Good morning everyone, Today marks exactly one month since my first attempt at setting up the system, and I’m declaring it a complete failure. I bought 3 Multiplus 48/5000, P/N PMP482505010, all from the same series HQ2250xxxxxx. My non-working setup is: GRID + SOLAREDGE → AC IN → 3 Parallel Multiplus + ESS + 30kWh Pytes batteries. See the image below for the full setup. [image] Here’s the reality: [image] Over the past year, I’ve read everything available on Victron’s site, watched all the pro videos, and gone through every group (Facebook and this one) trying to find a solution. The AC cables (in and out) are all 6 meters long with a diameter of 10mm². The battery DC cables are 70mm² and 2 meters long, with an additional 2 meters of 4/0 AWG cable to the batteries. Initially, I used just one Multiplus, and everything worked perfectly. Here were my settings: (I cannot add more that 5 images)… The problems started when I connected all three together. I spent weeks trying to figure out why every time I plugged AC IN into the 3 parallel Multipluses, they made these strange noises (woom…woom), typical of frequency issues. The Solaredge would shut down, and sometimes even the main breaker tripped. After countless attempts, I found the issue: it was the LOM. Once I disabled LOM, all three started working correctly. The documentation was vague here, talking about interference issues but never mentioning parallel setups with Grid Tie. Anyway, it worked, but not perfectly. When I was running just one Multiplus, the power drawn from or fed back into the grid was always around 0 (with the usual small spikes of ±50-100W). But with two Multipluses, ESS can’t hold the grid at 0 anymore. It starts drawing around 250W from the grid, fluctuating by ±100W consistently. When I add the third one, the grid draw jumps to an average of 400-450W with a variation of ±200W! I’ve tried endless settings and combinations. There’s no way to fix this behavior. In this image, you can see (from my monitoring software) how the green grid line is stable around 0. [image] Here’s what it looks like with 2 Multipluses in parallel (you can see it jumping off zero): [image] And here with 3 Multipluses: [image] You can see the green grid line way higher (around 450W) and only dropping when AC IN draw decreases (because the house consumes more). Can anyone help me before I sell everything and buy a 15000? Thanks in advance. glfp

@glfp Sell and buy the 15kVa. Parrallel set up is notorious for hair pulling. One of the reasons why it as a diy set up is not officially supported (noted in the documents). If you are not ready to give up yet, start with no AC PV. Run loads (inverting) check your load balance between units. If its not within 5% fix it there first. Possibly by switching to lower gauge AC wire. In the manual note it says to use longer thinner gauge. Resistance is the key to balance.

3 Multiplus in parallel + GRID + PV + ESS do not work

DIY

lxonline (LX) 20 September 2024 16:13 22

Maybe grid code regulation certificate differences? That side I am not familiar with as we don’t have one where we are. But that is all i can think of. Obviously if it is not a consideration then its not a problem for you either

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3 Multiplus in parallel + GRID + PV + ESS do not work

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