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Comment by nousermane | Hacker News Reader

Do GNU Units handle units with implicit parameters?

For example, 1500 mAh (milliamp∗hours) could be converted to 5.55 Wh (watt∗hours), or 19.98 kJ in SI units, in the context of a 3.7-volt battery.

Naive approach fails:

  $ units "1500 milliampere*hours at 3.7 volts" "watt*hours"
  conformability error
        1.9593687e+09 kg^2 m / s^4
        3600 kg m^2 / s^2

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You are multiplying mAh, volts, and atmospheres. (“at” is a unit not an operator.) You want to just multiply mAh and V like

  You have: 1500 mA hours * 3.7V
  You want: W hours
          * 5.55
          / 0.18018018

  You have: 1500 mA * hr * 3.7 V
  You want: kJ
          * 19.98
          / 0.05005005

  You have: 1500 mA * hr * 3.7 V
  You want: watt * hours
          * 5.55
          / 0.18018018

  You have: 1500 mA * hours * 3.7 V
  You want: watt * hours
          * 5.55
          / 0.18018018

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