...doesn't spec 3-stage for all their rigs. The additional costs involved at the OEM level are very little in the overall scheme of things in an RV in this price range!
Being in the battery business and an RV'er forever, I believe modern 3-stage converter/chargers are the only way to go! Many of the new RV's I've seen lately have stickers on the panel declaring 'Three Stage Charger' upgrades as Standard.
They are relatively 'idiot proof', meaning you don't have to worry about damage to your batteries if you are hooked to shore power for extended periods...Also, these chargers perform better when the battery bank is discharged...
1. bulk charge - for quicker recharging
2. finishing charge - tapers charge rate to bring battery bank up to full complete charge.
3. float charge - maintains bank at full charge without overcharging and water loss, or damage to AGM type batteries.
I got a 3-stage conversion unit from Best Converters and now enjoy well regulated battery charging without any worrys!
When I installed a 1500
watt Inverter, I used a three postiton switch on the AC input side of the circuit...SHORE-OFF-INVERTER. This is done on some boats. I can now select SHORE for normal AC external plug in service...or...INVERTER as the AC supply, and in this manner AC is supplied to all normal outlets on the rig...
I also added ON-OFF switches for the Converter/Charger and Refer AC supply so I can turn them OFF when using the INVERTER as the AC supply (don't want the conbverter running or the refer to switch over to AC during inverter use).
I have three 140 amp hour, 12 volt
batteries, and can run the microwave with this inverter...but it won't perform as well as when hooked to SHORE power or a Generator...we just use it for quick stuff when we don't want to fire up the generator...we also use it for Sat TV, etc late at night, and the inverter just loafs along, not heating up at all.