Power Supply stability

[Dduc]

In my motorcycle the Power Supply voltage changes between 12V and 14.1V. Do you recomand a stabilisation circuit supplying the lambda shield?

Kind regards

Daniel

[Christian_Bylund]

In my motorcycle the Power Supply voltage changes between 12V and 14.1V. Do you recomand a stabilisation circuit supplying the lambda shield?

Kind regards

Daniel

Hello Daniel, this is typically not required. The heating circuit is automatically controlled, independent of the supply voltage other than during the condensation phase. Lambda Shield 2 is not recommended to run over 24V. If you choose to power the Arduino using the X7 jumper it can handle up to 20V. You can find more information in the technical manual. If you have a spikes in voltage above the maximum rating, stabilisation is recommended.

Haven't had many motorcycle applications so it would be interesting to hear your experience.

[Dduc]

Hi Christian
Thank you for this information. You find this project here: https://www.diva-di-bologna.eu/viewtopi ... 4391#p4391
Kind regards

Daniel

[Christian_Bylund]

Hi Christian
Thank you for this information. You find this project here: https://www.diva-di-bologna.eu/viewtopi ... 4391#p4391
Kind regards

Daniel

Thank you Daniel, very interesting! I see that you are using the original Lambda Shield, it is limited to 15V maximum. If you risk running that high with peaks you can modify it to accommodate for a high supply voltage. It is simply the voltage divider to read the supply voltage that will max the ADC-range of the Arduino. Note, if you supply the Arduino with a lower supply voltage than 5V, the maximum supply voltage will also decrease.

This is one of the improvements of the Lambda Shield 2 compared to the original Lambda Shield.

[Dduc]

Hi Christian

Thanks for the hint. I have a very good, new and adjustable charge controller in my motorcycle. So the power supply will be okay. Since i use a LiFePo battery the voltage is limited to 14.1 V.

But now I have 2 problems to solve.
1. The RAM requirement increases with the graphic display. The Arduino UNO is no longer enough.
An option is the larger Arduino MEGA with the 2560. The lambda shield 2 is compatible. What can I do to use my old version with the MEGA?

2. The voltage Ubat fluctuates quite strongly. I measure values ​​from 814 to 864 with my power supply@12.2 V. I expect in this case a value of 840 with a fluctuance of +- 8. I have the same fluctuance with the 13 V on a higher absolut level powered by a LiFePo battery with 8400 mAh that can deliver over 30 A of current. Even with a normal voltmeter I don't notice any fluctuations. Where does it come from? Can I just damp the ADC values?

regards Daniel

[Christian_Bylund]

Daniel,

1. The RAM requirement increases with the graphic display. The Arduino UNO is no longer enough.
An option is the larger Arduino MEGA with the 2560. The lambda shield 2 is compatible. What can I do to use my old version with the MEGA?

You simply need to connect the SPI pins to the shield from Mega, have a look at this post.

2. The voltage Ubat fluctuates quite strongly. I measure values ​​from 814 to 864 with my power supply@12.2 V. I expect in this case a value of 840 with a fluctuance of +- 8. I have the same fluctuance with the 13 V on a higher absolut level powered by a LiFePo battery with 8400 mAh that can deliver over 30 A of current. Even with a normal voltmeter I don't notice any fluctuations. Where does it come from? Can I just damp the ADC values?

The ADC-value is a raw display of the voltage, a voltmeter for example will display a filtered value. You will need to implement a simple filtering to display a stable mean average result. I can show you an example. One thing to consider is that the voltage measured on the shield is actually reduced from the battery voltage as it passes a rectifier with a voltage drop of 1.1V or something.