Victron MPPT grounding wire size?

[Mx468]

Anyone know what’s the smallest size wire I can use to ground my Victron 100/30 MPPT controller to my chassis?

[daleyocum]

Originally Posted by Mx468

Anyone know what’s the smallest size wire I can use to ground my Victron 100/30 MPPT controller to my chassis?

Normally you wouldn’t ground it to the chassis but take the negative back to the bus bar at a central location. That’s to avoid ground loops.

Depending on the distance, 8-10 ga wire would be my first choice settling for 12 ga if really necessary and you have less than 400w of solar panels.

[pdavitt]

I think he is referring to the chassis ground for the controller. It has nothing to do with the DC negative.
Pat

[daleyocum]

Originally Posted by pdavitt

I think he is referring to the chassis ground for the controller. It has nothing to do with the DC negative.
Pat

If that’s what’s being asked the unit’s case CAN be grounded but doesn’t need to be as far as I can tell. Mine isn’t. The case isn’t connected to the negative terminals of the unit.

[pdavitt]

Originally Posted by daleyocum

If that’s what’s being asked the unit’s case CAN be grounded but doesn’t need to be as far as I can tell. Mine isn’t. The case isn’t connected to the negative terminals of the unit.

I've got an 8AWG ground wire running from the chassis ground stud on my Smart Solar 150/45 charge controller (48V Battery System) directly to the vehicle chassis ground point. I've found it is always prudent to give those pesky electrons some place to go if an electrical fault occurs in the device.

Just like I have a 2/0AWG ground wire running from my Quattro 48/5000 directly to the vehicle chassis ground stud. ABYC requires that the inverter/charger chassis ground wire be the same size as the DC Positive wire.

I almost got fried once by a device that did not have a proper chassis ground. Guess I am a little paranoid in this regard.

Pat

[GMFL]

In NEMA code ground wires can be down sized one size for anything 10ga and larger. So with that said. 12 ga wire will be plenty for a simple frame ground for your charger.

[rowiebowie]

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[johnnycla]

I am looking to upgrade the factory installed Adkinson solar controller to a SmartSolar MPPT 100/20 and have a wiring question. The Adkinson has a positive and negative wire from battery and a positive from the panel. If installing the MPPT controller would the negative panel connection on the contoller run to the negative bus bar? I have not yet investigated where the negative panel wire is terminated. Thanks.

[daleyocum]

Originally Posted by johnnycla

I am looking to upgrade the factory installed Adkinson solar controller to a SmartSolar MPPT 100/20 and have a wiring question. The Adkinson has a positive and negative wire from battery and a positive from the panel. If installing the MPPT controller would the negative panel connection on the contoller run to the negative bus bar? I have not yet investigated where the negative panel wire is terminated. Thanks.

On my 2018 FC25 the two wires from the panel, green and yellow, have small labels on them saying “solar” and come down where all the DC electrical stuff is collected and near where the controller is located. My GUESS is your panels do the same but the green negative wire is grounded nearby.