Guide for wire sizing from charge controller to battery bank?

softdown
softdown Solar Expert Posts: 3,812 ✭✭✭✭
Ideas?

I could probably look this up. Like food, fresh is better?
First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries

Comments

  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • softdown
    softdown Solar Expert Posts: 3,812 ✭✭✭✭
    edited October 2016 #3
    Am downloading a free 134 mb program that should open that calculator. I use a bunch of old, cheap computers for reasons unknown.

    http://www.openoffice.org/        This worked fairly well....except for "chopping off" the numbers for line loss.

    Thought I seen an easy chart in a solar book...once upon a time.

    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • Wheelman55
    Wheelman55 Registered Users Posts: 233 ✭✭✭
    Southwire has mobile apps for voltage drop and conduit fill.  Once on your smartphone or tablet they don't need an internet connection. 
    Off-Grid in Terlingua, TX
    5,000 watt array - 14 CS 370 watt modules. HZLA horizontal tracker. Schneider: XW6048NA+, Mini PDP, MPPT 80-600, SCP. 390ah LiFeP04 battery bank - 3 Discover AES 42-48-6650 48 volt 130ah LiFePO4 batteries
  • softdown
    softdown Solar Expert Posts: 3,812 ✭✭✭✭
    Southwire has mobile apps for voltage drop and conduit fill.  Once on your smartphone or tablet they don't need an internet connection. 
    Thanks! Using these numbers:

    Voltage.................40

    volts
    Maximum voltage drop...................3 %
    Typically, 3% or less is the recommended level for efficient operation of equipment.
    Length of cable run.................16 feet
    Current at the end of cable run......................16 amps

    Yielded this:

    Results

    1 conductors per phase utilizing a #12 Copper conductor will limit the voltage drop to 2.23% or less when supplying 16.0 amps for 16 feet on a 40 volt system.

    For Engineering Information Only:
    20.0 Amps Rated ampacity of selected conductor
    1.9029 Ohms Resistance (Ohms per 1000 feet)
    0.054 Ohms Reactance (Ohms per 1000 feet)
    1.2000000000000002 volts maximum allowable voltage drop at 3%
    0.889. Actual voltage drop loss at 2.23% for the circuit
    0.9 Power Factor

    I was inputting data for the final run from the combiner box to the charge controller. Guess I didn't need to install the 8awg yesterday after all.

    Also feel like I failed to account for one or two things.


    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • Wheelman55
    Wheelman55 Registered Users Posts: 233 ✭✭✭
    edited October 2016 #6
    Looking on the bright side you'll have less than 1% voltage drop using the 8 awg. 
    Off-Grid in Terlingua, TX
    5,000 watt array - 14 CS 370 watt modules. HZLA horizontal tracker. Schneider: XW6048NA+, Mini PDP, MPPT 80-600, SCP. 390ah LiFeP04 battery bank - 3 Discover AES 42-48-6650 48 volt 130ah LiFePO4 batteries
  • Wheelman55
    Wheelman55 Registered Users Posts: 233 ✭✭✭
    edited October 2016 #7
    Also got a box fill app from: snappyapz.

    http://snappyappz.com/ 
    Off-Grid in Terlingua, TX
    5,000 watt array - 14 CS 370 watt modules. HZLA horizontal tracker. Schneider: XW6048NA+, Mini PDP, MPPT 80-600, SCP. 390ah LiFeP04 battery bank - 3 Discover AES 42-48-6650 48 volt 130ah LiFePO4 batteries
  • softdown
    softdown Solar Expert Posts: 3,812 ✭✭✭✭
    Looking on the bright side you'll have less than 1% voltage drop using the 8 awg. 
    Apparently...yes. Sure didn't make a difference in my overnight battery voltage. Seems like batteries like to sit at ~12.5 volts with minimal drains ... unless charged within the past few hours.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries