Date: Tue, 5 Sep 2006 18:48:28 +0000
Reply-To: dhaynes@OPTONLINE.NET
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <dhaynes@OPTONLINE.NET>
Subject: Re: inverter lighter plug cable?
In-Reply-To: <11145424.1157469038982.JavaMail.gbourne@brunch.mit.edu>
Content-Type: text/plain; charset=us-ascii
Although inverters seem like simple devices, especially with their low cost, they are actually complex in thier design and it is difficult for them to do what they do. They do not ever simply pass current through. Old inverters consisted of a switching circuit to make pulses, and then used transformers to step up the voltage. New technology basically uses amplifiers, high speed switches, and voltage doublers to set up the voltage and ten make an"alternating" current. For them to maintain both the voltage and frequency, minimum input needs must be meet. This is where voltage drops and poor battery performance get in the way. Most inverters need a minimum of 10.5 to 11 volts, under load in order to work. They protect themselves and the equipment plugged into them by shutting down if the input voltage is not sufficient. This is a necassary evil.
The stock wiring is adequate for the designed loads. The factory cigarette lighter socket is designed for short term use and the wiring is only good for about 5 amps. That 150 watt inverter really needs 15+ to do the job. I would supply this with #12 wire, as short a run as possible to the battery and ground. If fully loaded, a 60 amp/hour battery will fade in ~ 3 to 4 under this load. Being a cheap inverter makes things worse. In the long run, you sort of get what you pay for.
I hope this answers your questions.
Dennis
----- Original Message -----
From: Joy Hecht
Date: Tuesday, September 5, 2006 11:16 am
Subject: Re: inverter lighter plug cable?
To: vanagon@GERRY.VANAGON.COM
> Hi Dennis (or anyone else),
>
> Would a 150 watt inverter also need to be plugged into something
> other than the cigarette lighter? I've got such an inverter -
> priced at $50 (Canadian) at Canadian Tire, though on sale for
> $15 - bought in an emergency when my puny 75 watter from Walmart
> blew out and I needed to be able to charge my computer. I've
> run it alternately on the lighter or on the socket connected to
> my spare battery.
>
> It also has an annoying quirk. It seems to read the incoming
> current (from the battery) and if it's not high enough it shuts
> itself down and stops letting current through. It will always
> work when I'm driving, but if the engine is off it doesn't work
> unless the battery is pretty highly charged. Very annoying,
> since it's always running off my second battery, and it doesn't
> matter if it runs down!
>
> The brand is Eliminator, it's non-sinusoidal, has a little fan
> to keep itself cool - that will keep running even when it's not
> passing current through.
>
> Has anyone else seen this in an inverter?
>
>
>
> Joy
>
> ****************************************************************
> Joy Hecht
> and Matilda, 1989 Burgundy Vanagon
>
> For musings about life and the vanadventures:
> http://www.joyhecht.net
>
> ****************************************************************
>
> :::-----Original Message-----
> :::From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM]
> On Behalf
> :::Of Dennis Haynes
> :::Sent: Monday, September 04, 2006 10:39 PM
> :::To: vanagon@GERRY.VANAGON.COM
> :::Subject: Re: inverter lighter plug cable?
> :::
> :::A 200 watt inverter needs ~20 amps. It shouldn't be plugged
> into the
> :::factory
> :::cigarette lighter socket. Get some heavy duty socket and
> plugs and
> :::install
> :::proper, (12 gauge) wire and you will be surprised how much
> better that
> :::economy inverter will work. A good auto, Marine or RV store
> will have
> :::what
> :::you need.
> :::
> :::Dennis
> :::
>
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