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rubberduck avatar image
rubberduck asked

Home layout PV with battery backup

Hi all,

I've been following allong to many of your adventures for a while an have now it is finally time for my own home battery/PV system. I'm looking to create system for my home that has a PV powered battery to catch any outages of the AC inlet. The main comonents as of now are:
- 16 x 410Wp PV panels
- 1x 15.4 kWh LVL battery by BYD

As such most likely I will have 8x2 or a 4x4 PV panel configuration that would allow charging the 48V battery using either:
- 2x MPPT 250/60
or
- 1x SmartSolar MPPT RS 450/100 or 450/200

I only have a single AC inlet meaning the inverer/charger will most likely be a MultiPlus-II 48/5000 or 48/10000. Now my main concern is spacing of all these components. My current home has the AC mains and electrical cabinet one side of the home on the ground floor. And the solar panals are right on the roof at the other end of the home (see image). There is some space in the basement right under the electrical cabinet I can extend to and there is quite some space under the roof to place components.

untitled-diagram1.pngThe big question I have is if it would be best to place all components as close to the PV panels as possible (location A). And simply have two large 3-phase wires going to and from this location the the AC-mains/electrical cabinet. The other option would be to place either the MultiPlus (and Battery) at location B. This would place them closer to the electrical cabinet but would require DC cabels running down to the bacement from the MPPT's.

I'm very curious if anyone has any good insights to the proposed system. We are a household of 2 adults and 2 children. Heating will be changed to a heatpump and as such the electrical system in the near future also.

Multiplus-IIMPPT ControllersMPPT SmartSolarquattro 10kva48v battery
untitled-diagram1.png (38.9 KiB)
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4 Answers
Duivert NL avatar image
Duivert NL answered ·

both options can work,

long PV cables (not the DC outpout from mppt's!) with the right cross section will work fine, i have PV on the roof and 6 pairs of PV cable's that run about 25m to 6x mppt's

ac cable's to location A is also an option, but could be expensive, also the multiplus is not silent! so if a bedroom is there or below it, it could be a problem

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JohnC avatar image
JohnC answered ·

@rubberduck

Best to keep all those blue boxes and the batteries close together. Handy if close to your AC board as well, but the basement might be a good spot if you're annoyed by fan noise from the Multi. People tend to overlook comms wiring somewhat, and these are best kept short.

An RS 450/100 would probably suit well. High V, so not heavy wires, And likely you'd need to run just 2 pairs of 6mm2 solar wire down to the mppt.

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Fideri avatar image
Fideri answered ·

@rubberduck

I agree with what is proposed by others. I have my panels, connected via a string combiner, 50 metres away from my Victron gear. I simply ran 25mm² wires to the Victron setup. I have an AC wall outlet at the location so I connected to that and just limited my Victron draw to 12 amps. That's enough for me.

I suggest you also get a GX device to see and, if necessary, adjust how your system is performing.

F.

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rubberduck avatar image
rubberduck answered ·

Thanks for all the great answers. Indeed it seems like probably a decent solution for me would be to run the DC PV cables coming from the tracks down to the RS 450/100 to charge the battery. I can then place the battery and all the victron boxes a lot closer to my AC inlet and where the sounds is not a problem. It would mean 4 DC cables traveling down but these are quite high voltage low current. And then all the other connections can be spaced close together to both the AC mains and internet inlet.

@duivert I see you are another Dutchie. By chance any advise on an electrician in the east of the NL that likes this type of systems?

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Duivert NL avatar image Duivert NL commented ·

Hi yes dutch too!

Im an electrical/electronics engineer, so did the install my self, so unfortunatly i dont have any recommendation

your victron dealer should be able to provide schematics, stroomwinkel will if you ask (pay?) them for it, so any electrician should be able to install the system, AC side should be easy


All the DC manuals and install guide’s on setup are also availble on the victron site

A victron dealer can also help you with the right parts needed for your system and advice on cabling and such

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