Batteries not dead?

[swimmer_spe]

I have a UK C8. I had it on for one dive, then forgot to shut it off for our surface interval. When I went to use it, the light was dead. Since it was during the day, it was not so bad.

I shut it off, and dove. I got home several hours, and turned it on, and it is fine.

What the?

 

[dfx]

Most likely it won't burn for very long after this. A battery goes seemingly dead once it's no longer able to supply either voltage or current required (under sustained load) to make the light burn. It doesn't necessarily mean that there's absolutely no charge left in it. If left alone for a while, it has time to regenerate a bit, voltage comes back and it's able to produce some current again. But once you put load back on it again, it's gonna die again very fast. You may be able to squeeze some more out of it if you reduce the load, i.e. turn on the light to a dimmer level.

Temperature also makes a difference. Cold batteries are less able to produce voltage/current than warm batteries. If you warm up a seemingly dead cold battery, it comes back to life for a little while. Another possibility is effects between multiple cells in a system (i.e. if your light uses not only one battery, but several) when some cells go dead sooner than others.

 

[Bob DBF]

Depends on the light, if it is a multiple battery C or D cell on their first use it should not be run dead that fast. The owners manual or online you should find the run time on a set of batteries in your light. Should the batteries be the ones included with your light when you bought it, change them out, I have rarely seen a set of included batteries that were quality products. If the run time is longer than your dive, check all connections and insure they are all clean, including the batteries themselves, and check that there is sufficient tension on the battery spring(s). Also check the lamp itself, if it is incandescent, it can be an intermittent failure before it quits. After this, it is warranty work or a DIY find the bad connection project.

Good Luck


Bob
-------------------------
There is no problem that can't be solved with a liberal application of sex, tequila, money, duct tape, or high explosives, not necessarily in that order.

 

[300winmag]

Most likely it won't burn for very long after this. A battery goes seemingly dead once it's no longer able to supply either voltage or current required (under sustained load) to make the light burn. It doesn't necessarily mean that there's absolutely no charge left in it. If left alone for a while, it has time to regenerate a bit, voltage comes back and it's able to produce some current again. But once you put load back on it again, it's gonna die again very fast. You may be able to squeeze some more out of it if you reduce the load, i.e. turn on the light to a dimmer level.

Temperature also makes a difference. Cold batteries are less able to produce voltage/current than warm batteries. If you warm up a seemingly dead cold battery, it comes back to life for a little while. Another possibility is effects between multiple cells in a system (i.e. if your light uses not only one battery, but several) when some cells go dead sooner than others.

^^^Exactly what I was going to say^^^