How to DIY a zero-ohm bridge in the shape of an alkaline battery?  - Page 1
Forum section: electronics / projects

author: RoGeorge
author_rank: Super Contributor
timestamp: October 23, 2024, 08:10:39 pm
content: The goal is to make a zero ohms battery, such that the body and the contacts of the battery remain intact, so it can be inserted in any battery socket, just like it would be a normal battery. In other words a zero-ohm bridge in the shape of a battery. Need that for testing, it's a one off, hobby level.Don't have access to machining, and don't want to get messy by cutting open the battery to take its top and bottom contacts (and glue them later on a plastic tube of the same length as an AA).Tried so far to make a solder ring between the + and the - at the bottom of the alkaline battery, but a complete ring of solder requires too much heat. The gasket melts, and it also vents the battery.Then I've tried on another battery to make only a small solder bridge, in only one point between the can and the bottom contact. This can be done with less heat, without compromising the isolation gasket between plus and minus, but the battery still vented. Both tries were made on already discharged AA alkaline batteries, less than 0.8V or so.Any ideas how to DIY a zero-ohm bridge with the exact shape and contacts quality as a battery, please?

author: Andy Chee
author_rank: Super Contributor
timestamp: October 23, 2024, 08:40:49 pm
content: There are many ways to make a dummy AA cell:

author: 2N3055
author_rank: Super Contributor
timestamp: October 23, 2024, 09:08:44 pm
content: There are 12mm copper tubes and endcaps for central heating installations.With pipe cutter you cut the length, put two caps, solder them and put heat shrink tubing on the outside, keeping tops open.

author: Manul
author_rank: Super Contributor
timestamp: October 23, 2024, 09:13:05 pm
content: My first idea would be to drill the alkaline battery from side, somewhere in the middle. Like a good 4-6mm diameter hole. Clean out some chemicals and solder a bridge between central collector pin and outer shell. Probably while heatsinking the negative terminal, so the gasket does not melt. Then put a piece of tape to cover the hole. Messy? Yes. But probably the easiest without constructing something yourself.

author: tszaboo
author_rank: Super Contributor
timestamp: October 23, 2024, 09:23:17 pm
content: You can buy these things for next to nothing. I use some to run a device from 1X 3.7V lithium instead of 3x AAA.

author: 2N3055
author_rank: Super Contributor
timestamp: October 23, 2024, 09:55:47 pm
content: Quote from: tszaboo on October 23, 2024, 09:23:17 pmI found it. A key word is battery eliminator Thanks!

author: RoGeorge
author_rank: Super Contributor
timestamp: October 23, 2024, 10:46:48 pm
content: Thank you all, will try tomorrow.Never knew there is such things to buy as a "battery eliminator". I would prefer to DYI, or else I can just connect a wire directly to the other side during the calibration.The sideways drilling is probably the best way to go in my case.Drilling and emptying the battery (even partially) would be messy, but if it can be done, that will also solve the risk of leaking later.

author: Kim Christensen
author_rank: Super Contributor
timestamp: October 23, 2024, 11:02:53 pm
content: Buying a premade battery eliminator is best.Another DIY method would be a piece of wood doweling with some copper tape wrapped in a U from end to end. Or put a screw into each end with a wire between them.

author: blue_lateral
author_rank: Contributor
timestamp: October 24, 2024, 03:11:27 am
content: Also called a "dummy battery".