Today I Learned: Laptop Battery Pin Out

I'm big into using whatever's already lying around for amateur radio, and the laptop batteries complete with an external charger—for a laptop I no longer use—weigh heavy on my mind each time I change out the (8!) AA batteries for the Rockmite 20. Well, I was finally able to put them to use. Unlike a two terminal AA battery, the MKFVP battery has a whopping 9 connector slots. I measured voltages between slots to no avail, I couldn't fine the advertised 11.4 volts I'd hopeed for. Then, the article at https://www.electroschematics.com/laptop-battery-secrets-part-1 came to my rescue. The article was about all manner of laptop batteries rather than my specific one, but that was enough. The author also noted that the outside terminals of laptop batteries are usually the power delivery leads analagous to the two terminals of a AA battery. I'd measured the voltage between those two connector slots already, and there was nothing... zero volts. However, the author also mentioned

Connecting the switch terminal to ground probably turns the battery on. Sometimes, this battery-wakeup pin is denoted as “system present/sense” pin.

Reasoning that my battery charger might also need to short the wakeup pin I set out with an ohmmeter to see if there was a pin shorted to the negative battery terminal.

There was! It was three pins away.

Armed with this information, I made the connections shown below, and sure enough, 12.22 volts appeared across the outside terminal! I've been operating the Rockmite on that battery since.

Radio operations on the laptop battery:

Coming soon:

Morse Code Amateur Radio Callsign Aliasing

github for Accumulating Screen Scrape History

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