Hi Marcel, thank you for telling us your solution.
Actually you can find out what pins will interfere with an upload.
It is unlikely to be pin 13.
But you can find that out by only connecting pin 13 to your board, if you'd like to hunt for the reason of these troubles.
Pins 0 and 1 are used for serial communications.
If you are using those with a shield, thjs might get you in trouble when attempting an upload.
Also keep in mind that you are limited in the power you consume with your setup, certainly when powering from USB only.
En verder, er is ook een Nederlands deel hier.
Maakt het communiceren een stuk gemakkelijker als het in het Engels wat lastig mocht zijn.
thanks for your reply.
i dont use pin 0 and 1 because that pins are for comunnication.
i run the arduino on a seperate 14v 300mA adaptor.
and i got another 5v 1A usb adaptor for the main voltage of my relais.
i think that that must be enough for this.
if i disconnect pin 13 everything works fine.
if i connect the pin 13 again i got that same massage.