Shunt wiring; Using same ground ok?

[Jared1048]

I know all the dc grounds should connect to the "other" side of the shunt to measure how much goes through it. From there its grounded out on the motor.

If I move one of these ground wires from the "other" side of the shunt and directy put it on the motor ground would its load still be accounted for?

To be clear: The "other" side of the shunt is the side the negative battery cables isnt on.

Thanks!
-Jared

 

[Sumner]

..If I move one of these ground wires from the "other" side of the shunt and directy put it on the motor ground would its load still be accounted for?..

No, I think you answered yourself...

I know all the dc grounds should connect to the "other" side of the shunt to measure how much goes through it. From there its grounded out on the motor....

On our two boats the "other" side is the cable to the negative post of the house batteries (2 shunts on one boat and 1 on the other),

Edit: ( I wrote the above too fast and mis-read the "other" on the original post. Our neg. loads go to a common buss...

...like in MS's photo above (that was linked to above), then thru the shunt and then to the negative side of the house bank.)

I'm still confused though from the orginal post if the loads are on one side of the shunt and then the other side goes to the engine block that is inturn grounded to the negative side of the house bank???

Sum

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[Stu Jackson]

Jared, it sounds like you know the different sides. You might think of what you're suggesting as "the other end of the same wire", since you're simply moving from the load side of the shunt wire to the engine, assuming you go to the same spot on the engine. Why not try it, then run a load and see if it registers. Issue is then you have multiple grounds on your engine on your engine if you don't connect to the same spot on the engine. You might also want to consider getting a bus bar or a Power Post and connecting all your load side negatives together and then run only one wire to the load side of the shunt, and keep that one ground wire to the engine from the bus bar. I am guessing you're thinking of doing this because you have too many wires going to the load side of your shunt?

 

[Jared1048]

Jared, it sounds like you know the different sides. You might think of what you're suggesting as "the other end of the same wire", since you're simply moving from the load side of the shunt wire to the engine, assuming you go to the same spot on the engine. Why not try it, then run a load and see if it registers. Issue is then you have multiple grounds on your engine on your engine if you don't connect to the same spot on the engine. You might also want to consider getting a bus bar or a Power Post and connecting all your load side negatives together and then run only one wire to the load side of the shunt, and keep that one ground wire to the engine from the bus bar. I am guessing you're thinking of doing this because you have too many wires going to the load side of your shunt?

Yes, exactly. I just upgraded from a single battery to 4 6 volts and the wiring is a lot more complex. it would save about a 4 ft run of cable if I just wired it to the same negative spot on the motor the negative shunt is on. It also carries the load better since the negative grounds are being carried over 2 wires now instead of converging at one point and having an oober wire coming back to engine ground.

Buss bar does sound like a good alternative though. If I have to wire anything else up I will have to go that route.

Thanks guys.

 

[willardj]

Here's a pic of one hooked up. may help.
http://www.pbase.com/mainecruising/image/131690814

 

[Maine Sail]

Here's a pic of an installation on a boat. The neg ground bus is connected to the engine, alt and ships DC system. There should be NOTHING on the battery side of the shunt...

 

[dparilla]

Great photos. Thank you.

 

[Jared1048]

Update...

I moved one of the -load wires from -buss and placed on the same grounding point that the negative buss connects to (engine) and it didn't register on battery monitor.

Jared

 

[Maine Sail]

Update...

I moved one of the -load wires from -buss and placed on the same grounding point that the negative buss connects to (engine) and it didn't register on battery monitor.

Jared

Jared,

you are going to have to draw it out. MS Paint works well...