A history of my battery builds.
24V 14Ah NiMh
20s2p New Cells - 2008
- 10s4p - 2008 Too small! Added cells to build next ...
- 10s8p - 2008
- 7s12p - 2008
- 7s12p - 2011
New RC LiPo - proposed build - 7s4p - 2011
New RC LiPo - proposed build - 10s3p - 2011
7s12p - 2011
Pack (.96Kwh) - 10s12p - 2011
Power tool rebuild
- 4s2p (14.4V 5.2Ah) - 2011
- 6s16p - 2013
- 8s12p - 2013
- 6s20p - 2013
w/11.1V 43.2Ah - 3s20p module added
- 9s20p - 2013
- 9s12p - Winter 2013-2014
- 7s12p - 2014 - passed 6500miles
- 6s14p - 2014
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 1stv 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
Postby DrkAngel » Thu Nov 12, 2015 4:14 pm
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.
DeWalt 18.5V RC Lipo
Postby DrkAngel » Tue Nov 17, 2015 9:10 pm
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.
Just got DeWalt Reciprocating Saw
Gotta find donor batteries for more rebuilds!
22.2V 34.56Ah >> 25.9V 34.56Ah - 6-7s16p 2016-17
Upgraded my 24V 20Ah SLA Homelite 20" mower last year.
Been running with upgraded 22.2V 34.56Ah (6s16p) Old used Laptop Lipo at possibly 25Ah+.
Works OK but, since I run as a mulching mower, the extra rpm and torque seems advisable.
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.
Yeah, oops ...
6s battery had no fuse installed.
Had to rewire, so bridged with a 40A fuse + holder - "good build" now.
Cells are surrounded and set upon closed cell foam.
Prevents movement and protects from vibration and rough handling.
At probably less than 1C discharge, I am not worried about battery heat.
... 25.9V 26.4Ah #1 finished - 2017
7s12p Samsung cells are capable of 120A continuous 240A surge but controllers are <30A and installed 40A fuse (trying new 58V fuses & holder)
Just finished 1, had to test drive it ... rain stopped for awhile.
No BMS installed! Turned out were only 20A continuous.
Mostly worried about parasitic draw when customers let set for the Winter.
10s2p Bricks disassembled into 8s2p + 2s2p and I was oh so tempted to build as 8s12p ... but needed for 24V bikes and I already have the 7s chargers.
... 25.9V 26.4Ah #2 finished - 2017
2nd pack ready
Not enough matched 7s2p premade strings. Used 4s2p plus 3x 1s2p pairs.
Made preliminary run and bank voltages were very similar, indicating cells of like condition ... age, batch etc.
Will double rails and retest before declaring acceptable.
#1 pack appears immaculate!
Discharged to 3.566-3.567V, all banks within 1/1000th V.
Recharged to 4.166-4.168V, within 2/1000th V.
... 33.3V 31.2Ah - 2018
- 9s12p is maximum number of cells that can physically fit in eZip RMB case.
Side A was nice and straight forward, nice straight runs with heavy tinned copper braid.
Any connection over positive ends of cells were protected with additional HD duct tape!
Side B required a few curves, which was easy if braid curved before flattening.
Installed the new 58V rated fuse holder with 40A fuse. Upgraded charging wire to 18ga, unlikely to charge over 5A, will upgrade to 14ga if I ever want to charge at max recommended 15A.
Entire battery wrapped in clear boxing tape to stabilize and protect. Meter leads poke through easily, for testing.
Sides wedged firmly with sturdy cardboard.
I did add 1/2 cell height wood blocks to support rows 2-4-6-8
33.3V 31.2Ah = 1038.96mAh - 1kWh+
9s12p = 108 cells
NOS from HP laptop batteries.
72 Sony 2600mAh + 36 Sanyo 2600mAh
Arraigned as 9s8p(Sony)+4p(Sanyo)
Both types effectively "empty" at a static 3.70V
20-21mph (will go 25mph in my upgeared eZips)
Including shell, battery build weighs 12lb 0oz