Any reasons against using magnets to stick contacts to a battery? - Page 1
Forum section: electronics / general

author: RoGeorge
author_rank: Super Contributor
timestamp: October 05, 2024, 05:37:43 pm
content: I've seen wires clamped to the ends of AA/AAA batteries with the help of strong magnets, but only as a DIY improvised socket, never as a solution in a ready made product. Seen the magnet method usually for alkaline batteries, but I would like to use magnets with rechargeable batteries, too.Searched online and couldn't find any reasons for why to NOT clip magnets at the ends of a battery, though I'm still not sure if there can be any damage, or unwanted side effects.Did anybody sees any reasons against attaching strong magnets to a rechargeable battery?

author: tom66
author_rank: Super Contributor
timestamp: October 05, 2024, 08:34:45 pm
content: The obvious one is not all batteries are made of ferrous materials, so it won't work with them. For instance, I've encountered lithium AA cells that are non-ferrous, this is particularly useful as we make devices that use magnetic compasses in them.

author: coppice
author_rank: Super Contributor
timestamp: October 05, 2024, 08:46:45 pm
content: Even if the battery terminals are made of a magnetic material, can you get a strong enough attraction to overcome shaking in any non-static application?

author: RoGeorge
author_rank: Super Contributor
timestamp: October 05, 2024, 09:07:56 pm
content: I've tried only on a couple of AA and AAA Ni-MH batteries. The coupling seems strong enough, but I guess it might disconnect at a strong shock, for example if dropped on the floor.

author: K5_489
author_rank: Regular Contributor
timestamp: October 05, 2024, 09:47:48 pm
content: My thoughts are more along the path of "why"Especially if you're talking AA/AAA size, actual battery holders are absolutely dirt cheap. Even if we're talking something like a 18650 cell, we're talking a dollar or two here, even in a grossly inflated USD market. I have a dozen of things sitting in a parts box now for various "quick grab and test" projects.

author: IanB
author_rank: Super Contributor
timestamp: October 05, 2024, 09:51:29 pm
content: I've used this method a lot as a working hookup for charging, discharging and testing NiMH cells. I simply sandwich a tinned copper contact strip between the battery terminal and a strong neodymium magnet. Works very well, and avoids messing around with spring clamps or other contraptions. Also produces a very low resistance contact compared to many battery holders with steel springs.(You can also temporarily stick a string of cells in series by joining them end to end with small magnets.)

author: RoGeorge
author_rank: Super Contributor
timestamp: October 05, 2024, 10:13:10 pm
content: Quote from: K5_489 on October 05, 2024, 09:47:48 pmI have about 100 batteries that have to be measured once in a while, and wanted to make a ZIF socket (Zero Insert Force) for batteries. So mostly for probing, or for measure real capacity during a controlled charge/discharge cycle in the lab.Sure, there are many ways to do that. Magnets seem particularly appealing to DIY a ZIF battery socket because they simplify the mechanics.

author: K5_489
author_rank: Regular Contributor
timestamp: October 05, 2024, 11:11:40 pm
content: Quote from: RoGeorge on October 05, 2024, 10:13:10 pmFair enough. I'm not seeing a need for ZIF on batteries, but I don't mean that in a dismissive of your ideas kind of way either. If it works for you, then no, I don't see any issues of using magnets in this way outside of potentially increasing the surface area of things that can possibly short circuit the battery, depending on the size of your magnet and/or contacts.To be fair, my initial thought of a magnet was one of these buggers -Why? I have absolutely no idea

author: IanB
author_rank: Super Contributor
timestamp: October 06, 2024, 12:30:13 am
content: Here's an example of how I have used magnets for quickly connecting to batteries:

author: RoGeorge
author_rank: Super Contributor
timestamp: October 06, 2024, 01:55:52 am
content: Quote from: K5_489 on October 05, 2024, 11:11:40 pmThose are huge and very strong, I have the square-shape pair.Once I've measured their magnetic field with a ruler and a piece of wire.Well, and a digital oscilloscope, too. Found about 65mT:https://www.eevblog.com/forum/projects/measure-a-magnets-b-field-with-a-rigol-ds1054z-oscilloscope-and-a-piece-of-wire/

author: 5U4GB
author_rank: Super Contributor
timestamp: October 07, 2024, 12:47:57 pm
content: Quote from: RoGeorge on October 05, 2024, 05:37:43 pmOnly an amateur would use magnets to attach wires to a battery. This is how the professionals do it.

author: bill_c
author_rank: Regular Contributor
timestamp: October 07, 2024, 09:52:12 pm
content: Do a search for magnetic test leads, not saying its right or wrong, but they do exist and may work.

author: RoGeorge
author_rank: Super Contributor
timestamp: October 09, 2024, 12:48:05 pm
content: Maybe the batteries didn't take any damage, but in practice I found the little magnets very annoying to have on the desk. They are snapping to all kinds of ferromagnetic objects or debris.

author: Seekonk
author_rank: Super Contributor
timestamp: October 09, 2024, 01:00:48 pm
content: I found what I thought were neat test leads on amazon with magnets on the end. Great for attaching to contactors and breakers with plastic wells to the screws. Problem was the magnets were weak and Philips screws always left one side with little contact on the screw. If lead was vertical there was a chance of it holding. In a control panel that was vertical as most are it would just fall out from the weight of the lead and those were skinny. Great idea I wish someone would make right.

author: IanB
author_rank: Super Contributor
timestamp: October 09, 2024, 02:12:05 pm
content: Quote from: RoGeorge on October 09, 2024, 12:48:05 pmYes, it is best not to let little magnets float around loose. Keep them stuck together and either store them inside a plastic container, or attach them to a solid metal object like a desk frame or shelf bracket.

author: MC Divit
author_rank: Newbie
timestamp: October 11, 2024, 01:43:41 pm
content: If the battery has any integrated electronics, such as battery management systems (BMS), strong magnets might interfere with their operation. This could lead to incorrect voltage readings, charging issues, or safety features being bypassed.