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  • Inverter size?

    I'm planning a DIY upgrade of two lithium batteries and adding an inverter in my 2600 RB . I like the simplicity of connecting the shore power cord to the inverter when dry camping as some people have done. One goal of my planning is to be able to add solar or more batteries later if desired without having to upgrade wiring etc. A 2000 watt inverter should be enough, but why not get a 3000 watt and be done with it? Would the 3000w be consuming too many of my available two-battery amps?
    Tom and Kathy
    2017 2600RB
    2011 Ford F150 ecoboost

  • #2
    Originally posted by tmrgn99 View Post
    I'm planning a DIY upgrade of two lithium batteries and adding an inverter in my 2600 RB . I like the simplicity of connecting the shore power cord to the inverter when dry camping as some people have done. One goal of my planning is to be able to add solar or more batteries later if desired without having to upgrade wiring etc. A 2000 watt inverter should be enough, but why not get a 3000 watt and be done with it? Would the 3000w be consuming too many of my available two-battery amps?
    There's a lot of variables to your question. A basic consideration when pondering 2000W vs 3000W is the battery bank and their "C" rate.

    The Battle Born 100aH battery I have is capable of delivering a maximum of 100 amps for 1 hour. That's called a "1C" rate. I believe "1C" means the battery can output 100% of it's rated capacity in one hour.

    If I only had one battery, it wouldn't matter if I had a 2000W or 3000W inverter--the max that I could get is 100 amps from the battery at a given moment. (I'm ignoring the surge capacity of the battery and inverter for simplicity.) Hopefully you know that 100 amps of 12v DC roughly equals 10 amps of 120vAC after inversion. A 2000W inverter is rated for ~16.7 amps of 120vAC and a 3000W for 25 amps. (Watts / Voltage = Amperage.) If we assume for now that the two lithiums you possess are rated at 1C and are in parallel, that means a max of 200 amps of 12vDC, so this is a good match for a 2000W inverter. (I have four Battle Borns in parallel connected to a 3000W inverter. If there's one thing I've learned over the last year or so--"size matters" when it comes to the battery bank!)

    The issue with a 2000W inverter is it could be easy to overload, especially if the microwave is on the "will be used" list. Do some homework on the current draw of your 120v components and you'll see how 16.7 amps can be tapped out quickly. (You do realize the air conditioner is not even a consideration--right? You'd need an enormous bank of batteries.)

    So...if you're going to go with a 3000W inverter, plan on adding a third battery.

    FYI, I learned this battery-to-inverter info from Garret Towne, the lead engineer at AMSolar. (Look up his YouTube videos--well worth the time to watch.)

    Howard
    Forum moderators are not GD employees--we are volunteers and owners presumably just like yourself. Unless specifically mentioned otherwise, we have nothing to gain should you choose to purchase a product or engage a service we discuss on this forum.

    2017 Ford F-350 DRW, '19 315RLTSPlus

    Comment


    • #3
      There's a lot of variables to your question. A basic consideration when pondering 2000W vs 3000W is the battery bank and their "C" rate.

      The Battle Born 100aH battery I have is capable of delivering a maximum of 100 amps for 1 hour. That's called a "1C" rate. I believe "1C" means the battery can output 100% of it's rated capacity in one hour.

      If I only had one battery, it wouldn't matter if I had a 2000W or 3000W inverter--the max that I could get is 100 amps from the battery at a given moment. (I'm ignoring the surge capacity of the battery and inverter for simplicity.) Hopefully you know that 100 amps of 12v DC roughly equals 10 amps of 120vAC after inversion. A 2000W inverter is rated for ~16.7 amps of 120vAC and a 3000W for 25 amps. (Watts / Voltage = Amperage.) If we assume for now that the two lithiums you possess are rated at 1C and are in parallel, that means a max of 200 amps of 12vDC, so this is a good match for a 2000W inverter. (I have four Battle Borns in parallel connected to a 3000W inverter. If there's one thing I've learned over the last year or so--"size matters" when it comes to the battery bank!)

      The issue with a 2000W inverter is it could be easy to overload, especially if the microwave is on the "will be used" list. Do some homework on the current draw of your 120v components and you'll see how 16.7 amps can be tapped out quickly. (You do realize the air conditioner is not even a consideration--right? You'd need an enormous bank of batteries.)

      So...if you're going to go with a 3000W inverter, plan on adding a third battery.

      FYI, I learned this battery-to-inverter info from Garret Towne, the lead engineer at AMSolar. (Look up his YouTube videos--well worth the time to watch.)

      Howard
      I just finished reading an explanation of the C rating. I see what your saying three 100h batteries(I've pretty much settled on the Battleborns) would be a better match if I go with the 3000w.
      I also did watch a couple of the Garret Towne videos and they're good.
      Thanks Howard!

      Tommy
      Tom and Kathy
      2017 2600RB
      2011 Ford F150 ecoboost

      Comment


      • #4
        Originally posted by tmrgn99 View Post
        Tommy
        Out of curiosity, how do you plan on recharging your batteries?

        Norm

        Norm & Karla
        2019 Imagine 2150rb
        2018 Chevrolet Silverado 2500HD
        2016 - 2018 Hobie Kayaks

        Comment


        • #5
          Originally posted by Oregon Fun-Guy View Post

          Out of curiosity, how do you plan on recharging your batteries?

          Norm
          I bought the 55amp Progressive Dynamic lithium replacement charger for the WFCO 8955 board's OEM charger from Best Converter. I'll also upgrade the 8 awg charge wire to 4 awg. Thanks to your comment on another thread I'll be getting that wire from the Windy Nation website, Their Amazon listings didn't offer good choices for the length I need. Your 2150RB electrical must closely resemble mine.

          http://www.bestconverter.com/PD-4655...l#.XrSkSpl7lpn

          I have a Westinghouse iGen2500 generator to run when dry camping. I might add solar in the future.
          Tommy
          Last edited by tmrgn99; 05-07-2020, 07:53 PM.
          Tom and Kathy
          2017 2600RB
          2011 Ford F150 ecoboost

          Comment


          • #6
            tmrgn99 Tommy, your trailer and mine are very much alike. You have a dinning area and longer counter to use up the extra three feet that your trailer is longer than mine. If you have any questions about what you are going to run into feel free to ask. Midwest Camper has the same model as yours and will be going through a similar project as you. BTW the wire change will benefit you greatly.
            Norm & Karla
            2019 Imagine 2150rb
            2018 Chevrolet Silverado 2500HD
            2016 - 2018 Hobie Kayaks

            Comment


            • #7
              Originally posted by howson View Post

              The issue with a 2000W inverter is it could be easy to overload, especially if the microwave is on the "will be used" list.
              Howard
              So Howard -- what do you make of the following:

              My battery bank is now 4 ea. 105 amp-hour lithiums. I have a 1500 AIMS inverter/charger with a surge rating (20s) of 4500 watts.

              Without thinking it thru, when I put my inverter subpanel in, I moved my 1500 watt (I know it's 1500 because I just read the door label) microwave load to the subpanel. The microwave has been working for me, even with my old AGM battery bank.

              As you may recall, I recently installed a Victron BMV-712 monitor. After reading your response in this post, I started shaking my head. Why am I able to run my 1500 watt microwave with a 1500 watt inverter? Well guess what the BMV says when I'm running the microwave. It says I'm pulling 1720-1800 watts out of the battery! And this is over a duration of minutes -- not the 20s surge duration.

              I called AIMS. He wanted to know the wattage consumption of the microwave, but I didn't have that information at the time. The only real conclusion he had was that a 1500 watt inverter was probably undersized for running a microwave.

              But the darn thing runs. And by the way, I checked the inverter and power lines. No overload lights, and the inverter was cool. Fan was running, but the inverter was cool.

              Any thoughts?

              -Steve
              2018 Solitude 310GK, disc brakes
              Morryde SRE4000/XFactor with heavy duty shackles, V-Brackets in spring hangers
              2012 Ram 3500 SRW 6.7 Diesel, air bags
              18k B&W Companion, non-slider
              640 watts solar, 400 amp-hour Lion Safari UT 1300 battery bank
              Aims 1500 watt inverter/charger with ATS
              Somerset, WI

              Comment


              • #8
                Originally posted by steve&renee View Post

                So Howard -- what do you make of the following:

                My battery bank is now 4 ea. 105 amp-hour lithiums. I have a 1500 AIMS inverter/charger with a surge rating (20s) of 4500 watts.

                Without thinking it thru, when I put my inverter subpanel in, I moved my 1500 watt (I know it's 1500 because I just read the door label) microwave load to the subpanel. The microwave has been working for me, even with my old AGM battery bank.

                As you may recall, I recently installed a Victron BMV-712 monitor. After reading your response in this post, I started shaking my head. Why am I able to run my 1500 watt microwave with a 1500 watt inverter? Well guess what the BMV says when I'm running the microwave. It says I'm pulling 1720-1800 watts out of the battery! And this is over a duration of minutes -- not the 20s surge duration.

                I called AIMS. He wanted to know the wattage consumption of the microwave, but I didn't have that information at the time. The only real conclusion he had was that a 1500 watt inverter was probably undersized for running a microwave.

                But the darn thing runs. And by the way, I checked the inverter and power lines. No overload lights, and the inverter was cool. Fan was running, but the inverter was cool.

                Any thoughts?

                -Steve
                How many watts does the BMV show being pulled from the battery with the microwave off? The difference is what is being inverted. If it's all 1800 watts I'm surprised the AIMS doesn't complain after a period of time in the overload condition.

                So my thoughts? With four 105aH lithiums, with an assumed 1C rate for each, that's 400 amps of 12vDC available so there's untapped capability due to the inverter size. That AIMS is running full tilt with the microwave running but apparently within it's capability. If it works, why mess with it? If you're looking to upgrade, the most expensive portion is already done (the batteries). WIth four batteries you can easily upgrade to a 3000W inverter.

                Is your system documented in a diagram here?
                Forum moderators are not GD employees--we are volunteers and owners presumably just like yourself. Unless specifically mentioned otherwise, we have nothing to gain should you choose to purchase a product or engage a service we discuss on this forum.

                2017 Ford F-350 DRW, '19 315RLTSPlus

                Comment


                • #9
                  Originally posted by howson View Post

                  How many watts does the BMV show being pulled from the battery with the microwave off? The difference is what is being inverted. If it's all 1800 watts I'm surprised the AIMS doesn't complain after a period of time in the overload condition.
                  Don't recall precisely, but I think the load with the microwave off is only around 25 watts. So most of the load is associated with feeding the microwave. I assume the number is higher than the 1500 watt microwave because the inverter spec says inverter peak efficiency is 88%. 1500 / .88 = 1705. 1705 + 25 = 1730. Pretty close.


                  Originally posted by howson View Post
                  If you're looking to upgrade, the most expensive portion is already done (the batteries). WIth four batteries you can easily upgrade to a 3000W inverter.
                  Have you priced 3000 watt inverter/chargers lately?

                  Originally posted by howson View Post
                  Is your system documented in a diagram here?
                  No. Not the whole thing in one place. Why? You think I may have come up with a way to make a 1500 watt inverter out perform?

                  -Steve


                  2018 Solitude 310GK, disc brakes
                  Morryde SRE4000/XFactor with heavy duty shackles, V-Brackets in spring hangers
                  2012 Ram 3500 SRW 6.7 Diesel, air bags
                  18k B&W Companion, non-slider
                  640 watts solar, 400 amp-hour Lion Safari UT 1300 battery bank
                  Aims 1500 watt inverter/charger with ATS
                  Somerset, WI

                  Comment


                  • #10
                    howson steve&renee amp;

                    Maybe the inverter manufacturer actually built in a "safety margin" between the published specs and what their product can actually do ?
                    What a novel engineering concept .

                    Rob
                    Cate & Rob
                    (with Border Collies Molly & Angel + Kitties Hazel & Elsie)
                    2015 Reflection 303RLS
                    2022 F350 Diesel CC SB SRW Lariat
                    Bayham, Ontario, Canada

                    Comment


                    • #11
                      Originally posted by Oregon Fun-Guy View Post
                      tmrgn99 Tommy, your trailer and mine are very much alike. You have a dinning area and longer counter to use up the extra three feet that your trailer is longer than mine. If you have any questions about what you are going to run into feel free to ask. Midwest Camper has the same model as yours and will be going through a similar project as you. BTW the wire change will benefit you greatly.
                      Thanks Norm, I do appreciate all advice and comments as this is my first attempt to do something like this.

                      I plan to not use that OEM battery switch and instead use a battery switch on the panel that I'll be building in the pass-thru to mount the inverter etc. That will eliminate abt 15' of charge wire.

                      One thing that continues to bother me at this time is that the only grounding to the trailer frame I've planned for is the original 3 foot 8 awg wire from the converter at the circuit board that is 22 feet from the battery bank(three 100ah battleborns). And another 8 or 10 awg wire from the Victron BMV 712 negative shunt to the trailer frame. Does the battery bank negative need to go to the trailer frame with a heavier wire?
                      Tommy
                      Tom and Kathy
                      2017 2600RB
                      2011 Ford F150 ecoboost

                      Comment


                      • #12
                        Originally posted by steve&renee View Post
                        Have you priced 3000 watt inverter/chargers lately?
                        If my reply came across as thoughtless I apologize. Sometimes the written word fails to convey intent as well as content.

                        Forum moderators are not GD employees--we are volunteers and owners presumably just like yourself. Unless specifically mentioned otherwise, we have nothing to gain should you choose to purchase a product or engage a service we discuss on this forum.

                        2017 Ford F-350 DRW, '19 315RLTSPlus

                        Comment


                        • #13
                          Originally posted by howson View Post

                          If my reply came across as thoughtless I apologize. Sometimes the written word fails to convey intent as well as content.
                          I certainly didn't take it that way. Not in the slightest way. Maybe it was me being flip. Though that was not my intent.

                          All is well. I value your experience, views, and opinions.

                          -Steve
                          2018 Solitude 310GK, disc brakes
                          Morryde SRE4000/XFactor with heavy duty shackles, V-Brackets in spring hangers
                          2012 Ram 3500 SRW 6.7 Diesel, air bags
                          18k B&W Companion, non-slider
                          640 watts solar, 400 amp-hour Lion Safari UT 1300 battery bank
                          Aims 1500 watt inverter/charger with ATS
                          Somerset, WI

                          Comment


                          • #14
                            Originally posted by tmrgn99 View Post

                            I plan to not use that OEM battery switch and instead use a battery switch on the panel that I'll be building in the pass-thru to mount the inverter etc. That will eliminate abt 15' of charge wire.

                            One thing that continues to bother me at this time is that the only grounding to the trailer frame I've planned for is the original 3 foot 8 awg wire from the converter at the circuit board that is 22 feet from the battery bank(three 100ah battleborns). And another 8 or 10 awg wire from the Victron BMV 712 negative shunt to the trailer frame. Does the battery bank negative need to go to the trailer frame with a heavier wire?
                            Tommy
                            Let me take the first crack at your question about the ground. My answer is what I did in light of a reputable article I read. I apologize for not having the link to the article. Their main pertinent statement was that the ground did not have to be the same size as the main positive wire. It could be one size smaller. I our case of switching to 4 AWG wire the ground could be 6 AWG. What I found out was the ground busbar originally used would not accept the 4 gauge so I bought two bigger lugs that would attach to the ground bar. The groundbar is located behind the converter which you will have to remove to pull the wires up. I attached one end of a 4 gauge wire to the power panel in place of the 8 gauge ground wire and then the other end to the lug attached to the ground bar. I attached another short length of 4 gauge ground wire to the second bigger lug on the busbar. The other end attached in place of the second ground 8 gauge wire attached to the frame. I got to the frame attachment by cutting two slits in the bottom cover of the trailer just big enough to get my impact driver to the wire connection. When done I taped the slits with Gorilla Tape and foamed up one opening in the bottom cover I created. If needed I could remove my power panel again and take pictures. Here's an HD link that shows a ground bar with a bigger lug. You can buy the lugs separately. This will all look familiar once you've seen the area behind the converter/power panel in your trailer. I guess in all of this I am saying that a new ground wie is doable and I would do it with 4 gauge wire.

                            I replaced my disconnect switch much the same way you planned. I followed howson 's lead and installed the switch side inside the living area attached to the "night stand". In my case this gave me easy access because I installed two battery banks and use this switch to quickly changeover the banks at night.
                            Norm & Karla
                            2019 Imagine 2150rb
                            2018 Chevrolet Silverado 2500HD
                            2016 - 2018 Hobie Kayaks

                            Comment


                            • #15
                              Originally posted by Oregon Fun-Guy View Post

                              Let me take the first crack at your question about the ground. My answer is what I did in light of a reputable article I read. I apologize for not having the link to the article. Their main pertinent statement was that the ground did not have to be the same size as the main positive wire. It could be one size smaller. I our case of switching to 4 AWG wire the ground could be 6 AWG. What I found out was the ground busbar originally used would not accept the 4 gauge so I bought two bigger lugs that would attach to the ground bar. The groundbar is located behind the converter which you will have to remove to pull the wires up. I attached one end of a 4 gauge wire to the power panel in place of the 8 gauge ground wire and then the other end to the lug attached to the ground bar. I attached another short length of 4 gauge ground wire to the second bigger lug on the busbar. The other end attached in place of the second ground 8 gauge wire attached to the frame. I got to the frame attachment by cutting two slits in the bottom cover of the trailer just big enough to get my impact driver to the wire connection. When done I taped the slits with Gorilla Tape and foamed up one opening in the bottom cover I created. If needed I could remove my power panel again and take pictures. Here's an HD link that shows a ground bar with a bigger lug. You can buy the lugs separately. This will all look familiar once you've seen the area behind the converter/power panel in your trailer. I guess in all of this I am saying that a new ground wie is doable and I would do it with 4 gauge wire.

                              I replaced my disconnect switch much the same way you planned. I followed howson 's lead and installed the switch side inside the living area attached to the "night stand". In my case this gave me easy access because I installed two battery banks and use this switch to quickly changeover the banks at night.
                              Norm,
                              Thanks! Your reply is spot on. You described perfectly what I was looking at and not liking any of the ideas I was coming up with. I did not know about those bigger lugs.Thanks for the link! I already have the slit in the bottom cover from having routed the BMV-712's UTP cable from the entertainment area to the front of the trailer. I'm looking at installing the batteries under the bed and having the inverter, switches etc. mounted to a panel on the adjacent wall in the pass thru.

                              The OEM battery was mounted on the tongue with it's negative 8 awg wire attached to the trailer frame at juncture with some other smaller white negative wires. All with the same bolt in the frame. I suppose I could remove that old negative battery wire and attach a new 4awg wire from that same frame junction to the load side of the BMV-712 negative shunt on the pass thru wall panel.
                              Tommy
                              Tom and Kathy
                              2017 2600RB
                              2011 Ford F150 ecoboost

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