Location: Phoenix, AZ, USA
Posts: 53
Threads: 8
Joined: Aug 2017
Reputation:
1
Total Cells: 1400 Total Capacity: 10.78 kWh
I'm designing a powerwall setup for the eventual move to off-grid solar. I'm collecting 18650s, and planning to connect them similar to HBPowerwall (14s80p, ~10kWh), and expand as I continue to collect cells.
- 48v system
- Charge controller: MPP PCM60x
- Inverter: TBD
- BMS: Leaning toward TinyBMS (awaiting a response to my questions)
I would also like to be able to charge a 48v electric bike and eventually an EV converted car, both of which will have 18650s in an 14sXXp configuration. That is, it would be nice to connect the bike's battery pack(s) to the powerwall or controller to charge, using connectors such as the APP PP75. As I understand, this will be doable in spite of differing capacities, as long as voltage capacity is the same.
I also plan to initially segregate the house so that all lights and small appliances running 110VAC will be able to run completely off-grid, with 220VAC (air conditioning, dryer, water heater, etc.) running on-grid in the short-term, due to a lack of cost-effective inverter options at the moment. My power company charges a monthly $50 "grid use" fee for on-grid solar, which is more than my average monthly bill (less taxes/fees), so I would like to keep it completely divorced to avoid this.
I'd appreciate any input on this proposed system.
Location: Phoenix, AZ, USA
Posts: 53
Threads: 8
Joined: Aug 2017
Reputation:
1
Total Cells: 1400 Total Capacity: 10.78 kWh
10-23-2018, 08:52 PM
(This post was last modified: 10-25-2018, 09:52 PM by higher_wire. Edited 3 times in total.
Edit Reason: update BMS
)
So a full year later, and I actually have a working off-grid solar setup for most of my electrical needs (air conditioning, stove, and clothes dryer notwithstanding). My current specs and equipment are listed below. This post will act as a quick reference and table of contents as things change. Be on the lookout for a system schematic and more photos.
Note that I'm still cleaning up the wiring
- Powerwall Specs: 51.8v nominal, 166Ah capacity, 8.614 kWh
- Powerwall Configuration: 14s/80p (effectively 48v)
-1120 cells @ 2078 mAh average/cell
-Modular so cells can be added in 20p (40 Ah) blocks
-I took inspiration from owitte's modular powerwall
-Connections are 5/8" copper HVAC tubing with PEX wall holders
-20p blocks use 2 strands of 12 AWG copper wire, with 28awg fuse wire on positive and 20awg negative
-I'm using this battery disconnect on the battery negative
- Solar Panels: qty 40 165w Solar Frontier SF165S CIGS panels (datasheet)
- Charge Controller: qty 2 Sunnysky 60a MPPT
-One controller for my rooftop array (24 panels)
-One controller for my garagetop array (16 panels)
-These allow you to set battery type, charge current, charge and voltage
-It comes with two flimsy L brackets, and hangs awkwardly on my stucco wall. But I haven't had any issues otherwise.


- Inverter: Sigineer 6000w 48v, 240v split-phase (USA)
- BMS: Chargery BMS24T
-The BMS controls charge and load via two Albright 200a SU-80 contactors, and claims a 1.2a balance function. It seems to be keeping the cells within ~50mA fairly well.
-The BMS monitors SOC% using a 600a shunt on battery negative. I connected mine directly to the battery disconnect switch.
- Misc:
-My panels came with a Hiasa enclosure. It included DIN rails, to which I was able to mount my breakers and ancillary equipment
-My solar (2P) and charge (1P) breakers
-My ANL battery fuse, connected to battery positive
-Here's my ground junction
-I used these DIN mounts for my contactors, fuse holder, ground junction, converter and fan control
-Because Phoenix gets stupid hot in the summer, I wired a 12v buck converter and cooling fan control
-The enclosure also came with an ABB INCA emergency stop button, which I wired to cutoff the contactors in case of emergency.
-The inverter AC output is connected to the house via this Reliance 50a transfer switch
My Wall: 14s100p modular, 49x 165w CIGS panels, a couple sunnysky MPPT controllers, Sigineer 6kW inverter, Chargery BMS24T
Location: Kyogle, NSW, Australia
Posts: 920
Threads: 36
Joined: Aug 2017
Reputation:
5
Total Cells: Total Capacity: 0.00 kWh
Excellent setup. Excellent write up. Thanks for sharing!
higher_wire likes this post
Location: Phoenix, AZ, USA
Posts: 53
Threads: 8
Joined: Aug 2017
Reputation:
1
Total Cells: 1400 Total Capacity: 10.78 kWh
My Wall: 14s100p modular, 49x 165w CIGS panels, a couple sunnysky MPPT controllers, Sigineer 6kW inverter, Chargery BMS24T
Location: Braunschweig, Germany
Posts: 247
Threads: 4
Joined: Oct 2016
Reputation:
10
Total Cells: 3360 Total Capacity: 26.11 kWh
(10-23-2018, 08:52 PM)hookemdevils22 Wrote: So a full year later, and I actually have a working off-grid solar setup for most of my electrical needs (air conditioning, stove, and clothes dryer notwithstanding). My current specs and equipment are listed below. This post will act as a quick reference and table of contents as things change. Be on the lookout for a system schematic and more photos.
Note that I'm still cleaning up the wiring
- Powerwall Specs: 51.8v nominal, 166Ah capacity, 8.614 kWh
- Powerwall Configuration: 14s/80p (effectively 48v)
-1120 cells @ 2078 mAh average/cell
-Modular so cells can be added in 20p (40 Ah) blocks
-I took inspiration from owitte's modular powerwall
-Connections are 5/8" copper HVAC tubing with PEX wall holders
-20p blocks use 2 strands of 12 AWG copper wire, with 28awg fuse wire on positive and 20awg negative
-I'm using this battery disconnect on the battery negative
- Solar Panels: qty 40 165w Solar Frontier SF165S CIGS panels (datasheet)
- Charge Controller: qty 2 Sunnysky 60a MPPT
-One controller for my rooftop array (24 panels)
-One controller for my garagetop array (16 panels)
-These allow you to set battery type, charge current, charge and voltage
-It comes with two flimsy L brackets, and hangs awkwardly on my stucco wall. But I haven't had any issues otherwise.


- Inverter: Sigineer 6000w 48v, 240v split-phase (USA)
- BMS: Chargery BMS24T
-The BMS controls charge and load via two Albright 200a SU-80 contactors, and claims a 1.2a balance function. It seems to be keeping the cells within ~50mA fairly well.
-The BMS monitors SOC% using a 600a shunt on battery negative. I connected mine directly to the battery disconnect switch.
- Misc:
-My panels came with a Hiasa enclosure. It included DIN rails, to which I was able to mount my breakers and ancillary equipment
-My solar (2P) and charge (1P) breakers
-My ANL battery fuse, connected to battery positive
-Here's my ground junction
-I used these DIN mounts for my contactors, fuse holder, ground junction, converter and fan control
-Because Phoenix gets stupid hot in the summer, I wired a 12v buck converter and cooling fan control
-The enclosure also came with an ABB INCA emergency stop button, which I wired to cutoff the contactors in case of emergency.
-The inverter AC output is connected to the house via this Reliance 50a transfer switch
very nice setup, but your wall is way too small!
Have sun!
Oliver
Location: Sweden, Växjö
Posts: 4,372
Threads: 28
Joined: Oct 2016
Reputation:
86
Total Cells: 29600 Total Capacity: 146.46 kWh
Nice work!
The Ultimate DIY Solar and build place
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Current: 10kW Mpp Hybrid | 4kW PIP4048 | 2x PCM60x | 83kWh LiFePo4 | 10kWh 14s 18650 | 66*260W Poly
Upcoming: 14S 18650~30kWh | Automatic trip breakers, and alot more
Location: Phoenix, AZ, USA
Posts: 53
Threads: 8
Joined: Aug 2017
Reputation:
1
Total Cells: 1400 Total Capacity: 10.78 kWh
Quote:very nice setup, but your wall is way too small!
Indeed it is! I have 7 more packs assembled, and picking up more cells soon. It gets me through the night as it is, but SOC hits about 5% at a voltage of ~48 by the time I check in the morning. I would have another full set of 14 packs, but I tried to run it with 14x1 packs without a proper BMS and ran a few flat.
My Wall: 14s100p modular, 49x 165w CIGS panels, a couple sunnysky MPPT controllers, Sigineer 6kW inverter, Chargery BMS24T
Location: Phoenix, AZ, USA
Posts: 53
Threads: 8
Joined: Aug 2017
Reputation:
1
Total Cells: 1400 Total Capacity: 10.78 kWh
My Wall: 14s100p modular, 49x 165w CIGS panels, a couple sunnysky MPPT controllers, Sigineer 6kW inverter, Chargery BMS24T
Location: Canada EH!
Posts: 887
Threads: 9
Joined: Mar 2017
Reputation:
16
Total Cells: 2882 Total Capacity: 23.44 kWh
Nice.
******Hi My name is Jason and I have SOCD (Solar Obsessive Compulsive Disorder)*******
Current Powerwall - 1400 Cells 7s200p (modular 40p packs) ~ 12kWh of storage 4x 315W Canadian Solar Panels
Working on the next 7s40p packs ~2.5kWh
Waiting on 2000 Cells of unused Sony vt4 (2000mah 30A) ~ 15kWh hehehehehe More Power
Location: Oregon, USA
Posts: 408
Threads: 4
Joined: Dec 2018
Reputation:
8
Total Cells: 5034 Total Capacity: 40.34 kWh
Very Cool! and I too have a working system that I hope to expand to power most of my house. Its a lot of FUN!
I also made the decision to avoid power company requirements - so my system is also off-grid.
I run the output of the Inverter into a sub-panel (seen in my profile picture) and then distribute power to various places.
1) Destination 1: A 240v@50amp circuit is run from the main panel AND a 240v@50amp circuit is run from the inverter to the automatic transfer switch (box at bottom of picture). The output of the automatic transfer switch feeds the Pro-Tran manual transfer switch - which is wired into main panel.
The manual transfer switch gives individual circuit control because GEN position will get power from the automatic transfer switch and LINE position will get power from main panel as it originally did.
2) Destination 2: A set of 30amp Go-Power automatic transfer switches power a set of 3000 watt APC UPSs. I ran sockets to key computer/tv areas in house that are powered from the output of the APC UPS. The 30amp Go-Powers get shore power from main panel and generator power from Inverter distribution box. This takes care of sensitive equipment that can't take the automatic power switch that occurs twice a day.
All of this lets me
1) Shut the PV/off-grid system off to work on it without any disruption to the house power.
2) Consume all the PV/off-grid power... and let grid take over automatically if the PV power is not enough for 24hrs for that day. This let's me maximize my ROI and of course in an grid-down emergency I could use less power so it never shuts off.
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