question

diegotam avatar image
diegotam asked

Ve.Direct Venus OS comuniction + Rx remote on/off

Hi there,

I have 3 smartsolar 75/15 connected to a Rspberry pi 3B+.

I've already read the documentation about the Tx and Rx functionality, it seams that if I have plugged in a Ve.Direct to USB cable (which I have..) I can't use the remote on/off function on the Rx pin.

I just made some test with the solar charger plugged into the Rpi3 via Ve.Direct, charging and displaying the data on the touch screen. At this point if I make a short between Rx and Gnd pins, I do not lose connection, and the smartsolar stops charging. Then when I relese the short, the smartsolar starts charging again.


My plan is to instal a relay to make the short between Rx and GND on demand, keeping everithing connected to Venus OS at the sme time.

It is safe to do so?


Thank you

Venus OSVE.Directremote console
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4 Answers
wkirby avatar image
wkirby answered ·

It's probably working as long as the Rx pin is not busy, when the MPPT is only transmitting data.
If you wanted to make any configuration changes or any sort of requests to the MPPT when the relay is shorting the Rx pin, then you'll experience problems.

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diegotam avatar image diegotam commented ·
Thank you! That’s fine, my idea is to use this function to stop charging if the BMS triggers a cell overcharge alarm. So it’s just a emergency state that hopefully will never happens.
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elvis avatar image
elvis answered ·

Typically an over voltage alarm on a BMS will stop accepting a charge and the Solar charger, having nowhere to push power will automatically stop.

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johanndo avatar image
johanndo answered ·

Why don't you use DVCC instead to control the charge current via Ve.Direct from the Pi, no wires, no relays necessary.

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diegotam avatar image
diegotam answered ·

Yes but I would like to use the SBMS0 to protect the cells from over/under voltage.

I like that one because it would give me some extra I/O pins to control various things like an active high current balancer, which needs to turn on just at high SOC.

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