The Forestry Forum is sponsored in part by:

TURBOSAWMILL GIANT SALE ON NOW UNTIL OCTOBER 31st


Forestry Forum
Sponsored by:


TimberKing Sawmills



Toll Free 1-800-582-0470

LogRite Tools



Norwood Industries Inc.


Sawmill & Woodlot Magazine



Your source for Portable Sawmills, Edgers, Resaws, Sharpeners, Setters, Bandsaw Blades and Sawmill Parts

EZ Boardwalk Sawmills. More Saw For Less Money!

STIHLDealers.com sponsored by Northeast STIHL


Woodland Sawmills

Peterson Swingmills

 KASCO SharpTech WoodMaxx Blades

Turbosawmill

Sawmill Exchange

BRUTE FORCE Authorized Dealer

Woodshax Outdoor Vending Solutions

FARMA


Council Tool

Baker Products

ECHO-Bearcat



Author Topic: Rebuilding 18 volt batteries for cordless tools.  (Read 7367 times)

0 Members and 1 Guest are viewing this topic.

Offline John Mc

  • Senior Member x2
  • *****
  • Posts: 4799
  • Age: 56
  • Location: Monkton, Vermont
  • Gender: Male
    • Share Post
Re: Rebuilding 18 volt batteries for cordless tools.
« Reply #80 on: September 09, 2018, 10:34:49 PM »
Backfeeding a Nicad battery does two things:
  • it may "wake the battery up enough that the charger for that battery will now recognize it and at least make an attempt to charge it up
  • When back feeding, it works better to do a few brief "zaps" rather than one long one: connect for a 2 seconds, disconnect, connect for 2 more second, etc. Do that maybe half a dozen times (or more if you are backfeeding with a lower voltage source). Doing this makes a sort of square wave feedin ginto the battery that can break up internal pathways that have formed and may be creating a partial short, draining the battery.

My electrical engineer friend had me use the above technique and hook up two 12 volt car batteries in series (to make 24 volts) and use that to back feed (connect + to + and - to -) my 18 V nicad tool batteries. It worked on a couple of them. The ones that it did not work on, he had me open up and use a single 12V car battery to back feed each individual cell. Doing individual cells is much more effective than trying to do the whole pack at once, but it's more of a hassle, so worth seeing if you can resurrect the battery without disassembling it first.

He also strongly recommended NOT trying to resurrect Lithium-Ion batteries back feeding them with a higher voltage. He aid you really just want to use their regular charger on them. You might get away with it, but if you don't, lithium-ion sometimes just won't take the abuse, and the results are "not pleasant". (He did admit to knowing a lot more about NiCad than LI-ion, however.)
If the only tool you have is a hammer, you tend to see every problem as a nail.   - Abraham Maslow

Online Dave Shepard

  • Senior Member x2
  • *****
  • Posts: 10848
  • Age: 2013
  • Location: Alford Massachusetts
  • Gender: Male
  • Geometrically proportional
    • Share Post
    • My homepage
Re: Rebuilding 18 volt batteries for cordless tools.
« Reply #81 on: September 10, 2018, 01:42:34 AM »
In the case of the Milwaukee chargers, if they don't see a minimum voltage, they won't charge. If a battery was left in a cold environment for a long time at a low charge, it can drop below that voltage. Normally the battery shuts off before it is too low to recharge, but long term storage or cold can drop it down. If this is the cause of not charging, the solution I've seen on YouTube, use at your own risk  ;), is to hook up a good, fully charged battery for a few minutes to get the dead battery over the threshold voltage. If you have a battery with a bad cell, then this won't work, and you may have a fire. I have one battery that was about 15v, and just needed a couple of volts to bump it up. The others were only 2-3 volts. They are junk. 

After considering the risks, time, and expense of messing with old batteries, I've decided not to bother with them. I've also ended up with so many newer, larger batteries, it became a non issue. 

There are a few more batteries and chargers not pictured. Four M18 chargers,  five Rapid Chargers, and 18 batteries (7-9.0ah) later, I seem to have enough:




Wood-Mizer LT40HDD51-WR Wireless, Kubota L48, Honda Rincon 650, TJ208 G-S, and a 60"Logrite!

Offline John Mc

  • Senior Member x2
  • *****
  • Posts: 4799
  • Age: 56
  • Location: Monkton, Vermont
  • Gender: Male
    • Share Post
Re: Rebuilding 18 volt batteries for cordless tools.
« Reply #82 on: September 10, 2018, 08:06:03 AM »
The Interstate Battery store near me will rebuild NiCad batteries, but they won;t touch Lithium-Ion. From what I undertand, their insurance company has a fit about working on LI-ion batteries. They don;t know if that is over concerns about some danger in working on them, or the liability if you were the last one to work on a LI-ion battery and it goes up in flames sometime later while in use or storage (same concerns the airlines have about bringing those batteries on board).
If the only tool you have is a hammer, you tend to see every problem as a nail.   - Abraham Maslow

Offline Banjo picker

  • Senior Member x2
  • *****
  • Posts: 2643
  • Location: Iuka Ms
  • Gender: Male
  • A goal without a plan is just a dream. Elbert H.
    • Share Post
Re: Rebuilding 18 volt batteries for cordless tools.
« Reply #83 on: September 10, 2018, 09:08:28 AM »
Banjo, is that a Lithium Ion or a NiCad battery?


They are all NiCads  I checked them this morning and two are extremely low.  They may have a bad cell, but if I have save half of what I started with, I consider it a win.  

Dave with that many batterys and chargers, you may want to seek out a counceling group. :D Banjo
Cooks AC 36--Prentice 210C--Morgan edger--Kubota M7040 with loader--Case 580 K with extendahoe--Case 850C dozer--Int 1700 series twin cylinder dump/log/flatbed truck--logging arch--2 Logrite mill sp.--Cat claw sharpening system--And a bulldog to make sure it all stays here.

Offline Corley5

  • Senior Member x2
  • *****
  • Posts: 7936
  • Age: 49
  • Location: Wolverine, Michigan USA
  • Gender: Male
  • Wolverine, Michigan
    • Share Post
    • Whittaker Farms
Re: Rebuilding 18 volt batteries for cordless tools.
« Reply #84 on: September 10, 2018, 09:20:48 AM »
Dave I'm impressed you know how many batteries and chargers you have :) 8) :) ;D ;D 
Burnt Gunpowder is the Smell Of Freedom

Offline Ianab

  • Administrator
  • *****
  • Posts: 12622
  • Age: 56
  • Location: Stratford , New Zealand
  • Gender: Male
  • Marmite on toast is a real breakfast
    • Share Post
Re: Rebuilding 18 volt batteries for cordless tools.
« Reply #85 on: September 10, 2018, 03:53:05 PM »
Why you don't mess with Lithium batteries. The lithium is so reactive that it burns in almost anything, including water. If you short one out and it catches fire....

Weekend warrior, Peterson JP test pilot, Dolmar 7900 and Stihl MS310 saws and  the usual collection of power tools :)

Offline ljohnsaw

  • Senior Member x2
  • *****
  • Posts: 3221
  • Age: 59
  • Location: Northern California
  • Gender: Male
  • Happily retired... Working harder than ever!
    • Share Post
Re: Rebuilding 18 volt batteries for cordless tools.
« Reply #86 on: September 10, 2018, 04:44:57 PM »
Backfeeding a Nicad battery does two things: it may "wake the battery up enough that the charger for that battery will now recognize it and at least make an attempt to charge it up When back feeding, it works better to do a few brief "zaps" rather than one long one: connect for a 2 seconds, disconnect, connect for 2 more second, etc. Do that maybe half a dozen times (or more if you are backfeeding with a lower voltage source). Doing this makes a sort of square wave feedin ginto the battery that can break up internal pathways that have formed and may be creating a partial short, draining the battery.
 

Way back (mid-70's) I was into Remote Control (R/C) airplanes.  NiCad was the best we had and they were expensive.  You had to maintain those batteries year round.  If you didn't, they built up the internal shorts, ruining the battery.  An old R/C magazine had an article about zapping them back to life.  I made one.  Basically a large capacitor bank (about 3,000 mfd) that you would charge up with a 4 or 5 vdc source (IIRC).  You would place a AA battery in the holder that had a VOM attached to it.  You would then press a momentary switch a few times and watch the VOM to see if the battery would hold volts.  The ability of the capacitors to dump a LOT of amps of lower voltage is what did the trick.  It worked quite well!
John Sawicky

Just North-East of Sacramento...

SkyTrak 9038, Davis Little Monster backhoe, Case 16+4 Trencher, Home Built 38" cut Bandmill up to 54' - using it all to build a timber frame cabin.

Offline Don P

  • Senior Member x2
  • *****
  • Posts: 4793
  • Location: Southwestern VA
  • Gender: Male
    • Share Post
    • Calculator Index
Re: Rebuilding 18 volt batteries for cordless tools.
« Reply #87 on: September 10, 2018, 04:54:27 PM »
I've also charged up failing battery packs then open them up, disassemble the jumpers from each cell and find the bad ones. I've taken 2 failing packs and made one decent battery. You can also buy those sub C batteries online and refurbish a pack that way.

Offline 78NHTFY

  • Senior Member
  • ****
  • Posts: 326
  • Age: 65
  • Location: NH
  • Gender: Male
  • I'm old!
    • Share Post
Re: Rebuilding 18 volt batteries for cordless tools.
« Reply #88 on: September 10, 2018, 08:42:56 PM »
Don P--have done the same.  Now have three working Ryobi and two DeWalt 18 volt batteries.  Cost of the generic 18 volt batteries is about $ 13 ea.  A little soldering and it's a lot cheaper than $ 50 plus per new battery.  Youtube is good for stuff like that....All the best, Rob. 
If you have time, you winů.


Share via delicious Share via digg Share via facebook Share via linkedin Share via pinterest Share via reddit Share via stumble Share via tumblr Share via twitter

xx
Cordless Tools

Started by clintnelms on General Woodworking

30 Replies
2044 Views
Last post August 24, 2016, 11:38:30 AM
by clintnelms
xx
28 Volt Battery Power Tools

Started by Kirk_Allen on General Board

6 Replies
1159 Views
Last post January 14, 2005, 10:11:49 AM
by Weekend_Sawyer
xx
Ryobi cordless tools - Good or bad luck?

Started by Saki on General Board

36 Replies
12291 Views
Last post December 08, 2006, 11:19:26 PM
by brdmkr
xx
farmall cub 6 volt to 12 volt converson

Started by Polly on General Board

8 Replies
8486 Views
Last post May 15, 2009, 08:45:35 PM
by Polly
 


Powered by EzPortal