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Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

The New Hotness

  • UPS SLA Batteries: Old vs. New

    For completeness, all of the surviving UPS sealed lead-acid batteries compared with a new battery:

    UPS SLA 2021-10-22
    UPS SLA 2021-10-22

    They’re all discharged at 4 A, far higher than the nominal “20 hour” rate of 450 mA = 9 A·hr / 20 hr, but an order of magnitude closer to the rated UPS output of a few hundred watts which would call for a few tens of amps.

    The new battery delivers 73 W·hr under those conditions, perhaps 50% more than the 50-ish W·hr from the used batteries, and with a much higher overall terminal voltage during the discharge.

    Nothing unexpected, but now we know …