search

hamishcunningham / pi-tronics

Source code for Raspberry Pi GATE projects.
http://pi.gate.ac.uk/
42 stars 15 forks source link

Loss in voltage #57

Closed jeberhardt closed 9 years ago

jeberhardt commented 9 years ago

There seems to be a difference between the voltage of the batteries themselves and the output of mopicli.

If I use mopicli -v, it'll show 7100 for example. If I take the leads from my multimeter and apply them to the wires connecting the batteries, it'll show 7.40 (the equivalent of 7400). I'm wondering what is accounting for the difference in voltage, and if there's a way I can reduce that difference, ensuring I'm getting everything possible out of the batteries. Thank.

hamishcunningham commented 9 years ago

Batteries under load vs. not? On 25 Aug 2015 15:14, "James Eberhardt" notifications@github.com wrote:

There seems to be a difference between the voltage of the batteries themselves and the output of mopicli.

If I use mopicli -v, it'll show 7100 for example. If I take the leads from my multimeter and apply them to the wires connecting the batteries, it'll show 7.40 (the equivalent of 7400). I'm wondering what is accounting for the difference in voltage, and if there's a way I can reduce that difference, ensuring I'm getting everything possible out of the batteries. Thank.

— Reply to this email directly or view it on GitHub https://github.com/hamishcunningham/pi-tronics/issues/57.

guruthree commented 9 years ago

A small voltage loss is unavoidable across the Schottky diode we use to balance the two input sources. This sounds like what you're measuring!

jeberhardt commented 9 years ago

That seems to be the likely source of the voltage loss. Thanks for the explanation.