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Re: 2000 Sienna max size of power inverter
On Fri, 14 Jul 2006 11:33:12 -0500, JC <jstcn@coax.net> wrote:
[color=blue]
>What is the maximum size of a power inverter that I can use on a 2000
>Sienna with a stock alternator? I have a 400 watt power inverter that I
>want to use to power a laptop for my daughter to watch video's on. The
>last thing I want to do is damage my electrical system while on the road.[/color]
The alternator should be able to handle another 400 Watts during the
day with no problem, because your headlights are off. You could end
up in a bit of a power deficit if you are in stop and go driving at
night, with the lights on and a lot of idling - the alternator doesn't
give full output unless the engine is above 1800 - 2200 RPM.
Where your problem will hit first is at the cigarette lighter socket
- don't use it. Lighter sockets are usually supplied with small wire
and fused rather small, around 10 to 15 amps (140W to 210W), and that
400-watt inverter can easily draw more than that at full load. And
lighter sockets have a thermal fuse inside, if you draw full power for
too long you'll pop it. And the thermal fuse is not serviceable, you
have to replace the whole socket.
If you have an "Accessory Power" socket in your car, great - if not,
go get the kit at an auto parts store (socket, dashboard bracket,
heavy wire, fuseholder and fuse, crimp terminals) and install one.
They are usually designed for 25 amp (350W) or 30A (420W) loads, and
they are fused, but it's a regular fuse where you can get to it.
Okay, you've installed an accessory power socket. Now that you've
gone through all that - you still aren't using the right power supply
device. ;-)
You have a lot of inefficiency when you turn 13.8V DC into 120V AC
(one conversion loss) then the laptop power supply converts the 120V
AC to 14 to 18V DC (second conversion loss). Each conversion can lose
10% to 40% of the incoming power to heat and/or transformer losses
when going to AC, so that second conversion really hurts...
Go get a dedicated laptop converter from Targus, Kensington, Go
Power, or the like. Make one conversion directly from the
alternator's 13.8V DC to the laptop's filtered 14~18V DC.
You still need the Accessory Power socket, you'll just cut the load
on it by an amp or two. And on a car, every single amp counts.
--<< Bruce >>--
--
Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop
Electrician for Westend Electric - CA726700
5737 Kanan Rd. #359, Agoura CA 91301 (818) 889-9545
Spamtrapped address: Remove the python and the invalid, and use a net.
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