lithium battery or charger makes a snapping noise?

[Admin]

I was charging my lithium battery but after a loud snapping noise the charger gives a flashing error message . . . there was no smoke and nothing felt even remotely warm. It now refuses to charge again.

setup:
wall-wart 12V power supply connects to a E-flite lithium battery balance charger

the balance charger is rated from 11.5V to 15V input, for a 7.4V and 0.5A output

the lithium battery is 7.4V and 900mAh

I've normally used a normal power supply to power the charger with no problem in the past. This is my first time using the crude wall-wart charger.

I don't currently have a multimeter as I'm traveling a lot, so can't verify any voltages on any of the components.

Other than that, anyone have any ideas?

[pomprocker]

Is it a regulated or unregulated power supply?

[Razor Concepts]

Is the wall wart that came with the charger or a different one? Usually the stock charger and wall wart are fine, no problems with them.

[Admin]

Its an unregulated power supply wall-wart that I bought off the street in Bangkok.

It has this little dial that lets you select the output voltage from 3V to 12V.

The balance charger came with my RC helicopter.

I really need to get a multimeter . . . but they are really expensive and low tech/quality here . . .

[Trumpkin]

I have one of those kind of wal-warts and they aren't very accurate. I measured mine with a multimeter and it was off by about 1 volt.

[pomprocker]

yeah I have a 9vdc unregulated wall wart that puts out around 14vdc, so be careful

maybe regulate it on a breadboard with the LM317, caps, and a pot

[HDL_CinC_Dragon]

Does it make the snapping noise every time you power it up or did it do it once and then just died basically?

Sketchy power supply source + sketchy variable power supply = you fried something. Thats my opinion anyway

I would assume you killed a control IC. I did the same thing to a computer PSU that I was modifying to be a bench top power supply. Accidently shorted the 5vdc trigger wire to the 120vac line destroyed the IC but I couldnt tell. There was no smoke what so ever and there was also no visible damage to the IC. I looked up the datasheet on the IC that was closest to the trigger wire and found out it was the power cycle changer thingy...(basically responsible for telling the PSU to let the juice flow). I found another PSU that used the exact same IC and just swapped the IC out and it worked perfectly fine after that. The IC was an 8 pin IC that looks exactly like a 555.

Hope this helps at all.

[paulstreats]

Most wall warts these days have the output jack polarised the same way, but about 10 years ago it was different. Sometimes the inner part was +ve and sometimes it was gnd. Universal ones were created with a switch back then in order to change the polarity depending on the device it was used for. Maybe you picked up a cheap one that used opposite polarity for the charger application. (I plugged a battery in the wrong way the other day and the voltage regulator made a snapping noise and needed replacing)

[Admin]

yeah I have a 9vdc unregulated wall wart that puts out around 14vdc, so be careful

That's what I'm thinking/worried happened too. I would have tested it before using it if I had a multimeter . . .

Maybe you picked up a cheap one that used opposite polarity for the charger application.

I tested the polarity using an Axon so that's not a prob. The wall-wart actually has a polarity changer too!

I'm worried that the battery exploded, or that the charger had an IC pop . . . The charger seems not not be fried as it takes a few seconds to give an error light.

I guess my question was does anyone know if a snapping sound is common for a failed lithium battery?

[want2learn]

A lipo I fried about 18 months ago went kinda pop/snap but it was obvious that one was knackered because the pack had bulged.
The noise was like a snap at low bass levels. Dunno if that made sense?

[Admin]

There is no obvious damage to the battery . . . but if you also heard a pop noise when yours failed, then my battery is probably dead too.

(it was a Tenergy battery)

As soon as I get a multimeter I'll report whether my power supply broke it, or if it was a bad battery . . .

[want2learn]

I wouldn't write off the battery just yet, check it when you get the chance. It may be something inside the charger.

I fried my battery through stupidity. I designed and built a charger and didn't test it before hooking up the battery.
Turns out my maths was a bit off. I charged the cells at 10C for about 10hours (instead of 1C). The over temperature protection didn't work either because I hadn't soldered the connector on the panel to my pcb.

Not one of my proudest moments but now I try to make sure I triple check everything.

[Razor Concepts]

(it was a Tenergy battery)

Aha, there's youre problem. Generally tenergy batteries are crap. Many people have tried their nimh batteries, and they tend to overheat and die very quick. Your charger might even be perfectly fine, just the Tenergy battery died out. I would get a Rhino or Zippy at www.hobbycity.com, they have the cheapest prices and the quality is great.