Old FAA document on dry cell battery recharging

[Dr. Jones]

I came across this document a while ago; thought that it might be of interest to some here:

https://apps.dtic.mil/sti/trecms/pdf/AD0620018.pdf

Dated 1965, it's entitled Feasibility of Recharging FAA In-Service Dry-Cell Batteries, and was compiled by the FAA's Systems Research & Development Service.

The document contains bits of arcane information on several obscure or obsolete battery types, but its main focus is on the recharging of carbon-zinc dry cells with an eye towards keeping them in service longer. Ultimately, however, the study concluded a program involving the recharging of carbon-zinc cells wasn't worth following, but instead recommended that alkaline batteries be regularly recharged, up to 40 or 50 times, after shallow discharge.

Hope that you find it of interest.

 

[PhotonWrangler]

Dry cells are a misnomer. They're technically damp cells, and a common failure mode is when the electrolyte dries out.

A long time ago I read that one could rejuvenate some dry cells by drilling a shallow hole near the bottom on two sides, then sitting it in a cup of water for awhile to rehydrate the electrolyte. I tried this, and it actually worked to some degree. It also made a mess with all that carbon.

 

[Dr. Jones]

They're relatively dry, compared to a flooded battery.

I seem to recall hearing long ago that one could rejuvenate a dry cell battery by drilling an exceedingly small hole in bottom, off to the side, and injecting a solution of water mixed with the tiniest bit of detergent as a wetting agent into the electrolyte; I've never attempted it myself.

 

[PhotonWrangler]

They're relatively dry, compared to a flooded battery.

I seem to recall hearing long ago that one could rejuvenate a dry cell battery by drilling an exceedingly small hole in bottom, off to the side, and injecting a solution of water mixed with the tiniest bit of detergent as a wetting agent into the electrolyte; I've never attempted it myself.

Interesting. I never heard about the detergent trick though.

 

[Dr. Jones]

Interesting. I never heard about the detergent trick though.

I think it's sole function was to assist the water in permeating into the electrolyte.