Quote: (Originally Posted by
jaap)
What sort of batteries are used? Alkaline C type cells?
Looks like they can generate quite a lot of gas on a deep discharge:
Energizer Design Considerations - Hydrogen Generation
They abusive charge value really looks scary!
Thanks for that link
yup C cells.
given the volumes in the battery compartment that much off gassing (assuming normal deep discharge) would result in roughly a 3 times increase in the internal pressure. I suspect the design can handle an internal delta P of 2 bar though but without doing a FEA on the design can say for certain as its not a simple shape internally. Given that it can handle a delta P of 20bar or more from outside I suspect battery off gassing was not the cause although of course that doesnt necessarily prove anything when pressure gradient goes the other way
pic of offending crack
- guess i must have twatted it at some stage (read: dragged it up side of some cave)
the newer models dont have wetswitches, [the bottom one looks to be the initation sight of the crack (perhaps from contact with something) ] so newer models should be more robust. (I have never dropped the unit - only a bit of light dragging)