Next up:
Multi RS Solar has 2 MPPT trackers per inverter, the roof above the shed and partly the flat roof above the garage can hold 12 more solar panels, so next project is adding 2 strings of 6x 465Wp PV direct DC into inverter → battery.
Isolated shed… but not fireproof, cladding the walls with fire resistance board like Knauf Diamond would be my first job.. here i have a battery room finished with 3 layers Knauf Diamond, smoke, heat and gasalarm and a emergency stop switch, (1x RS 6000, DIY batteries, DIY busbar)
Partly because i want to be able to heat the house using a heatpump, charge the EV and use the induction cook top. But also being able to run the whole house when the grid goes offline. But i think it would be perfectly fine with a smaller system indeed
Agree, 2 emergency stops on the way, one in the shed itself and the other inside the house. Smoke/heat alarms as well. And i’m planning to clad at least the back wall with 2 layers of Knauf gipsplaat.
Why did you use thinner dc wire for the batteries?
Seeing the DC amperage is devided for 3 inverters, those 3 cables take less amperage then your 2x 16KW battery system. You can also see that difference in your fusing. Using lower amp fusing for your inverter, versus the higher amp fuses for your battery packs.
I would rather use thicker wires for your batteries, and thinner wires for the inverters. I’m going to install a similar system, but with 3x multiplusII 4k5, and for the dc wiring I’m going all 70mm, because I just ordered it all in one go. But if I wanted to, I also could have used 50mm for the 3 multiplusses.
I ordered the NKON ESS Pro 16kWh batteries and they included 50mm2 cables. I had the same feeling as you described, and maybe will upgrade to the 70mm2 cable instead. But the 50mm2 should be just fine for the 150A per battery that the NKON’s can deliver.
wouldn´t it make more sense to limit DC current in MP2 to a much lower value, save money - instead of spending it for the few minutes a day that much power is needed?
Fusing should take the weakest link into account. The wiring might be capable of handling a lot more amps, more than say a BMS or battery. In that case a higher fuse rating, matching the wires, makes no sense to me.
Yup indeed, i am using the Schneider Electric Harmony XB4 with 3 contact elements for each emergency stop. Would fireproof paint also do the job enough you think? That would save me some time
edit: I think i’m going to place Fermacell to the wall behind the installation, and paint the direct wall parts next to it and a part of the roof above it with fire resistant paint. Thanks for pointing me in that direction
Good question, and a long answer I wanted to use the Victron T-Class Busbar which only supports T-Class fuses from 225A onwards. The BMS is limited to 150A for each battery so the fuse is there in case a short circuit occurs which will then be a multitude of 225A flowing through the fuse. Increasing the cable diameter will be the most elegant solution, i agree and i might do that in the future. Fusing the Multi RS units with 200A and connecting them by 70mm2 is what the Victron documentation recommends you to do, so i did.
I’m trying to find those inverter 200A MEGA fuses, as a detailed pic of the PowerIn (like the T) is missing, where did you hide them ?
But my $1M question is: “Why on earth is there EMAT stuff everywhere in a setup like this ???”. Using any other decent brand (Hager, ABB, Eaton, pick your choice…) would be less than <1% of the budget.
Forget the fuses and larger wires, I would recommend to invest in a decent fire distinguisher (or two… )
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