Another RV thread

[time2roll]

So the one difference is I got be able to hand a 240V input or a 120V input. That is why I was debating on putting the transfer switch in. As far as power is concerned I probably am about 1 AC based on the battery just due to the simple fact I think I will kill the battery too quickly otherwise. I do in fact have 2 ACs in the trailer though. I try and get away with fans whenever I can vs AC and just suffer overnight. I am in the northeast so in general it isn't as bad as it would be south and west. I do like the fact of the ability to use a lot of my stuff I already have for 24V vs 48V but it is mainly fuses or small circuit breakers. I would need a new DC to DC regardless. I also like the redundant factor built in to the 24V system. I do worry about the 3KW starting my AC though.

The system can handle 6000 watts pushing a single 120v onto both hot feeders.
If 50amp utility power is available then it switches back to 12,000 watts.

 

[mmmmmdonuts]

I wish I saw that AC before I replaced mine last year. I still need to figure out how to do the solar. 5 panels makes it a little awkward but I could possibly get to 6 if needed. I worry about overall space on the roof. Initially I thought series but I do tend to park under trees so maybe series parallel combination or full parallel.

I don't have any 240V loads at this time so I would just wire it all in series. I might have to an adapter or something when connecting to the split phase at the park.

 

[eXodus]

The LRA on my 15k Dometic is like 57amps. I think the 13k is 52a and idk the furrion 15.5k but they say they have a

in my humble opinion:
Hardstart kits are very cheap $8-15 and solve most issues with inverter system. They do not reduce the LRA - but the time to get the compressor up to speed. For most high frequency inverters with limited surge capacity - that is usually enough.

Sure a Softstart system would solve that too, but they are so expensive... further they are a fix for ancient technology.
The world moved on to inverter and DC driven A/C units. North America is just the usually 10-15 years behind in HVAC.

 

[justinm001]

How many watts from the inverter and also batteries does running 3 ACs pull?

For me and the 24 volt 3000 watt Samlex inverter, starts fine,

My 15 k BTU pulls 1400 watts from the inverter but with inverter losses, close to 1700 watts from the battery.

Two ACs would pull 3400 watts continuous from the batteries, and that is 48 volt territory.

That's only like 80% efficiency, I'm usually around 90% it depends on load because I have massive inverters.

I have 6 AC units and a mix between models but they run around 1200-1500w each including the idle load for inverters.

My setup has 2x5kw victron quattro 48v in split phase setup with 4 ACs split between the phases. The other 2 are connected to my 12v quattro 5kw inverter but have only used 1... they're in far front and rear. I figured if any issues like my 48v system dies I can kick these on instead. I use the far front one the most to cool while driving.

I usually set the thermostats a couple degrees off and have microair thermostats which I think stagger start the ACs. Typically I'll run 2-4 of them for a few minutes to quickly cool down the interior then it pretty much just uses one I think

 

[justinm001]

in my humble opinion:
Hardstart kits are very cheap $8-15 and solve most issues with inverter system. They do not reduce the LRA - but the time to get the compressor up to speed. For most high frequency inverters with limited surge capacity - that is usually enough.

Sure a Softstart system would solve that too, but they are so expensive... further they are a fix for ancient technology.
The world moved on to inverter and DC driven A/C units. North America is just the usually 10-15 years behind in HVAC.

I agree. The problem isn't with the inverter as much as it is with the wiring and/or BMS tripping in my experience. 50a at 120v is 500a at 12v and my eg4 rack batteries are only 200a bms each so you'd need 3 of them (I have 2). On a 48v system it's around 100a which is right at 1 of my SOK batteries (also have 2).

I was having a hell of a time getting my 1 furrion 15.5k to run off my 12v inverter without blowing the bms and/or inverter low voltage cutoff. The 4/0 wiring needs to be perfect and crimped perfectly. I redid my entire wiring and it now works but should get a 2nd 4/0 wiring setup or something.

I agree we're very behind. But iirc an inverter AC is only more efficient if it's oversized. The point is DC can adjust speeds of motors and such thus stage up/down components. Most RVs have undersized ac units and they're left on all day to keep cool, unlike a house that'll cycle or might want more airflow and less cooling. When cycling it's ideal to slowly ramp up/down the compressor so it's more efficient. I guess the dc motors might want the compressor at a lower rate depending on the outside temps or so

 

[mmmmmdonuts]

Is there any reason to not get the bigger 5kW versions vs the 3kW if doing 48? I don't see many 3kW with the higher power. Guess would be ideal power consumption possibly? I guess it would be for the one time we run a microwave while the AC would be on for some headroom.

 

[justinm001]

Is there any reason to not get the bigger 5kW versions vs the 3kW if doing 48? I don't see many 3kW with the higher power. Guess would be ideal power consumption possibly? I guess it would be for the one time we run a microwave while the AC would be on for some headroom.

A bit more idle consumption and a but less efficiency at lower wattage, plus weight, size and cost. But not having to deal with worrying about power usage is well worth it

 

[eXodus]

Is there any reason to not get the bigger 5kW versions vs the 3kW if doing 48?

not really. My Class RV has a 24V system and there 3KW is a pretty sweat spot.

For my new trailer system I went with 48V and a 6kw inverter. The EG4 6000XP 48V has about 40-50W idle, while my 3000 Growatt 24V is at about 30-35W

So yes, if every watt counts - the bigger inverter needs more, but it's not a lot more. 10-15W difference. That's about 0.25 - 0.36kWh a day. Not nothing, but not a lot either.

 

[Tomthumb62]

So yes, if every watt counts - the bigger inverter needs more, but it's not a lot more. 10-15W difference. That's about 0.25 - 0.36kWh a day. Not nothing, but not a lot either.

In the context of larger RV's like in this thread, where you can easily get 1200-2500W of solar on the roof (depending on the size of the RV of course), the idle draw issue dramatically decreases. Every extra panel you can fit up there makes a huge difference on a day-to-day basis.

In the context of "small RV's" like vans, small trailers, small cargo trailers, etc, idle draw can make a bigger difference. Some people only have room for 200-400W of solar. Since they're most likely flat mounted, a 400W array might only net an average of 250W outside of winter. If 30 of those watts is going to power the inverter, that adds up much quicker than on a larger RV with a larger array. It ended up being cheaper for us to downgrade to a smaller inverter with greater efficiency (our idle draw was 24W on a 2000W inverter, now 2-3W on a 1000W inverter in ECO mode), but then again our loads are quite minimal (no air conditioning or electric heat; typical 12v house loads a 120V mid-size fridge).

 

[mmmmmdonuts]

not really. My Class RV has a 24V system and there 3KW is a pretty sweat spot.

For my new trailer system I went with 48V and a 6kw inverter. The EG4 6000XP 48V has about 40-50W idle, while my 3000 Growatt 24V is at about 30-35W

So yes, if every watt counts - the bigger inverter needs more, but it's not a lot more. 10-15W difference. That's about 0.25 - 0.36kWh a day. Not nothing, but not a lot either.

So which inverter series do you like more? I got to be mindful of minimum voltage for the mppt.

Right now I was going to go with 5x of the suntech STP295 watt panels in series. Open circuit is 45.1V and 35.7V at max current. I may do more panels but right now I was going to start here.

*Edit* Is the EG4 6000 capable of charging from the grid and the solar at the same time? It isn't clearly stated. The growatt looks like that is definitely a possibility of doing that.

 

[eXodus]

I only got the 6000XP like two weeks ago and just started putting everything together - so I do not have opinion on it yet.

What I bought it for: all breakers are integrated - it connects to my battery, so a very clean install with little wiring outside the box, it can do 120/240v

The Growatt runs flawless for the last 3 years. I do not like that it PV input maxes out at 145V. With the MPPT only going to 125V. Makes panel selection and upgrades difficult. I do charge from the Grid/Generator and Solar all the time.

The EG4 does the same, I do not see an option to disable Solar charging. (aside of putting in a current limitation to 0A) So my assumption would be it always uses solar.

In the context of larger RV's like in this thread, where you can easily get 1200-2500W of solar on the roof (depending on the size of the RV of course), the idle draw issue dramatically decreases. Every extra panel you can fit up there makes a huge difference on a day-to-day basis.

In the context of "small RV's" like vans, small trailers, small cargo trailers, etc, idle draw can make a bigger difference. Some people only have room for 200-400W of solar. Since they're most likely flat mounted, a 400W array might only net an average of 250W outside of winter. If 30 of those watts is going to power the inverter, that adds up much quicker than on a larger RV with a larger array. It ended up being cheaper for us to downgrade to a smaller inverter with greater efficiency (our idle draw was 24W on a 2000W inverter, now 2-3W on a 1000W inverter in ECO mode), but then again our loads are quite minimal (no air conditioning or electric heat; typical 12v house loads a 120V mid-size fridge).

I used to have Van with 200W of solar - there I needed to save every single watthour. (1-2kWh production a day)

Now I got 1350W and producing 6-15kWh every day. (seasons) so that quarter kWh of the inverter standby draw is not as critical anymore

 

[mmmmmdonuts]

The more I am looking at it I am thinking about it I am leaning heavily towards the two growatts due to cost. The other one I saw a lot of positive things out of was the Orient Power 6548. I think the 6000XP is starting to get out of my price range ($1399) of what I want to spend unless there is a very good reason to go that way.

The one thing with the growatt is the MPPT voltage seems to vary widely with them.

I was looking at the:
Growatt SPF3000TL LVM-ES - $689 (signature solar) - I think a has everything I want minus higher current rating
Growatt SPF3000 TL LVM-24 - $659 (signature solar) - Worry about the low MPPT
Orient Power LV6548 - $1080 - Best for expandability

Thoughts? Ideally I would have the solar take care of everything all summer and not need any external power if possible especially when not camping. Does either system monitor batteries without BMS well for SOC? I haven't dove too much in the manuals yet. Just trying to narrow down my choice.

Thoughts on mounting the panels to the roof? Z brackets? Or strut with z brackets?

 

[eXodus]

Does either system monitor batteries without BMS well for SOC?

All LFP have BMS, but not all talk to the AOI.

My Growatt is not communicating with the 24V batteries but does a decent job at charging them to 99% and then stopping. Never had a overcharge protection tripping.
I am using the Bluetooth of my batteries to monitor the SOC. The Growatt is showing garbage SOC - 75%-100% it never goes below. Even when almost empty. It's not an issue - I got the low voltage cutoff programmed 0.2V above the battery recommendation - leaving about 5% on the table.

The EG4 is interfacing with the battery and can do all sorts of magic, you can setup a dozen functions depending on charge, start a generator, etc.
I do not know a fraction of it yet.

Thoughts on mounting the panels to the roof? Z brackets? Or strut with z brackets?

depends on the shape of the roof and spacing.

You might want to search in all forums here.

I've used those: https://a.co/d/hueHnWR they are not available at the moment, but worked great for my large 465w panels on a curved RV roof.

 

[mmmmmdonuts]

All LFP have BMS, but not all talk to the AOI.

My Growatt is not communicating with the 24V batteries but does a decent job at charging them to 99% and then stopping. Never had a overcharge protection tripping.
I am using the Bluetooth of my batteries to monitor the SOC. The Growatt is showing garbage SOC - 75%-100% it never goes below. Even when almost empty. It's not an issue - I got the low voltage cutoff programmed 0.2V above the battery recommendation - leaving about 5% on the table.

The EG4 is interfacing with the battery and can do all sorts of magic, you can setup a dozen functions depending on charge, start a generator, etc.
I do not know a fraction of it yet.

This is going to have to be my approach at this point. I have a bluetooth shunt currently but I got to see what it is rated for. Do you have any pictures on how they are mounted in the vehicle? Trying to figure out how i will do that with the trailer. Is the 3000W growatt and EG4 about the same size?

 

[eXodus]

This is going to have to be my approach at this point. I have a bluetooth shunt currently but I got to see what it is rated for. Do you have any pictures on how they are mounted in the vehicle? Trying to figure out how i will do that with the trailer. Is the 3000W growatt and EG4 about the same size?

The EG4 is bigger, you have to lookup dimensions. The Growatt is a nice small box, got it mounted with self tapping screws into the aluminum frame of the RV sidewalls underneath one of the cabinets. My cat likes the warm air coming from it when it's cold in the RV

I have not mounted the EG4 yet. I just bench tested it. Hope to get to that this weekend.

 

[eXodus]

Most RVs have undersized ac units and they're left on all day to keep cool, unlike a house that'll cycle or might want more airflow and less cooling. When cycling it's ideal to slowly ramp up/down the compressor so it's more efficient. I guess the dc motors might want the compressor at a lower rate depending on the outside temps or so

I think you need to read up more how Inverter type units are working. - It is fascinating. They can do a lot more then slowly ramping up and down. My inverter units run always and need about 1/2 the power the conventional united needed before. With a massive increase in comfort. (less noise, no lights dimming, constant temperature and no swings between the thermostat kicks in)

A modern HAVC system has a dozen sensors (ambient air-, inside air-, condenser-, evaporator-temperature, low and high side pressure etc.)
You have 3 output variables to play with in an DC or Inverter HVAC system - exterior Fan Speed - Compressor Speed - Internal Fan Speed.

By controlling this 3 - you increase condensation to remove more moisture from the air, you can increase cooling - with less moisture removal and bunch of other scenarios. A conventional A/C can only control one variable - run-time - everything else is fixed.

- ideally a Air conditioner runs constant during cooling- no starts and stops. My inverter unit starts when the sun comes up does not stop till it's after dark during shoulder seasons One compressor start a day, when it's warm during the night in the summer - it runs 24/7 - for weeks. That means not compressor starts for weeks. It always runs.

 

[mmmmmdonuts]

In my case, I saw no need for the 240 volts. A 3 kW inverter is a little less power than a 30 amp RV hookup, which is a single 30 amp leg that gets jumpered and sent to both legs of the RVs circuit breaker box.

Also in my case, I opted not to install a transfer switch and if I use shore power, or hook a generator up, I disconnect the Inverter plug from the shore power jack and hook up shore power. For the RV plug, I wired a 50 amp RV plug by jumper ing the two phases together

The trailer is split phase power or has the ability to do it. So how do you handle the jumpering of the 50Amp service? In my ideal situation I would be able to use the 50A straight from the plug or use the jumpered 30A plug for the 120 from the generator.

I think if I go with the bigger 6000W unit I should still be good to go and could power it based on 2 ACs at once.

 

[mmmmmdonuts]

The EG4 is bigger, you have to lookup dimensions. The Growatt is a nice small box, got it mounted with self tapping screws into the aluminum frame of the RV sidewalls underneath one of the cabinets. My cat likes the warm air coming from it when it's cold in the RV

I have not mounted the EG4 yet. I just bench tested it. Hope to get to that this weekend.

Thank you for the pictures. They are definitely worth a thousand words.

 

[justinm001]

I think you need to read up more how Inverter type units are working. - It is fascinating. They can do a lot more then slowly ramping up and down. My inverter units run always and need about 1/2 the power the conventional united needed before. With a massive increase in comfort. (less noise, no lights dimming, constant temperature and no swings between the thermostat kicks in)

A modern HAVC system has a dozen sensors (ambient air-, inside air-, condenser-, evaporator-temperature, low and high side pressure etc.)
You have 3 output variables to play with in an DC or Inverter HVAC system - exterior Fan Speed - Compressor Speed - Internal Fan Speed.

By controlling this 3 - you increase condensation to remove more moisture from the air, you can increase cooling - with less moisture removal and bunch of other scenarios. A conventional A/C can only control one variable - run-time - everything else is fixed.

- ideally a Air conditioner runs constant during cooling- no starts and stops. My inverter unit starts when the sun comes up does not stop till it's after dark during shoulder seasons One compressor start a day, when it's warm during the night in the summer - it runs 24/7 - for weeks. That means not compressor starts for weeks. It always runs.

I'm not really understanding how these variables make cooling more efficient though. In a well insulated home you need airflow and want to fine tune HVAC so its comfortable. But In an RV thats horribly insulated and small with an undersized AC you need it running 100% all the time to keep cool. Running at max BTU 100% 24/7 is an inverter AC much more efficient than a conventional AC?

For instance with my RV I have 6 AC units, there's a rule with passenger busses it needs to cool 30 degrees in 30 minutes. In the summer I'd run 4 of them to bring down the temps very quickly and had the thermostat set for each one a couple degrees different so it'll go from 4/3/2/1 and then run 1 constantly all day. I figured this is the most efficient way to keep my coach cool. I also have 15.5k, 15k, 13k and i think 11.5k AC units so it kinda works. I've replaced 4 of the units and have 3-4 new ones laying around waiting to be installed (found a place to get Amazon returned AC cheap cheap). Not sure if replacing 1 or 2 with an inverter makes more sense or not. Startup amperage isn't really an issue with my massive inverters and I have 2 easystarts just laying around disconnected.

I'm also redoing my ceiling in my RV so still trying to figure how to do the ducting. I'm thinking I should duct all together but smaller channels between them or between each 2.

 

[mmmmmdonuts]

I'm not really understanding how these variables make cooling more efficient though. In a well insulated home you need airflow and want to fine tune HVAC so its comfortable. But In an RV thats horribly insulated and small with an undersized AC you need it running 100% all the time to keep cool. Running at max BTU 100% 24/7 is an inverter AC much more efficient than a conventional AC?

For instance with my RV I have 6 AC units, there's a rule with passenger busses it needs to cool 30 degrees in 30 minutes. In the summer I'd run 4 of them to bring down the temps very quickly and had the thermostat set for each one a couple degrees different so it'll go from 4/3/2/1 and then run 1 constantly all day. I figured this is the most efficient way to keep my coach cool. I also have 15.5k, 15k, 13k and i think 11.5k AC units so it kinda works. I've replaced 4 of the units and have 3-4 new ones laying around waiting to be installed (found a place to get Amazon returned AC cheap cheap). Not sure if replacing 1 or 2 with an inverter makes more sense or not. Startup amperage isn't really an issue with my massive inverters and I have 2 easystarts just laying around disconnected.

I'm also redoing my ceiling in my RV so still trying to figure how to do the ducting. I'm thinking I should duct all together but smaller channels between them or between each 2.

The way I would consider this would be sort of how motors work. In this case it would be comparing a traditional AC type motor vs a brushless system which is vastly more efficient. Typically the brushless push way more air with way less power with fans. I imagine these work more like a mini split and geothermal vs a more traditional AC.