I’m an enthousiast learning a lot about setting up a Multiplus ESS at home. I’m trying to start small and minimalistic so i can learn and upgrade over time.
I have a Cerbo GX, and a 48V - 3000VA - 35A, with a simple 5KW battery pack. Everything is working fine on the DC side, and the AC out side. But the AC IN seems complicated as i’m only putting 1 fase in parallel in a 3 Fase system. (I fear my minimal setup might be causing complexity), but according to chapter 7 in the ESS design & installation manual this should work. (sorry i only have link in dutch: 7. Meerfasen-regulatie - verdere informatie )
I’ve made a quick drawing below. So only fase 1 is in parallel, but the Residual Current Breaker with Overcurrent protection( Aardlek Automaat in Blue below) breaks whenever the Multiplus wants to charge the battery and pull power over this line. (Its a 25A B-kar 30mA breaker.)
The AC Input current limit has been put on 16A just in case in VE Configure 3 too.
Could it have something to do with the Neutral which is shared across the 3 fases?
another possible complication is that my 3 fase heatpump is connected seperately to the distribution block, fase 1 power should come from the MP, but it has a Neutral connected directly to the distribution block and not going through the MP.
You need to feed L1 of the pump from the mains. If its wired as its drawn, then L1 of the pump will be fed by the ACout of the inverter, but L2 and L3 are fed from mains, i suspect this would be the issue that lets the RCD trip.
I personally would have left the distribution block completely on mains, and simply feed the ACout directly to the L1 breakers. As its wired now, you are using L1 of the distro block for the ACout, but L2, L3 and N of the same block are still fed by mains. Not inherently wrong, but also not really nice. Depending on your local regulations this could also be forbidden, to feed a distribution block from two different sources
Hi Chrigu, thx for your response, The reasoning behind the current setup is to put the Multiplus directly on the mains so that i do not need a seperate powermeter i can just use the multplus.
But if i understand you correctly, you recommend that a fully split and just limit the multiplus connection to the 1 group and putting the HeatPump on fully on mains like so:
This is simpler i guess, but my poor heatpump wont get any batter power ;)… i guess i can live with that for now. I guess this will be an OK setup for my test before i get Multiplus 2 and 3. Will try this out tomorrow and let you know if it works .
Just wanted to let you know that the simplified test setup does indeed work, thank you for your help! I’m now more motivated to get the next 2 multipluses ASAP.
don’t forget transfer switch to power your house from grid while you do maintenance on MP2, like a firmware upgrade.
The transfer switch need late opening and early closing neutral, like Kraus Naimar.
Whole can look line on pictures…
I use ACout1 und ACout2, therefore have two transfer switches. The 50A-MCBs are also used as switches. Out1, out2 and in are connected to phoenix’s clamps down left.
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