Okay, then, if $170 is too much, how about $7.56 including shipping?Spehro Pefhany wrote:
On Tue, 04 Jan 2011 17:22:27 -0500, the renowned "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:
klem kedidelhopper wrote:
I have a 24 volt military truck that I use for snow plowing. In the
past I've had trouble finding 6000 series 24 volt sealed beam lamps
for the plow frame.. And when I did I have found them to be very
expensive. So I came up with a circuit using a DPDT switch in which
both the high and low circuit lamp filaments are wired in series when
power is applied. I was very careful to initially select two lamps
that drew exactly the same current when tested on my bench power
supply. The arrangement has worked flawlessly for the past few years.
The other night I had occaision to look at the lights from outside the
truck while it was running. Charging voltage on a 24 volt system can
run as high as 28 volts on a typical 24 volt system. Although I didn't
try to measure the voltage accross each lamp, I noticed that one lamp
is slightly brighter than the other on the low circuit. I'm assuming
that filament is getting weaker and thinner and will likely fail
shortly. And of course when that happens I'll lose the low circuit. I
can rematch two more lamps but before I do the thought occurred to me
if there was any practical easy way the equalise the voltage accross
both lamps in order to compensate for any minute differences in
filament resistance. I think that the total current, (two lamps in
series) is about 5.0 amps. Thanks for any suggestions. Lenny
How about a 24 V to 12 V converter to power the headlamps? National
Semiconductor makes the 'Simple Switcher' series of regulators.
You could also just buy a DC-DC converter.. 24:12 at 200W will run
around $170, in stock at Mouser.
http://www.meanwell.com/search/SD-200/SD-200-spec.pdf
Looks expensive compared to the raw components, perhaps, but I'll bet
most parts for your truck cost more than that.
There's enough adjustment range that you can set it to 13.8VDC or
whatever you think should be nominal. It will also run the lights at
full brightness with the motor off (at the expense of some battery
life, of course).
Probably, but it's 14 years old and I've not spent more than $100 in
repairs in the 3 years I've owned it.
Or this one for $11.72 shipped which is claimed to be 20AOn Mon, 10 Jan 2011 00:54:59 -0500, the renowned "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:
Spehro Pefhany wrote:
On Tue, 04 Jan 2011 17:22:27 -0500, the renowned "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:
klem kedidelhopper wrote:
I have a 24 volt military truck that I use for snow plowing. In the
past I've had trouble finding 6000 series 24 volt sealed beam lamps
for the plow frame.. And when I did I have found them to be very
expensive. So I came up with a circuit using a DPDT switch in which
both the high and low circuit lamp filaments are wired in series when
power is applied. I was very careful to initially select two lamps
that drew exactly the same current when tested on my bench power
supply. The arrangement has worked flawlessly for the past few years.
The other night I had occaision to look at the lights from outside the
truck while it was running. Charging voltage on a 24 volt system can
run as high as 28 volts on a typical 24 volt system. Although I didn't
try to measure the voltage accross each lamp, I noticed that one lamp
is slightly brighter than the other on the low circuit. I'm assuming
that filament is getting weaker and thinner and will likely fail
shortly. And of course when that happens I'll lose the low circuit. I
can rematch two more lamps but before I do the thought occurred to me
if there was any practical easy way the equalise the voltage accross
both lamps in order to compensate for any minute differences in
filament resistance. I think that the total current, (two lamps in
series) is about 5.0 amps. Thanks for any suggestions. Lenny
How about a 24 V to 12 V converter to power the headlamps? National
Semiconductor makes the 'Simple Switcher' series of regulators.
You could also just buy a DC-DC converter.. 24:12 at 200W will run
around $170, in stock at Mouser.
http://www.meanwell.com/search/SD-200/SD-200-spec.pdf
Looks expensive compared to the raw components, perhaps, but I'll bet
most parts for your truck cost more than that.
There's enough adjustment range that you can set it to 13.8VDC or
whatever you think should be nominal. It will also run the lights at
full brightness with the motor off (at the expense of some battery
life, of course).
Probably, but it's 14 years old and I've not spent more than $100 in
repairs in the 3 years I've owned it.
Okay, then, if $170 is too much, how about $7.56 including shipping?
http://www.dealextreme.com/details.dx/sku.36230
They also have 15A/20A for 14.89/16.42 including shipping.
I'd go for that in a heart beat. you could set it in series with the
On Mon, 10 Jan 2011 00:54:59 -0500, the renowned "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:
Spehro Pefhany wrote:
On Tue, 04 Jan 2011 17:22:27 -0500, the renowned "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:
klem kedidelhopper wrote:
I have a 24 volt military truck that I use for snow plowing. In the
past I've had trouble finding 6000 series 24 volt sealed beam lamps
for the plow frame.. And when I did I have found them to be very
expensive. So I came up with a circuit using a DPDT switch in which
both the high and low circuit lamp filaments are wired in series when
power is applied. I was very careful to initially select two lamps
that drew exactly the same current when tested on my bench power
supply. The arrangement has worked flawlessly for the past few years.
The other night I had occaision to look at the lights from outside the
truck while it was running. Charging voltage on a 24 volt system can
run as high as 28 volts on a typical 24 volt system. Although I didn't
try to measure the voltage accross each lamp, I noticed that one lamp
is slightly brighter than the other on the low circuit. I'm assuming
that filament is getting weaker and thinner and will likely fail
shortly. And of course when that happens I'll lose the low circuit. I
can rematch two more lamps but before I do the thought occurred to me
if there was any practical easy way the equalise the voltage accross
both lamps in order to compensate for any minute differences in
filament resistance. I think that the total current, (two lamps in
series) is about 5.0 amps. Thanks for any suggestions. Lenny
How about a 24 V to 12 V converter to power the headlamps? National
Semiconductor makes the 'Simple Switcher' series of regulators.
You could also just buy a DC-DC converter.. 24:12 at 200W will run
around $170, in stock at Mouser.
http://www.meanwell.com/search/SD-200/SD-200-spec.pdf
Looks expensive compared to the raw components, perhaps, but I'll bet
most parts for your truck cost more than that.
There's enough adjustment range that you can set it to 13.8VDC or
whatever you think should be nominal. It will also run the lights at
full brightness with the motor off (at the expense of some battery
life, of course).
Probably, but it's 14 years old and I've not spent more than $100 in
repairs in the 3 years I've owned it.
Okay, then, if $170 is too much, how about $7.56 including shipping?
http://www.dealextreme.com/details.dx/sku.36230
They also have 15A/20A for 14.89/16.42 including shipping.