Reply to thread

Message

<blockquote data-quote="helotaxi" data-source="post: 1498945" data-attributes="member: 550915">Manville Smith of JL audio did some very extensive testing of chassis grounds on different vehicles.&nbsp; He found that on most unibody cars using the car sheetmetal in for your amp ground with a trunk mounted amp and the amp grounded next to the amp the resistance between that ground and the battery was equivalent to a single run of 4 ga wire.&nbsp; If your amps (all of them total) are drawing more power than you would supply with 4ga, then using the sheetmetal as a ground is a chokepoint in the current delivery path.&nbsp; In a unibody car (basically anything that isn&#039;t a truck, SUV or van built on a ladder frame) your best ground is going to be a large gauge wire running back to the battery.&nbsp; In a vehicle with an actual frame you can ground to the frame, not the sheetmetal and get a very low potential ground.&nbsp; For this to be applicable, you have to ground the alt/engine block similarly to complete the path with the alt and be able to get max current with min voltage drop from the alt.The basic rule I would put forward is that if you are building a system in a unibody car and your primary power wire from the battery to the amp is larger than 4ga, you should strongly consider running an equal sized cable back to the battery neg terminal or the battery ground point.</blockquote>

[QUOTE="helotaxi, post: 1498945, member: 550915"] Manville Smith of JL audio did some very extensive testing of chassis grounds on different vehicles. He found that on most unibody cars using the car sheetmetal in for your amp ground with a trunk mounted amp and the amp grounded next to the amp the resistance between that ground and the battery was equivalent to a single run of 4 ga wire. If your amps (all of them total) are drawing more power than you would supply with 4ga, then using the sheetmetal as a ground is a chokepoint in the current delivery path. In a unibody car (basically anything that isn't a truck, SUV or van built on a ladder frame) your best ground is going to be a large gauge wire running back to the battery. In a vehicle with an actual frame you can ground to the frame, not the sheetmetal and get a very low potential ground. For this to be applicable, you have to ground the alt/engine block similarly to complete the path with the alt and be able to get max current with min voltage drop from the alt. The basic rule I would put forward is that if you are building a system in a unibody car and your primary power wire from the battery to the amp is larger than 4ga, you should strongly consider running an equal sized cable back to the battery neg terminal or the battery ground point. [/QUOTE]

Verification