Did I ruin my battery?

Factual Questions
1

I have one of those external batteries one uses to charge a phone or tablet. It’s actually rather old – I used to show it off as the newest, greatest gadget before everyone had these things. Anyway, it puts out 5v at 2.1 amps via a USB/A port.

My laptop charges via a USB/C port. (You know where this is going…) I have a USB/A -->USB/C cable. I attempted to power my laptop using this battery. I knew the battery would be inadequate for a full charge, but I thought it would be better than nothing.

At first, everything was fine except that the laptop was using more power than it was gaining (I was using the laptop, not just charging it). After about fifteen minutes, I noticed that the external battery was very hot and the case had deformed a bit. I disconnected the battery and it cooled fairly quickly.

What happened? Obviously, the laptop demanded more than the battery could provide, but why didn’t the battery just refuse or give all it had, then die? Is the battery still safe to use?

2

If it got hot enough to deform the case I personally would retire it with full honors. Battery fires are nothing to fuck around with and a replacement is not so expensive to be worth risking burning down your house over or blowing up your laptop.

3

Batteries are cheap. Retire it (Recycle safely!) and buy a newer one.

4

Presumably the battery pack lacks, or has faulty, current limiting and behaved like an old “dumb” battery which will heat up and break if used in a high current application. All batteries have internal resistance and the faster you drain them the the hotter they get.

5

I can’t add to this so I’ll just reinforce it; scrap the battery and get a new one. And don’t try to power your laptop from a battery that isn’t rated for the required current.

Stranger

6

Yeah, there are dozens available on Amazon starting at twenty bucks.

7

Yeah, although be aware that the market also contains abundant fakes, especially at the low price end - either in the simple form where the capacity of the device is massively overstated, or actual fakes where the casing contains weights to make it seem like it is full of cells, or some of the internal cells themselves are filled with sand.

8

So, based on the advice here, I have decided to recycle my battery. I have replaced it with this one from Best Buy. It appears to have the cajones to charge the laptop as well as keep my phone happy, too.

9

Here’s a particularly bad one. Only a 66mAh e-cig batt packed with flour for a 18650 cell:

10

(Has the OP been sufficiently answered to make jokes in FQ?)

At today’s food prices, I’d expect to buy a 5 pound bag of flour and find 3 pounds of batteries in it.

11

The same thought occurred to me. Why use useful flour instead of soil or scrap bean cans?