if you think the problem is vibration you can buy "ruggedized" bulbs at your
local discount department store. I bought one for the trouble light I use
when working on the car after a couple of the regular household bulbs went
out. the ruggedized bulbs cost a bit more.

Tom Best ) writes:
I would appreciate some help with a 12 volt question.

I set up a 7 light long string of 12 volt, 40 watt bulbs on a strand
of 12 guage, outdoor lighting, copper wire. The bulbs and bases were
standard Edison screw base types. The lights were connected to a 300
watt DC converter made for outdoor yard lights. In theory, I would
like to take the same string (with lower wattage bulbs) on sailing
trips.

In 4 days, 6 of the seven lights have burned out. One light continues
to burn at normal brightness.

Any ideas or comments on these failures apprecitated.

Thanks
Tom


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putting more lights on the cicuit will not change the maximum power output
of the converter. putting more lights on the circuit will mean less
current to each bulb once the total wattage of the bulbs exceeds the power
output of the converter. putting too many bulbs on the circuit will make
all the bulbs dimmer. perhaps it would damage the converter or blow a
safety fuse if there is one on the ciòcuit but it should not damage the
bulbs.

I suggest boatbuilders approach electricity using the water flow
analogy.


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William R Watt National Capital FreeNet Ottawa's free community network
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if you think the problem is vibration you can buy "ruggedized" bulbs at
your
local discount department store.
Yes, they work great. The Americans call them "Rough Service" bulbs.


(¯`·._.· £ãrrÿ ·._.·´¯)





"William R. Watt" wrote in message
...
if you think the problem is vibration you can buy "ruggedized" bulbs at
your
local discount department store. I bought one for the trouble light I use
when working on the car after a couple of the regular household bulbs went
out. the ruggedized bulbs cost a bit more.

Tom Best ) writes:
I would appreciate some help with a 12 volt question.

I set up a 7 light long string of 12 volt, 40 watt bulbs on a strand
of 12 guage, outdoor lighting, copper wire. The bulbs and bases were
standard Edison screw base types. The lights were connected to a 300
watt DC converter made for outdoor yard lights. In theory, I would
like to take the same string (with lower wattage bulbs) on sailing
trips.

In 4 days, 6 of the seven lights have burned out. One light continues
to burn at normal brightness.

Any ideas or comments on these failures apprecitated.

Thanks
Tom


--
--------------------------------------------------------------------------
----
William R Watt National Capital FreeNet Ottawa's free community
network
homepage: www.ncf.ca/~ag384/top.htm
warning: non-freenet email must have "notspam" in subject or it's returned

Thanks for the info. Small (important?) corrections and additional
info follows:

Seven bulbs in paralled and are 25 watts, not 40 watts. Resulting in
a total of 175 watts on a 300 watt transformer. However, one bulb
still burns at regular brightness.

The copper wire is 12 guage and stranded. About 30 feet long.

I though the low voltage yard lights were transformed to 12 volt DC
not 12 volt AC. Is that the issue?

Tom

"Tom Best" wrote in message
om...

I though the low voltage yard lights were transformed to 12 volt DC
not 12 volt AC. Is that the issue?

The light bulb would not care if it got 12 VDC or 12VAC.

It might help if you provided more detail on the "DC Converter".

Why are you using a DC converter instead of a simple AC transformer?

You said it was made for this so one would assume the voltage is correct,
but you should measure it anyway. Have the lights been on 24 hours a day, or
just a few hours each evening?

Light bulbs are rated in number of hours they can be expected to last. Some
light bulbs will last thousands of hours. Others, like a projector bulb for
example, may last only tens of hours.

Heat, shock and vibration are reasons for premature bulb failure. Some
bulbs are not rated to operate in an "upside down" position, as it will
cause the base to overheat. Make sure that the bulb is not being used in an
inappropriate application.

Perhaps if you told us exactly what bulbs you were using it would help. You
said they were in a screw base, are these the 12volt bulbs that are often
used in RVs or boats?

Rod McInnis

My apologies to all for bothering you with a stupid question. The yard
light converter converts from 120 V. AC to 12 V. AC. Not DC as I assumed.

I never would have guessed. Thanks for the help.

Tom


"Calif Bill" wrote in message
link.net...
Check the voltage. My Malibu is 12V AC from what I remember.

"Tom Best" wrote in message
om...
I would appreciate some help with a 12 volt question.

I set up a 7 light long string of 12 volt, 40 watt bulbs on a strand
of 12 guage, outdoor lighting, copper wire. The bulbs and bases were
standard Edison screw base types. The lights were connected to a 300
watt DC converter made for outdoor yard lights. In theory, I would
like to take the same string (with lower wattage bulbs) on sailing
trips.

In 4 days, 6 of the seven lights have burned out. One light continues
to burn at normal brightness.

Any ideas or comments on these failures apprecitated.

Thanks
Tom

Thomas,
your query remains as sensible as it did before you mentioned the AC
output. The lamps would have failed from overvolts (not much is
necessary!) or vibration - whether the supply was AC or DC.

Brian W

On Wed, 03 Dec 2003 00:33:11 GMT, "test"
wrote:

My apologies to all for bothering you with a stupid question. The yard
light converter converts from 120 V. AC to 12 V. AC. Not DC as I assumed.

I never would have guessed. Thanks for the help.

Tom


"Calif Bill" wrote in message
hlink.net...
Check the voltage. My Malibu is 12V AC from what I remember.

"Tom Best" wrote in message
om...
I would appreciate some help with a 12 volt question.

I set up a 7 light long string of 12 volt, 40 watt bulbs on a strand
of 12 guage, outdoor lighting, copper wire. The bulbs and bases were
standard Edison screw base types. The lights were connected to a 300
watt DC converter made for outdoor yard lights. In theory, I would
like to take the same string (with lower wattage bulbs) on sailing
trips.

In 4 days, 6 of the seven lights have burned out. One light continues
to burn at normal brightness.

Any ideas or comments on these failures apprecitated.

Thanks
Tom

Tom,

Nothing to apologize for. I tend to think that the AC in this case
would not harm the bulbs as Rod said. Do you have a multimeter that
you can use to check the converter to see what the actual output
voltage is? Also, where did you obtain these bulbs and what were
they marketed for?

-JimL



test wrote:
My apologies to all for bothering you with a stupid question. The yard
light converter converts from 120 V. AC to 12 V. AC. Not DC as I assumed.

I never would have guessed. Thanks for the help.

Tom

"test" wrote in message
...
My apologies to all for bothering you with a stupid question. The
yard
light converter converts from 120 V. AC to 12 V. AC. Not DC as I
assumed.

I never would have guessed. Thanks for the help.

Tom


AC/DC a light bulb doesn't know the difference. Remember the High
Intensity desk lamps? Tensor was a brand? A 12v AC supply and a tail
light bulb.

del cecchi

I would think it would be from excessive vibration if they were
originally for fixed service in the yard.
Agreed.

A good way to check for vibration is to set a dish of water near the bulbs,
rev up the engine while you observe ripples on the surface of the water.

I'd bet you'll see signs of excessive vibration at various throttle
settings. This is bad news for a hot filament (as you already know).


--
(¯`·._.· £ãrrÿ ·._.·´¯)



"Leanne" wrote in message
...

"Tom Best" wrote in message
om...
I would appreciate some help with a 12 volt question.

I would think it would be from excessive vibration if they were
originally for fixed service in the yard.

Leanne