van electrical wire gauge help!

AngeWAngeW Registered Users Posts: 4
edited January 11 in Solar Beginners Corner #1
Would appreciate any input on my electrical wiring for my van. Especially concerned if i have the proper wire gauges selected! Schematic sketch attached. Thank You!

Comments

  • PhotowhitPhotowhit Solar Expert Posts: 5,543 ✭✭✭✭✭
    AngeW said:
    Would appreciate any input on my electrical wiring for my van. Especially concerned if i have the proper wire gauges selected! Schematic sketch attached. Thank You!
    I don't see your suplimental source of power. You are likely going to be short with a fridge which runs 24/7. I would hard wire this, 50 watts is a lot to run through a cigarette plug.

    You can look to your inverter manual for the wire gauge for it, a 1500 watt 12 volt should need a wire capable of running the max load, something like 1500/11.5=130amps.

    Your charge controller isn't spec'd as being MPPT type, if it's a PWM you should have the panels in parallel. 


    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • mcgivormcgivor Solar Expert Posts: 3,714 ✭✭✭✭✭✭
    There are some issues that need to be addressed, the battery is fused at the fuse block with a 200 A fuse, then the inverter is connected via a 300A fuse which is redundant  because the 200 A would protect the 300 A. The inverter should be connected directly to the battery with a fuse or circuit breaker as close to the battery as possible, a secondary wire of smaller gauge, also with appropriate fuse/breaker could be used to feed the fuse block.

    The NEC  current rating for 90°C #2 awg is ~130 A but will carry significantly more particularly if the run distance is extremely short, something not indicated, 300 A is too high, a 175 A would be more appropriate, this would handle 1500 W rating of the inverter at minimum voltage The sole purpose of the fuse / breaker is to protect the conductors downstream of it hence the importance of placing them close to the energy source, batteries can provide extremely high current in the hundreds or thousands of amps in short circuit. 
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • AngeWAngeW Registered Users Posts: 4
    Photowhit said:
    AngeW said:
    Would appreciate any input on my electrical wiring for my van. Especially concerned if i have the proper wire gauges selected! Schematic sketch attached. Thank You!
    I don't see your suplimental source of power. You are likely going to be short with a fridge which runs 24/7. I would hard wire this, 50 watts is a lot to run through a cigarette plug.

    You can look to your inverter manual for the wire gauge for it, a 1500 watt 12 volt should need a wire capable of running the max load, something like 1500/11.5=130amps.

    Your charge controller isn't spec'd as being MPPT type, if it's a PWM you should have the panels in parallel. 


    thanks! Fridge is a 12v camper fridge, peaks at 7.5 amps.

    for the inverter i will size down the fuse, originally sized it to the max surge but that isnt necessary.

    Charge controller is PWM.
  • AngeWAngeW Registered Users Posts: 4
    mcgivor said:
    There are some issues that need to be addressed, the battery is fused at the fuse block with a 200 A fuse, then the inverter is connected via a 300A fuse which is redundant  because the 200 A would protect the 300 A. The inverter should be connected directly to the battery with a fuse or circuit breaker as close to the battery as possible, a secondary wire of smaller gauge, also with appropriate fuse/breaker could be used to feed the fuse block.

    The NEC  current rating for 90°C #2 awg is ~130 A but will carry significantly more particularly if the run distance is extremely short, something not indicated, 300 A is too high, a 175 A would be more appropriate, this would handle 1500 W rating of the inverter at minimum voltage The sole purpose of the fuse / breaker is to protect the conductors downstream of it hence the importance of placing them close to the energy source, batteries can provide extremely high current in the hundreds or thousands of amps in short circuit. 
    Thanks!
    So you suggest a 200A fuse at battery from fuse box and 175 fuse at battery from inverter?
  • AngeWAngeW Registered Users Posts: 4
    Also the charge controller, inverter and batteries are all within a couple feet of each other.
  • mcgivormcgivor Solar Expert Posts: 3,714 ✭✭✭✭✭✭
    edited January 11 #7
    AngeW said:
    mcgivor said:
    There are some issues that need to be addressed, the battery is fused at the fuse block with a 200 A fuse, then the inverter is connected via a 300A fuse which is redundant  because the 200 A would protect the 300 A. The inverter should be connected directly to the battery with a fuse or circuit breaker as close to the battery as possible, a secondary wire of smaller gauge, also with appropriate fuse/breaker could be used to feed the fuse block.

    The NEC  current rating for 90°C #2 awg is ~130 A but will carry significantly more particularly if the run distance is extremely short, something not indicated, 300 A is too high, a 175 A would be more appropriate, this would handle 1500 W rating of the inverter at minimum voltage The sole purpose of the fuse / breaker is to protect the conductors downstream of it hence the importance of placing them close to the energy source, batteries can provide extremely high current in the hundreds or thousands of amps in short circuit. 
    Thanks!
    So you suggest a 200A fuse at battery from fuse box and 175 fuse at battery from inverter?
    My suggestion was to use a 175 A fuse / breaker at the battery to power the inverter, if using #2 awg, then use a second fuse / breaker at the battery to feed the fuse block. The capacity of the secondary  protection should correspond to the gauge of conductors  feeding the fuse block, which will be less since the inverter has its independent feed, the loads powered by the fuse block, along with the fuse block's actual maximum capacity will determine the size of all said equipment.

    Being limited to vague outlines regarding the capacity limitations of the fuse block, only vague and limited information can be provided or suggested, details are so important.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • BB.BB. Super Moderators, Administrators Posts: 31,425 admin
    An ~200 Amp 12 volt fuse/breaker is pretty large for a 200 AH @ 12 volt (AGM) and 200 Watt solar array--And a 1,500 Watt AC inverter...

    More or less (always read the manual) a 1,500 Watt @ 12 volt inverter would use a fuse/breaker/wiring rated at:
    • 1,500 Watts * 1/0.85 AC inverter eff * 1/10.5 battery cutoff voltage = 168 Amps minimum
    • 168 Amps * 1.25 NEC derating for continuous loads = 210 Amps "nominal" conservative block
    So--For a 1,500 Watt inverter--Yes, that 175-200 Amp breaker+wiring is the right size... HOWEVER, expecting to draw ~168 Amps from a 200 AH AGM battery is expecting a lot... While AGM can have high current and surge ratings (C/1 hour discharge or even C/0.5 hour discharge)--That is still very hard on the battery bank and is typically designed for heavy short term loads--Such as a UPS (uninterruptible power supply) for computer rooms where they just need 15 minutes or so to get the backup gensets running.

    You do need to look at your AC loads... For a "cabin" / small off grid system... As an example, say you want 5 hours a night for 2 nights and 50% max planned discharge (for longer battery life, and allow for a day of poor sun). That is 5+5+10=20 hour discharge rate...
    • 200 AH / 20 hours = 10 amps average loads (DC)
    • 200 AH * 1/20 hours * 12 volts * 0.85 AC inverter eff = 102 Watt average load (120 VAC)
    A 1,500 Watt AC inverter is almost 15x the "typical"/average load for an overnight power system.

    And for charging--200 Watts of solar will take a lot of sun to recharge the bank. Depending on where you will be, seasons, if you tilt the array to the sun, etc.--A good summer harvest for a flat array of around 4 hours of sun per day:
    • 200 Watts * 0.59 off grid AC+AGM system efficiency * 4 hours of good sun = 472 Watt*Hours of 120 VAC per day average harvest
    • 200 Watts * 0.69 off grid DC+AGM system efficiency * 4 hours of good sun = 552 Watt*Hours of 12 VDC per day
    • 552 WH of DC / 12 VDC = 46 AH per day of 12 VDC energy
    There is a move in the RV world to use induction cook tops instead of propane (or if you need to run a small skill saw every so often, etc.)... Typically done with LiFePO4 Lithium Ion battery banks--But you still need to figure out how to recharge the bank after a day or so of cooking (run vehicle engine, genset, shore power, etc.)....

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • PhotowhitPhotowhit Solar Expert Posts: 5,543 ✭✭✭✭✭
    AngeW said:
    Photowhit said:
    AngeW said:
    Would appreciate any input on my electrical wiring for my van. Especially concerned if i have the proper wire gauges selected! Schematic sketch attached. Thank You!
    Your charge controller isn't spec'd as being MPPT type, if it's a PWM you should have the panels in parallel. 
    Charge controller is PWM.
    So you need to wire your panels in parallel, NOT in series as shown.
    Parallel vs Series Solar Panel Connections - e Marine Systems

    AngeW said:
    Photowhit said:
    AngeW said:
    Would appreciate any input on my electrical wiring for my van. Especially concerned if i have the proper wire gauges selected! Schematic sketch attached. Thank You!
    I don't see your suplimental source of power. You are likely going to be short with a fridge which runs 24/7. I would hard wire this, 50 watts is a lot to run through a cigarette plug.
    Fridge is a 12v camper fridge, peaks at 7.5 amps.
    Please look at the type of fridge. It sounds like a thermal electric fridge, which is on all the time. a 50 watt continuous draw is a lot of energy!

    50x24 hours a day = 1200watts. 4 amps x 24 hours is roughly half you battery capacity. 1 cloudy day could put you in serious negative numbers.

    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
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