lctorana
Flashlight Enthusiast
I've just invented an entirely new Hotwire. It's cheap and simple.
The host:
Back last October-ish, I bought one of those 4D Osram poor-man's-Dolphin torches for $4.95 in a supermarket clearance. A silly whim, and even siller when I found it broken inside.
You can see it here http://www.osram.com.au/retail/pdf/torchesflyer.pdf under the name "Krypton Power". The OEM bulb is Osram's own peculiar-looking version of the familiar KPR113.
It's quite a nice looking torch, with a vaguely hand-mixer shape, metal clad head, and the nicest-looking bezel and refletor I've seen.
But with the positive terminals all smashed and unrepairable, I put it away, hoping for later inspiration.
The bulb:
RS Components sell a 12V, 15W, 450-lumen halogen bulb, cat no 370-3083, with a BA9s bayonet base.
The bulbholder:
**** Smith Electronics sell a very compact BA9s socket, cat no P8171, which, with a bit of filing and bending, fitted nicely in the bulb post. I thought of wiring in a 2.2 ohm NTC, but didn't bother in the end; I just hard-wired it, reasoning that 12V bulbs are probably made for automotive use and need to cope with the ignition on. All joints soldered easily.
The batteries:
12 x Varta "15 minute" 2Ah AA in 4 el-cheapo battery carriers. Current draw is less than 1.5A, so the holders should cope, and the extra resistance is welcome without the NTC. (These cells have been my hotwire battery of choice, under the presumption that since they are made to cope with 15-min charging, then logically, they must be able to cope with some discharge abuse. Nine more of them also power my Mag85.)
Note the 12V bulb is overdriven by supplying it with 14.4V or more, less wiring/contacts/switch voltage drop.
The verdict
As both the 15W and 450 claimed bulb lumen ratings would suggest, this is noticeably brighter than the 11W RoP low (and the RoD, too), and noticeably less bright than the 24W RoP high. But it's still very impressive, and a joy to use - it feels good in the hand, it doesn't weigh too much, and the soft-touch switch is a genuine forward clicky.
(Oh, and I noticed the Osrams in Bunnings last weekend for $5...)
Total cost - less than $30, not counting batteries.
The naff name:
Since the host retails under the name "Osram Krypton Power", I have christened this the "Halos" - "Halogen Osram"
The host:
Back last October-ish, I bought one of those 4D Osram poor-man's-Dolphin torches for $4.95 in a supermarket clearance. A silly whim, and even siller when I found it broken inside.
You can see it here http://www.osram.com.au/retail/pdf/torchesflyer.pdf under the name "Krypton Power". The OEM bulb is Osram's own peculiar-looking version of the familiar KPR113.
It's quite a nice looking torch, with a vaguely hand-mixer shape, metal clad head, and the nicest-looking bezel and refletor I've seen.
But with the positive terminals all smashed and unrepairable, I put it away, hoping for later inspiration.
The bulb:
RS Components sell a 12V, 15W, 450-lumen halogen bulb, cat no 370-3083, with a BA9s bayonet base.
The bulbholder:
**** Smith Electronics sell a very compact BA9s socket, cat no P8171, which, with a bit of filing and bending, fitted nicely in the bulb post. I thought of wiring in a 2.2 ohm NTC, but didn't bother in the end; I just hard-wired it, reasoning that 12V bulbs are probably made for automotive use and need to cope with the ignition on. All joints soldered easily.
The batteries:
12 x Varta "15 minute" 2Ah AA in 4 el-cheapo battery carriers. Current draw is less than 1.5A, so the holders should cope, and the extra resistance is welcome without the NTC. (These cells have been my hotwire battery of choice, under the presumption that since they are made to cope with 15-min charging, then logically, they must be able to cope with some discharge abuse. Nine more of them also power my Mag85.)
Note the 12V bulb is overdriven by supplying it with 14.4V or more, less wiring/contacts/switch voltage drop.
The verdict
As both the 15W and 450 claimed bulb lumen ratings would suggest, this is noticeably brighter than the 11W RoP low (and the RoD, too), and noticeably less bright than the 24W RoP high. But it's still very impressive, and a joy to use - it feels good in the hand, it doesn't weigh too much, and the soft-touch switch is a genuine forward clicky.
(Oh, and I noticed the Osrams in Bunnings last weekend for $5...)
Total cost - less than $30, not counting batteries.
The naff name:
Since the host retails under the name "Osram Krypton Power", I have christened this the "Halos" - "Halogen Osram"
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