KaBoom! Ya Think?

[wptski]

Just purchased an accessory LED light for a camcorder which comes with two Li-Ion 7.2V 2200mA batteries which are wired in parallel. It comes with a wall charger for one battery but the unit has a so-called charging port marked 7.4-14.8V DC and nothing mentioned as to the current rating needed.

I waiting on a dual-bay charger for convenience but charged them using a linear power supply. I had the batteries inserted and plugged in a 12V 500mA wall wart. I noticed it got pretty warm after a short use and unplugged it.

I rigged up a test with a two channel scope to read voltage and current. One thing is that it draws around 1400mA which is why my wall wart got warm.

I had fully charged batteries connected with various jumper wires. Unit OFF, a 12V 1500mA wall wart plugged in applies around 15V which is the no load voltage of wall wart to the batteries! I only did this for a few seconds of-course. It was only drawing 30mA at this time. I wonder if somebody not knowing about this left it charging dead batteries what would happen??? KaBoom in the night?

I did read one review on Amazon where the user stated that a battery blew up in his office and burned his carpeting.

 

[CuriousOne]

Link or pictures to device would be more informative. And there are no 7.2V lithium cells. If battery is marked such, it has 2 cells in series, not in parallel. As I guess, you have some video light, that uses Sony NP-F series battery clone Does your batteries look like this?

http://g02.a.alicdn.com/kf/HTB1pHhB...й-ионная-батарея-для-Sony-NP-F570-NP-F330.jpg

 

[wptski]

Link or pictures to device would be more informative. And there are no 7.2V lithium cells. If battery is marked such, it has 2 cells in series, not in parallel. As I guess, you have some video light, that uses Sony NP-F series battery clone Does your batteries look like this?

http://g02.a.alicdn.com/kf/HTB1pHhB...й-ионная-батарея-для-Sony-NP-F570-NP-F330.jpg

True, there aren't any 7.2V cells, cell means singular but batteries means a pack or more than one cell. Depending on the chemistry, they are either 3.6V/cell or 3.7V/cell. In this case these batteries are marked 7.2V although most any charger these days use 3.7V/cell as a standard or 4.2V/cell as a charging voltage which I used also.

Here's a video of some guy unboxing a unit, it should show what comes with it but I didn't watch the whole thing: https://www.youtube.com/watch?v=l31cYEUxnQ0