G'day, I have a customer that we installed a Fronius 5kW AC Coupled to a 5kVa Multiplus in an off grid install. I've also DC Coupled in a SmartSolar and connected to SunGel Carbon Gel batteries.
The customer is now experiencing his AC powered clocks running fast and I suspect it is caused by frequency shift as the Multi controls the Fronius.
Is there a solution to remedy this issue? Thanks in advance!
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!
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