DiveRite HID

[RedBarediver]

Hi all,

I have an old DiveRite HID Wreck Light that I plan to use as a cave diving light (or rather a backup cave diving light). It's small enough so that it won't be too hard to carry along with my regular primary and two small backup torches. I have it lying around in my parts box and I might as well use it. I have the correct charger for it as well.

However... a while ago I took it diving and it lasted all of two minutes into the dive before it quit on me. I figured that water must have gotten into it and completed the dive with a different light. Since then I have;

1. Taken it apart and checked for water ingress - dry as a bone. Not a drop of water got in anywhere.
2. Recharged it and checked the battery with a multimeter (I have two batteries for it). No issues there. Both batteries read 12 volt (or very close to it (11.9 V)
3. Figured the bulb may be bad - so bought a new bulb
4. the ballast may be bad - so bought a new ballast

Nothing seems to work to get it back to a working state. I bypassed the switch on the battery pack and checked that power is delivered to the ballast - no problem. Ballast receives 12 V. I have not been able to check what voltage reaches the lamp yet but the ballast I have is brand new and I doubt there is a problem with that. Does anyone have any experience with a HID divelight that can point me in the right direction?

I don't have all the details with me now but can take pictures of the ballast, the bulb and the whole setup tonight or on the weekend if that will help?

I am reluctant to dump the light completely just because I'm an idiot with two left hands and would rather get it working again. A decent extra cave light can make the difference between having to call a dive and turn around when one primary light fails, or being able to continue and still have a primary and two backups.

I would appreciate any wisdom you can throw my way.

 

[XeRay]

Possibly the batteries cannot provide enough current for starting, the voltage drops too low under the starting load.

 

[RedBarediver]

Interesting. How high would the start voltage have to be in your opinion? I wouldn't have thought it could be that much higher than 12 volts as the cell doesn't really hold more than 12 volts (I presume).

Complete newbie to this stuff so I'll be asking all sorts of daft questions. Hope you don't mind.

 

[badtziscool]

Interesting. How high would the start voltage have to be in your opinion? I wouldn't have thought it could be that much higher than 12 volts as the cell doesn't really hold more than 12 volts (I presume).

Complete newbie to this stuff so I'll be asking all sorts of daft questions. Hope you don't mind.

I don't think it's a matter of whether the batteries can provide over the 12v they're rated for, but more like, how low does the voltage go when there's a load on the batteries. You can measure the voltage of the batteries at rest and it will be at 12v, for example, but as soon as you put a load on it, it may register 10v. In general, the older the batteries are, the lower the voltage will sag when there's a load and I think that's what XeRay is asking about.

 

[XeRay]

Exactly right, thanks for answering him. The ballast has a minimum voltage requirement as well.

 

[RedBarediver]

Thanks, that makes sense. I don't know how old the batteries are (one is definitely very old but the other is a more recent replacement). I'll have a play around again with it on the weekend and will see if I can measure anything sensible.