Victron Smartshunt says x while load tester says y

[archjeb]

Hi folks.

First I want to say this forum is awesome. I've learned so much and appreciate all the dialog among experienced folks on this forum. Thank you for all the insight and info on other threads I've posted.

Switching gears, I ordered one of those load testers off Amazon and gave it a shot the last couple of days.

Trying to figure out why there is a discrepancy between what the load tester is saying and what my Victron smartshunt is sayings. Its about a 2% delta.






This is my first victron smartshunt. So rookie question here.... Do I need to calibrate it?

I tested with an external clamp on Ammeter and the Victron is about 2% low on the current draw. Clamp on meter is close to the load tester current draw.

Thx.

J

 

[629658]

Hi folks.

First I want to say this forum is awesome. I've learned so much and appreciate all the dialog among experienced folks on this forum. Thank you for all the insight and info on other threads I've posted.

Switching gears, I ordered one of those load testers off Amazon and gave it a shot the last couple of days.

Trying to figure out why there is a discrepancy between what the load tester is saying and what my Victron smartshunt is sayings. Its about a 2% delta.

View attachment 131964

View attachment 131965


This is my first victron smartshunt. So rookie question here.... Do I need to calibrate it?

I tested with an external clamp on Ammeter and the Victron is about 2% low on the current draw. Clamp on meter is close to the load tester current draw.

Thx.

J

Yes you will have to calibrate it and have the correct setup parameters entered. I believe you can set the bottom if you’re empty. Personally I made sure I was fully charged and then you calibrate the shunt at 100%. It will be necessary to get your batteries to full 100% SOC every day or two to keep your shunt accurate.

 

[mikefitz]

You calibrate to zero current using the app. See section 7.2.13 of the pdf manual. This procedure is only to calibrate for a zero current offset.

 

[629658]

You calibrate to zero current using the app. See section 7.2.13 of the pdf manual. This procedure is only to calibrate for a zero current offset.

That’s correct you synchronize at 100%.

 

[mikefitz]

Fully charged and setting SOC and getting a sync to100% are not under discussion.

The OP has found a possible error in the shunts measurement of current. This may be due to a zero current offset that can be corrected .
Perhaps the OP is expecting too much from the Smart Shunt.
The specifications state: resolution +/- 0.1 amp and accuracy +/- 0.4%

There will be resolution and accuracy factors associated with the power meter and clamp meter.

 

[629658]

Fully charged and setting SOC and getting a sync to100% are not under discussion.

The OP has found a possible error in the shunts measurement of current. This may be due to a zero current offset that can be corrected .
It's possible the OP is expecting too much from the Smart Shunt.
The specifications state: resolution +/- 0.1 amp and accuracy +/- 0.4%

He asked about calibration in his original post. To function it must be synchronized or “calibrated “ to 100% SOC. So I believe it is under discussion. Showing 2% SOC in his post you think that is correct? Not the only issue but one that needs attention.

 

[629658]

He asked about calibration in his original post. To function it must be synchronized or “calibrated “ to 100% SOC. So I believe it is under discussion. Showing 2% SOC in his post you think that is correct? Not the only issue but one that needs attention.

I wasn’t even focused on the 2% discrepancy. He has multiple settings issues to get his shunt operational.

 

[archjeb]

I have it setup so that when the voltage reaches 42.6v that it resets to 100% SoC (the "charged voltage" setting). The reason being is...typical boat electric trolling motor use case:

1. Full charge
2. Use boat, catch fish
3. Return home and plug into charger

The point is, I only use the shunt to know what my SoC is for that trip alone so I don't get stuck with a dead motor.

Mike, you mentioned "The OP has found a possible error in the shunts measurement of current. This may be due to a zero current offset that can be corrected. Perhaps the OP is expecting too much from the Smart Shunt.
The specifications state: resolution +/- 0.1 amp and accuracy +/- 0.4%
"

That is indeed what issue I have that is is not accurately measuring the current draw; it is showing 60mA too low. That looks like its still within the tolerance of accuracy of the smartshunt...I guess I'm expecting too much

I wasn't sure if there was a way to calibrate the measurement to get that accuracy a little closer than 100mA