Solar rookie seeks help with 15-amp miter saw

jackypaperjackypaper Posts: 14Registered Users ✭✭
Hello, friends.  I've been chatting with BB., who has been gracious in his responses when helping this solar n00b with beginner-level questions.  He suggested that I post here.

My goal: To operate a 15-amp saw with solar power

My current set-up:  Two 100-watt panels --- SunSaver 20L Controller --- two 6-volt series-connected Tojan T-105s --- 450-watt inverter.

My plan: Simply replace the small inverter with a 3000-watt inverter to provide for the saw's needs of 1800 continuous watts and 3600+ watt start-up

My questions: (1) Is running that saw for extremely short periods of time (like, two seconds per cut) possible with a 12-volt system?  (2) If so, how large of an inverter is required?  (3) Do I need a 24-volt system instead if I hope to run that saw at all?

Thank you all so much for taking the time to help a solar-power beginner. 

Comments

  • jonrjonr Posts: 954Solar Expert ✭✭✭✭
    edited March 2017 #2
    If it has a universal motor, it should work to add a 15A dimmer.  This would allow a softer start and far less startup amps.
  • westbranchwestbranch Posts: 5,024Solar Expert ✭✭✭✭
    edited March 2017 #3
    I usually use my 3000W genset with the sliding miter-saw, but tried it on the 2000W generator last week (continuous 1600W ) and it would suck wind every time I spun it up... so  it will put a big drain on your 2 small batteries in all likelihood.... use the genny if you have one... and yes, 24 Volt...  Look at the Exelteck inverters 2000W/4000 surge
     
    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, Hughes1100 Sat Modem
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • Raj174Raj174 Posts: 589Solar Expert ✭✭✭✭
    It would be cheaper and more practical to get a 3500 watt generator.
    12 x 300W Renogy PV, MNE175DR-TR epanel modified, MN Classic 150, Outback Radian GS4048A, Mate3, 54.4V 207AH HI Power LiFePO4 no BMS, 4000W gen.
  • EstragonEstragon Posts: 2,332Registered Users ✭✭✭✭
    For this application, you might want to consider using AGM automotive starting batteries instead instead of deep cycle.  Starting batteries have thin plates with lots of surface area for short bursts at high discharge rates.  Don't draw them down deeply though. 
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • PhotowhitPhotowhit Posts: 4,544Solar Expert ✭✭✭✭
    jackypaper said:
    My goal: To operate a 15-amp saw with solar power
    I'm going to work with this and assume you understand that this isn't cheap or most practical.
    My plan: Simply replace the small inverter with a 3000-watt inverter to provide for the saw's needs of 1800 continuous watts and 3600+ watt start-up
    What makes you think that there will be a 3600 watt + startup?

    It is very likely a saw spinning up will not be the maximum load, it will likely be <1500 watts with a peak load when cutting into hardwood and binding. I have started my Table saw on an 1800 watt inverter (Prosine with a 2900 watt peak), it's a Delta pulley driven, I think rated as 15 amp.
    My questions: (1) Is running that saw for extremely short periods of time (like, two seconds per cut) possible with a 12-volt system?  (2) If so, how large of an inverter is required?  (3) Do I need a 24-volt system instead if I hope to run that saw at all?
    I think you have a good grasp. I think you could likely run a smaller inverter, pure sine for 2 second cuts on a 12 volt system. Perhaps even on just your 2 T105's. Your challenge will be in voltage drop. Thick wires (4/0) cabling between the batteries and to the inverter and very short distances. I think it's possible for short 2 second cuts.
    Another Option;
    I'm not sure about your needs and desires here, If it's to be able to make some cuts from a 12 volt DC system I would offer a cheaper option than a 1800-2000watt pure sine inverter.

    Buy a Used DeWalt 18 volt saw, plan on the batteries to be dead but be sure to find one with a charger. <$100 used Buy the newer 6 1/2", buy a couple 2000Ah aftermarket pod batteries from Amazon $60. The chargers produced after 2000 will even work on a square wave inverter (some of the earlier ones don't)

    I framed up an 'A' frame with the old trim saw (smaller 5 3/8th") I had a solar supply much like what you have and purchased a new drill and saw kit in 2001. They are limited, but less so than 2 second cuts.



    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • jackypaperjackypaper Posts: 14Registered Users ✭✭
    Raj174 said:
    It would be cheaper and more practical to get a 3500 watt generator.

    You know, this might end up being the better option. 
  • jackypaperjackypaper Posts: 14Registered Users ✭✭
     
    My plan: Simply replace the small inverter with a 3000-watt inverter to provide for the saw's needs of 1800 continuous watts and 3600+ watt start-up
    What makes you think that there will be a 3600 watt + startup?
    Thanks for your reply!

    From what I've read, I assumed that an 1800-watt saw would require at least twice that amount for its initial start-up.  Is that not accurate?
  • PhotowhitPhotowhit Posts: 4,544Solar Expert ✭✭✭✭
     
    My plan: Simply replace the small inverter with a 3000-watt inverter to provide for the saw's needs of 1800 continuous watts and 3600+ watt start-up
    What makes you think that there will be a 3600 watt + startup?
    Thanks for your reply!

    From what I've read, I assumed that an 1800-watt saw would require at least twice that amount for its initial start-up.  Is that not accurate?

    It's not under load, for something like a compressor it's under a large load and making that first cycle is it's largest load. I don't "know" but would think it's unlikely. You wouldn't happen to live in Missouri? ExelTeck 1100 watt inverter will start and run my 12 amp chainsaw, I do it regularly. Exeltech will clip it's wave to run higher wattage items at a different power factor (I don't understand how that works, but it does.



    I do worry that it would be frustration only being able to make short run cuts. I like the idea of using the solar to power the tools, and would hope you will consider the DeWalt Power tool option. People are moving to the newer lithium powered tools which makes a lot of sense, but the older pod battery tools can use the lithium batteries with an adapter and can be found very cheap now. I did a quick search on Craigslist and found a new set in KC MO drill, circular and recip 1 battery and charger for $125 and a saw and battery and charger for <$90 in St Louis. likely most pawn shops would have them as well.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • oil pan 4oil pan 4 Posts: 670Solar Expert ✭✭✭✭
    I run a skill saw and mig welder off my samlex 2000w pure sine 12v input inverter off my 72ah LiFePO4 battery. It works fine.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • jackypaperjackypaper Posts: 14Registered Users ✭✭
    Just as a follow-up, in case anyone is interested, I'm now successfully running my 15-amp miter saw off of two 6-volts and a 2500-watt inverter.  It's a thing of beauty . . .
  • PhotowhitPhotowhit Posts: 4,544Solar Expert ✭✭✭✭
    Just as a follow-up, in case anyone is interested, I'm now successfully running my 15-amp miter saw off of two 6-volts and a 2500-watt inverter.  It's a thing of beauty . . .
    Good deal!
    Mostly during the day with the solar producing?
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • jackypaperjackypaper Posts: 14Registered Users ✭✭
    Photowhit said:
    Just as a follow-up, in case anyone is interested, I'm now successfully running my 15-amp miter saw off of two 6-volts and a 2500-watt inverter.  It's a thing of beauty . . .
    Good deal!
    Mostly during the day with the solar producing?

    Correct.  I've powered my fluorescent lights and stereo at night, but I put a strain on the batteries with the saw only during the Texas sunshine.
  • BB.BB. Posts: 27,446Super Moderators admin
    Very happy to hear that this is working well for you.

    Take care,
    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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