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kristophertaft
Samba Member
Joined: February 13, 2011
Posts: 13
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 Posted: Sat Apr 10, 2021 4:59 pm Post subject: Power from the alternator? |
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I am wanting to connect my onboard ARB compressor to power so that it will only work when the engine is running. At 23amps under load I've killed a battery or two and want a connection that is fool proof - does not allow me or anyone else to run the compressor if the van isn't running.
I've consulted the Bentley but for some reason all my connection points seem to come up dry. I have an '87 Syncro Westy w/ a 2nd battery system and an old GoWesty 2nd battery relay. I thought the blue wire from the relay would give me the power I'm looking for but it doesn't seem to work. Can't I just run a wire from the back of the fuse panel?
Any help would be MUCh appreciated. |
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MarkWard
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Joined: February 09, 2005
Posts: 17105
Location: Retired South Florida
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| Posted: Sun Apr 11, 2021 5:09 am Post subject: Re: Power from the alternator? |
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Where is the pump installed? You can get key on power from the fuse box and from the ignition coil. 23 amps is a lot. I’m assuming you are using a relay?
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RGS Paul
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Joined: April 20, 2007
Posts: 663
Location: Los Alamos, NM
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| Posted: Sun Apr 11, 2021 6:07 am Post subject: Re: Power from the alternator? |
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One option would be to wire it directly to the primary battery with an inline fuse through a relay switched off the lug with the blue wire on the alternator. That would give you the highest voltage at the pump and is foolproof. That's how I ran the fan on my oil cooler (granted at MUCH lower current draw).
Paul
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'87 Syncro 7-Pass. Adventure Touring Vehicle
"Simplicate, then add lightness." Colin Chapman |
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kristophertaft
Samba Member
Joined: February 13, 2011
Posts: 13
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| Posted: Sun Apr 11, 2021 8:42 am Post subject: Re: Power from the alternator? |
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| MarkWard wrote: |
| Where is the pump installed? You can get key on power from the fuse box and from the ignition coil. 23 amps is a lot. I’m assuming you are using a relay? |
I bought GoWesty's ARB Compressor a bunch of years ago and the wiring harness that it came with has a relay. I've had it installed next to the water tank and previously had it run directly to house batteries, but now I'd like to have a more fool proof way to never draw down batteries.
I'm wiring this positive load to a fused bus bar that is under the driver's seat so I just need to be able to run the right gauge wire from the fuse panel to this load. I'm looking at the Bentley (97.104) and wondering where to plug in and what gauge wire is needed? |
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MarkWard
Samba Member
Joined: February 09, 2005
Posts: 17105
Location: Retired South Florida
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| Posted: Sun Apr 11, 2021 9:14 am Post subject: Re: Power from the alternator? |
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Without knowing what I am talking about. The supplied relay should have 2 leads that carry the pump load. Typically labeled 30 and 87 The other 2 leads operate a small magnetic coil in the relay that completes the circuit. They can be small gauge wires. Labeled typically 85 and 86. One lead is a ground to the chassis and the other would go to your key on power. Either lead can be switched to operate the compressor.
The campers had a factory relay pre wired and installed. It energizes by the alternator charging. That relay would be more than adequate to operate your pump. There are open slots on the face of the fuse box for key on power. A test light comes in handy for probing. Available slots vary van to van. There is also a fuse adapter for taking power from an H type fuse.
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