Help needed on switch install for Inverter

**eazyrog** · 07-23-2004, 04:29 PM

Hi all

i've got fed up of going to the bloody boot every time i wanna turn the computer on via the Inverter so decided to run a switch to the front of the car.

Basically the Inverter has a samll on/off switch built into it, i want to remove this switch and extend the + & - cables inside the car and install a nice new looking switch.

So, i bought myself a switch and the connectors are different, the old switch has a simple red and white however the new switch has 3 connectors, they are labled as follows: Earth, Supply and Load, can you please tell me first of all if i can use this, if so what 2 connectors do i use and also what is the 3rd for.

Thanks guys.

**Jackso** · 07-23-2004, 04:38 PM

It is usually easier to leave the inverter switch switched to on all of the time, and then just switch the power that you supply to the inverter. Use a relay rated at the current you require.

As for your question, Earth is ground, supply is +12, load is the wire to inverter, thus most likely connection is to ground the earth, red from the inverter to the supply, white connected to the load (you should check with a voltmeter/test light the red and white wires. One of them will have a constant 12V on it all the time, the other won't. The one with 12V goes to supply, I'm guessing that it is the red wire.). You apparently have purchased a lighted switch, that is why there are those three connections.

**eazyrog** · 07-23-2004, 04:54 PM

Jackso,
Thanks for the quick reply, many thanks.
I decided not to run the master power cable to the front and use a relay for a fewreasons, here they are:
1, my main power cable is 4g and goes to a fused distibution box which then splits to a 8 g which geos directly to the inverter (its a BMW so all in the boot)
2, As the master cable is very thick would bo too much hassel to run it to the front.
3, i have no idea and no experiance with relays etc.
4, Just thought it would be a lot easier to open the inverter up, snip the existing swithc off and extend it.

You a corrent, the switch i bought has a light.

I have decided to bin the new swithc and just extend the red and white sires to the front and will use the existing inverter switch.

i'l also put in a little blade fuse in the red wire, any idea what fuse size i shoud use.?

Thanks mate

**fantomas** · 07-23-2004, 05:02 PM

Originally Posted by eazyrog

Jackso,

i'l also put in a little blade fuse in the red wire, any idea what fuse size i shoud use.?

use a multimeter to determine the amperage draw and find a fuse as close to that as possible

**eazyrog** · 07-23-2004, 05:05 PM

fantomas,

Thanks but dont have one of those and also would not know how to use it.

My inverter simply runs a HP EPC, this mini pc comes with a 19V AC Adaptor (like the ones that come with Laptops)
Its a Piii, 60gb disk, cd, and a usb GPS Mouse.

any ideas

**Defiler** · 07-23-2004, 06:37 PM

If you have a 300W inverter use a 30 Amp fuse if 350W use a 35Amp fuse.

**Jailer** · 07-23-2004, 06:49 PM

I presume the switch is the light up variety? Use the 2 wires from the inverter on the supply and load pins (which lead goes to which pin doesn't matter). The earth lead goes to ground.

**grahamrb** · 07-23-2004, 07:07 PM

There should be no need for a fuse in line with the switch if you are simply extending the current one that was in the inverter as it would only be using a very small amount of current as it would be switching the inverter on and off via a relay as well. The only sure way to tell how much current is running through the switch is to use a multimeter.

**Defiler** · 07-24-2004, 01:01 AM

Correct this would be for the + wire powering the inverter.

Originally Posted by grahamrb

There should be no need for a fuse in line with the switch if you are simply extending the current one that was in the inverter as it would only be using a very small amount of current as it would be switching the inverter on and off via a relay as well. The only sure way to tell how much current is running through the switch is to use a multimeter.

**eazyrog** · 07-24-2004, 07:42 AM

All done, thanks all, just extended the wires and also run a ground and installed the new switch with a light, looks great and now i dont have to open the boot, just put the system into Hibernate when i'm done and then switch it off using the new switch, when i turn it back on it powers up ready for use.

Thanks to all here once again.