Wiring question. Battery grounding.

[Cory Kelley]

I am adding an AGM battery to my hawk shell. I am adding solar panel and victron batt monitor too. I think I’ve got it all pretty well sorted out but have a question about grounding.

I know that I need to run the neg from battery, solar and loads to the shunt. Do I need to ground the battery to the truck or camper somehow too? If so do you have any suggestions? Wire Gauge and where to ground would be helpful. 2016 f150.

Thank you for all the help. These forums have really helped me sort all of this out.

 

[Wandering Sagebrush]

Cory, I can’t give a definite answer, but I see no reason to ground the shunt to either the camper or the truck. My electrical schooling of 50 years ago has me thinking the shunt only needs to be an in-line part of the circuit. Did the manufacturer say otherwise?

Let’s see what some of the better educated have to say...

 

[MidAtlantic]

Not sure about being better educated, but isn't the battery grounded if the shunt is in-line on the negative side of the battery?
See Fig. 4.
https://www.victronenergy.com/upload/documents/Quickinstallsheet_BMV70x_part1_2.pdf

 

[Bosque Bill]

Not sure about being better educated, but isn't the battery grounded if the shunt is in-line on the negative side of the battery?
See Fig. 4.
https://www.victronenergy.com/upload/documents/Quickinstallsheet_BMV70x_part1_2.pdf

That PDF shows the battery grounded, yes, but I don't believe that connection is required unless there are loads connected between hot and the frame/chassis (in which case those would not be monitored by the shunt.)

I don't believe I've grounded my batteries, but as my camper is currently still in storage I can't check.

But then again I've got some weirdness in my system that prevents my battery separator from functioning properly (it started after adding the solar system.) As the solar keeps my batteries charged I've disabled the separator, but even with a degree in electrical engineering I've never been able to figure this one glitch out.

 

[MidAtlantic]

That PDF shows the battery grounded, yes, but I don't believe that connection is required unless there are loads connected between hot and the frame/chassis (in which case those would not be monitored by the shunt.)

I don't believe I've grounded my batteries, but as my camper is currently still in storage I can't check.

But then again I've got some weirdness in my system that prevents my battery separator from functioning properly (it started after adding the solar system.) As the solar keeps my batteries charged I've disabled the separator, but even with a degree in electrical engineering [my emphasis] I've never been able to figure this one glitch out.

The Trimetric installation guide is slightly more informative, including connection of "CHASSIS GROUND (IF APPLICABLE)".

F. Load side of Shunt. Negative WIRES from ALL charging sources and loads CONNECT HERE TO MEASURE CURRENT including SOLAR PANELS, CHARGE CONTROLLER, ALTERNATOR, INVERTER, AND CHASSIS GROUND (IF APPLICABLE). Okay to use bus bar as long as connection is ultimately to the shunt. Note: The shunt measures all current to be displayed by the meter.

https://www.solar-electric.com/lib/wind-sun/TM-2030_Installation_User_Guide.pdf

BTW I think you have also resolved the question of who among us is better educated.

 

[Vic Harder]

I grounded my system through the shunt to the camper frame. Camper and truck are connected/grounded via the 2g wire from alternator to camper batteries. Does it need to be grounded? I dunno.

However, the comment above "unless there are loads connected between hot and the frame/chassis" is true in a lot of cases in FWC, who sometimes use the frame as the return wire. I'd hate to see what would happen if somehow the battery ground was disconnected and all that current tried to go through the frame to some tiny wire inside the walls of the camper.

 

[pvstoy]

I am adding an AGM battery to my hawk shell. I am adding solar panel and victron batt monitor too. I think I’ve got it all pretty well sorted out but have a question about grounding.

I know that I need to run the neg from battery, solar and loads to the shunt. Do I need to ground the battery to the truck or camper somehow too? If so do you have any suggestions? Wire Gauge and where to ground would be helpful. 2016 f150.

Thank you for all the help. These forums have really helped me sort all of this out.

Connect the "battery" negative terminal to the negative stud on the battery monitor shunt. Attach everything negative from... solar, truck alternator charging, all return loads from camper... to the aux side of the shunt.

The camper negative wiring is connected to the camper frame from a negative buss bar. As long as those grounds go back to the shunt then the shunt will see the return current back to the battery.

The shunt will tell the battery monitor what is going in and out (closes the circuit loop) from everything attached this way.

If you have anything bypassing the shunt and attached to the negative side of the battery directly then the battery monitor will never see this.

Picture the battery as a loop, positive out to load and returns as ground back to the battery. It takes both to complete the circuit.

So the ground from the battery should be already grounded to the camper frame at the breaker/fuses location by a buss bar. Also note that at the buss bar the power inverter has a wire that connects to it and then goes to the battery negative return. If your camper has standard factory wiring then you already have a attached wire from the camper frame to the battery wired properly, just attach that wire to the input side of the shunt as that is the only negative wire from the camper.

 

[PaulT]

I think there is a semantic problem in using the word “ground.” I prefer “battery return” as ground is overloaded with different meanings. There are at least the following meanings:
1. Battery return
2. Alternator/truck battery return
3. AC ground in reference to the AC shore power
4. RF ground if you have radio transmitters like Ham, CB, cell booster, satellite units.

What did I miss?

Anyway, the above are enough to cause me grief in understanding what applies when and what best practices are.

Paul

 

[pvstoy]

That's ok as in my head I understand what is happening, while my lips or fingers typing don't always say it the proper way. I apologize if it offended the more electrically inclined persons that know the proper terminology.

 

[PaulT]

That's ok as in my head I understand what is happening, while my lips or fingers typing don't always say it the proper way. I apologize if it offended the more electrically inclined persons that know the proper terminology.

Didn't mean to imply any issue with your specific post. Just that, in general, the word "ground" makes my head hurt when I am trying to understand what is meant in our short bits of text in posts.

Paul

 

[Vic Harder]

Connect the "battery" negative terminal to the negative stud on the battery monitor shunt. Attach everything negative from... solar, truck alternator charging, all return loads from camper... to the aux side of the shunt.

The camper negative wiring is connected to the camper frame from a negative buss bar. As long as those grounds go back to the shunt then the shunt will see the return current back to the battery.

The shunt will tell the battery monitor what is going in and out (closes the circuit loop) from everything attached this way.

If you have anything bypassing the shunt and attached to the negative side of the battery directly then the battery monitor will never see this.

Picture the battery as a loop, positive out to load and returns as ground back to the battery. It takes both to complete the circuit.

So the ground from the battery should be already grounded to the camper frame at the breaker/fuses location by a buss bar. Also note that at the buss bar the power inverter has a wire that connects to it and then goes to the battery negative return. If your camper has standard factory wiring then you already have a attached wire from the camper frame to the battery wired properly, just attach that wire to the input side of the shunt as that is the only negative wire from the camper.

Love this explanation... thanks!

 

[pvstoy]

No worries Paul, In a lousy weather funk today maybe the blood sugar is low. I agree about English language how it can be.

Thanks Vic.

Kinda let loose and rambled on in the other post....Time for a food break, or nap......

 

[ntsqd]

I vote for nap. Then again, I'll always vote for nap.

To me "ground" means exactly that, but it doesn't automatically refer to any specific item, wire, or cable in isolation, but it could depending on context. It is simply the side of the circuit on the Negative side of the load in the singular sense and all of the loads in the plural sense. Some books on low voltage DC wiring refer to a "ground(ing) system". I guess that works too, just seems overly wordy to me.

Given that the PO is dealing with a shell model there may not be any pre-existing wiring? Assuming that there is not, then I see no need or reason to have to ground to the camper or the truck for grounding's sake. If the truck or camper frame is used as part of the ground side of any particular circuit, then it will need to be grounded, but if each charge source and load added to the camper has its own ground wire that is brought back to a ground bus or the loads side of the shunt then there's no need to ground to the truck or camper.

 

[smlobx]

I vote for nap. Then again, I'll always vote for nap.....

I don’t have anything substantial to add to the conversation but I have to say this was the funniest thing I’ve read today!
Thanks for the laugh...

 

[pvstoy]

Late lunch was had and a nap followed.... life is good naps are great!

Thom good points and agree with your comments.

 

[roverjohn]

The OP doesn't seem to mention having a charge controller. If he had one there might not be a need for the Victron as a good one will usually show power usage if you think that's important.

Is it just me because I find it odd that you would want to chassis ground the neg lead of your panel. What would be the purpose of that?
With any chassis ground you're likely connecting dissimilar metals together just to save a little wire?

 

[Vic Harder]

The OP doesn't seem to mention having a charge controller. If he had one there might not be a need for the Victron as a good one will usually show power usage if you think that's important.

I am not presently aware of any charge controller that includes a shunt for accurate state of charge readings. Providing the right charge from you panels is what the controller is responsible for. Battery and power usage is what your Battery Monitor is for.

 

[CougarCouple]

Roverjohn I believe as good practice both are done.

Russ

 

[ntsqd]

The solar panels on both the install that I did and the Professional Install on the Cuchara that we just bought both only connect their grounds to the solar controller and nowhere else. I've never seen anything that suggested the solar panel ground be connected to chassis/camper ground and I dimly recall reading somewhere a long time ago specifically to NOT do that. If I could only recall here that was I'd dredge it up or prove my memory faulty.

 

[pvstoy]

and my solar install run from panels to charge controller to battery positive and negative to shunt to battery negative. Of course all grounds attach to the shunt then to the battery, so the camper has a negative buss bar attached to camper frame that is also attached to the same shunt terminal. If it was not for FWC to use the aluminum frame as grounding some stuff you would not need ground to the frame at all.