Ni-MH battery has a small tear - Page 1
Forum section: electronics / beginners

author: niemand
author_rank: Contributor
timestamp: September 06, 2022, 11:07:15 pm
content: I caused this tear. Does this tear on the wrap pose any hazard? The battery goes inside an electric toothbrush (https://www.eevblog.com/forum/beginners/why-do-wires-from-battery-to-motor-get-hot/).Thanks.

author: jpanhalt
author_rank: Super Contributor
timestamp: September 07, 2022, 04:50:44 am
content: For a single battery like that, there is no added risk from the tear. If multiple batteries together in a pack, then metal case to metal case contact can cause a short.

author: rooppoorali
author_rank: Regular Contributor
timestamp: September 07, 2022, 05:09:30 am
content: As suggested by the previous answerer, It sometimes depend on how many batteries are there.

author: james_s
author_rank: Super Contributor
timestamp: September 07, 2022, 06:51:21 am
content: If you're concerned about it just slap a piece of vinyl or polyamide tape over it and call it good.

author: magic
author_rank: Super Contributor
timestamp: September 07, 2022, 01:48:25 pm
content: Taping it over is probably pointless in this case.Like in electrolytic capacitors, the metal can holds all the dirty stuff inside and the foil is just for decoration and insulation.The can is usually electrically connected with the negative terminal.

author: golden_labels
author_rank: Super Contributor
timestamp: September 07, 2022, 03:58:05 pm
content: The only risk is when you have more than one such battery and exposed parts of their cans are in contact. That would cause a short between terminals of a cell through the can of the other cell. If you find a battery holder in which batteries are pressing against each other (they do exist, I do not deny that!), do you think the chances are high for both batteries being positioned in the exactly right position for that to happen? Don’t worry.If you want to be sure, just put a piece of tape on the tear. Just plain office tape is sufficient. The goal is to provide physical separation.

author: magic
author_rank: Super Contributor
timestamp: September 07, 2022, 06:44:52 pm
content: Quote from: golden_labels on September 07, 2022, 03:58:05 pmThat's not true, the risk of short exists if there is any other exposed conductor that could come in contact with the can

author: golden_labels
author_rank: Super Contributor
timestamp: September 08, 2022, 05:57:28 am
content: Quote from: magic on September 07, 2022, 06:44:52 pmThat’s not exactly true either. The risk of short existsif there is any other exposed conductor that could come in contact with the canand the conductor is connected with the terminal opposite to the can, or there are at least two conductors that should not be allowed to be in contact.Do not try to outpedant me. You are destined to lose.

author: magic
author_rank: Super Contributor
timestamp: September 08, 2022, 06:24:46 am
content: Quote from: golden_labels on September 08, 2022, 05:57:28 amo rly?Quote from: golden_labels on September 08, 2022, 05:57:28 amThat still doesn't cover all cases.Quote from: golden_labels on September 08, 2022, 05:57:28 amAnd now you are just being overly paranoid to compensate.There is absolutely no reason to worry if they can't come in contact(Which is likely the case here).

author: Mechatrommer
author_rank: Super Contributor
timestamp: September 08, 2022, 06:33:10 am
content: Quote from: golden_labels on September 08, 2022, 05:57:28 amthere corrected for you.Quote from: golden_labels on September 07, 2022, 03:58:05 pmno if exposed parts that are in contact are the same node (net) in the circuit (paralleled batteries).