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pablo79 asked

SmartShunt and Smart MPPT 75/15 current draw

Hello all, first post here.

A couple of days ago I installed a SmartShunt 500/50 and a 75/15 Smart MPPT controller in a motorhome. When everything is off and nothing can be used the shunt is showing current draw of 0.10A to 0.20A.

According to the datasheets, the MPPT has self consumption of 10mA, and the SmartShunt is <1mA. 11mA combined for the two. However, I'm drawing 10 to 20x more. The accuracy of the shunt is ±0.1A, so shouldn't it be reading 0.1A as a maximum? I appreciate this is a minor amount... I'm just curious as to why the numbers are 10 to 20 times out.

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A couple other question while I'm here:

Is there any value in creating a VE network and joining both devices?
For the shunt, I only updated the battery Ah. Did I need to do anything with other settings and options (Sync SOC, zero current calibration, charged voltage etc)?

I didn't really know anything about solar and electrics before this, so it's been a steep learning curve! Many thanks in advance.

MPPT ControllersSmartShunt
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ecarriel avatar image ecarriel commented ·

Hello,


Were you able to figure this out?


I have the same problem and I’m reading 0.15A constant draw (24/7). To put into perspective I have a 50ah battery. It was at 99 perfect around 10pm and by 9am it was at 96 percent. Nothing else connected - crazy!

I’m going to disconnect my BCDC (Redarc 1225D) to see if that’s drawing current and I have a low voltage disconnect that I will also be disconnecting to rule that out. Super odd but it definitely adds up quickly.

Redarc says the BCDC consumes <100mA

Low voltage disconnect standby current <5mA

- operating current <0.1A

Will let you know what I find...

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seb71 answered ·

No inverter?

Disconnect everything from the battery (except the shunt) and check the current draw. You can perform a shunt zero current calibration at this time if necessary.

Then connect one device at a time and check again.

Both the solar charger and the SmartShunt need to be configured. Start by reading the manuals.

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quadrille-in-jb avatar image quadrille-in-jb commented ·
I have the same problem, my 702 reads -0.47A when everything is disconnected but the shunt and the 702. How do I perform a zero current calibration?
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pablo79 answered ·

Thanks for the reply.

No inverter. The two leisure batteries are the only things that side of the shunt. Will disconnect things and see where that leads.

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seb71 avatar image seb71 commented ·

First disconnect the PV panels from the solar charger. Only after that disconnect the solar charger from the battery.

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pablo79 avatar image pablo79 seb71 commented ·

Will check tomorrow and report back

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