Cordless Tool Conversion

So I had 2 cheap drills who's packs were dying and I converted them over to 18650s because I had some spares from a pack built (see Homemade Pack thread)

And I posted a thread about a dangerous voltage inversion on one of the 18650s that I pushed too hard, at which point it devolved into a tool conversion thread. Thus, here is a thread for DIY tool conversions.

For my 18v cheap drill, I opened the battery case, ripped out the guts, kept the connector and shoved 4s2p into the case and wired it up. No balance lead, I just want to see how it performs over time.

For the 12v drill, I did the same thing but only put in a 3s2p pack.

My 18v XRP Dewalt drill I'm more protective of. I have 3 batteries, 1 good, 1 bad, 1 dying at 15v. The bad one I ran with an idea someone mentioned of an external pack.

I opened the bad pack, ripped out all the cells but the one in the stem. The stem has a cell that fits perfect. It holds the connector fine, so I fixed it in place and soldered a bypass around it to the connector. Then ran these 18ga wire to an external pack and put them in a leather hip pouch that is thick enough to protect it in the field. I found the 18ga wire gets hot while using a sawsall. I'll fix that with 14 or 10ga wire from my stocks.

The pack itself was 5s6p at about 12ah, with a balancing lead coming off it. I just used packing tape to tape that out of the way while in the pack. For charging, I'm just using the aligator clips on my icharger to clip to + and - and charge off of it. In the future as I convert the rest, I'll convert the stock Dewalt charger with a modded meanwell or other powersupply.

I have converted several power tool NiCd packs to Lithium.
A few using 18650 cells a few more using RC LiPo and several more using Laptop LiPo.

I don't remember if my 1st was a 14.4V B&D Firestorm (14.4V 1.2Ah NiCD upgraded to 14.8V 5.2Ah)...



or my 75th Anniversary Craftsman 12V VSR drill (12V 1.2Ah NiCD upgraded to 11.1V 4.8Ah?).

Will try to take a bunch of pictures today and post up tonight.

I began labeling converted packs with a large white duct tape - don't want to accidentally charge Lithium with a NiCd charger.

DrkAngel said:

I have converted several power tool NiCd packs to Lithium.
A few using 18650 cells a few more using RC LiPo and several more using Laptop LiPo.

I don't remember if my 1st was a 14.4V B&D Firestorm (14.4V 1.2Ah NiCD upgraded to 14.8V 5.2Ah) - Quantity 1

Click to expand...

With special care I was able to squeeze 4s2p 2160mAh Lipo into the Firestorm 14.4V
Required a V formation, splitting the retention tab spring location
(14.4V 1.2Ah NiCD upgraded to 14.8V 4320mAh) - Quantity 2



Possibly my 1st conversion, 3s2p 2400mAh 18650 cells.
Used no balance connector but most recent test showed nice natural balance and very good capacity.
Not bad for a used daily 7+ year old build!
(12V 1.2Ah NiCD upgraded to 11.1V 4800mAh) - Quantity 2



My 1st LiPo RC upgrade
18650s were a bad fit and my Laptop Lipo were too long
Fortunately, I had acquired a quantity of 4s1p 2000mAh 10C Lipo, and was able to squeeze 1 in.
20A rated was perfect for the 5½" saw ... if used gently ...
(14.4V 1.4Ah? NiCD upgraded to 14.8V 2000mAh RC Lipo) - Quantity 2



Upgraded more:
18V B&D Firestorm
18V Craftsman
19.2V Craftsman
24V B&D Firestorm

Will post up pics and specs later ...

Future upgrades:
Ryobi 18V Nicd to RC Lipo
Ryobi Lithium to Laptop 18650 for light duty
DeWalt 18V to RC Lipo

My super crude RC lipo conversions. Open up the pack, remove dead nicads. Solder wire and bullet connectors to the contacts inside, and put the pack back together.

To use, I can either use a fanny pack and long wire, or use a coroplast strip and some screws to attach the RC pack to the bottom of the NiCad pack housing.

But I just learned that Batteries Plus will rebuild a Ryobi pack with new NiCad cells for about 20 bucks. That's pretty sweet if you can handle still using nicads. Ideal for a pack that is no longer sold, or sold but too pricy.

I think I'll have them rebuild one of my 24v B&D packs, so I have two strong NiCad packs for my drills. But the Ryobi sawsall, and the B&D circular saw could certainly benefit from a 5 ah RC pack driving them. The Ryobi is 18v, but really runs nice on 24v.

• 24V B&D Firestorm pack
• Fit 6s2p 2160mAh laptop Lipo for 22.2V 4.32Ah
  Excellent Hammer Drill, Sawzall
• Fit 4 x 3s 2000mAh 10C LiPo for 22.2V 4.0Ah (required Swastika pattern)
  Excellent for 7¼" saw etc.

Either were half the weight of the <50% capacity NiCd.

Note: 18V and 24V 7¼" saws seem identical. Same sound-pitch indicating same rpm from same 18.5V pack.
I modified 24V tools to accept 18V packs because 24V NiCd still worked.
Then modified many 18V to run from 24V pack @ 22.2V LiPo.
Did not modify 18V lights. Previously converted 18V Firestorm lights for optimal LED output at 18.5V (≤21V).
Found picture of test fitting 6s2p 2000mAh 10C Lipo into B&D Firestorm pack.

Pulled bad 18V 1.4Ah? NiCd and replaced with 18.5V 5s 2000mAh 10C RC LiPo



Just 1 ...
Only 1 DeWalt 18V power tool.
A 5½" power saw.

Nice! I just end up using what I have laying around, configured to 24v for my lawnmower.

So at the moment, that's 6s 5000mha packs, permanently paralleled to a 6s 10,000 mha. Definitely won't fit inside the case, but it does run the saw or the weed whacker a long time. 8)

22.2V is the way to go ... for external packs.
Well, for me ... I have nearly unlimited 3s2p 2160mAh (11.1V 4320mAh) LiPo "bricks".



18V power tools @ 22.2V seems acceptable. (except for lights)
Higher speed, more torque with an effective higher capacity is nearly universally beneficial.

22.2V in 24V power tools seems to result in minimal speed loss compared to new NiCd and improves performance when compared to most somewhat used NiCd packs.

High demand uses requires individual cell fuse bypass.
Larger packs run just fine at ~3C+ (with fuses intact).
It is simple to switch 22.2V power tool pack to 11.1V inverter pack.
11.1V inverter pack matches inverter LVC of ~10.5V nicely.

You sure do have a good supply of those smaller pouches. how are you knowing when to stop, just by how the thing feels? (RPM)

I had low voltage buzzers around, so I put one on the saw pack when I use it. But the mower starts to bog down enough on thick grass to want to stop well early, long before a cell gets to 3.5v. So I don't need one on the mower.

Part of this is I don't retire the pack to the mower use till it's at least 2 years old, low capacity, saggy as hell. So it really can't stand running much more than half a discharge on the mower.

A very long time ago, my NiCD 12V cordless drill was beaten into retirement, and I gutted one of the battery oacks and put on a 4-ft cord with alligator clips to run it off of a car battery. It worked fine, but for my birthday one year I got an 18V lithium makita drill, love it for lightness and performance.

If I ever get some spare time to kill, I have some half-used 18650's and a cheap Harbor Freight 18V Sawzall with worn batteries that I want to upgrade the batteries. Spurious post is to help me find this thread again. My worthless blather will be replaced with pics and data.

dogman dan said:

You sure do have a good supply of those smaller pouches. how are you knowing when to stop, just by how the thing feels? (RPM).

Click to expand...

While I do have balance plugs installed on nearly all conversions, I tend to rely on large capacity and familiarity.
Balance plugs are internal but a simple slot could allow external VMA (Volt Meter Alarm) use.

B&D FireStorm
18.5V 4.32A pack WeedEaters all around the store and neighbors yard then Blowers 300'+ of lawnmower clippings off the sidewalks. (Blower is better and cheaper than canned air for "cleaning out" computers - outside so dust cloud or spurious critters dissipate harmlessly)

In one setting, I've never emptied a pack ... except ...
I take multiple packs when clearing fallen trees, branches etc off the local trails - with SawZall and 12" blade.
If I do notice a slowing of speed or battery getting warm I stop immediately!

After a couple initial disappointing conversions I began
#1 eliminating self-discharging cells
#2 matching cells by similar IR
#3 matched banks with accurate capacity balance

12V CraftsMan 75th Anniversary drill (3s2p 18650 conversion) has been used daily for ~7 years and never needed balancing.
So I have more than a dozen conversions that are liable to outlive me ... ?

Makes sense. warm battery is getting higher resistance, and closer to discharged. I can see this working fine with experience.

I used to run a voltmeter on my mower, but now just know to stop when it starts to sag under load too much. Again, since my cells are already old and tired, they sag to 3v or less under load, while still well above 3.8v resting. So I really can't mow them down too low, if the grass is thick.

FWIW, I use the mower to discharge dead packs to 0v for disposal. Even a 1s pack will turn the blade slowly.

dogman dan said:

FWIW, I use the mower to discharge dead packs to 0v for disposal. Even a 1s pack will turn the blade slowly.

Click to expand...

Thinking of adding momentary switch & 1s pack to brush motor on non-freewheel eTrike as reverse function = simple <1 mph backup function.

Battery Packs With Cell in Stem

Yes I do typically leave NiCd cell with contacts in stem. = Much simpler and less work!
But, it is important to bypass or disable the cell.
Bypass involves running battery wire to terminal-contact at top of cell.
Disable involves 1st confirming empty or emptying cell. 2nd, I solder a shunt or tab from neg to pos then attach power lead at bottom of cell.

Built 3 battery "packs" recently, from recycled Lipo cells. ... ...

1. Inverter pack 3s20p = 11.1V (12.6V charged) 43.2Ah Pack in sturdy CD case as an inverter pack to run an off grid gaming laptop.

2. UV floodlights power supply 3s12p = 11.1V (12.6V charged) 25.92Ah in GameBoy hip pack to power 3 x 12V 9w UV flood lights (Converted 10w LED flood lights to 365nm UV LED to shine against white sheet to attract insects (moths) as part of an entomological survey)

3. Homelite electric mower 6s18p = 22.2V (25.2V charged) 38.88Ah to replace worn out 24V 20Ah SLA.
I would estimate at ~350% run time compared to new SLA battery at ~45% the battery weight.
22.2V provides acceptable blade speed and was determined as optimal with mowers 21V LVC good for Lipo (3.50V per cell). There is room inside battery shell for an additional 18s1p if 25.9V (29.4V charged) seems advisable.

Electric Wheel Barrel Upgrade

click on picture

DrkAngle do you have a cement vault for all that potential power ?

999zip999 said:

DrkAngle do you have a cement vault for all that potential power ?

Click to expand...

The piles of Laptop LiPo?
(48Wh per 6pack) = ~6kWh Gathered for eMotorcycle project that fell through ...
Used about 3kWh on recent projects, so only about 3kWh left.
But still have another (best-maintained best LED fuel level) 6kWh in oem hard cases waiting for proper project

Unlike high output RC LiPo ...
These cells are designed for home laptop use with excellent quality control and admirable stability.
Quality might be exemplified by some 8 year old individual samples tested as high as 95%+ of original rated capacity.
Charged to 4.10V, every cell has demonstrated no noticeable discharge over several months.
(Any packs with voltage loss were separated and bad (self-discharging) cells removed to contained storage)

Oh - Each cell is individually fused as an oem safety measure!

Picked up a decent quantity of Samsung ICR18650-22P cells. (near 600, "new")
In 10s2p bricks w/BMS - 36V 4.4Ah
Graph shows "effectively empty" at 3.40V - (static condition)

Cells are rated at:
10A max sustained output
20A surge output

Much better than the LiPo and 18650's I've pulled out of laptops.

At 2p, that's 20A continuous and 40a surge, they look perfect for rebuilding NiCd power tool packs!
Tested for fit in:
12V 1.2Ah NiCd >> 3s2p 11.2V 4.4Ah B&D Firestorm battery packs - 2 built
14.4V 1.2Ah NiCd >> 4s2p 14.8V 4.4Ah B&D Firestorm battery packs
18V 1.4Ah NiCd >> 5s2p 18.5V 4.4Ah B&D Firestorm battery packs - 2 built
24V 1.4Ah NiCd >> 6-7s2p 22.2-25.9V (need to test fit and function of 7s) 4.4Ah B&D Firestorm battery packs
18.5V 3-4Ah Li-ion >> 18.5V 5s2p 4.4Ah Ryobi Lithium

Broke open 2 - 10s2p bricks and:
2 x 18V(5s2p) Firestorm = 20 cells
and
2 x 12V(3s2p) + 1 x 14.4V(4s2p) = 20 cells
for Lithiumization.

5s2p went nicely into 18V packs


Note: I arraigned cells so that the metal negative strip is positioned directly over the negative casing of the negative cell.
A lucky happenstance ... perhaps.

3s2p went nicely into 12V packs


Planned! was this circuitous series route that similarly placed the negative cell casing under the metal negative tab.

2 x 18V and 2 x 12V completed.
14.4V (4s2p) will take a bit more planning, either a bit of reforming or some iffy case trimming.

14.4V (8s2p) will take a bit more planning, either a bit of reforming or some iffy case trimming.

I have to credit my 2nd cousin(?) ... cousin's son, with a "solution" for:
B&D 14.4V lithiumization.

Involved cannibalizing an 18V pack, fortunately I have spares, to create an 18.5V 4400mAh pack for my 14.4V tools.
This does increase tool speed and torque an additional 28% ...
and capacity (18.5V x 4400mAh = 81.4Wh) ÷ (14.4V x 1200mAh = 17.28Wh) to 471%.

Black and Decker 14.4V Firestorm tools was my 1st cordless power tool set.
Higher voltage will be perfect for my:
VSR drills
Reciprocating saw Variable Speed (higher voltage less damaging than "bogging down" damage?
5⅜" circular saw - seemed anemic at 14.4V
Questionable will be:
Light - will need to get higher voltage bulb or convert to ≤ 21V LED

By creating a Hybrid 14.4-18V pack, 4s2p or even 5s2p will fit comfortably.
Just used the bottom of an 18V and cut a 14.4V top and finished with the partial top of the 18V.


Add on top allows easy, 2 screw, access for balance.
4s2p 14.8V Lithium at present, just a prototype ... 5s2p fits nicely!



Another advantage is the larger, more stable base for standing tools.



No 14.4V tool seems to suffer interference from longer base . ... ?

dogman dan said:

My super crude

Click to expand...

and my not so much a conversion but a battery pack mismatch from a left on a construction site Makita (with good Konion cells) strapped to a $30 naked recipro saw going cheap from a closing down hardware store



I can also use this battery on other 18v tools with dead cells

With good 18.5V 4400mAh batteries ... I decided to re-inventory my 18V Black and Decker tools.
More impressive than I remember, I keep picking up stuff at yard sales etc.

18V Black & Decker

Standard
5⅜" circular saw
2 Range VSR Drill
Halogen Light
10" Weed Whacker
Blower-Sweeper 100cfm

Premium
6½" Circular Saw w/Laser
Reciprocating Saw
Dual Chuck 2 Range VSR Drill
Hammer Drill
Jig Saw
Sander
10" Chain Saw
9w LED Light (converted with voltage down converter)
1w-2¼w-3w switchable LED Light (on/off/on switch with 3 value resistors)
Hand Vacuum
12" Weed Whacker
Blower-Sweeper 140cfm

New Problem-Project!

... Just found a box of ...
24V Black and Decker Fire Storm
7¼" Circular Saw w/Laser
Reciprocating Saw
Jig Saw
2 Range VSR Hammer Drill
Have 2 x 22.2V Lithiumized batteries
6s2p 4320mAh Laptop LiPo
6s2p 4000mAh RC LiPo

"24V" Projects

1. But ... Gotta try to squeeze 7s 25.9V into the 24V packs! (Not tested with 18650's yet)
Will have to experiment with cell layout pattern

2. Adapt for 18.5V battery compatibility
24V packs are same format-connection as 18V, just taller
Need to cut small 18V keyway in bottom of tool

3. Convert 18V Halogen Light to 24V 10w LED Light
Got V-A 10w regulators to convert ≤30V DC to 10w LED modules

14.4V Black and Decker Fire Storm - Inventory
5⅜" circular saw
Reciprocating Saws
VSR 2 range drills
Dual Chuck VSR 2 range drills
Halogen light

Sadly, my 12V Black and Decker inventory is pitiful
~ a dozen, mostly new VSR drills ... that's it - (bargain auctions on eBay)
So, 2 great 4400mAh batteries and no worthy tools! ... ?

.
... Black and Decker 24V 1.4Ah Nicad Battery converted to 25.9V 4.4Ah LiCo.

18V packs can, tightly, squeeze in 5s2p 10 18650 cells.
24V is noticeably taller.
7s2p 14 18650 cells is the target.
scrap (flashlight) cells used for testing. Samsung ICR18650-22p for actual builds.



After a fair bit of finagling, success!
Only have to separate and wire together 1 pair.
Bottom layer lies flat

4 Cells


2nd and 3rd layer will stand vertical pairs, but pictured as singles to demonstrate positions.

+5 Cells
View attachment 1

+5 Cells


= 14 Cells .......... 25.9V 4400mAh 20A continuous 40A surge capable

Power comparison vs 120V
20A @ ~30V = 5A @ 120V 600w (very powerful drill, modest to gentle sawing)
40A @ ~30V = 10A @ 120V 1200w (Powerful reciprocating saw, respectable circular saw)
.

DrkAngel said:

Mower upgrade
Upgraded my 24V 20Ah SLA mower last year.
Been running with upgraded 22.2V 34.56Ah (6s16p) Old used Laptop Lipo at probably 25Ah++.

20Ah SLA >> 22.2V 34.56Ah LiPo >> 25.9V 34.56Ah LiPo
So, pushed over the main brick and was able to squeeze in another 1s16p.
Previous 6s were matched in capacity and IR, added bank was just insured to be of better!
Lesser would drag down whole pack - better allows full use, with power to spare.

Yeah, oops ...
6s battery had no fuse installed.
Had to rewire, so dropped in a 40A fuse + holder.
Too wet to try and weather won't dry up for a few days but I expect performance to be noticeably improved!

Click to expand...

Made my 1st run with 7s16p recycled Laptop LiPo.
Mowed store's yard, neighbors yard, small community park and 2nd small community park.
Blade speed and torque are noticeably improved!
Original bank's discharged voltages ranged from 3.731V to 3.728V and add in bank @ 3.78V, so looks excellent!
Cell temperature, after mowing both parks, was < 100ºF on 80ºF day.
iMax "bulk" charge from 3.73 to 4.17V = 26.97Ah
4.176 - 4.182V bulk charge resultant voltage.
3.7V (safe empty) to 4.10V (Optimal) looks to be 25Ah+ usable, with generous safety margins!
24V SLA leds showed 75%, with motor idling over sidewalk, when cells near 3.75V (7s=26.25V )

Very happy and is liable to last "my" lifetime ... might want to get a spare Homelite mower?

Sony Laptop LiPo mower battery
7s16p 2160mAh cells
25.9V 34.56Ah

Previously capacity mapped
So I was able to compare tested vs proposed vs actual capacity



Charged 3.73V to 4.17V = 27Ah
Proposed 3.70V - 4.10V = 28Ah
Full capacity 3.68V - 4.20V = 31.4Ah ( 91% of new rated - without tapping the energy below 3.68V! from 8-10 year old cells!!! )

.

Checking cordless electric mower battery
Ready for 1st mow of the season.
6 months setting and all battery banks were within 5/100V.
Balanced up @ 4.14V but plan on bulk charging @ 28.7V for 4.10V per cell.
7s modded Meanwell supplies 4.78A @ 20-29.4V ... External pot-knob and volt meter integrated.
Alternate MeanWell Mega-Mod has Volt-Amp meter with external pots for 16-30V 0-5A adjustments.