When you AC couple PV with Victron and the inverters frequency shift to back off the PV inverters, the increase frequency is causing appliances with clocks to speed up because it’s the hz that keeps the time on appliances.
has anyone come across this and does anyone have a suggestion to mitigate this? For example automatically lowering hz to adjust the clocks over time to keep the time consistent.
related post:
another related post…
https://communityarchive.victronenergy.com/questions/67/frequency-shift-affecting-clocks-1.html
From Guy Stewart (Victron Community Manager)](https://communityarchive.victronenergy.com/users/14/guy.html) answered · Sep 24 2018 at 2:17 AM Best AnswerACCEPTED ANSWER
I can confirm that it is caused by the increase in AC frequency that happens when the batteries are full and the Multi is sending the the signal to the Fronius to stop producing.
One remedy is to replace the clocks with those that use a quartz timer instead of the AC frequency.
Another solution would be to have a dump load available that consumes any surplus power when the batteries are full so that the solar production has somewhere to go without needing to be turned off (such as hot water).
This is a common and known consequence of all frequency shifting power control setups. It is also one of the reasons that DC solar charge controllers are preferred when off grid and charging batteries.
A last resort (and I have had a customer do this) is to get a battery charger, battery and seperate inverter and create ANOTHER micro-power system just for running his favourite bedside alarm clock!
Yes I have the same problem I am afraid. With two of the heaters. Nothing to be done unless you remove the frequency shifting.
I have been trying to get around this too. I have a device that senses frequency and will turn on a dump load before PV starts to throttle. But frequency will still be higher than the default 50Hz. In my installation, PV throttling starts at 51hz and ends at 52hz. So my device will turn on the dump load from 50,5hz to 51hz (0% load and 100% load).
I used to have SMA sunny island inverters and they hada feature where the system would count the ammount of time grid frequency was higher and later lower it to 49hz for a equivalent ammount of time, so that would compensate differences in clock time. Would be nice to see a feature like this added to victron.
Good afternoon,
Check this topic,
My system is virtually without any high frequency anymore, it mostly runs on 50.05-50.08Hz when in “frequency mode”.
Use a PID regulator with a 5KW Fadisel “pwm chopper” and hot water coil, finished story, resetting timers, only about 7-9 minutes a month…
Regards, Jeroen.