Does anyone near Bracknell, Berkshire have an old Salvo battery NiMH i can test?

[jb2cool]

My 21w Salvo HID has cut out on a few dives recently, i think it's just the battery being old (very old) but before i go ahead and buy a new battery from Strikalight i'd like to be confident this is the cause and it's not the balast or cable.

[Woz]

It's just 12V you can use any battery for a test.

[Steve Clark]

It's just 12V you can use any battery for a test.

Just be super careful with the polarity - there is no protection in the HID head.

[jb2cool]

Thanks both, in that case i don't think it is the battery (voltage looks fine) but in fact more likely to be the bulb or something else like ballast. Will have a think about my next steps, is it time to stop keeping this torch going and move to a more modern technology.

[Steve Clark]

If it’s the cable, it’s most likely a failure directly above the gland on the pack. Give it a wiggle whilst it’s on. I’ve fixed mine once by shortening the cable by a couple of inches and re-soldering in the lid.

Asssiming it’s a Nimh pack, they start at 13.5-14v when fully charged and then run at about 12.5v for 4hrs (9Ah / 21w) and then suddenly tail off and the light goes out. They will then recover to above 12v but quickly die again. Just because it reads 12v when open circuit, it may still be on the way out. I had one that was barely lasting an hour before I chucked it out.

[jb2cool]

Can i rule out the battery by attaching the charger directly to the canister head (and thus the switch/cable/ballast/bulb or is that stupid?)

[Nickpicks]

Can i rule out the battery by attaching the charger directly to the canister head (and thus the switch/cable/ballast/bulb or is that stupid?)

The charger may not be able to provide enough current to run the head - most chargers "trickle" charge.

You could rule out the battery by charging it, then connecting it to a car headlamp bulb and measuring how long it lights for, converting the hours x watts / volts to amp-hours.