I researched this pretty heavily when I was considering an inverter.
Let's clarify something up front.
The ProSines don't "power-condition" or "regulate" AC campground power. Nowhere in their User Manuals or on their web site do they claim to do so. By code, the external AC connection must be disconnected from trailer when a connected generator or inverter, including the inverter section of the ProSine, is running. That's what the transfer switch does. If you're plugged into "dirty" power, the ProSine transfer switch may, depending on the definition of "dirty," disconnect your trailer and appliances from the "clean" inverter output, and connect them, as well as the battery charger input, to the "dirty" campground power.
The only time you get "clean, regulated sinewave power" from the ProSines is when they are providing power from the batteries.
The User Manuals are very clear about what the ProSines do when they DO detect what they consider to be "bad power" on the external AC line.
They switch the load to the inverter output provided by the batteries instead of the campground power. According to the User Manual, on the 2.5 (2500W) and 3.0 (3000W) models, the transfer switch disconnects the load from the campground power and connects it to the inverter if the campground power drops below 90 volts. The manual does not indicate this is user adjustable and many consider it to be too low to protect an air-conditioner. The 2.0 (2000W) User Manual outlines how the user can set thresholds for low and high campground voltage and frequency, and lists several conditions it considers "bad power," which will cause the transfer switch to move the load to the inverter section providing power from the batteries.
Code:
AC Bad Cause Details
None There is no problem with the AC input.
Low Cycle V In The rms voltage as calculated over one cycle (0.016s) was
less than the user-set minimum acceptable operating voltage.
High Cycle V In The rms voltage as calculated over one cycle (0.016s) was
greater than the user-set maximum acceptable operating
voltage.
Low Average V In The rms voltage as calculated over 16 cycles (0.25s) was
less than the user-set minimum acceptable operating
voltage.
Hi Average V In The rms voltage as calculated over 16 cycles (0.25s) was
greater than the user-set maximum acceptable operating
voltage.
Low Frequency The frequency was less than the user-set minimum
acceptable operating frequency.
High Frequency The frequency was greater than the user-set maximum
acceptable operating frequency.
V In Cycle Delta The present cycle of shorepower is significantly different
from the previous cycle. This is a fast method of
recognizing an imminent power failure and is caused by a
sudden change in the waveshape, magnitude, or frequency
of the shorepower AC.
V In Step Delta The shorepower contains large, repetitive, sharp edges
which are incompatible with the PROsine and which you
may not want to pass to your loads. This might be caused
by a "modified sinewave" inverter or generator.
The question is, whether you want to continue to operate totally off batteries at high loads, such as those generated by air-conditioning, which may discharge the batteries in less than an hour. You may consider this a bad thing if you aren't there when it happens. A 3000W inverter may have the capacity to do so without overloading until it has run the batteries down sufficiently far. A 2000W is more likely to overload sooner and not run the batteries down. The bottomline is that
you don't need a huge 3000W inverter just on account of your air-conditioner or other big loads you normally won't be running off batteries. The transfer switch will have your trailer disconnected from the inverter when you're plugged into external AC and these items are in use.
What you do need is outlined below.
If you want a whole-house (trailer) inverter, you need a 30A transfer switch if your trailer is wired 30A. That can be built into the inverter, or separate, and the inverter need not provide 30A, or even 25A (3000W).
If you don't want possible interference on electronics, or overheating on motor or inductive/transformer-driven appliances, you need a pure sine wave inverter.
If you want the inverter to replace the converter for battery charging, you need it to be an inverter/charger, such as the ProSine 2.0 (2000W), 2.5 (2500W), or 3.0 (3000W), which also all have internal 30A transfer switches.
The ProSine 2.0 is really about as much as most folks would need in an Airstream. It can power a 1500W (1000W cooking power) microwave oven, OR a 900W two-slice toaster, OR 1600W hair dryer, and still have power remaining to keep a laptop computer operating/charging off its AC adapter, or an AC TV and satellite receiver going.
At at 17.7" X 11.2" X 5.7" and 24 lbs, the 2.0 is also much smaller and lighter than the behemoth 2.5/3.0 at 20.1" X 15.2" X 6.1" and 32 lbs. The 3.0 comes with the Advanced Control System (ACS) remote and sells for $2188 at one site. The 2.0 sells there for $1444 without the ACS, which is $194 extra, if you feel you need it.
The 2.0 supplies up to 100A of charge current, which is sufficient to charge 333AH of batteries at 30%, 400AH of batteries at 25% and 500AH of batteries at 20% of rated capacity. Keep in mind, that at 100A, it's using at least 1/3 of the 30A campground or generator power, and may have to cut back the charge rate when the air-conditioner or other appliances come on. These also monitor the battery temperature
during charging if the sensor is connected, and adjust the charge rate according to temperature. You don't want to charge most batteries at more than 20% of rated capacity without it.
The ProSines, when connected in whole-house configuration DO MONITOR the total AC current being used from the campground and can "power-share," that is, cut back on their battery charging and thus reduce the amount of external AC the charger is using, if the total current approaches that of the campground, or the trailer's 30A breaker rating.
Airstreams are obviously not designed for inverter use with the batteries at one end and the AC hub at the other. Keep in mind that if you run cable from the rear of the trailer where the power cable is, to the front for the transfer switch, and back to the circuit breaker box, you're talkin' about a lot of length and voltage drop when you're on external power, including a generator when you consider the trailer power cord. I wouldn't use smaller than 6AWG wire, even though you only need the ampacity of 10AWG for 30A. And it certainly should be in conduit to protect it under the trailer, however, by code, other things like TV/satellite cable, phone or network cable, should not be in the same conduit.
Then there's the consideration of battery capacity. Just as you don't want to charge more than 20% of capacity without temperature monitoring, as a general rule of thumb, you don't want to discharge more that much either without monitoring. I'm still unclear as to whether the ProSines provide this protection when inverting, as they do when charging. For example, 50A, or 500W is the point beyond which you'd want to monitor a pair of T-105 golf cart batteries for overheating.
T-105 batteries have 230AH of rated capacity at the standard 20 hour rate, i.e. when discharged at 230/20=11.5A they have 20 hours (1200 minutes) of output until battery voltage drops from full charge to a minumum voltage considered fully discharged. Looking up their Peukert Factor (or calculating it) and finding 1.24, a "capacity number" can be calculated by C=20*11.5^1.24=413.
We can use this to find the total charge life time at the 200A a ProSine 2.0 would draw at rated output. 413/200^1.24=.58 hours or 34.7 minutes. 1200/34.7 means that every minute at 2000W, is like running 35 minutes at 11.5A.
At this discharge rate, the AH rating of two T-105s is 200*.58=116AH, about half that of the specified capacity at the 20 hour rate (11.5A) and you're actually using 2AH of the 230AH capacity for every AH of use at this rate. The Xantrex Link models are only one of two amp-hour meter brands that take the Peukert Factor into account. The Trace TM500 and Trimetic TM2020 do not.
The charge curve of a battery starts getting very flat beyond 80-90% charge, meaning it takes even longer to charge that last little bit than it does to go from 20-80%. You're probably not going to want to run the generator beyond 90% charge. If you also try to not discharge below 50% for long life, you're working with 40% of the capacity, which is 90AH at 11.5A discharge, but only 45AH at 200A discharge. I believe I once calculated that a coffeemaker run only for 12 minutes to brew takes 1/3 of this 40% capacity.
A second pair of T-105s (or using larger batteries) reduces the impact of high discharge possible with the inverter. 460 AH is close to the minimum I'd want for a 2000W inverter. One might also consider using two 130AH Group 31
12V batteries in the factory compartments, with a third in a battery box in the tool box behind the LP tanks for 390 AH.
In the end, I realized what Tinsel Loaf said in
this post was true, "The inverter draws 60 watts when it is running but
you will find you will not be using it much while boondocking." It saves us a LOT of money ($2000-$2500), a lot of work, storage area under the couch (not to mention in the arm), and battery capacity requirement, just to step outside the door and pull start one or both of the EU2000s when we want to use the microwave, toaster, or vacuum at other than the evening generator run time. And the guys with the electric start EU3000s or Yamaha 3500s have it even easier, especially with a remote start. But if it's worth all this to you not to start the generator every now and then, go for it. It's your Airstream and your money.
Wiring the Inverter
Linear Mode
