, for redundancy, but it was an added cost and expense that didn't seem worth it.

I have charged single cells using that hobby charger, by sticking a cell in that single cell holder above and using the crocodile clips that came with the charger, but it's easier to use a spare DX 18650 charger I have spare. I mostly did the single cell charging with the hobby charger to determine cell capacity and quality.


----------



## mntn-biker (Sep 12, 2010)

mattthemuppet said:


> I mostly did the single cell charging with the hobby charger


Do you have a link to the hobby charger you are referring to?


----------



## mattthemuppet (Jul 16, 2004)

this one, although I didn't get it from Amazon.com, can't actually remember where I did get it from. Came with more cables than I can ever use, although I'm not sure if that's the case with all resellers, so it would be worth checking first. I picked one cable and spliced on a Magicshine connector to match the connector on my packs. The balance plugs I bought from digikey as build your own bits, but it would probably be easier to buy them pre-wired from eBay, as they're fiddly little gits to put together.


----------



## ljracer (Nov 6, 2009)

OK I have limited wiring knowledge....

deal extreme has a 7.4v 2x18650 battery holder case box with leads SKU 100997 (can't post links)

Is it possible to use something like this for the magic shines? it seems one by itself would be a good two battery pack (using protected 18650's) and is it possible to wire up two of them together (red/red black/black) to get a 4x pack?


----------



## Vancbiker (May 25, 2005)

ljracer said:


> OK I have limited wiring knowledge....
> 
> deal extreme has a 7.4v 2x18650 battery holder case box with leads SKU 100997 (can't post links)
> 
> Is it possible to use something like this for the magic shines? it seems one by itself would be a good two battery pack (using protected 18650's) and is it possible to wire up two of them together (red/red black/black) to get a 4x pack?


This would work for a MS light


----------



## mntn-biker (Sep 12, 2010)

ljracer said:


> OK I have limited wiring knowledge....
> 
> deal extreme has a 7.4v 2x18650 battery holder case box with leads SKU 100997 (can't post links)
> 
> Is it possible to use something like this for the magic shines? it seems one by itself would be a good two battery pack (using protected 18650's) and is it possible to wire up two of them together (red/red black/black) to get a 4x pack?


Depends what voltage the MagicShine light requires. Click here for Battery Wiring 101.


----------



## mntn-biker (Sep 12, 2010)

Here's my 4x18650 holder pattern from the 3D printer:










Next step - create a silicone mold from this pattern.


----------



## mntn-biker (Sep 12, 2010)

Here's my partial silicone mold. I didn't quite have enough silicone in the mold and resin kit I bought :madman: No worries. The hobby shop says the silicone bonds to itself really well so I can finish the pour when they get more silicone in stock.


----------



## ThinkBike (Jun 16, 2010)

mntn-biker, do you have a 3D printer at work or did you have to go to a shop that did the printing?


----------



## mntn-biker (Sep 12, 2010)

ThinkBike said:


> mntn-biker, do you have a 3D printer at work or did you have to go to a shop that did the printing?


I have a business associate that offered to print this for me for free. I had done a number of file translations here and there for his company so we're square now. Back a few posts is his red printer printing my pattern. I really wish I had a 3D printer. I could make some really kewl bike stuff :thumbsup:


----------



## borrower (Feb 26, 2011)

Slightly moribund thread, but wanted to note that the DX single 18650 holder sku 100999 is pretty rubbish. The wires are super thin, and it has a really tight fit with protected 18650s (the one I tested with is an AW 2900). 

Most bad is that the AW 2900 doesn't have a pronounced button on the + end, so it doesn't make contact unless you squeeze.

This advice may also apply to the 2x (sku 100997) and the 3x (sku 100996).

Anyone in the UK want two of these for shipping cost?


----------



## maaboo (Mar 11, 2011)

Does anyone know about the most waterproof holder?

I think i need 3x18650, may i use 4x?

Or i need to to waterproof shell by myself anyway?


----------



## brad72 (Jun 12, 2009)

maaboo said:


> Does anyone know about the most waterproof holder?
> 
> I think i need 3x18650, may i use 4x?
> 
> Or i need to to waterproof shell by myself anyway?


One way to waterproof your batteries is to dip them into plastidip or spray them with the stuff. 
I know that lipo batteries can be fully sealed but I am not sure if li-ion need a vent. Maybe someone else could chime and an confirm.


----------



## maaboo (Mar 11, 2011)

brad72 said:


> One way to waterproof your batteries is to dip them into plastidip or spray them with the stuff.
> I know that lipo batteries can be fully sealed but I am not sure if li-ion need a vent. Matbw someone else could chime and an confirm.


How to charge such huge solid unit? 
I'm noob to the lights. I only have DX 2x18650 charger.
Better if there will be a waterproof holder such as in my DX headlamp.


----------



## brad72 (Jun 12, 2009)

Well the 3 or 4 batteries would need to be charged as a pack using a smart charger rather than charging individual cells so in you case plastidip may not be the best option.


----------



## Rob UK (Sep 22, 2010)

Has anyone got a solution to waterproof the FMA 1s2p protected 18650 holder? To charge the cells I need to extract them to place in a charger and I'm not up on creating a waterproofed (plastidip) battery pack yet.


----------



## Ofroad'bent (Jul 10, 2010)

Rob UK said:


> Has anyone got a solution to waterproof the FMA 1s2p protected 18650 holder? To charge the cells I need to extract them to place in a charger and I'm not up on creating a waterproofed (plastidip) battery pack yet.


You don't have to remove the cells for charging.
If your charger doesn't have a jack for charging battery packs, you can open it and solder one to the connectors. EL34 has a good photo of this on his website.
LED Bike Lights

FMA also has some cheap chargers that would work.

You can wrap the batteries and holder in self-fusing silicone tape for waterproofing, then use heatshrink over for toughness. Ktronik has a good trick where he uses a slightly longer piece of heatshrink, folds the ends nice and flat while hot, then glues the edges.

I like to dip or paint plasti-dip on the ends, but it's probably not essential.

I have some pre-made FMA packs on order and I'll take a photo of how I seal them.


----------



## Rob UK (Sep 22, 2010)

Ofroad'bent thanks for the rely. I've had a look at EL34's adaption and am alittle unsure whether I could find the correct tabs to solder cables to it. 

Unit I have bought is a XTAR WP2 II charger (sorry not enought posts for a link yet), I'll google to see if there are any adaptions on the web.

If you do El34's adaption does it still balance 1s2p cells through one lead?

Would be good to see some pic's of how you seal yours. I've built a single XML 1" sled and all I need is the FMA holder to turn up to get it on my lid and working.


----------



## Ofroad'bent (Jul 10, 2010)

This charger?








Review of Charger Xtar WP2

If you're not confident to open it up and solder the contacts, you could make a dummy cell that fits in one bay and connects.

1S2P packs don't need balancing, as they are already wired in parallel.

One other option for water-resistant covering that will allow you to remove the batteries is to do something like Golddigger did here: https://forums.mtbr.com/8972557-post145.html

but without gluing the edges down. Maybe just slip another inner tube over the whole thing.


----------



## Rob UK (Sep 22, 2010)

Yep that's the charger. Rather than the dummy cell I may just crocodile clip to the + - on the charger and link up that way, to keep it simple. Then I'll have the 1s2p 3.7v FMA holder with protection wired straight to one side of the charger to recharge.

Can't help thinking at somepoint pre-charge switch on I'll be diving behind the sandbags shouting "fire in the hole" as I click the on switch. 

If I can get the idea above working I'll use Golddiggers simple idea in the first instance as I've got enough old inner tubes lying round; then plasticcoat or similar once I'm up an running. 

If the FMA holder doesn't turn up soon I may have to build a 18650 holder in the interim so I can get out with the light.


----------

