Flashlight using 9V battery?

On 12/4/2009 7:22 PM Yong Huang spake thus:

Never seen one myself, though such things probably exist. Old-school (i.e., incandescent) flashlights tend to use 2-3 cells, and almost all the newfangled LED lights I've seen use 3 cells (4.5 volts) for some reason.

Hey, maybe you could put 2 LED lights in series and use a 9-volt battery for them ...

Here's a couple of sources. There are others...

Yong Huang wrote in news:f987613f-8232-4d68-a5d8- snipped-for-privacy@o10g2000yqa.googlegroups.com:

Don't forget to take the battery out of the flashlight before putting the battery in a vise to squeeze the last of the juice out of it.

Smitty Two wrote in news: snipped-for-privacy@newsfarm.iad.highwinds-media.com:

Technology...I tell ya, it's killin' me.

I think you might get better results if you used a #70 drill but drilled through the post at a 50 degree angle. This way the venturi effect multiplies the force of the centrifugal accelerator, the #60 drill is for the linier accelerator.

One thing I have not seen mentioned is that AA batteries do not last too long in many cameras before they do not have enough power left to work the camera. A camera needs a short, high power burst to actually take the pix. The batteries will power other devices long after they will not power a camrera.

Most devices using a 9 volt battery will drain them at a low, slow discharge and when they are 'dead' there is almost no power left in them.

"Ralph Mowery" wrote in news:h-SdnfC_UKM6PIfWnZ2dnUVZ snipped-for-privacy@earthlink.com:

the electronic flash is what draws the most power. so,if you don't need flash,keep it off.

Many digital cameras have an LCD screen on the back. If your camera also has a regular viewfinder, shutting off that LCD can save a lot of battery life, too. It probably draws as much or more than the flash.

I'll second that. After 40-some years of using a real camera, I feel lost without a viewfinder to squint through, so I always change the default setting to keep the LCD off except when using menus or reviewing pictures.

-- aem sends...

Ralph,

Are you saying the 9 volt batteries that stop working on my smoke detector or multimeter won't have enough juice either to power an LED flashlight? I'm about to order one from Amazon as Bob suggested (in message #3)?

Yong Huang

Check the 9 volt cells with a VOM. Below 8 volts, they don't have much energy left.

Yes, I am. The multimeter takes very little current to operate. When the battery will not operate it about all the power is used up. Unless you use a multimeter a lot almost every day you probably will not be replacing too many batteries. I have several meters at home and at work. I don't use them that often and the batteries probably only get replaced every year or so. By then even if they are still good enough to operate something, I thik they are old enough to throw away before they leak out the chemicals. I have thrown away a few flashlights because of leaking batteries that were several years old.

If you're leaving the batteries in your smoke detectors until they actually quit working in it, you've got bigger problems than too many flashlights! Generally the safety folks recommend replacing your smoke detector batteries annually, or even twice annually; at that level, they should have lots of life left in them for LED flashlights.

(I would characterize smoke detectors as using the batteries to maintain a static bias charge over the ionization chamber, with very little current draw, except when the unit is actually alarming. )

Chip C Toronto

item 1420391 - led flashlight head attaches to standard 9 volt cells

paul