As expected with Zinc Carbon the capacity is low and the current handling is very bad. It also looks like there is significant capacity differences between the batteries (the 0.002mA trace is shorter than the 0.005mA trace).
Conclusion
For a Zinc-Carbon battery this is fairly decent, but that do not mean it is a good battery, it is only to be used on low power loads.
My DMM uses one, smoke alarms, some radio alarm clocks for power backup to keep the time. IR temp meters some childrens toys occasionally need them. that’s the few I know off the top of my head.
More and more things that in the past typically used 9V batteries are being designed to run from one to four AA or AAA cells, modern devices are made to run from much lower voltages, or that use highly efficient switch mode voltage converters.
Thanks for the tests HKJ.
It only confirmed my conclusion that it’s not worth buying alkalines as they have only double capacity and 4-times the price.
And if you need rechargeable, just buy alkaline and recharge with the 9V 14mA output that many old chargers have. They don’t leak as they don’t have vent.
You might even get more juice out of them then some of the pricy rechargeable baits.
Depending on application alkaline can last 10 times as long.
Both types leak, with 9V you are a bit safer because they usual have a double enclosure. This means a significant part of the leaking will often stay inside the 9V block.
Yea smoke alarm always use 9v batteries. They need the extra voltage to operate. Hard wired smoke alarms are becoming popular now but even they have a battery back up. Some scales also use 9v batteries.
alkaline 9v often pop when recharged.
a neighbor had 2 pop loudly in a motion sensor that had a small solar panel on it.
it was meant for a nicad.
i measured 6ma in full sun.still enough to pop the alkaleaks.