Newbie question - Difference between Renogy inverter vs Inverter charger and lcd display vs no display

[Mia]

Hi, Just wondering if somebody can help explain when one would need the Renogy sine wave inverter charger with display vs the Renogy sine wave inverter without a lcd display? We currently have 200 watts of solar (2 x 100 watt panels) mounted on our TC with a 30 amp MPPT controller and also installed a Renogy 40 amp dc to dc charger (to keep the 2 100 aHr FLA batteries charging while driving on the less than sunnier days and to supplement the solar panels.)
We are now also looking at adding a 2000 or 3000 watt pure sine wave inverter (in hopes of being able to use items we otherwise would need to be connected to shore power to use while boondocking.) But not sure if we should be looking at the Renogy inverter charger with lcd display or just the inverter without a display? And wondering if we will need to add an additional item with a display for the inverter that doesn’t have one, and if so, what info will the display provide; And what am I looking to order for such a display?
Also, is the 3000 watt overkill or is it better to go large in order to run the AC while boondocking in hot climates?
*Thanks in advance!

 

[rmaddy]

Display or no display there is a big difference between an inverter and an inverter/charger. An inverter only takes power from a battery and gives you AC. An inverter/charger does that but it also can take in AC (such as shore power) and in addition to giving you AC power it can also charge your batteries from that AC input. This is all done with an internal automatic transfer switch.

In either case the addition of a display lets you see what is going on and it likely lets you control what is going on.

That's a general overview independent of it being Renogy or any other brand.

Using an inverter/charger is a nice choice if you need an inverter as well as the need to connect to shore power (often or only occasionally). If you are boondocking then everything runs off of the batteries (both DC and AC). If you connect to shore power then your DC still runs off of the batteries but the shore power allows the batteries to be recharged and the AC in your trailer gets most (if not all) of its power from shore power. It's all automatic.

As for running an A/C while boondocking, the size of the inverter is only part of the equation. First off, what size A/C do you have and how many watts max does it use while running? Also note that many A/C units will have a surge on startup. Even it it runs at, say for example 1000W, it may surge at 3000W for a second on startup. So while a 2000W inverter could handle the 1000W load, it would fail when the A/C first starts due to the initial surge. It may require the addition of a soft start modification to the A/C.

Then there is the issue of trying to run the A/C with only two 100Ah FLA batteries while boondocking. Since you can't go under 50% you only have 100Ah of usable capacity. Let's say your A/C actually uses 500W on full. You have 12V x 100Ah = 1200Wh from the batteries. 1200Wh / 500W = 2.4 hours. And that's before taking into account power losses and inefficiencies in the system so maybe 2 hours. Since the A/C may only run at full some of the time you might get 3-5 hours depending on the temperature. If your A/C uses more than 500W then of course you get even less time.

But you only have 200W of solar. You probably won't be able to fully recharge your batteries in a day, even in good sun. So trying to run the A/C for a couple of hours each day while boondocking is not likely feasible without more solar and more battery.

Do the math with your actual numbers. It's not just the A/C. What else would the inverter be powering? Add it all up and see what your needs really are. Then see how much battery you need to meet those needs. Then see how much solar you need to recharge the batteries. Keep in mind cloudy and rainy days.

 

[Mia]

Ok, thanks so very much for your reply!

I guess I was confused about the inverter charger being redundant in regard to the 40 amp Renogy DC to DC charger combined with the 30 amp MPPT charge controller we had installed initially for the solar. (But I guess its not redundant as the inverter charger is converting the shore power automatically upon a connection to AC ; versus the dc to dc charge connection from the alternator to the Tc battery bank.)

We are also contemplating converting our 2 current 100 aHr FLA battery bank to LiFePO4 (minimally 170 aHr or possibly 228 aHr, which would allow us to draw up to 80% vs just the 50% availability of the batteries.)

Thats a great point about confirming what the greatest surge allowance for the items we are looking at starting up and running actually are.

We also have 2 additional 100 w panels we can take from our camp if it would be beneficial to do so. I just didn’t think it would be necessary as we only have the 2 FLA batteries and there’s only so much power needed to charge them up on sunny days, but I guess we could use it up on the other electronic loads as for the AC or the fridge (which we don’t currently have not been using while boondocking)

We also have a portable gas generator if necessary, but would like to get away from using it as much as possible, as well as propane for the fridge if that’s possible too.

(in the past we didn’t really need the AC and just ran the fridge on propane as the longest trips generally were only around a week or two max, but once we retire we planned to travel and boondock and are probably going to areas where we could use the AC as electric blankets or heat, as such comforts are preferable as we’ve aged, lol!)