Forum Discussion

phemens's avatar
phemens
Explorer
Oct 04, 2017

Question on inverter/converter setup

I apologize if this has been covered to death elsewhere, it wasn’t obvious to me, so I’ll ask the questions and feel free to chastise me as warranted ;)

I’ll be taking possession of a used 5er in a couple of weeks, so i’m Making my list of projects I want to tackle. In my current setup, I have a 2000 watt pure sine inverter connected to 4 T-125 batteries (yes, with 4/0 wiring throughout). When I turn on the inverter, I plug in the shore power cord, and cut the breaker for the converter, works fine, no issues. We dry camp 95% of the time.

In the new rig, I am thinking of going with AGMs, which may require or warrant changing out the stock converter. At the same time, i’m wondering if it would be worthwhile to go with a combined unit for the converter & inverter. I plan on having a minimum of 600 amp hrs in battery bank, along with at least 750 watts of solar.

Bear with me here, I sometimes have trouble grasping the concepts. If I understand correctly, the combined unit would automatically switch to the inverter to power all the RV 120v, correct? I’m assuming it’s smart enough to cut out the converter function, so that would be one less thing to have to do in my current set up (in addition to plugging in the shore cord to the inverter and turning on/off the inverter).
Questions:
1. what do you do about the fridge/hot water/etc, do you manually set it to LP when the inverter kicks in or when you know you’ll be dry camping?
2. Do you leave the inverter to run all the time - do you worry about any parasitic draw or is there a way to simply disable the inverter when I want?
3. How easy is it to install - other than a simple swap of the existing converter to the new dual unit, any other work to do?
4. Recommended units? Looking for something that could support AGM charge profile (ideally lithium if ever I go that route), and at least 2000w pure sine.
5. Are there any units that also incorporate a solar charge controller. Looking for around 60 amps MPPT. Would it be better to have separate units/ any advantage to combining?

Thanks!
  • 2oldman's avatar
    2oldman
    Explorer II
    Oct 06, 2017
    phemens wrote:

    2. Do you leave the inverter to run all the time - do you worry about any parasitic draw or is there a way to simply disable the inverter when I want?
    3. How easy is it to install - other than a simple swap of the existing converter to the new dual unit, any other work to do?
    4. Recommended units? Looking for something that could support AGM charge profile (ideally lithium if ever I go that route), and at least 2000w pure sine.
    I had a Prosine 2.0 for years and loved it. The simplicity of having everything in one box is nice. Since I had solar I never turned it off, so no, I worried not about parasitic draw.

    3. A whole-house install is very easy. Shore to inverter in, inverter out to existing panel. And the Pro was an excellent surge protector too.. as long as you installed it whole-house.

    4. If you're going to Li that's a different story. They have no absorb settings, and some no float, so that takes a bit more research.

    Good job on going AGM anyway! That'll reduce your maintenance to zero.
  • MrWizard's avatar
    MrWizard
    Moderator
    Oct 04, 2017
    For me lp appliances are always on LP, even when i have hookups, which is rare
    I leave them on LP manually all the time

    Yes the combo unit only charges when external 120vac is available aka shore or generator, no worry about plugging in or turning off converter power
    No endless battery drain loop
  • BFL13's avatar
    BFL13
    Explorer II
    Oct 04, 2017
    I would not go 24v. Too much confusion, already have 12v things that still work just fine, not any real advantage to be gained except in theory for scenarios never lived. YMMV

    The big thing to decide is whether to go whole house on inverter using the shore cord plug- into the inverter trick, or go to some work and do it with transfer switches and sub panels and all that wiring business like some folks do.

    With an inverter/charger you are pretty much into the sub-panelling and transfer switching where you have the built in transfer switch in the I/C plus the other transfer switch between gen and shore power if fitted. Then some more stuff about bonding that drives me crazy. I zone out when that starts on here. :)

    I do the shore cord trick, have no transfer switches, and I don't have or care about bonding. But also I do not have a built in gen like many MHs do to make life more complicated.
  • phemens's avatar
    phemens
    Explorer
    Oct 04, 2017
    The 5er is a 2012, the current location of the converter is adjacent to the front storage bay, so the potential wire run isn't too bad. I get the advantage of separate systems, that's how I roll today, was just wondering if there is a major advantage to combining the converter & inverter other than a bit of convenience.

    Time2roll - if I go 24v on the batteries, the converter will take that draw and output 12v where needed? I run a couple of things straight off the 12v system, including CPAP machine for my wife.
  • time2roll's avatar
    time2roll
    Nomad
    Oct 04, 2017
    Since you are buying everything for a fairly large system... consider going 24 volts on the main battery. You could reduce the controller to 30 amps and use smaller than 4/0 wire for inverter connections. Further I recommend a stand alone inverter, converter and transfer switch or switches. You would need a small 24/12 DC/DC converter to supply existing 12v system.

    You could rewire the fridge but I just put mine on propane. In fact my fridge about always runs on propane. You can put the converter on it's own breaker with the fridge or connect them both before the transfer switch.

    I like separate components so you just need to replace what breaks and easier to fix on the road.
  • BFL13's avatar
    BFL13
    Explorer II
    Oct 04, 2017
    In the new 5er, the location of its converter away from wherever the batteries go might be different from the existing RV. So your options for keeping the big inverter close to the battery bank may not be the same. You might need to place the new charger elsewhere from the converter's location.

    I would leave the new 5er's converter in place and use it for when on shore power. I would place the inverter and a big amp charger (whether one unit or as separate units near the battery bank) It can be easy to have the charger wires go over to the inverter's input wires to share the fat inverter wires from there to the battery bank.

    Make the charger an adjustable voltage type, such as the PowerMax PM3-100ADJ, which lets you match any battery spec and also tweak the voltage from the spec for temperature if need be. I have that one. I doubt it can be run with a 2000w gen though. I use my 3000.
    They do have a 75 amp ADJ but that would be slower recharging on a big battery bank.

    The solar controller also goes near the batteries. All of these things have their negs go to the Trimetric shunt, so it is convenient to keep them close together and put the shunt there too close to the neg battery post.

    Yes you still need to run the fridge and WH on gas. However there might be a way to do a PT with his Magnum thingy.

    It is cheaper to get them all separate and if one dies you can keep going on the other things. All in one, and you are doomed.

About Technical Issues

Having RV issues? Connect with others who have been in your shoes.24,190 PostsLatest Activity: Jan 23, 2025