Darkbuster Battery

[webjester]

Hi all you darkbusters,

I have a 24W darkbuster with a 5200mAh battery. While the light output is just awesome the battery just died recently on a trip to Cozumel. I hadn't used it for several months. Technically it was already dead before I left.

The symptoms:
The light didn't switch on after having been on the shelf for a while. After recharging, which only took a few minutes(!) it burns for about 20 seconds. Then you can repeat the same cycle.

The findings:
I unscrewed the head and found the battery voltage at the connector to be 0V. After charging (again, only a few minutes) it goes to 11.6V and the light burns for again 20 secs after which the voltage drops to 0V again. However, the batteries measured before the internal control circuitry of the battery pack itself show that they are fully charged. So, apparently, the internal control circuit is toast and not the batteries.

Questions:
1) Did anybody have this problem?
2) Is this an indication that the battery pack is just too old (see batteryuniversity post 34 How to prolong lithium-based batteries)
3) Is the battery pack from darkbuster a special pack or just a standard 6-cell Li-Ion pack (HIDs have a high start-up current, which may be limited by standard packs)

I have quite a bit experience with automotive 35W HID (worked for a manufacturer) and built my own dive light with those and Li-Ion batteries. The output beat everything out there but after several dives to 130ft it took on water. I couldn't get the housing (made from 4in PVC pipes) sealed reliably.

Thanks

 

[deepstops]

A six cell Li-ion battery would have voltage of about 22v (3.7v each).
It's more likely to be a three cell pack.

 

[Packhorse]

No it will be a 6 cell pack of 2600ma cells. 2P3S giving 11.1v 5200ah.
They are probably 18650 cells in this configuration

 

[deepstops]

No it will be a 6 cell pack of 2600ma cells. 2P3S giving 11.1v 5200ah.
They are probably 18650 cells in this configuration

Perhaps I should have worded it as "two sets of three cell packs wired in parallel" since that's what you've described. That would be six cells total.

 

[Doubler]

Volts don't mean squat. Test the amps. I betting the battery is charging to 11 volts and about .01 amps. Do a flash test for amps. Charge up the battery, Set the meter to amps, connect it to the battery, turn on the light. If the amps fall off rapidly it is a bad battery.

 

[Blazinator]

Bummer to hear about your light. I love my Darkbuster. Got it wet inside once (cleaned gear with hose with the charging cap off) and simply replaced the inline fuse - very glad it had a fuse.

The light is so inexpensive, I figured that if anything went wrong, I'd just buy a new one - maybe a good option for you? I sure would like to see you fix it though.