when elcheapo scooters go BOOM!

hi guys... i was talking to this diver about his el-cheapo scooter that went boom on him on the first dive and here is a write-up about it http://dive.landfeldt.com/. SCROLL down to "scooter" to click the link

in the meantime, ive given him my seadoo scooter (refer home page for pic of it) that i won down here as its been sitting in the lockup for months unused and so far so good with not blowing that one up also

on sunday he retrieved the missing battery

wow, just wow!

heheheeh - i know its a pool toy compared to the stuff you guys use but BOOM underwater is not good!!!!

almitywife:

heheheeh - i know its a pool toy compared to the stuff you guys use but BOOM underwater is not good!!!!

Click to expand...

Interesting story. Sounds like the battery was offgassing hydrogen, or reacting to something in the motor compartment. Spraying things like WD-40, or additional lubricants would be a no-no in a scooter.

X

Saltwater leak+battery=hydrogen

Sounds like it it initially flooded, which means it stopped, then the hydrogen generation from the battery + saltwater partially cleared it for it to run, then, when the gas mix reached to the motor bang!

On my cheap scooter you need to make sure the pop lug is secured properly (the screw in plug that allows you to pump air in to pop the sealed upper internal casing off). Also, these will not take any rough handling and tend to crack along the fin causing an instant leak into the motor and battery area.

Luckily mine did it in fresh water so there wasn't the electrolytic reaction (at least not as much) as would have been in salt water. It just stopped working and got really negative as far as buoyancy (usually I leave it positive so it will float up)

Mike

Batteries off gas hydrogen in use and when charging. A good quality gell type battery wll not normally produce much hydrogen unless drawn hard or charged fast, over charged. If you look on a SEALED gell cell you will see small vents. Guess what comes out of those vents! Yep, your little pool toy scooter is a mini Hindenburg. My Tekna has a history of exploding. It has a light inside the battery case--and you charge it assembled which means either hit the light button or when you connect the charger--boom! I have modified my Tekna to prevent such things and of course they at least had and have hydrogen absorbant that gets changed out yearly. Now, scooters generally don't have an internal light, they are charged with the top shell off and they have a motor that is sealed from the battery compartment. They use batteries that generally don't produce hydrogen in normal operation and they use absorbant. This generally eliminates explosive possibilities. Those Chinese/Taiwan made scooters may not meet these standards.

Dive lights can suffer the same fate, hydrogen off gassing of a bad battery pack and a spark--kaboom. There was a thread on scubaboard recently where a hand held light exploded I think it was.

N