I have recently had my system upgraded to a second inverter and a third battery. The amount of power generated during the day is more than enough to fully charge the system. However, the system often prefers to send the power back to the grid. It's not too much of a problem at this time of the year, but if it works like this during winter, I will be using peak electricity due to running out of battery, making this system upgrade a bad investment.
I had a 2nd AC3 inverter + EMS installed several months ago, I already had 2 batteries (2 x 9.5KwH).
8kWh of solar in total (East, West & South)
Mine is working fine BUT what I have noticed it that the EMS is considerably slower at managing what power / energy goes in / out of the batteries compared to when the inverters managed it themselves, which has a knock on effect of causing a slight increase in the amount of energy imported from and exported to the grid.
An example of this is comparing our electricity import over the 2 weeks we were away on holiday this year against last year.
2024 = daily import of 0.1 - 0.2 kWh
2025 = daily import of 0.2 - 0.7 kWh
We are I imagine classed as a high usage household with a couple of small computers (+Raspberry Pi) running 24/7, 2 freezers and 10 security cameras.
But during that period we averaged 34.1 kWh of solar generation per day so my batteries were pretty much full at sundown every day.
I've been hoping we might get a firmware update that address's this BUT it might be something that can't be addressed and is the payoff of having more than 1 inverter
Graham_Harrison Is this a "feature" of the way ECO mode is handled? I assume that now, as the house load moves up and down, the EMS has to instruct one of the two inverters to take up the change which takes longer than the original single inverter used to. Are there any settings to sequence the 2 inverters rather than run them in parallel so that you can use the fast response of the inverter?
I'll need to look back through but I understand the EMS polls the inverters at around 1.2s intervals commanding them what to do. I'm unsure how often the EMS polls it's grid meters to decide what to command the inverter every 1.2s.
If you were on faster response fw before the EMS then it may well have responded faster than the EMS does.
hoggy That clearly explains the longer delay.
I wonder why it was implemented like this. I would have not done something digitally with this inherent latency but would have dynamically switched the clamp between the inverters so that just one was activated at a time to meet the load based on each batteries state of charge i.e. sequenced, with some logic when the demand exceeded one inverters capability. That would mean you kept the fast response of a single inverter.
Of course maybe they did try that and it performed a lot worse so was ditched.
Windy Miller as I understand the inverters also get a special firmware that basically lobotomises it - they simply follow the commands like zombies that the EMS gives them - hence why if you screw these EMS installs up like try and control an inverter directly with givTCP the inverter just sits there doing nothing (rather than going off and doing its own thing)
I guess they ripped out a lot of the code inside to run like this so I don't think there's any fast fw logic left in them!
Windy Miller just one was activated at a time to meet the load
It is I think!
I'm pretty sure that when charging or discharging my batteries if power demand or availability can be met by just 1 inverter then only 1 inverter is used and they constantly swap back & forth
[unknown] three questions,
hoggy three questions,
Smk82
1: faster FW came for those ages ago - if it starts D5.... then it's slow, if it starts D2 it's fast.
2: i dont have 2 AC3 inverters but that would be a fairly standard config (although not one that Givenergy officially support)
3: provided you switch on the "in RAM" register mode so you don't constantly write to the flash memory I can't see why not. Lots of people seem to use balancing scripts in the Givtcp group on FB.
