Dive Lights 101

I probably have enough lights with enough problems so that someone besides me would benefit from answers to my issues.

all 21 watt HID: old old Sartec, 2 Halcyon and 1 Salvo.


One battery stayed real hot today up to an hour after charging: bad battery, bad charger?
One light seems to be getting dim: bad bulb or battery
how do you test the battery to see if OK? Burn time? voltage?
put a voltmeter on two batteries today at site and read abt 8 volts
One charger doesn't light up but seems to be working at lease some: how well i Don't know
how do I test a charger?

I think I can get my hands on a light meter to reference compare.

Keep in mind my expertise is in regs, not lights, but this is what I'd do:

Hook up each battery to its charger and monitor its progress with a digital volt meter. Then place each light head in a bowl of water and burn test it, again monitoring the battery with the meter. This should give you an idea if one or more component is awry.

Several cycles should tell you what is suspect.