User Tag List

Page 1 of 2 12 LastLast
Results 1 to 10 of 15
  1. #1
    Left The Driveway
    Join Date
    Apr 2023
    Posts
    7
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)

    Inverter and Shunt

    Hello, I am installing a 3000 watt inverter in a new 324MBS. I have 2 questions. Do I run the ground for the inverter through the shunt? The left side of the shunt goes to the battery. The right side is coming from a solar charger and then to a chassis ground. Second, Should I power the inverter from the terminal block? Or is it too much draw and should the positive go straight back to the battery? Thanks in advance for the help!
    Attached Thumbnails Attached Thumbnails IMG_2461.jpg   IMG_2462.jpg  

  2. #2
    Site Sponsor Mark_303RLS's Avatar
    Join Date
    Jan 2018
    Location
    Cambridge, Ontario, Canada
    Posts
    37
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by CaptD103 View Post
    Hello, I am installing a 3000 watt inverter in a new 324MBS. I have 2 questions. Do I run the ground for the inverter through the shunt? The left side of the shunt goes to the battery. The right side is coming from a solar charger and then to a chassis ground. Second, Should I power the inverter from the terminal block? Or is it too much draw and should the positive go straight back to the battery? Thanks in advance for the help!
    Question #1 The inverter must go through the shunt. I will not read the battery draw correctly if loads are wired around the shunt.
    Question #2 The buss bar would not handle that kind of load. For a 3000w inverter you should probably have a T Class fuse rated for the inverter load and a disconnect switch then connect to the battery.

    Make sure you do your homework before connecting a 3000w inverter. They can draw a lot of power. Cables and terminals need to be sized correctly.
    Cambridge, Ontario, Canada Eh!
    2018 303RLS
    2008 Silverado 2500 HD Duramax

  3. #3
    Site Team Redapple63's Avatar
    Join Date
    Mar 2020
    Location
    SoCal
    Posts
    2,761
    Mentioned
    26 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by CaptD103 View Post
    Hello, I am installing a 3000 watt inverter in a new 324MBS. I have 2 questions. Do I run the ground for the inverter through the shunt? The left side of the shunt goes to the battery. The right side is coming from a solar charger and then to a chassis ground. Second, Should I power the inverter from the terminal block? Or is it too much draw and should the positive go straight back to the battery? Thanks in advance for the help!
    Hi CaptD103,

    Not sure of you configuration, but run the pos for the batteries through a fuse and a switch into a buss bar an then to the loads from the buss bar. Run the neg fro the batteries through the shunt and into the neg buss bar then from that buss bar to the loads.

    The loads would be things like the converter, solar charge controller (if you have one) and the inverter.

    I hope that helps.

    Bill
    2019 GMC 3500 SRW Sierra Denali Duramax
    2020 Reflection 315RLTS

  4. #4
    Left The Driveway
    Join Date
    Apr 2023
    Posts
    7
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Thanks. I think that helps. I have 1/0 cable, a 300 amp inline fuse, and battery disconnect switch to wire inline. My cable runs will be less than 2'. I figured I'd have to go direct to the battery and skip the buss bar. I have 3 x 100AH batteries. I'll upgrade all the battery cables to 1/0 as they're all #6 or #4 now. While it is 3000 watt, I'll probably never actually use 1/2 of the capacity.

  5. #5
    Rolling Along
    Join Date
    Mar 2020
    Location
    Whatever state the landing gear sits upon (Texas c
    Posts
    763
    Mentioned
    16 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by CaptD103 View Post
    Hello, I am installing a 3000 watt inverter in a new 324MBS. I have 2 questions. Do I run the ground for the inverter through the shunt? The left side of the shunt goes to the battery. The right side is coming from a solar charger and then to a chassis ground. Second, Should I power the inverter from the terminal block? Or is it too much draw and should the positive go straight back to the battery? Thanks in advance for the help!
    I do not want to come across as anything else but informative and helpful, BUT you are in SERIOUS risk of causing harm to yourself and/or your coach...

    First and foremost, the fuse is there to protect the wires. 1/0 cable is rated for 125-150amps (generally). Unless you run 2 pcs of 1/0 cables, you are not only far oversized on your fuse (should be rated for the wire around 150 amps MAX) but are far undersized on your cable (should rated to run 250 amps MIN).

    Second, you do not run the ground through anything. Grounds can be continuous or grounded separate depending on the application.

    Third, you would smoke your coach trying to run the inverter off that terminal block, which is barely rated for 100amps IMO.

    Lastly,.please do some more research or consult a professional (or head over to DIYsolar forums and READ READ READ).

    If you have questions, ask, but please don't continue with your intended setup.

  6. #6
    Site Team Redapple63's Avatar
    Join Date
    Mar 2020
    Location
    SoCal
    Posts
    2,761
    Mentioned
    26 Post(s)
    Tagged
    0 Thread(s)
    Agree with sizing wires and fuses properly.

    I am using the Victron Lynx distributor and Pike Industries Pos and Neg buss bars to tie the two batteries together.

    My two batts have 200 amp BMS each, so using 4/0 cables and a 400 amp t-fuse. Going from the Victron Lynx buss bar to my individual loads. From my inverter to the Lynx I am also running 4/0 cable.

    Bill
    2019 GMC 3500 SRW Sierra Denali Duramax
    2020 Reflection 315RLTS

  7. #7
    Seasoned Camper
    Join Date
    Jul 2022
    Location
    Santa Maria, Ca
    Posts
    180
    Mentioned
    9 Post(s)
    Tagged
    0 Thread(s)
    I just finished up the install of my 3k inverter. I went with 3/0 cable do to the short runs. Instead of the Lynx Distributor, I went with the Lynx Power In and added fuses. Even if you only use half the inverter capability, you should size everything based on the total output capacity of your battery bank. If you had a dead short in one of the cables, you want the fuse to blow before that cable melts and causes a fire. Below is a link to the video of my install.



    Here is a link to a great wire sizing calculator.
    https://www.explorist.life/wire-sizing-calculator/
    Last edited by Jomani; 05-06-2023 at 11:01 PM.
    2022 Ram 2500 4x4, 6.7 Cummins, RamBox, Air Lift 5000 Ultimate Plus, B&W Companion
    2022 Reflection 303RLS, Progressive hardwired EMS, Airborne Sidewinder
    YouTube Chanel

  8. #8
    Left The Driveway
    Join Date
    Apr 2023
    Posts
    7
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Thanks everyone. This group is a great resource. I don't know what wire size chart I used before, but the calculator recommended above is great. Using that calculator, it is sill telling me 1/0 cable for 250 amps with 10' of length (which is probably 4x my actual run). This holds true even if I drop the voltage to 10 volts, which would never happen.

    I see that 300 amp fuse is too high, although I'm confused by the 427 max fuse size in the calculator? If I drop the fuse to 250 amps but keep the 1/0 cable, do you think I'm OK? I keep getting different answers depending on where I go for information. I get everything from #4 on some, to 1/0 from this calculator to as much as 400. Length of run seems to be the big determining factor and my total run won't be 3'. Click image for larger version. 

Name:	Wire Size.jpg 
Views:	13 
Size:	79.9 KB 
ID:	46211

  9. #9
    Seasoned Camper
    Join Date
    Jul 2022
    Location
    Santa Maria, Ca
    Posts
    180
    Mentioned
    9 Post(s)
    Tagged
    0 Thread(s)
    @CaptD103
    I am not sure where you are getting the 250 Amp number. A 3k inverter can draw 350 Amps continuous and even higher than that with an AC surge. Keep in mind you will also have all of the DC load as well.

    Most 100hah lithium batteries are capable of 100 Amps continuous output but will allow higher surge output (check with your battery manufacturer). At minimum you should scale your system for 300 Amps. That means cable, bus bars, switch, and fuses that exceed that. When calculating the length of a wire run you need to think round trip - from the negative terminal back to the positive terminal.

    It sounds like you plan to keep the factory bus bar and converter circuit. There is nothing wrong with that as long as you make that a branch circuit and not the main bus bar. If you watched my video you saw my circuit diagram. I use the Lynx Power In as my main bus bars. From there I have a branch circuit that goes through an 80 Amp fuse to my new converter. That same circuit feeds the original battery disconnect and the original bus bar.

    For my inverter circuit, I am currently using a 250 Amp fuse in the Lynx only because I am currently running off a single 200ah battery. When I add a second battery I will bump that fuse up to 300 Amps. I also have a 300 Amp battery terminal fuse. Since my battery’s BMS will allow up to a 280 Amp surge, I made sure the first fuse in the system exceeded that.

    The next big question - are you planning to use an inverter prep circuit or do you plan to power the whole rig? If you go inverter prep you will need an automatic transfer switch and/or a way to keep your converter from running when powered by the inverter.

    I suggest you draw this all out on paper before you start. Again, take a look at my video and pause it on the wiring diagram. When thinking about fuses, think about where the power is coming from and how you will protect the wire in the event of a dead short. While your primary power source is the battery, you also have power coming from your solar controller and converter. I moved my solar controller circuit over to the Lynx as opposed to running it directly to the battery. Since that circuit is fused in the Lynx, I eliminated the factory circuit breaker to make for a cleaner install.

    With 3 lithium batteries you also need to think about upgrading your battery disconnect. I opted to keep my original disconnect to power the factory bus bar and DC panel. The new disconnect will kill power to everything.

    There is a lot to think about before heading down this rabbit hole. Planning ahead will save you a lot of money and heartache.

    You might also want to check out the videos I made for the inverter prep circuit and battery disconnect - link in my signature block.
    Last edited by Jomani; 05-07-2023 at 10:49 AM.
    2022 Ram 2500 4x4, 6.7 Cummins, RamBox, Air Lift 5000 Ultimate Plus, B&W Companion
    2022 Reflection 303RLS, Progressive hardwired EMS, Airborne Sidewinder
    YouTube Chanel

  10. #10
    Rolling Along
    Join Date
    Mar 2020
    Location
    Whatever state the landing gear sits upon (Texas c
    Posts
    763
    Mentioned
    16 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by CaptD103 View Post
    Thanks everyone. This group is a great resource. I don't know what wire size chart I used before, but the calculator recommended above is great. Using that calculator, it is sill telling me 1/0 cable for 250 amps with 10' of length (which is probably 4x my actual run). This holds true even if I drop the voltage to 10 volts, which would never happen.

    I see that 300 amp fuse is too high, although I'm confused by the 427 max fuse size in the calculator? If I drop the fuse to 250 amps but keep the 1/0 cable, do you think I'm OK? I keep getting different answers depending on where I go for information. I get everything from #4 on some, to 1/0 from this calculator to as much as 400. Length of run seems to be the big determining factor and my total run won't be 3'. Click image for larger version. 

Name:	Wire Size.jpg 
Views:	13 
Size:	79.9 KB 
ID:	46211
    Honestly, I'm surprised his calculator is calling for that. He is very knowledgeable, but none of that makes sense, and I'm wondering what variables he's accounting for. Here's my math with references:

    You must rate off capability of inverter , so a 3000watt (continuous) inverter is roughly 250 amps constant (3000W ÷ 12V = 250A). BUT it's best practice to go off peak wattage capability (varies by inverter), so maybe find that out.

    I always add 10-15% for safety margins, so that means I would recommend a cable and fuse capable of handling 275A.

    MOST 1/0 copper will not clear 150A. Yes, there's something to be said about short distances, but 250A over 1/0 over any distance is nuts. Battleborn recommends 4/0 to parallel their batteries (even 2P1S), and that's over very short distances.

    See numerous references for cable ampacity ratings below. There are variances in cable type and construction, but I always say to play it safe and go off the lower number. If you don't know the specific rating of your cable, then go off lowest possible.

    I can tell you with my own experiences that 250A over 4/0 cable roughly 22" long will get that cable pretty warm. And that's with multi-strand high-end 105C rated cabling.

    Chart #1

    chart #2

    cable size calculator
    Last edited by A.Texas.Yankee; 05-07-2023 at 11:07 AM.

Page 1 of 2 12 LastLast

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

DISCLAIMER:This website is not affiliated with or endorsed by Grand Design RV, LLC or any of its affiliates. This is an independent site.