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mediacut avatar image
mediacut asked

Wiring smart Shunt - negative cable length

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Hello,

I plan to finish my Tesla battery Powerwall Setup and need to add a Smart Shunt to negative cable.

Because i have 2 separate battery packs, I need to connect them in parallel, (2 cables 50mm each) in 1 point, an I was thinking to connect them direct in the shunt terminal and from other side of the shunt to go to the inverter with only one cable (70mm)

From batteries I have 3m of cable....will be a problem if the shunt is mounted 3m away from negative terminal?

Thanks


SmartShunt
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2 Answers
Paul B avatar image
Paul B answered ·

No thats fine re the smart shunt.

HOWEVER as a side comment the positive and the neg cables from BOTH batteries should be the same length, having one shorter than the other means that the shorter length cable will draw more from that battery than the other, due to the longer cable having more resistance (and thus more volt drop)

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mediacut avatar image mediacut commented ·

Thanks Paul.

Negative and positive cable will have same length.

My problems was regarding shunt position away from batteries. Many people says that the shunt needs to be connected direct on negative bateery terminal, and for me is almost impossible to do that.

I will prefer to put 2-3m away from batteries.

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klim8skeptic avatar image klim8skeptic ♦ mediacut commented ·

I will prefer to put 2-3m away from batteries.

Copper co$t$ money. Be it the cable between the shunt>battery, or between your loads/chargers>shunt.

Be practical, even bus bars can have copper in them.

The voltage losses have to be minimal overall....

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Paul B avatar image
Paul B answered ·

To be clear It does not matter where in the negative cable that the shunt is placed , as long as its after the Neg battery terminal and before the first load or charge point.

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mediacut avatar image mediacut commented ·

Thanks Paul!

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