Dell has today announced the recall of more than 4 million laptop batteries over fears that they could overheat and start a fire.

There may well have been some data quality issues involved in the manufacture of these batteries (by Sony), but what concerns me is the opportunity for error when checking whether a battery is potentially dangerous or not.  Here’s a shot of the label on my own laptop battery:

Can anybody tell me how many times the number and the letter O appear in the code?

[click on the picture to expand it]

I was so uncertain that I tried a number of different permutations, with the following results:

Based on past experiences there is enormous potential for a significant number of these 4 million batteries to be left in circulation.  The website appears to offer no validation of the data entered whatsoever – you can type in anything and it won’t complain.  This is no way to handle a safety recall, especially when the product labelling is so ambiguous.

For anyone that isn’t squeamish, you can read a true story about how a laptop can get too hot to handle at The Register.