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Ideas with some hypothetical numbers for extended boon docking in RV

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  • Ideas with some hypothetical numbers for extended boon docking in RV

    Hi all,

    My first post, been lurking and trying to understand as much as I can, please bear with me. I do not own an RV yet and have not bought anything for this adventure.

    I have thoughts of modifying a 25 ish foot bumper pull RV for a one ish year 'walkabout', mostly in southwest. From what I have read I think I would have 400-600ah battery bank.-AGM? A 3000 watt pure sine hybrid inverter/charger with the ability to use mostly generator and battery power for surges.
    Honda EU2000 portable generator if I would need to run the air unit or to charge batteries. Solar panels and mppt solar charger and of course battery monitoring system. I am leaning towards Victor equipment for compatibility reasons.

    I have done extensive camping in a tent and have never stayed or played in an RV. I don't know much about converting watts to AH and hope I can get some help on here. I know I have left out the water pump and any furnace blower usage. I have guessed at some of the wattage and thought this was good enough to share here. I think without considering any inefficiencies I would use 221ah in a day?

    AC Watts Hours used
    AC watts DC Watts
    Router 10 6 60
    Apple TV 2 6 12
    Vornado
    Fan
    44 6 264
    2-Fantastic
    Roof Fans
    12 860
    Tv 100 4 400
    Laptop 100 4
    Phones 4 96
    Ipad 4 48
    Microwave 1500 0.1 150
    Hair Dryer 1500 0.1 150
    Toaster 800 0.2 160
    Radio 5 100
    Inverter 6 180
    Lights 5 50
    1196 1334
    Dc amps 110 111

  • #2
    you came here more prepared than others

    If I understand your table correctly both columns AC watts and DC Watts actually mean Watt-hours so your loads demand 1196 + 1334 = 2530 Wh of energy per day. Now if you take 12V 221Ah battery it would have 12 x 221 = 2652 Wh stored. 'Dc amps' line actually means Ah required from 12V battery. So far so good except AGM is probably poor choice for your application due to costs but they will be less messy for sure.



    Last edited by max2k; 09-14-2017, 12:02 AM.

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    • #3
      Thanks for the response Max2k.

      Yes you understand the table as it was meant to be! I do like to make sure I spend my money wisely the first time...

      When I was researching it looks like most boondockers are happy with 400ah of battery. When I haphazardly through numbers on the wall for my usage I came up with 500ah+. I was hoping my numbers or calculations were off somehow. Is there anyone here that has first hand experience with this type of setup that can say I will need more or less ah in the batter bank?

      The main reason for AGM is with a bumper pull trailer the easiest location for the battery bank is a direct addition to the tongue weight and two L16's will weigh 250# with out wires, inverter, charger or temperature control. I can't find travel trailer with the ability to add that much weight to the tongue of empty trailer. So unless I am not understanding something simple I will need to mount the battery bank closer to middle of trailer. AGM should allow for faster charging also, but I have not understood all that I have read about the C rating with regards to charge and discharge. I am sure there is time for that later.

      Everything now is hypothetical until I can nail the exact trailer down and figure out the available Real estate on the roof. I have thoughts of panels mounted to top of trailer similar to awning and tipping up to 145 degrees for best angle for where and when I am parked. It would be nice if they were able to be removed and carried inside rv too, maybe someone already makes this type of setup?

      Comment


      • #4
        To save weight, you could look into:
        a) energy diet and use smaller batteries
        b) Lithium batteries (much lighter weight, and less mature tech)
        Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
        || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
        || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

        solar: http://tinyurl.com/LMR-Solar
        gen: http://tinyurl.com/LMR-Lister

        Comment


        • #5
          I believe the wife and I are conservative with electricity and we will get better.
          I have looked at lithium batteries and it has an added cost of $5000 from what I could find. At this point I believe I would be better off spending extra money on solar panels and wire to back of travel trailer to AGM battery bank.

          Comment


          • #6
            Originally posted by Treejohnny View Post
            I believe the wife and I are conservative with electricity and we will get better.
            I have looked at lithium batteries and it has an added cost of $5000 from what I could find. At this point I believe I would be better off spending extra money on solar panels and wire to back of travel trailer to AGM battery bank.
            what Mike was probably referring to is LFP prismatic cells- they have many advantages, cost is actually comparable to FLA (way cheaper than AGM) and are the safest type among Lithium batteries. They are still capable of starting good fire if not used properly. Many RV- ers use them and posted on this forum- try google those threads, there were few in the past so you can even find updates after few years in use. I'd stay away from other types of Lithium batteries for your application due to their much less forgiving nature often ending in fire.
            Last edited by max2k; 09-15-2017, 12:25 AM.

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            • #7
              Well done on the planning. I'll offer some input from the boondocking perspective not necessarily related to your chart - I suggest downsizing the 3000 watt inverter and only using the microwave, hair drier, and toaster off generator power. It takes a lot of battery to make heat and complicates the DC side of your design due to having to accommodate the hundreds of amps that it requires. Your Honda EU2000 can easily handle those loads, although it will have to be one at a time. I would recommend going no larger than 1000 or 1500 watts on the inverter side, that will cover most AC loads you'd want to run from an inverter. You can also probably save some money by avoiding the hybrid inverter/charger unit and just go with a pure sine wave inverter. Recognizing that you'll still want a way to bulk charge quickly using a generator/shore power means you'll want to upgrade the onboard converter to a more boondocker-friendly one. Most new campers seem to come with a WFCO model converter that claims to be a 3-stage smart charger but in practice never actually uses its boost mode (14.4V). It will charge to no more than 13.6V which won't get you charged up quickly at all. Progressive Dynamics and Iota are popular converters that have boost modes that work properly that can also be manually engaged. If you will be driving frequently then consider upgrading the charging capability from your tow vehicle as well.

              If you want to run your rooftop air conditioner (likely a 13.5 kBtu unit), your Honda EU2000 may not be strong enough to overcome the startup surge. If you'll always be at low elevations, then maybe it will be to do it but it will be marginal at best. However, there is a product on the market called "Micro Air" that is a soft start kit that you install on your air conditioner that minimizes the start up surge. It costs around $350, but it works. I installed on this year and we can now reliably run our rooftop air conditioner with our Yamaha 2400 gen. There are success stories using the Honda EU2000 as well. I know you mentioned that your plan would be to use the hybrid inverter/charger as a way to deal with the surge and I've read success stories about this as well. I just offer the Micro Air solution as an alternative that is probably cheaper and can also simplify your design.

              We strictly boondock camp and get by just fine with 200 ah battery bank (2x6V GC batteries in series) and 280 watts of solar mounted fixed and flat on the camper roof. Mine are 12V nominal panels with a PWM controller. This works for us, but we are long weekend warrior campers so we don't have to necessarily worry about long stretches of poor solar harvest. Having a generator as backup means you wouldn't necessarily have to either. But for your plan I would say twice the battery and solar that we have would be a good plan. MPPT as well.
              Last edited by ewarnerusa; 09-15-2017, 12:48 PM.
              I'm an RV camper, mine has 280 watts of solar

              Comment


              • #8
                Originally posted by Mike90250 View Post
                To save weight, you could look into:
                a) energy diet and use smaller batteries
                b) Lithium batteries (much lighter weight, and less mature tech)
                Mike - I have seen a couple of threads that talk of the LFP batteries but when I search on google the batteries cost more than AGM and that is not including the BMS. Unless I am missing something?

                Comment


                • #9
                  ewarnerusa - I do like to plan!

                  I have gave a lot of thought as to what will be sustainable for our fulltime adventure, I don't think pulling a generator out every time we want to use the microwave is sustainable. If I had mounted genset with starter, that would be different and I should look into that.

                  Some of the reasons behind my product decisions are if everything changes these parts could be used off grid at a house. The hybrid inverter can be 'stacked' with another to get 6000 watts or 3000 wats at 240.

                  I have looked into the capacitors that 'soft start' the air conditioner and that seems like an easy decision.
                  Last edited by Treejohnny; 09-21-2017, 08:40 AM.

                  Comment


                  • #10
                    Just to clarify, I'm referring to a soft start kit called Micro Air and not a hard start capacitor. The hard start cap approach is usually to install the SUPCO SPP6 cap. We tried that, too, and it didn't help all that much. The Micro Air did.
                    We have used our camper microwave one time in 6 years. So I forget we even have that capability. I use ours for storage!
                    3000 watts / 12V = 250 amps of DC current that you'll have to plan around.
                    Last edited by ewarnerusa; 09-21-2017, 09:11 AM.
                    I'm an RV camper, mine has 280 watts of solar

                    Comment


                    • #11
                      LFP batteries are not cheap, and the tech and supporting BMS is not fully mature. If you are able to educate yourself about them, and can manually manage your own bank, that "could" work, I just am not confident with the "turnkey" packages yet, one aspect is lacking on each of them. One forgets the good BMS, someone else has good BMS but wires it wrong, Someone else forgets to set the battery cycles to 20%-80% and report the reduced bank capacity (only 60% of the battery nameplate, because you sacrifice capacity for longevity.)
                      Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
                      || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
                      || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

                      solar: http://tinyurl.com/LMR-Solar
                      gen: http://tinyurl.com/LMR-Lister

                      Comment


                      • #12
                        Thanks everyone for all of your suggestions and input!

                        I have been working a bigger truck for the tow veichle....

                        I have an idea about a solar awning and looking for your thoughts.
                        If I have a frame that would allow 6

                        Comment


                        • #13
                          I can tell you from experience that you don't want to leave your camper awning out unattended. The wind will pick up and destroy the arms from the sail whipping in the wind. If you can't leave your solar out every day all day, I'd personally say not worth it. Fixed and flat on the roof is the easiest and hands free. It works everyday all day when the sun is shining with no user input. You suffer some inefficiencies from not having ideal angles, but the convenience makes up for it.
                          I'm an RV camper, mine has 280 watts of solar

                          Comment


                          • #14
                            ewarnerusa - I am glad you shared your experience! It seemed like such a great idea in my head...


                            I am mostly decided on an ATC toy hauler trailer. It comes with the 50 amp version 4500 series converter by progressive dynamics. It has its own breaker box built in.
                            -It looks like this should work with my plans.

                            It also has a Lyght LPT50BRD automatic transfer switch for shore power.
                            -Will this be sufficient?
                            -The Honda EU2000 genset would use this too?
                            -I believe that I will need additional switch for the inverter power to enter into the 4500 converter box?

                            The (huge) battery area is in the front of the trailer and the converter is in middle of 28' trailer.
                            -If I use AGM batteries I can have inverter located right above the battery bank?
                            -I can have MMPT solar charger above battery bank?
                            -How do I keep DC power to converter/trailer and use inverter?

                            I am having an issue figuring out the battery bank. I would like to have 300AH useable and 600ish AH bank. With the RV using a bit of 12 volt DC I should have two or four 6 volt batteries to reach 12 volt or two 12 volt in parallel to get even charging and discharging. I have been leaning towards Crown for a manufacturer and the gassing idea would be problematic for my application. Does anyone have a better idea?

                            I have replumbed and rewired every house I have bought so far but I have zero experience with an RV, please bear with my ignorance.
                            Last edited by Treejohnny; 10-02-2017, 02:28 PM.

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                            • #15
                              Treejohnny

                              2 x Crown AGM 6 Volt 390 AH in series
                              https://www.wholesalesolar.com/99601...6v-l16-battery


                              2 x Trojan 6 Volt L16-AGM 370AH in series
                              http://www.trojanbattery.com/product/reliant-l16-agm/


                              6 x 2 Volt Lifeline AGM 630AH in series
                              http://lifelinebatteries.com/product...es/gpl-31t-2v/
                              Last edited by NEOH; 10-03-2017, 05:51 PM.

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