When my NiteRider 6 Volt battery packs died for my Digital Pro 6 and Digital Headtrip I did not want to spend over $200 to replace these packs. I had no experience at building battery packs, but was able to find a lot of wonderful info and sources for this on the internet. I am now able to build packs for under $20, so I thought some others here may be interested in my findings.

The last 2 packs I built was from C cells with solder tabs. I was able to purchase 10 C cells for $33 and built 2 flat packs. I purchase the cells from: http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=217
I am getting over 2 hours burn time with these and I could not be happier. My original headtrip battery pack was a little smaller, but the C size batteries are small enough and have the same capacity. I had previously purchased some prebuilt packs which worked well, but the burn time was only 1 hour and they were to big for my headtrip to carry in my camelback. http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=433
I was able to stuff one of these packs in my Niterider bottle, but I plan to replace that with one of the new flatpacks I made since it has greater capacity.

All the battery packs charge with the original NiteRider smartchargers that came with my lights. I decide to use different connector plugs so I could use the same chargers for multiple battery packs. I had no solder experience, but with the solder tabs on the cells it was quit simple. Helpful tips can be found at: http://www.briananddebbie.com/images/Scuba/Homemade/NiMH%20Batteries/nimh_batteries.htm
I also bought my connectors and pvc shrink for battery packs at batteryspace.com. I was able to heat the pvc shrink with a blowdryer on the flatpacks.

Many of the newer lights have higher voltage packs which would require more cells. Each cell is 1.2 volt, so a 12 volt pack would require 10 cells. Hopefully these packs I made will not fry my lights, but so far so good. I was surprised how easy and inexpensive it was to build these.

If you can get some get some of the new Sanyo 3600 capacity cells they are supposed to be very high capacity. You could also try Li-Polys or Li-Ion. I don't have either just throwing in an idea.

Most bike lights use 4/3A cells that run 3800mAh to 4500mAh. These cost about $4-$7 each at:

http://www.batterystation.com/nicads.htm

I had Batteries Plus build me some new batteries for my Specalized Fire Ballz, they have a funky NiCad waterbottle style battery. Batt+ used some NiMh to build up two more cells for me. The NiMh have about 2X the run time over my old NiCad. Each cell was 50.00, check around or the retail price of a NiMh battery from a light company...its a steal and a half.

Most bike lights use 4/3A cells that run 3800mAh to 4500mAh. These cost about $4-$7 each at:

http://www.batterystation.com/nicads.htm

They'll also package them for you all soldered up and shrinkwrapped with pigtail for nominal fee. I bought a couple sets - my favorite being a 6cell 4/3A to overvolt an old NiteRider light. I put a bypass switch on the light to disable the digital function (which freaks out until voltage drops a bit). This light is 30% brighter than original. The only downfall, is you'll only get 10% of the bulb life out of it - ~200hrs.

I have two Digital NRiders - one battery just died, and need to address. Has anyone found the security-hex tool needed to take the sucker apart? They too use the above Sanyo cells.

Has anyone found the security-hex tool needed to take the sucker apart? They too use the above Sanyo cells.

You should be able to get the security tool at Sears. Is it a allen or a torx? I know security torx are definitely available at Sears and other places tools are sold.

You should be able to get the security tool at Sears. Is it a allen or a torx? I know security torx are definitely available at Sears and other places tools are sold.

I tried there first - no luck, as it's an allen. Yes, the security torx (or tamper torx) are readily available.

The other pain in the !@#$ is, you need a full handle with skinny shaft to size of bit. The ~3/4" bits will not work, as the tip that hold the bit will not fit (tried to jamb the torx in there).

I'm sure I can find them on the web, but was being lazy. I'm thinking of drilling a hole in an allen - not sure how tempered they are though.

It's not a big deal now, since I still have 2 running lights, but it's nice to be able to lend it to those that forgot to bring a light or charge battery.

http://www.wihatools.com/753TRser.htm

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=360-206

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=360-097

http://www.wihatools.com/753TRser.htm

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=360-206

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=360-097

Well, that was quick! I've been able to find those, but can't use a bit: the holder of short bit or top part of longer bit itself (1/4" hex) will not fit in there. I need a T-handle, or regular handle tool. Thanks for the effort thus far ! Regards

Edit: This may do it: http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=360-225

I'm not really sure of the size, but it is ~1/8" - thanks for the links.

There was a whole forum or thread here dedicated to building battery packs. More pics and posts than you can shake a sh!##y stick at. Do a search here on MTBRs forums.