It depends on a few things. Now as it happens I drive a Damon Gasser.
The particular coach I have Damon put in a Progressive Dynamics IntellaPower 9180 WITH the optional charge wizard. After taking delivery I did a lot of research into converters and battery charging and frankly I was unable to find a converter that was better, And I looked hard, I did find a few that are as good, but non better, at least for flooded wet cell batteries (the common kind where you add water every year, on my rig.. And I do mean EVERY YEAR, not every week, not every month, but every YEAR. I normally keep my rig plugged in 24x7 save for 2 weeks in Quartzsite that I could not make this year and I have to add water every YEAR, 13 months in fact. Your millage may vary
Now, I have heard from folks who have "lesser" chargers, Oh, not Xantrex (I have a Prosine 2.0 as well) which is "Very nearly as good" for Flooded wet cells and perhaps a bit better for AGM's, but I mean LESSER chargers.
Some of these folks can boil a battery by overcharging in as little as a week.
My guess is one of two things....
1: The dealer sells a lot of low end hardware (The 2nd converter is not uncommon in smaller trailers) or 2: Damon put cheaper hardware in your neighbor's gasser (I doubt that but I won't say it is not possible)
Most of the hardware in my Intruder is 1st rate, Only real hardware complaints I have are the VCR (Zenith) the Microwave (Dometic) and the wire they used for the roof-mounted sat antenna (RG-59)
Zenith is now a Lucky Goldstar brand. Zeinth, back in the 60's, advertised "The quality goes in before the name goes on" Well... Today the name that goes on is LG and ... Now that the LG name goes on.. The quality is left out!
The microwave was also made by LG and as I've been known to say they changed from Goldstar to Lucky Goldstar because you are LUCKY if a GOLDSTAR product works properly.. I think I have fixed it now... Might have been cheaper to replace it though (Had to do some re-engineering, get some GE parts, because they are designed better and fit perfectly, better than the original in fact, Things like that,,, Hours of research.. If I charged myself for the work I did I could not afford it)
You see. Goldstar has made many things in the past.. I worked in a computer store and the company who's products we sold let a contract to Goldstar for monitors,,, Warranty return rate was well over fifty percent.. A microwave purchased for my office darn near burned the place down...... Bad design. The VCR would not properly pull a T-120 tape (I did not have a T-60 to test with) due to what truly was a minor adjustment but since I have surplus VCR's I used a Panasonic repair kit.. The Panasonic that replaced it works perfectly. The Microwave in my Motor home is a "Turnstyle" Type, (has a plate that rotates in the bottom) and the motor that drives it, 1: They cut the shaft too short, 2: they drilled a hole too small, so the turntable arms did not fit snugly on the shaft and the table would not turn... I replaced the motor with a nearly identical GE part (longer shaft) and drilled out the hole so the parts fit together better, so far it's working.
But Dometic and Zeinth are both well known brands noted for quality, so that's not Damon's fault they let bids to Goldstar.
Oh, and the next rig I buy, the awining will be by Carfree, NOT A&E
