Author Archives: Jim

It works!

Posted on December 4, 2010 by Jim

The good news is the discharge board and initial software work!  Here’s a discharge of a 14 cell test battery: Battery Discharger version 0.90 Enter number of cells 1-15: Running test with 14 cells. Test ends at 13.30 volts. Press … Continue reading →

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New cap for tab welder

Posted on December 1, 2010 by Jim

The new “Volfenhag” capacitor for the battery tab welder arrived.   Here is it with the old crummy red Pyramid “1.5F” cap.  Doing a discharge test with a resistor, voltmeter and a stopwatch to find RC, it measured at 1.2F.  Not … Continue reading →

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It’s a shield!

Posted on December 1, 2010 by Jim

The battery discharge tester hardware is essentially complete.   You can see the 15 clip leads that go to the cell connections plus the red/black heavy clips that go to the very top and bottom to carry the discharge current. The … Continue reading →

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Eeprom test

Posted on December 1, 2010 by Jim

My order of ten 64Kbyte 24C512 I2C eeprom chips from China arrived.  They’re SOIC (small outline IC) rather than the more traditional 0.1″x0.3″ DIP package, and the part number on the chip was unrelated to 24C512 and I couldn’t find … Continue reading →

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Is good enough good enough?

Posted on November 24, 2010 by Jim

OK – I screwed up.  I missed implementing 2 features in the original board design, and now I’m paying for it trying to figure out how to hack the boards into doing what I need. The first missing feature was … Continue reading →

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New cap on its way for battery tab welder!

Posted on November 22, 2010 by Jim

The capacitive discharge battery tab welder (inspired by various web postings including ledhacks and the seminal philpem note) has been sort of on hold since I discovered the nominally 1.5F cap I bought measured at 0.3F.  I had even made … Continue reading →

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PCB progress

Posted on November 22, 2010 by Jim

There were some bad copper bridges on the daughterboard from the “fuzzy” area spotted by someone at the PCB making demo.  (I suspect it was a small bit of crud holding the artwork away from the board.)  I opened those … Continue reading →

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Discharger PCB hacks

Posted on November 22, 2010 by Jim

I never think of everything in time. The analog mux chips give me 16 channels to connect to individual cells.  For NiCd, that’s a max of 16*1.2V=19.2V packs.  That covers almost all battery packs – great. But the discharger also … Continue reading →

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Discharger Arduino code thoughts

Posted on November 22, 2010 by Jim

One of my biggest fears for the Arduino code is that a bug will turn on inappropriate analog switches, resulting in a short or other undesired connection, probably damaging either the mux chip or the Arduino itself.  To help avoid … Continue reading →

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Notes for installation of solar panels

Posted on November 22, 2010 by Jim

This summer I was seriously considering putting ~2.5KW worth of PV solar panels on the roof of the house and the garage.  (That was all that would fit.)  I was working with a guy from Earth Wind and Solar, and … Continue reading →

Posted in Solar Panel Installation Notes | 1 Comment