Another RV thread

[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.

 

[eXodus]

I'm not really understanding how these variables make cooling more efficient though

Thermodynamics, dew points (water, refrigerant) , really advanced physics calculation. Nothing you can explain in a single discussion post.
Just trust me it - its not magic - it is real science and proven.
I replaced a 3 ton (36 BTU conventional unit) with a 8K and a 12K Inverter style unit and keeps the house at the same temperature, lower humidity and higher comfort. While dropping the power bill by 50%

My rule of thumb is with a inverter you can use a 1/3 smaller unit to achieve the same results in residential. Convential units do a lot of time nothing plus during on-off the pressure takes minutes to stabilize before cooling gets efficient.

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.

That is a great way going about it with old style A/C units.

Even when you run a regular unit at capacity - full blast all day - your external temperature fluctuates during the day. That means your efficiency fluctuates. A inverter unit can change condenser or compressor or evaporator speed. Depending what the algorithm sees fit for best use.

 

[justinm001]

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.

If you don't think you'll use over 4.5kw you can easily just use 1 leg of the 50a shore (6kw) coming in.

Jumpering the 50a inside you just need to be cautious of the neutral leg size but likely its all 6ga and that'll handle 50a.

 

[justinm001]

Thermodynamics, dew points, really advanced physics calculation. Nothing you can explain in a single discussion post.
Just trust me it - its not magic - it is real science and proven.
I replaced a 3 ton (36 BTU conventional unit) with a 8K and a 12K Inverter style unit and keeps the house at the same temperature, lower humidity and higher comfort. While dropping the power bill by 50%

My rule of thumb is with a inverter you can use a 1/3 smaller unit to achieve the same results in residential. Convential units do a lot of time nothing plus during ramp up and down - the pressure takes minutes to stabilize before cooling gets efficient.

Even when you run a regular unit at capacity - full blast all day - your external temperature fluctuates during the day. That means your efficiency fluctuates. A inverter unit can change condenser or compressor or evaporator speed. Depending what the algorithm sees fit for best use.

I completely agree with everything but can an inverter AC make more BTU per watt? I don't think it can, it just uses the BTU more efficiently.

The biggest efficiency gain is an inverter AC can ramp up the cooling and fan to maximize the cold air through the system. They can modulate the compressor to control the coil temp and fan speed to keep the cooling at max. This is where the 30% gain is which is MASSIVE in a large ducted system as there's massive losses. Mini splits cut out a lot of the air losses since the coil is in room. These also help in comfort as temps are consistent and system isn't turning on/off every 4-5 degrees.

RV systems are basic and the compressor cools the coil then a fan shoots it straight down or across. There's massive temp changes every foot away from the AC and they put the AC in the middle for this reason. Its very efficient but not at all comfortable and can have 40 degree temp swings a few feet away. I feel the 30% efficiency gain is only 3-5% in an RV scenario as the losses are on the insulation on walls and not in the HVAC ducting.
The major benefit for an RV is not dealing with AC motor starts on the electrical system and being able to run the AC at different speeds to modulate temps especially when outside temps are close to ideal inside temps. There's many cases where insulation isn't the issue but sunlight heating the RV or cooking is causing the temps to be higher inside than outside and wanting to run AC. Although many open windows but having an efficient AC would be better.... especially for someone like me with massive allergies (including firewood)

 

[eXodus]

I completely agree with everything but can an inverter AC make more BTU per watt? I don't think it can, it just uses the BTU more efficiently.

It is about how BTU is are rated from the factory and Standard defintions.

ASHRAE vs. SACC BTU Comparison
Old ASHRAE BTU	New DOE BTU SACC	Coverage Area
8,000 BTUs	4,000 - 5,000 BTUs	Up To 250 Sq Ft
9,000 BTUs	5,000 - 6,000 BTUs	Up To 300 Sq Ft
10,000 BTUs	6,000 - 7,000 BTUs	Up To 350 Sq Ft
11,000 BTUs	7,000 - 8,000 BTUs	Up To 400 Sq Ft
12,000 BTUs	8,000 - 9,000 BTUs	Up To 450 Sq Ft
13,000 BTUs	9,000 - 10,000 BTUs	Up To 500 Sq Ft
14,000 BTUs	10,000 - 11,000 BTUs	Up To 600 Sq Ft
15,000 BTUs	11,000 - 12,000 BTUs	600 Sq Ft+

https://www.sylvane.com/ashrae-vs-sacc-btu-ratings.html

Inverter units are usually rated according to the new definition and single stage units are on the old standard.

The old standard assumes a constant operating temperature of 80F outside. But that is not how climate reality works.

Lets say how we rated A/C units in the past had been less then ideal. When testing with the new standard - you existing units would have a lesser rating. That's why we probably do not see much evolution on the conventional units anymore - since they would have them newly tested and your 13.5k unit would be only a 10k unit now.

You can see it either way - A inverter unit puts out more BTU then the paper suggests. Or a old unit puts out less then what is written. Both are perfectly legal - they are just measuring against different standards.

 

[justinm001]

It is about how BTU is are rated from the factory and Standard defintions.

ASHRAE vs. SACC BTU Comparison
Old ASHRAE BTU	New DOE BTU SACC	Coverage Area
8,000 BTUs	4,000 - 5,000 BTUs	Up To 250 Sq Ft
9,000 BTUs	5,000 - 6,000 BTUs	Up To 300 Sq Ft
10,000 BTUs	6,000 - 7,000 BTUs	Up To 350 Sq Ft
11,000 BTUs	7,000 - 8,000 BTUs	Up To 400 Sq Ft
12,000 BTUs	8,000 - 9,000 BTUs	Up To 450 Sq Ft
13,000 BTUs	9,000 - 10,000 BTUs	Up To 500 Sq Ft
14,000 BTUs	10,000 - 11,000 BTUs	Up To 600 Sq Ft
15,000 BTUs	11,000 - 12,000 BTUs	600 Sq Ft+

https://www.sylvane.com/ashrae-vs-sacc-btu-ratings.html

Inverter units are usually rated according to the new definition and single stage units are on the old standard.

The old standard assumes a constant operating temperature of 80F outside. But that is not how climate reality works.

Lets say how we rated A/C units in the past had been less then ideal. When testing with the new standard - you existing units would have a lesser rating. That's why we probably do not see much evolution on the conventional units anymore - since they would have them newly tested and your 13.5k unit would be only a 10k unit now.

You can see it either way - A inverter unit puts out more BTU then the paper suggests. Or a old unit puts out less then what is written. Both are perfectly legal - they are just measuring against different standards.

Ahhh this makes sense thanks.

 

[mmmmmdonuts]

Thinking more and more about this I am heavily leaning towards a 48V system especially looking at Will's new video and his mobile setup. https://www.mobile-solarpower.com/mobile-48v-system.html

I was initially like mentioned in this using the EG6548XP but I am worried with the extremely high power consumption especially in a mobile application (>80+W with no idle mode). I see signature solar has refurbed unit for $900 on their website so it is very tempting. If anyone knows away around this that would be great.

The one shown in the mobile setup is the EG 3000EHV-48 which looks really nice especially with a 15W idle consumption (standby) vs 50W in normal operation. I worry I would need two to run both AC's at once though or use a grid bypass.

I really like the victron but you need separate MPPT chargers. Just spending far too much time at looking at this stuff and really wish I knew a better way at the moment. It is unfortunate that the fans just don't spin when actually needed since it seems most of these 6548s that is the real idle power draw.

 

[mmmmmdonuts]

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

For some reason I kept confusing the EG4 6000XP (split phase) vs. the 6500XP (120v)

So are you guaranteeing the Split phase input on the rv? The idle consumption of the 6000xp seems much more palatable vs the 6500xp at 80W plus.

 

[eXodus]

So are you guaranteeing the Split phase input on the rv?

What do you mean?

240V Splitphase - just like the same with any other 50A RV plug? 2x 120V, Neutral, Ground.

 

[mmmmmdonuts]

What do you mean?

240V Splitphase - just like the same with any other 50A RV plug? 2x 120V, Neutral, Ground.

Basically, a lot of the campgrounds I go to are 30A -120V service so how do you plan to handle that? I also have a 2 small generators that are 120V only out. I have a larger one that's 240V so I could possibly use that.

Would you use something like a chargeverter to handle that situation to just use it to keep batteries charged as a universal input and use the inverter output in this situation.

Or would use possibly one of the autotransformer from growatt or victron? (Leaning on this)

 

[justinm001]

Basically, a lot of the campgrounds I go to are 30A -120V service so how do you plan to handle that? I also have a 2 small generators that are 120V only out. I have a larger one that's 240V so I could possibly use that.

Would you use something like a chargeverter to handle that situation to just use it to keep batteries charged as a universal input and use the inverter output in this situation.

Or would use possibly one of the autotransformer from growatt or victron? (Leaning on this)

This is why I went with dual Victron Quattros setup in split phase but turned off switch as a group. I can run 13a 120v on one inverter then it'll invert the other inverter to give it 240v. Or 100a 240v from my 20kw genset.

If I were you I'd just get a 30a 120v charger connected to the batteries.