I am thinking about installing low voltage landscape lighting (12v). I
learned of voltage drop in that light bulbs further away from the
transformer will be dimmer than ones closer to the transformer.
The solution is to try and set up your lighting runs such that
clusters of fixtures are sufficiently close together so that the
voltage differentials are small.
My question is would it be possible to also vary the wattages of the
light bulbs on the same run to even out the light output. For example
I would place a 20w bulb close to the transformer. And then further
down the run I would put say a 50w bulb. The 50w bulb would have lower
voltage, due to the power transmission losses, but would draw more
current and hence get to the same light output.
Has anyone tried this? Or is it that in practice it is very difficult
to get the light outputs to match well.
That would be the case if the lights were wired in series. But if they
are wired in parallel, each light bulb would get the equivelant
voltage the power supply is capable of. The power rating of the power
supply you get depends on how many bulbs you intend on using.
When I did mine, I ran the wire as a big loop with both ends connected to
the transformer (don't get the ends mixed up). That effectively doubles the
current rating of the wire and halves the voltage drops making for more
In a slight variation, you could feed one of the wires at the 'near' end
(the other wire not connected at the 'near' end). Feed the other wire at
the 'far' end. All bulbs will be the same brightness.
If the bulbs are run in series, the current through each bulb is the
same. If the same type bulbs are used, each will be the same brightness.
Wired in parallel, the voltage at the far end is lower because of
voltage drop along the wire as the OP said.
Not true. While the current is the same, the voltage across each bulb
will not be the same because of the voltage drop across each bulb.
I think you have your series and parallel circuits mixed up. You will
definately have a lower voltage at the far end if you wired the bulbs
in series, but if you wire them in parallel, and assuming you use a
heavy guage wire and a high KVA power supply, you should get little or
no voltage drop at the far end.
Think out what you're saying. In series the bulbs will be the same
brightness. This statement is dead wrong: "You will definately have a lower
voltage at the far end if you wired the bulbs in series"
"Same type bulbs" means same resistance for each bulb. Same current
through same resistance means same voltage drop across each bulb. Same
current and same voltage at each bulb means same wattage at each bulb
and same brightness.
If the near end bulb gets the same voltage, increasing the power supply
KVA has no effect on voltage drop between ends.
If you use a superconductor there will be no voltage drop at the far
end. The OP asked a question about the wire he was likely to use.
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