Category Archives: Battery Rebuilding

Quickie 1-cell discharger

Posted on June 1, 2014 by Jim

Wow – I wasn’t planning to make this.  But as I fantasized about just building a simple discharger while struggling with 1-cell problem on the big 18 cell discharge tester, it sounded too simple to resist.  I could get to … Continue reading →

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Battery discharger problem with 1 cell

Posted on May 31, 2014 by Jim

The big battery discharger works well (or so I thought) except for the case of testing single 1.xV cells.  It just doesn’t work – reporting 0V often.  There’s even a comment in the code dated 2/15/11 (right under the V1.3 … Continue reading →

Posted in Discharge tester - PCB build | Tagged | 1 Comment

Dell laptop battery test / rebuild

Posted on June 15, 2013 by Jim

My dear (7 year) old Dell Inspiron 700m with extra capacity 8 cell battery has been running out of battery more quickly than I think it used to.  Since Bob G recently bequeathed a couple of laptop batteries to me, … Continue reading →

Posted in Battery Rebuilding, LiPo Conversions | 3 Comments

Ryobi battery rebuild with more learning opportunities

Posted on January 26, 2013 by Jim

My 14 year old 12V cordless drill is finally back on the air, with a battery pack rebuilt for the manyth time.  Two more cells replaced this time, but once again, some surprises.  I remember when I thought the hard … Continue reading →

Posted in Battery Rebuilding | 3 Comments

Trickle current limiter for B&D charger

Posted on May 5, 2012 by Jim

I’ve worried for years that at least some of the NiCd chargers’ trickle charge regimen was cooking my batteries into oblivion.  They say you can charge sub-C NiCds at 100mA forever without problem, but for stuff that’s charging for months … Continue reading →

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Battery tab welder has foot pedal and charger cutoff

Posted on March 17, 2012 by Jim

Faced with a potentially large number of welds for rebuilding a DeWalt battery, I finally integrated two improvements that have been waiting in the wings:  a MOSFET charger disconnect and a foot pedal to disconnect the charger and fire the … Continue reading →

Posted in Battery Tab Welder | 1 Comment

DeWalt battery rebuild

Posted on March 17, 2012 by Jim

What better birthday gift for my friend Ed than a handmade rebuilt 18V DeWalt battery made from recycled sub-C cells?  OK, especially when he provided 2 of the old packs I scavenged from. In addition to Ed’s donations, Mike D … Continue reading →

Posted in Battery Rebuilding | 2 Comments

Welder foot switch

Posted on January 29, 2011 by Jim

I put the foot switch together entirely from scrap.  I found 2 microswitches on a little bracket, a scrap of paneling, and old hinge, a block of wood and some closed-cell foam for a spring.  The wire is a scrap … Continue reading →

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Welder is taking shape

Posted on January 26, 2011 by Jim

An old battery charger, re-purposed as the charging supply for the welder is rewired and functional.  With thanks to some correspondence from Bob Van Valzah, I went with the dual half-wave arrangement using the center tap to get one diode-drop … Continue reading →

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Improved battery discharger current accuracy

Posted on January 16, 2011 by Jim

I swapped in a 0.9Ω resistor for the old 0.1Ω current sense resistor, giving 9X better current accuracy without reducing the 2A design max discharge current.  The original was just a poor choice. Since that resistor will dissipate 9X more … Continue reading →

Posted in Discharge tester - Arduino and perl code, Discharge tester - PCB build | Leave a comment