Aloha from my off-grid farm on the Big Island of Hawaii

OffGridHawaii

OffGridHawaii

New member
Joined
Jun 14, 2020
Messages
13
Aloha,

I'd just like to introduce myself. I am going to be reaching out over the next fewweeks as I build my systemand would greatly appreciate some feedback on my questionsand system choices.

About my situation:
I have a hydroponic farm and seedling nursery / homestead on the Big Island of Hawaii which is entirely off grid.We catch our own rainwater and are completely solar powered (650w system at the moment). We have some very large loads including; Tesla Model 3, irrigation pumps, washer & dryer, hydroponic equipment, stove/oven,water heating, etc. Therefore I have planned a massive system to accommodate our needs.At 20N we capture plentiful solar, and also live on the leeward side of[size=small] the island with abounding[/size]sunny days year-round. I have purposefully constructed a largewarehouse with a roof aspect arranged due south at an 18.5 angle optimizingour solar catchment.

Items I have purchased for my off-grid system

* 1pallet (32 panels) of Hanwha 325w monocrystallinesolar panels (totaling 10,400w of catchment).
*2,408 brand new Panasonic NCR18650BD 3,180 mAh cells which I am going to arrange into a 14s172p configuration. (32 kWh)
*kweld spot welder, and all other powerwall components based on AverageJoe's videos.
*Batrium Watchmon4 with corresponding Longmons.
* Solark 8K Inverter/Charge Controller

I have lurked for months and still have some nuanced questions regarding parallel group assembly, BMS setup, configurations, etc. I greatly look forward to completing this build and will greatly appreciate you folks chiming into to help! I hope to be of service to the community.

Mahalo!
 
Very cool - I like your list of parts!

The one thing that jumps out at me is the battery bank (24kwh) while perfectly OK to get started withit seems to small (in my personal experience)forwhat you might want in the longer run - and I'd advise just leaving room for expansion in the future.

More detail:
In my first year (2019) on a 7kw PV arrayIconsumed 8,932kwh on a 40kwh battery bank with an average 32% DOD - perfect!. This year I expandedwith alarger,12kw PV array and 80kwh battery, but now thatI'm in spring/summer/fall,I'm having to do 50-60% DOD to supportconsumption pattern (55-65kwh/day).My original goal was to stay <40% DOD to shoot for max cycles- but I'm not making that with my current config.

Your design is in a similar range as my 7kw -> 12kw PV experience - is why I mention this for thought :).
 
OffGridInTheCity said:
Very cool - I like your list of parts!

The one thing that jumps out at me is the battery bank (24kwh) while perfectly OK to get started withit seems to small (in my personal experience)forwhat you might want in the longer run - and I'd advise just leaving room for expansion in the future.

More detail:
In my first year (2019) on a 7kw PV arrayIconsumed 8,932kwh on a 40kwh battery bank with an average 32% DOD - perfect!. This year I expandedwith alarger,12kw PV array and 80kwh battery, but now thatI'm in spring/summer/fall,I'm having to do 50-60% DOD to supportconsumption pattern (55-65kwh/day).My original goal was to stay <40% DOD to shoot for max cycles- but I'm not making that with my current config.

Your design is in a similar range as my 7kw -> 12kw PV experience - is why I mention this for thought :).
Click to expand...
Thanks for chiming in. I've calculated that most days I'll fall within a 50% DOD, which is acceptable to me. We have so much sun in the tropics. My Solark has a smart load feature, so essentially once the battery is charged the solark will divert excess solar energy into the loads of my choosing (Tesla and water heating).
 
OffGridHawaii said:
OffGridInTheCity said:
Very cool - I like your list of parts!

The one thing that jumps out at me is the battery bank (24kwh) while perfectly OK to get started withit seems to small (in my personal experience)forwhat you might want in the longer run - and I'd advise just leaving room for expansion in the future.

More detail:
In my first year (2019) on a 7kw PV arrayIconsumed 8,932kwh on a 40kwh battery bank with an average 32% DOD - perfect!. This year I expandedwith alarger,12kw PV array and 80kwh battery, but now thatI'm in spring/summer/fall,I'm having to do 50-60% DOD to supportconsumption pattern (55-65kwh/day).My original goal was to stay <40% DOD to shoot for max cycles- but I'm not making that with my current config.

Your design is in a similar range as my 7kw -> 12kw PV experience - is why I mention this for thought :).
Click to expand...
Thanks for chiming in. I've calculated that most days I'll fall within a 50% DOD, which is acceptable to me. We have so much sun in the tropics. My Solark has a smart load feature, so essentially once the battery is charged the solark will divert excess solar energy into the loads of my choosing (Tesla and water heating).
Click to expand...

Welcome! You are going to love the Sol-Ark!I have the 12k Sol-Ark and I am amazed at the efficiency and performance that they were able to build.
 
Solardad said:
OffGridHawaii said:
OffGridInTheCity said:
Very cool - I like your list of parts!

The one thing that jumps out at me is the battery bank (24kwh) while perfectly OK to get started withit seems to small (in my personal experience)forwhat you might want in the longer run - and I'd advise just leaving room for expansion in the future.

More detail:
In my first year (2019) on a 7kw PV arrayIconsumed 8,932kwh on a 40kwh battery bank with an average 32% DOD - perfect!. This year I expandedwith alarger,12kw PV array and 80kwh battery, but now thatI'm in spring/summer/fall,I'm having to do 50-60% DOD to supportconsumption pattern (55-65kwh/day).My original goal was to stay <40% DOD to shoot for max cycles- but I'm not making that with my current config.

Your design is in a similar range as my 7kw -> 12kw PV experience - is why I mention this for thought :).
Click to expand...
Thanks for chiming in. I've calculated that most days I'll fall within a 50% DOD, which is acceptable to me. We have so much sun in the tropics. My Solark has a smart load feature, so essentially once the battery is charged the solark will divert excess solar energy into the loads of my choosing (Tesla and water heating).
Click to expand...

Welcome! You are going to love the Sol-Ark!I have the 12k Sol-Ark and I am amazed at the efficiency and performance that they were able to build.
Click to expand...
I'm looking forward to the simplicity of the system! Did you have to connect a grounding rod by chance?
 
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