My Battery Bank Question for Today, Cable Sizing?
Posted: Mon Nov 28, 2011 5:29 pm
>> Hello Samuel, Thanks for taking my call last night and all the emails were
>> great. Since you made your Battery Bank video tutorial the price has
>> gone up a bunch. I started to think of going to 16 batteries in
>> my battery bank.
>> If I do that will I need to go with larger cable and if so, what size. I learned
>> a bunch from your emails about parallel circuits and voltages. So I think I
>> know the answer already but just playing it safe. I have been reading the
>> inverter manual and see a bunch of confusing info in there. Thanks, Bill
Hi Bill,
It's good to read the inverter book but will cause lots of extra un-necessary communication and support work for both of us. That is all very generic and global information that will apply to all kinds of configurations not necessary to the support and install of what we are doing specifically.
So, stick to my information, drawings, and direction as completely as possible. Don't entertain drawings, specs, or directions from other sources.. it will just muddy the water and cause distraction or worse cause a system failure. I only focus to what is necessary and appropriate to my system and the quick training and installation of it. There's nothing general or not required in that info from me.
A 4/0 wire will carry up to and beyond 12kW of power, we are only putting in a 4.2kW system. 4/0 would be very unnecessary. A perfect example of why the manufacturers info causes extra worry. Worse are the multiple battery diagrams using 12v and other un-related stuff that doesn't apply.
2 AWG is fine for the 4,2kW with 8 batteries but is at that config not so heavy duty.. just adequate. Now that the HomeDepot has gone up in price so much there's no steal on that cable like before..
2 AWG has proven to be fine for 16 battery banks as well but at this point based on actual testing and experience the 2 AWG is being upgraded on systems over 4.2kW and 8 battery bank.
- 2 AWG is appropriate on systems up to 4.2kW and 8 battery bank.
- 2/0 AWG is recommended on systems above 4.2kW and 8 battery bank.
- 4/0 AWG is recommended on systems above 10kW and 8 battery bank.
*These are updated recommendations. We have many, many, systems in the field that perform fine with 2 AWG which are above 4.2kW and 8 battery bank.
I just wired one using 2/0 all the way on a 4.2kW with 12 battery bank and it was a nice heavy duty touch on the system. Probably $100 of copper upgrade well placed at the heart of your system. Given the lack of great price on 2 AWG cable now I am updating my recommendations to this.
You can buy it in 50' lengths here and it comes in 25' lengths if you find you need that some time. Here's part numbers and pricing where I am sourcing these days. 50' will leave you some left over and 25' will not be enough to finish...
The last item, cable cutter, can probably get $20 or so cheaper at Home Depot or Lowes.
1ea...BLACKSTONE 2/0 x 50' Cut/Boxed Welding Cable..50Ft
SKU: 0812017................................$264.00ea... $264.00
http://www.fastenal.com/web/products/de ... ku=0812018
5ea...BLACKSTONE 2/0# Cable Lug With 3/8" Stud Hole.....2/pk
SKU: 0844022...................................$4.52ea... $22.60
http://www.fastenal.com/web/products/de ... ku=0844022
2ea...2/0 5/16" Max Non-Plated Lug.....................10/pk
SKU: 0717079..................................$21.30ea... $42.60
http://www.fastenal.com/web/products/de ... ku=0717079
1ea...BLACKSTONE Welding Cable Lug Crimper Hammer Style..
SKU: 0844004..................................$25.37ea... $25.37
http://www.fastenal.com/web/products/de ... ku=0844004
1ea...16-3/4" Red Handle 350MCM Capacity Utility Cable Cutter
SKU: 0252460................................$105.22ea... $105.22
http://www.fastenal.com/web/products/de ... ku=0252460
Anyone wanting a small wind turbine, fill out the contact form and I can connect you with the dealer for your area. There are still areas open in most states for new dealers but many counties and a few entire states are taken up and several people are saying they are going to get their territory. So, if you are interested in becoming a dealer fill out the same form and we can see if your area may still be open.
Thanks, Samuel H.
>> great. Since you made your Battery Bank video tutorial the price has
>> gone up a bunch. I started to think of going to 16 batteries in
>> my battery bank.
>> If I do that will I need to go with larger cable and if so, what size. I learned
>> a bunch from your emails about parallel circuits and voltages. So I think I
>> know the answer already but just playing it safe. I have been reading the
>> inverter manual and see a bunch of confusing info in there. Thanks, Bill
Hi Bill,
It's good to read the inverter book but will cause lots of extra un-necessary communication and support work for both of us. That is all very generic and global information that will apply to all kinds of configurations not necessary to the support and install of what we are doing specifically.
So, stick to my information, drawings, and direction as completely as possible. Don't entertain drawings, specs, or directions from other sources.. it will just muddy the water and cause distraction or worse cause a system failure. I only focus to what is necessary and appropriate to my system and the quick training and installation of it. There's nothing general or not required in that info from me.
A 4/0 wire will carry up to and beyond 12kW of power, we are only putting in a 4.2kW system. 4/0 would be very unnecessary. A perfect example of why the manufacturers info causes extra worry. Worse are the multiple battery diagrams using 12v and other un-related stuff that doesn't apply.
2 AWG is fine for the 4,2kW with 8 batteries but is at that config not so heavy duty.. just adequate. Now that the HomeDepot has gone up in price so much there's no steal on that cable like before..
2 AWG has proven to be fine for 16 battery banks as well but at this point based on actual testing and experience the 2 AWG is being upgraded on systems over 4.2kW and 8 battery bank.
- 2 AWG is appropriate on systems up to 4.2kW and 8 battery bank.
- 2/0 AWG is recommended on systems above 4.2kW and 8 battery bank.
- 4/0 AWG is recommended on systems above 10kW and 8 battery bank.
*These are updated recommendations. We have many, many, systems in the field that perform fine with 2 AWG which are above 4.2kW and 8 battery bank.
I just wired one using 2/0 all the way on a 4.2kW with 12 battery bank and it was a nice heavy duty touch on the system. Probably $100 of copper upgrade well placed at the heart of your system. Given the lack of great price on 2 AWG cable now I am updating my recommendations to this.
You can buy it in 50' lengths here and it comes in 25' lengths if you find you need that some time. Here's part numbers and pricing where I am sourcing these days. 50' will leave you some left over and 25' will not be enough to finish...
The last item, cable cutter, can probably get $20 or so cheaper at Home Depot or Lowes.
1ea...BLACKSTONE 2/0 x 50' Cut/Boxed Welding Cable..50Ft
SKU: 0812017................................$264.00ea... $264.00
http://www.fastenal.com/web/products/de ... ku=0812018
5ea...BLACKSTONE 2/0# Cable Lug With 3/8" Stud Hole.....2/pk
SKU: 0844022...................................$4.52ea... $22.60
http://www.fastenal.com/web/products/de ... ku=0844022
2ea...2/0 5/16" Max Non-Plated Lug.....................10/pk
SKU: 0717079..................................$21.30ea... $42.60
http://www.fastenal.com/web/products/de ... ku=0717079
1ea...BLACKSTONE Welding Cable Lug Crimper Hammer Style..
SKU: 0844004..................................$25.37ea... $25.37
http://www.fastenal.com/web/products/de ... ku=0844004
1ea...16-3/4" Red Handle 350MCM Capacity Utility Cable Cutter
SKU: 0252460................................$105.22ea... $105.22
http://www.fastenal.com/web/products/de ... ku=0252460
Anyone wanting a small wind turbine, fill out the contact form and I can connect you with the dealer for your area. There are still areas open in most states for new dealers but many counties and a few entire states are taken up and several people are saying they are going to get their territory. So, if you are interested in becoming a dealer fill out the same form and we can see if your area may still be open.
Thanks, Samuel H.