Comments on: Ask Hackaday: When Good Lithium Batteries Go Bad

By: Dom

Dom — Tue, 21 Oct 2025 09:23:15 +0000

A tub large enough to submerge the entire unit.
1 cup of salt (NaCl) per 10 litres of water, dissolve thoroughly.
Submerge unit in brine for 2-3 days.
Advice from Queensland Fire and Emergency Services:

“If safe to do so, damaged lithium-ion batteries may be de-energised before disposal by placing in a large bucket filled with 10 litres of water containing 1 cup of table salt (sodium chloride) for 48 hours. This should be done outdoors in a well-ventilated area.”
In other words, SALT WATER, STAT!

By: Worf

Worf — Tue, 21 Oct 2025 09:19:46 +0000

First thing to do is discharge the batteries. Once they get below 50% charge they will be defanged. Fire is caused by the stored energy, not the lithium ions and discharging the batteries means they won’t have enough energy to start a fire. Then the internal materials and electrolyte are flammable which keeps the fire going.

Once you do that, they are remarkably safe to handle. Even if you puncture the cells you will vent gas and that’s it. Of course, keep away from flame. Then recycle at any facility that can recycle batteries.

By: Johnu

Johnu — Tue, 21 Oct 2025 08:12:24 +0000

In reply to Foldi-One.

Yeah I have a few lithium batteries (EG from a laptop or other device – nothing controversial) and can’t find any sensible way to properly dispose of them in my local area.

The local tip took a couple of things with batteries inside (eg toothbrush) but it didn’t seem like they had any real mechanism for dealing with them, they were just kinda throwing them in the small appliances bin and ignoring the battery issue.

By: Aknup

Aknup — Tue, 21 Oct 2025 01:15:12 +0000

Over here if a city recycling place would not take them people would just dump them at the curb, at the place (hopefully) after hours, let the city deal with what they are suppose to deal with would be the thinking.
Obviously the smart ones would remove identifying markers. But that’s not the vast majority, the rest when confronted would just lie and say someone stole them or some such.
Is that a good thing? Yes and no, the city has responsibilities assigned to them by the government and international agreement in terms of recycling, and sometimes you have to force their hand if they don’t follow through and don’t do what the taxes pay them to do.

The US of course is not the same as the EU, so I get it if this does not apply.
I’m sure Tr*mp scoffs at recycling and mocks orgs and cities that have a program.

By: SmellyFartGuy

SmellyFartGuy — Tue, 21 Oct 2025 00:30:44 +0000

In reply to asheets. They pay us for our batteries... (I'm in US also)

By: Hans

Hans — Tue, 21 Oct 2025 00:07:24 +0000

The regional waste management authority usually rotates “hazmat disposal days” between towns’ or county recycling centers, scheduled every 2-3 months or more frequently in summer. A few calls or googling will reveal the schedule

By: Randlin

Randlin — Tue, 21 Oct 2025 00:06:11 +0000

In reply to Randlin. But this does not necessarily mean the other (not so expanded) cells of the battery are actually bad, there just might have been one factory bad cell. If it is cold damaged though, then I'd consider using the other ones only after watching several power cycles and seeing if they expand or heat up unusually. All in all, LiFePo4 is rather robust.