Crimp Daddy
Member
- Joined
- Feb 21, 2018
- Messages
- 973
This was my first project where I converted a Snap-On NiCad battery pack to Lithium... just wanted to share and get any input!
No BMS, but I use a hobby charger to charge. These cells can really deliver some power!
I've owned this Snap-On impact gun for at least 8-10 years now...
Its a damn good gun, but back in those days Lithium wasn't really an option, and those Nickle Cadmium batteries it came with have faded away over the years. Surprisingly its lasted this long, so I guess those Japanese made batteries held up pretty well but one of the packs went completely dead. After a full charge, only takes a month of sitting to see 0 volts.
I looked at replacements and those are $100 each, no way am I paying that for Nickle Cad packs...
I looked at a replacement, new Snap-On, and wasn't in to mood to shell out $600 on a set setup.
I looked at the Milwaukee M18 fuel 1/2 impact and its not bad at all for $350, but a brand new impact still has similar specs as my 10 year old Snap-On! Impressive for something I bought that long ago considering its still very valid today.
So with only the packs holding me back, I decided to rebuild them, but I wanted Lithium.
I set off to find some beast mode lithium cells and came across the Samsung INR 25R. These are high discharge / high drain cells. After reviewing the spec sheet I purchased a few to play with.
After testing individual cells, I started assembling them into a 5S1P (5 series 1 parallel) pack. That gives me a max of 21v fully charged. Its the most I could fit into the stock pack.
I marked the tab locations for the series connections...
Its recommended to use a spot welder, but I dont have one, so soldering it is. Its helps to scuff up the surfaces and flux for good flow and adhesion.
I wanted to be able to balance these lithium packs as well, so I made a custom balance cable with the intention of having this port externally accessible. I made the dongle and routed the balance leads accordingly.
Using a high quality hobby charger typically used for RC hobby stuff, I checked the balance leads. I can now monitor and balance each individual cell along with being able to charge the pack itself.
Everything looked good, tested well, so I started packaging it all up and made it secure in the original pack with Anderson Power poles so I can service or rebuild the pack for the rest of its service life.
Because I used Anderson connections, I can easily open the pack for testing. Here is my inline amp meter I used for testing performance.
Here are the results from my 4Runner with lugs @ 83 ft/lb. 23 amps / 460 watts! It literally spins the lugs off like butter. Also well within the battery performance specs.
Here are the results from my Chevy Silverado with lugs @ 140 ft/lb. 41 amps, 712 watts! Its a beast... works like new, and still throw those lugs off with authority. I am really impressed with how much current those cells can deliver. Really impressive for a single series string of batteries.
All in all, a successful project and a new love for a tool I have had for a long time. I really enjoy how light the new packs are too, its easier to handle and just less weight to swing around.
The only thing that has really changed is charging. I use a hobby charger now but its worth the trade off.
I no longer have to worry about my packs going dead in storage, or on the trail. Those Ni-Cads could have left me stranded. There were times it felt full, the the packs loose juice over time.
I always have power and it never fades in storage. Since my charger is DC, I can easily charger it off the trucks 12v battery.
New life to an old tool, and it really does work better as well or better than it did when I got it. I have already started converting other old Hitachi drill pack to Lithium.
No BMS, but I use a hobby charger to charge. These cells can really deliver some power!
I've owned this Snap-On impact gun for at least 8-10 years now...
Its a damn good gun, but back in those days Lithium wasn't really an option, and those Nickle Cadmium batteries it came with have faded away over the years. Surprisingly its lasted this long, so I guess those Japanese made batteries held up pretty well but one of the packs went completely dead. After a full charge, only takes a month of sitting to see 0 volts.
I looked at replacements and those are $100 each, no way am I paying that for Nickle Cad packs...
I looked at a replacement, new Snap-On, and wasn't in to mood to shell out $600 on a set setup.
I looked at the Milwaukee M18 fuel 1/2 impact and its not bad at all for $350, but a brand new impact still has similar specs as my 10 year old Snap-On! Impressive for something I bought that long ago considering its still very valid today.
So with only the packs holding me back, I decided to rebuild them, but I wanted Lithium.
I set off to find some beast mode lithium cells and came across the Samsung INR 25R. These are high discharge / high drain cells. After reviewing the spec sheet I purchased a few to play with.
After testing individual cells, I started assembling them into a 5S1P (5 series 1 parallel) pack. That gives me a max of 21v fully charged. Its the most I could fit into the stock pack.
I marked the tab locations for the series connections...
Its recommended to use a spot welder, but I dont have one, so soldering it is. Its helps to scuff up the surfaces and flux for good flow and adhesion.
I wanted to be able to balance these lithium packs as well, so I made a custom balance cable with the intention of having this port externally accessible. I made the dongle and routed the balance leads accordingly.
Using a high quality hobby charger typically used for RC hobby stuff, I checked the balance leads. I can now monitor and balance each individual cell along with being able to charge the pack itself.
Everything looked good, tested well, so I started packaging it all up and made it secure in the original pack with Anderson Power poles so I can service or rebuild the pack for the rest of its service life.
Because I used Anderson connections, I can easily open the pack for testing. Here is my inline amp meter I used for testing performance.
Here are the results from my 4Runner with lugs @ 83 ft/lb. 23 amps / 460 watts! It literally spins the lugs off like butter. Also well within the battery performance specs.
Here are the results from my Chevy Silverado with lugs @ 140 ft/lb. 41 amps, 712 watts! Its a beast... works like new, and still throw those lugs off with authority. I am really impressed with how much current those cells can deliver. Really impressive for a single series string of batteries.
All in all, a successful project and a new love for a tool I have had for a long time. I really enjoy how light the new packs are too, its easier to handle and just less weight to swing around.
The only thing that has really changed is charging. I use a hobby charger now but its worth the trade off.
I no longer have to worry about my packs going dead in storage, or on the trail. Those Ni-Cads could have left me stranded. There were times it felt full, the the packs loose juice over time.
I always have power and it never fades in storage. Since my charger is DC, I can easily charger it off the trucks 12v battery.
New life to an old tool, and it really does work better as well or better than it did when I got it. I have already started converting other old Hitachi drill pack to Lithium.
I have seen it happen alot. For adhesion just use proper solder and soldering iron and its not a problem. You will never be able to remove that solder before you destroy the battery 
