Overcharging using VE smart network data?

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philippo asked Jul 8, '24

Overcharging using VE smart network data?

I've created a VE smart network so that the smart shunt data can be used by the chargers (Orion XS and Blue smart). I was hoping it would provide more accurate battery voltage data and negate any voltage drop....

But the chargers seem to over compensate and are producing 14.8v as measured at the shunt instead of the 14.7 Abs voltage in settings. Any ideas why this is? It's only a small discrepancy but quite consistently 0.1v high.

The voltage drop for the Orion XS is close to zero so it would actually be better not using the shared data....

VE.Smart Network

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Answer 1 · 2024-07-08T15:03:38Z

nickdb answered · Jul 08 at 03:03 PM

Do you have temperature compensation enabled?

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philippo commented · Jul 08 at 04:53 PM

No not enabled. No temperature sensor.

I thought it might be another quirk of the Orion XS but now seeing the same behaviour with the Blue smart 240v charger

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philippo commented · Jul 08 at 05:00 PM

Oh sorry yes! I just double checked. It was enabled for both devices. -16.2mv/°C. Could that be doing it then? Is there some ambient temperature sensor? As I have no external temp sensor connected.

I would have thought that would reduce the voltage...not increase it

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Alexandra ♦ philippo commented · Jul 08 at 06:38 PM

@Philippo

0.1v is probably also due the volt drop over the cable. If the battery is at the right value then all is good.

0.1v is also what is allowed in what is calle margin of error (why most batteries give a 0.3v range for charged voltage)

Temp compensation in the manual it uses the internal temp sensor if one is not provided. Make sure the value is correct for your battery if you are using lead based. Chances are it detected a temp that is slightly cooler than 25°C so a slight increase in the final value.

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philippo Alexandra ♦ commented · 6 days ago

No, the 14.8v (+0.1v) is at the battery as measured by the shunt. That's why I created the network as there is some volt drop for the 240v charger. I expected it to be right on 14.7

I didn't know there was an internal temp sensor. I'll monitor it some more with temp compensation disabled. I think that may be discrepancy, ambient is below 25°C Although it doesn't really correlate with -16.2mv/°C

I think that's the answer.

Thanks All

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