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stocksy avatar image
stocksy asked

Argo which terminal for Alternator sense?

Hi, I've installed Argo FET split charger to charge my starter and 2 (separate) LFP banks. The Balmar MC614 Regulator states to place the Alternator voltage sense wire onto the largest bank if using a split charger, so in my case that would be the 400ah LFP bank.

Just a little concerned that this will potentially expose my starter to too much current and force it into a high voltage state.

I did think that using the MC614 Batt temp sensor on the starter battery might help. Other option would be to place the sense wire onto the starter battery, but then would that not prevent the LFP banks from charging?

Hope someone with a better understanding of this can help.

Thanks,

Michael

Lithium BatteryArgo FET Diodestarter battery
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kyleolmstead avatar image kyleolmstead commented ·

I am in the process of installing an ArgoFET as well and have the same question - where should I connect the sense cable on my alternator. I am not using a a regulator. Hopefully someone has an answer?

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kyleolmstead avatar image kyleolmstead kyleolmstead commented ·

Hi Michael, Did you get any other information on this? I have been occasionally getting 15/15.1 volts are my batteries (too high) when my batteries are full without anything connected to the sense terminal. My next plan is to connect the sense terminal to the house battery.

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kyleolmstead answered ·

I asked a marine electrician. I"m not sure of his familiarity with battery isolators, but this is what he said: "If you are going to connect the S terminal, it should be connected to the battery. The regulator will adjust the output from the feedback voltage at this input. It will compensate for voltage loss from the wiring and the isolator."


I'm going to try using the isolator without connecting the S terminal, and then connect it if it doesn't work.

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kyleolmstead avatar image kyleolmstead commented ·

Update. I installed my alternator, and with my alternator, it worked well without anything on the sense terminal. (There was previously something on the sense terminal.) It's a 51A Mando (Westerbeke) Alternator and I was getting 20 Amps out of the alternator in neutral.

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lehrling avatar image lehrling kyleolmstead commented ·

If you are seeing 20 amps it might be indicating the battery is not fully charged.

It would be wise to recheck your charging voltage to see what it is once amperage drops low.

If I had an alternator with a sense feature I would use it, and connect on the battery directly.

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kyleolmstead avatar image kyleolmstead lehrling commented ·

Thanks! The amps I'm getting sounds right. When the batteries are lower I get 40 amps and as the fill it drops down to just a couple of amps. But, as they fill up, the voltage goes up to 15/15.1 volts. I'm planning to attach the S terminal of the battery to see if that lowers the voltage when the batteries are charged - glad to hear that's what you would do too. It has been a challenge to find any more information on this situation and my alternator.

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menagoesenog avatar image menagoesenog kyleolmstead commented ·

I totally agree with putting the S terminal directly on the battery. But with an Argofet and two banks, on which I connect my sensor wire. Start or house?

Thank you

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menagoesenog answered ·

I totally agree with putting the S terminal directly on the battery. But with an Argofet and two banks, on which I connect my sensor wire. Start or house?

Thank you

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jwfrary avatar image
jwfrary answered ·

As your using a Lithium bank it would be better not to use a split charge type system and charge the lithium house bank directly from the balmar which should be programed for lithium batteries.

The starter battery can be charged via a DC to DC charger like the Orion series. This will keep the stater battery charged. If you have a bow thruster bank or windlass bank either use your Argo fet to split the charge of the DC to Dc changer or add another one.

This will give you maximum charge for the house bank and a safe trickle charge for the starter

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Related Resources

Product page Argofet Battery Isolators

Product page Argodiode Battery Isolators

Product page Diode Battery Combiners

Additional resources still need to be added for this topic