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tim-prophit avatar image
tim-prophit asked

Argofet isolator connection, Alternator output wire

Per instructions that came with Argofet battery isolator. I ran a wire from the alternator output to the isolator. What was not clear in the instructions is, should the old (original) output wire be disconnected from the alternator, or, remain connected. Thanks for any assistance with this.

Argo FET Diode
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2 Answers
michaeld avatar image
michaeld answered ·

@Tim Prophit

Yes, assuming the original output wire connects to your starter battery. Disconnect it from the alternator and connect it to one of the argofet outputs. The other output connects to your house bank.

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tim-prophit avatar image tim-prophit commented ·
I believe the original alternator output connects to starter. I now have an output wire from alternator connected to input of Argofet isolator. To clarify your response, are you saying I need to disconnect the original alternator output wire from the alternator, and connect it to one of the Argofet outpts?

Thank you.

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michaeld avatar image michaeld tim-prophit commented ·

Your alternator was originally connected to the starter as that's the closest (and chunky) connection to the starter battery. The only cable connected to the alternator output should be to the argofet input. One of the argofet outputs will go to your leisure batteries, and the other to your starter battery. Since you already have an existing cable connected to the starter battery (alternator to starter) you could use that as the argofet starter battery output to make life easier. So in answer to your question, yes :)

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tim-prophit avatar image tim-prophit michaeld commented ·
So, I just wired it up, exactly as you described. Here's my problem. Even with the battery selector switch turned to the off position, my distribution panel is still getting power. To confirm I extended the old alternator output wires and connected them to the output of the starting battery. My concern is that the starting battery will be going to the distribution panel, as well as the house batteries, when they are switched on. This will drain my starting battery. Please advise because I don't think this solution is right. Thank you.

To be specific, the one alternator output wire goes to the Argo fet input. The old alternator output wires were extended, and connected to the Argo fet output of the starting battery.

Any suggestions you may have to correct this would be much appreciated. I need the ability to turn the batteries off. Thank you.

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tim-prophit avatar image tim-prophit tim-prophit commented ·
More detail. There was an orange 8 gauge wire and a green 12 gauge wire that were part of the original alternator output. When I connect only the green to the Argo fet starting battery output I do not get power to the distribution panel. If I connect the orange, I do get power to the distribution panel. I hope this helps resolve this. Thank you
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michaeld avatar image michaeld tim-prophit commented ·

Could you draw a diagram of your setup (including any switches) and/or take some photos of the back of the alternator? The smaller green wire usually runs to the charging warning light to excite the alternator when the ignition is on, but colours vary from install to install. That one should stay as is.

I wonder if you have a 1/2/both switch that is connecting the battery positives together? These were common in installations before split charge relays/FETs came in. When I redid my setup I had to replace it with separate isolator switches for the starter and house batteries, as the argofet is the only device that should be connecting the positives together.

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tim-prophit avatar image tim-prophit michaeld commented ·
I do have a 1 2 both switch. 1 is House, which is 2 LiFePo4 batteries wired in parallel. 2 is Start, a single AGM battery. Batteries will be on either 1 or 2, only, except when passing Both, to change from one to another. The excite or energize wire is a blade plug, and is connected from the alternator to the energize connection on the argofet.

Knowing this, do you still need photos?

Thank you.


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michaeld avatar image michaeld tim-prophit commented ·

Understood. I would lose the 1-2-both switch if I were you, as the argofet does its job to combine the batteries when charging. You could include a single switch between the two battery positives if you ever needed the house batteries to jump start, though with lithium batteries the high currents from cranking the engine could cause the BMS to trip. In that case maybe keeping a small mains charger on hand to top up the starter battery would be a better idea.

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tim-prophit avatar image tim-prophit michaeld commented ·

Back of alternator. New orange wire goes to Argofet input

20230306-123522.jpg

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tim-prophit avatar image tim-prophit michaeld commented ·

Orignal orange and green wires run to this harness connector 20230306-124004.jpg

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tim-prophit avatar image tim-prophit michaeld commented ·

Other end of harness goes to cockpit controls

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tim-prophit avatar image tim-prophit michaeld commented ·

Cockpit controls20230306-124214.jpg

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tim-prophit avatar image tim-prophit michaeld commented ·

White wire from harness to solenoid, small nut. Red fused wore from harness to solenoid, big nut. Another fused red wire from solenoid, big nut, to distribution panel. Lastly large reg from starter solenoid to battery switdh20230306-124114.jpg

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tim-prophit avatar image tim-prophit michaeld commented ·

20230306-124105.jpgOne more view starter solenoid

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tim-prophit avatar image
tim-prophit answered ·

Thank you. This is for a battery conversion/upgrade on a 45 year old sailboat. From alternator to batteries/isolator requires 18' of wire, so I wanted to be sure. Thank you for your very helpful response.

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michaeld avatar image michaeld commented ·
No worries! I'm on a narrowboat so space is scarce and everything's in an odd place, so well used to it :)
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