Another RV thread

[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.

 

[mmmmmdonuts]

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.

That makes complete sense. I think I wasn't grasping the 6500ex vs 6000xp initially until I went further digging into things. I will look into a charger. Any recommendations? I may have one sitting around at home possibly.

Also have a few 12v chargers and could possibly always use a DC/DC converter off the 12V to 48V.

 

[justinm001]

That makes complete sense. I think I wasn't grasping the 6500ex vs 6000xp initially until I went further digging into things. I will look into a charger. Any recommendations? I may have one sitting around at home possibly.

Also have a few 12v chargers and could possibly always use a DC/DC converter off the 12V to 48V.

Not sure but it's always nice to have a backup charger just incase.

 

[eXodus]

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.

Yes exactly that - two cords coming out of the RV

30A 120V going to the Chargverter
50A 240V going to the 6000XP

big sticker on the 50A - DO NOT USE ADAPTER

 

[mmmmmdonuts]

Yes exactly that - two cords coming out of the RV

30A 120V going to the Chargverter
50A 240V going to the 6000XP

big sticker on the 50A - DO NOT USE ADAPTER

That makes complete sense. I think this what I am going to do. Can't wait to see your install pictures on this.

And you're installing the 50A service to the grid inlet on the 6000XP correct.

I do have an adjustable power supply with PFC from 0-70V at 11A out and may start here, but I do love the idea of the of being able to charge much quicker with the chargeverter since I only have 100Ah batteries so far.

Next thing I want to figure out about running AC out of my 3kW truck inverter to the trailer rather than DC and probably use the AC/DC charger on the trailer.

 

[eXodus]

you're installing the 50A service to the grid inlet on the 6000XP correct.

I think I am going to use the Generator inlet on the 6000XP. Since plugging in Campground is more intermittent for me.

I am mostly off-grid camping then in campgrounds with power. That also gives me the ability to use my 5500W generator with the same 50A cord.

Hope to get to installing this and next weekend.

 

[mmmmmdonuts]

I think I am going to use the Generator inlet on the 6000XP. Since plugging in Campground is more intermittent for me.

That makes sense. I want to do some reading about this. Probably 50% of where I stay has power but 95% of the time it is only the 30A - 120V service.

I am mostly off-grid camping then in campgrounds with power. That also gives me the ability to use my 5500W generator with the same 50A cord.

This I am starting to debate what I use. I have two Champion 2000W dual fuel generators that I currently use but at home my back up generator is a 7500W open frame inverter generator which I converted to Tri-fuel for propane use. It is quite a bit louder than the two I take camping but I am just trying to think what makes the most sense to bring.

Hope to get to installing this and next weekend.

Awesome! Can't wait to see pictures if you post them.

 

[RoadTurtle]

For a couple of reasons, I used the factory installed ATS and added a 50a input right by the ATS and Multiplus. When plugged into 50a power, I use the rear plug, with converter turned off. Batteries and panel support 12v, 120v comes from shore. When on less than 50a, I use the front plug, and MP on the generator side of the ATS manages both 120v and 12v. Boon docking, batteries supply 120v and 12v.

 

[mmmmmdonuts]

For a couple of reasons, I used the factory installed ATS and added a 50a input right by the ATS and Multiplus. When plugged into 50a power, I use the rear plug, with converter turned off. Batteries and panel support 12v, 120v comes from shore. When on less than 50a, I use the front plug, and MP on the generator side of the ATS manages both 120v and 12v. Boon docking, batteries supply 120v and 12v.

Can you elaborate on this? ATS = auto transfer switch? or auto transformer ? Do you have a diagram?

 

[mmmmmdonuts]

Trying to figure out where to mount the converter and battery in the trailer. The electrical box is under the ward / pantry towards the back of the trailer. Initially was thinking under the king bed for the batteries but that inverter (6000xp)is not going to fit. It is a 2018 keystone cougar 34tsb. Favorite part "half-ton" towable. What a joke at over 10k lbs.

 

[eXodus]

The inverter is going to have fan noise - you want to put it somewhere where it's not bothering you.

What about that exterior kitchen / bunk combination?