MilbankAustralia
New Member
- Joined
- Jul 13, 2021
- Messages
- 18
Hi all,
I'm hoping to get some feedback advice on my system plan. Want to thank Svetz who is a member here who provided very useful feedback on my first plan. This is v2 and hopefully it is nearly there!
I do have some questions about grounding/earthing the system though!
Combiner box to MPPT then MPPT to fuse block (40-45A MIDI on fuse block, close to battery)
Battery bank (4 in series) to fuse block via 200A marine rated battery fuse.
Fuse block to inverter/charger via 125A MIDI fuse.
I've worked out the current carrying capacities of the cables for the installation methods and think that and the fuses should be correct.
Voltage and temperature sensor will be connected to the MultiPlus II GX, and it will connect to the SmartSolar via VE.Direct to utilise distributed voltage and current control (which should share the temp and voltage info with the MPPT). I'll monitor using the MP2GX's wifi, the SmartSolar's BlueTooth and VictronConnect on my phone, or via the Mk3 VE.Bus to USB on PC (and for firmware updates).
My outstanding questions which I'd really appreciate advice on:
Have learned a lot from the forums (I hope), and thank you all in advance for your valuable advice.
Cheers,
Simon
I'm hoping to get some feedback advice on my system plan. Want to thank Svetz who is a member here who provided very useful feedback on my first plan. This is v2 and hopefully it is nearly there!
I do have some questions about grounding/earthing the system though!
- PhonoSolar PS270P-20/U 270W panels x6, Vmpp 31.44V, Isc 9.09A
- SuperSafe SBS 190F AGM 190Ah (10hr rate) batteries x4
- SmartSolar 150/35
- Victron MultiPlus ii GX 48/3000/35-32
- ZJBenny combiner box BHS-2/1 (15-20A string fuses, SPD & 2 pole disconnect)
- Bussman LMI Input Module (M8 stud) + 3*LMI MIDI holders + 4 way bussbar with PEC/Prolec 58V MIDI fuses: 40/45A (MPPT), 125A (Inverter), 5A (DC-DC stepdown)
- 200A MRBF fuse and terminal fuse holder (designed for M8 terminal), M6 stainless steel washer and nut for M6 terminal on our battery
- 6mm2 XLPE for PV connections and combiner box to MPPT
- 16mm2 class 5 stranded XLPE for MPPT to fuse block
- 70mm2 XLPE for batteries series cables, battery to fuse block & fuse block to inverter/charger
- Negative bus of some variety
Combiner box to MPPT then MPPT to fuse block (40-45A MIDI on fuse block, close to battery)
Battery bank (4 in series) to fuse block via 200A marine rated battery fuse.
Fuse block to inverter/charger via 125A MIDI fuse.
I've worked out the current carrying capacities of the cables for the installation methods and think that and the fuses should be correct.
Voltage and temperature sensor will be connected to the MultiPlus II GX, and it will connect to the SmartSolar via VE.Direct to utilise distributed voltage and current control (which should share the temp and voltage info with the MPPT). I'll monitor using the MP2GX's wifi, the SmartSolar's BlueTooth and VictronConnect on my phone, or via the Mk3 VE.Bus to USB on PC (and for firmware updates).
My outstanding questions which I'd really appreciate advice on:
- Can I earth of the SPD in the combiner box on one of the PV frame earthing rods? The combiner box will be on one of the solar racks as it is.
- If the panels are touching, and mounted to a galvanised steel frame, does each panel frame need to be in contact with the earth conductor or can I earth from either the rack or just one of the panel frames?
- Can I use 6mm2 XLPE cable to connect the panel frames/racks to earth rods? Can I use the same for SPD to earth?
- Can I use the 70mm2 XLPE cable for the common earth for the MPPT and inverter chassis and the battery negative? Can these cables be joined before they get to the earth rod and if so what is a good way to do this without increasing resistance much? Can I attach them to a common stud and then run a single cable to the earth rod (<3m away)?
- Assuming correctly installed residual current circuit breakers on the AC circuits, is any further earth/grounding required on the AC side or is this all handled through the inverter/charger (i.e to the battery earth when not running from a generator and to the generator earth when running that way)?
- When the system is running on the generator it is earthed through the generator. The generator I am using is portable so I will need to connect it to an earth rod when using it to run the inverter/charger. Can I use the common earth rod the battery negative, MPPT and inverter chassis are connected to? Or does it need its own earth rod? And what type and size cable should I use to attach the generator chassis to this earth?
- Should I have a disconnect switch between the battery and the fuse block? I've had a hard time finding any that are rated for the 58V the batteries will be getting charged at so would appreciate suggestions if this is necessary.
- What does a shunt add? The low voltage cutoff will be on and I can monitor battery state through Victron Connect. I expect this system is oversized for our immediate needs and the loads to begin with will be pretty simple. I'm not sure it is worth the extra money but would be interested to hear opinions.
Have learned a lot from the forums (I hope), and thank you all in advance for your valuable advice.
Cheers,
Simon
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