...I'm certainly hoping to keep this boat for many years. So I'd rather do it right now, whatever we do, than use half measures.
Our current unit is a 2000W inverter and 100amp charger. Since we won't be able to rely on the Xantrex like we thought, I'm returning the weaker charger and have to get a stronger one, and the inverter, and the two remotes, or a combo and one remote. I have to get it shipped so I can get it installed really soon.
If I can't charge the batteries, I can't use the DC stuff, and with no shore power, I can't use the AC stuff either! We do have things like iPads, iPods, phones... along with a couple fans (none of the DC fans are useful yet - we are working on that). The lights are all DC and most of them are LEDs. We plan to get all our nav lights switched over to LEDs too.
I know I can head down and run the engine to charge the batteries. Keep the bilge pump going. The wind generator isn't hooked up as far as we can tell so that won't help.
Trust me, I don't want to be rushed into this. But if the Xantrex is dead, I don't have any choice....
There is a frantic, "gotta have it now" tone to your message that is unnecessary. I think you need to SLOW DOWN and GO SAILING.
There are so many issues here that I don't even know where to start.
First, I'm not convinced that your current charger/inverter is bad. It could be your batteries, or your wiring, or a ground fault or loop. You could waste a bunch of money on a new charger/inverter and end up with the same problem when you're done.
Was your motor running when you tried your inverter? I've always been told not to run an inverter (or electric windlass) off of batteries without the alternator supplementing the power. I suspect that switching on your huge inverter might have pulled the voltage down on the batteries too much, which set off all your warning lights. But that's just a guess - there are SO MANY other things that could have caused your problem that are not the inverter.
You really should follow Dave's advice to simplify things to get you through the rest of the season, and plan out a more thorough diagnosis and, if needed, upgrade to be done over the winter.
What would I do? I would take my automotive charger down to the boat and get the batteries charging for the time being. At this point I'd do this for the rest of the season if needed. Just take care to remove the charger when the batteries are fully charged, since automatic sensing of full charge state is where cheap chargers often fall short. You really don't want to end up PSOC issues on the batteries, so get them charging now. I'd keep doing this interim step until I have a permanent solution worked out.
What else would I do? I would build up a better 12v infrastructure on the boat. You really have NO NEED for an inverter for just weekending on a boat. Charging phones and computers off of 12v is far more efficient than inverting from 12vDC to 120vAC, only to have your power bricks convert it back to 12vDC. So I'd install a few 12v automotive connectors in convenient locations and use them for this very low power charging of devices. As an interim step, Battery Tender has very nice cords with fuses built-in that could attach direct to a battery and provide a 12v socket on a pigtail. It's not marine grade but it will get you through the season. I know people here say everything needs to be hardwired, but for temporary and transient use I would consider it good enough. (Others here may disagree.)
I'd also buy a few lithium ion battery packs that can supply backup USB power to your devices. Keep them charged up, and they can power your phones and iPads over a weekend. I gave these things to everyone in my family as stocking stuffers last year. ($6 each at Staples on black Friday) Also buy automotive plug-in 12v chargers for your laptops.
I would also buy a jump charger from the auto department. These usually have a 12v socket and a couple USB sockets, in addition to the jump cables for starting cars with dead batteries. These can power all your devices for a weekend, and you never know when you might need it to start your diesel. I have two of these, and end up using them several times a year. I use one to power my CPAP on 12v overnight, because the long wire run to a 12v outlet causes too much voltage drop for it to start up reliably. I also use them every winter when the boat is on the hard and the house batteries are disconnected.
I think you're too obsessed with having a big inverter on this boat. My current boat came with a brand new 50w/1000w Magnum charger/inverter, and I have yet to even turn on the inverter. Hopefully my surveyor tested it, because I haven't. I just didn't care that much about it during survey. Do you realize that a 2000w inverter will draw up to 170 amps from your batteries? That's more than most electric windlasses, and will really test the quality of your batteries.
With a decent 12v infrastructure, you could get by without an inverter. Even with an inverter, you should not be running it constantly, only for short spurts when you want the microwave or TV. My TV only draws 19-25 watts, so I could use a little portable inverter for it instead of the big Magnum house inverter.
Which reminds me - you really should get a Kill-a-Watt meter and determine how much power each of your AC devices draws in real world conditions. That, more than anything, will inform you around whether you need an inverter, and how big it needs to be.
I think for a couple hundred dollars you could buy a nice automotive charger, jump charger, a few battery packs, and some 12v sockets, and get through the season without spending a few thousand that may not solve your problem. Even if you eventually get an inverter, all of these items will have enduring value around the house and on the boat in the future.
Deferring the permanent work also allows you to shop around for specials at the boat show.