Dual battery setup

[ocxplant]

Hello all-

I have a 2019 JL Sport S with the V6. Since it has the two battery system linked together and I suck at electricity knowledge, I have what may be a dumb question:

I bought the VIAIR 300P portable compressor for airing up after the trails. Can I just hook the alligator clips to the positive and negative battery terminals on the main 12v battery like usual? Or does having the extra battery wired to the main (in series I assume) affect anything? My concern is that with both batteries it would be too high of a voltage for the compressor. Or maybe I have to hook the clips up to only a special part of the terminals?

Thanks for any insight you all can provide!

Sponsored

 

[melendez69]

I use the 450... you'd clip them to the main battery. The 2nd battery for the ESS.

 

[Rahneld]

If the VIAIR 300P portable compressor would be one that you could hook up to another vehicle's 12V battery without issue (I don't know the product) then there should be no issue with you hooking it up to the JL's main battery terminals as well.

Heck, on your version of the JL, you could hook it up to the ESS battery (if you could get to it). You could hook up the positive terminal of one battery and the negative to the other.

It's all good. Here's why, barring an ESS event when the JL is cranked/on, the batteries are hooked up in parallel (not series) and as such voltage is constant, only amperage (the ability to delivery current) is increased.

(The rules are different when a series connection is made. But the batteries are simply not connected in series, ever.)

More amperage as a result of this parallel connection is not delivered to your device in a way that would fry it. Rather, more amperage simply means that the batteries, upon an appliance's (like your air compressor) request are capable of delivering said power. Your compressor doesn't request it, and all is good.

By analogy, if you plug your phone charger (a very low current demanding appliance) into a (large) 30 amp 120V A/C line, absolutely nothing bad happens. The 30 amp line is simply capable of delivering much more amperage (power) than that needed by the phone charger, but doesn't, because the charger (the appliance) doesn't demand it. : - )


~~~~~~~~~~~~~~~

 

[ocxplant]

If the VIAIR 300P portable compressor would be one that you could hook up to another vehicle's 12V battery without issue (I don't know the product) then there should be no issue with you hooking it up to the JL's main battery terminals as well.

Heck, on your version of the JL, you could hook it up to the ESS battery (if you could get to it). You could hook up the positive terminal of one battery and the negative to the other.

It's all good. Here's why, barring an ESS event when the JL is cranked/on, the batteries are hooked up in parallel (not series) and as such voltage is constant, only amperage (the ability to delivery current) is increased.

(The rules are different when a series connection is made. But the batteries are simply not connected in series, ever.)

More amperage as a result of this parallel connection is not delivered to your device in a way that would fry it. Rather, more amperage simply means that the batteries, upon an appliance's (like your air compressor) request are capable of delivering said power. Your compressor doesn't request it, and all is good.

By analogy, if you plug your phone charger (a very low current demanding appliance) into a (large) 30 amp 120V A/C line, absolutely nothing bad happens. The 30 amp line is simply capable of delivering much more amperage (power) than that needed by the phone charger, but doesn't, because the charger (the appliance) doesn't demand it. : - )


~~~~~~~~~~~~~~~

Wow great info! That really explains it for me. Thank you very much for taking the time to detail it out for me. This community is awesome.

Sponsored