Category Archives: Discharge tester – PCB build

Battery discharger problem with 1 cell

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

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Improved battery discharger current accuracy

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

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Discharger pictures

I found my camera . It hurt, but I clipped off the daughterboard (and removed the cut off pins).  There were a LOT of modifications to the board before it was done, but it seems to all work and I … Continue reading

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It works!

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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It’s a shield!

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

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?

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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PCB progress

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

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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