I have recently made a custom board out of project which I prototype on arduino.
Without going into to much detail about it just yet it consists of the following
1x Relay (24v DC, 250V AC, typical relay)
2.8’ ili9325 Touch Screen
It allows your to program relay events from the touch screen.
I have found the RTC very accurate and suitable for my needs, but I have discovered that when I have a 24v load hooked up the the relay it effects the accuracy of the RTC. It goes from +1 / -1 second per month on average to -1 second per week!
My guess is the load being sent through the relay a few times per days for a few seconds at a time is effecting the RTC Crystal leading to time keeping accuracy reduction.
QUESTION FOR THE EXPERTS
In general terms, what considerations should be made to ISOLATE a relay from the rest of the components on a PCB?
Is my findings on the relays load effecting the RTC crystal plausible?
What component could be added to the properly isolate the RTC / and or Relay?