Gerhard wrote:
I have made some measurements on the noise voltage density in batteries. The short result is: 1. NiCd rulez. 2. Size DOES matter.
Nice work! (But not exactly news.) As noted in the NIST paper you quote, the noise of batteries is very closely correlated with their internal resistance, because the primary noise mechanism is Johnson noise and NiCads have the lowest internal resistance of commonly available batteries. As you discovered, the internal resistance of many NiMH batteries rises when current is drawn (one of the great drawbacks of NiMH batteries for high-drain uses such as model aviation and even high-lumen flashlights).
It would be nice to see measurements under load for all of the batteries (using a more suitable lithium battery -- perhaps a CR123A or a similarly-sized or larger rechargeable lithium), and results for small SLA batteries.
Best regards, Charles _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
