Backup for charging PV battery pack

https://www.ebay.com/itm/254451756993?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=254451756993&targetid=1263094004826&device=c&mktype=pla&googleloc=21161&poi=&campaignid=10454522294&mkgroupid=121089751606&rlsatarget=pla-1263094004826&abcId=2146002&merchantid=6296724&gclid=CjwKCAjw87SHBhBiEiwAukSeUUd-4Q6F2BycyI05JmUjjHd1mNlQEYpvhmOm9Z7EInu1p-vEXtahBRoCNt4QAvD_BwE


Not endorsing this product, but throwing it out here for discussion.  I read of a lot of folks going to 48v battery packs for the PV systems.  This kind of alternator ( probably not one but in multiples to get enough power) looks like it would be a good candidate connected to a small diesel engine to recharge the battery pack when days are cloudy, or some part of the system is not functioning  properly.  Am I am on the right track?  Does a 48v alternator actually product more than 48v?  My ebike battery charger is 48v, but it charges up to 53 or 54 volts.

The pma will have a variable voltage as it speeds up so yes you could use it for bulk and absorb. You would need a good governor to make sure you engine speed stays steady. I would pair it with a good wind controller with a dump load to make sure you didn't boil your batteries or some sort of engine timer to shut it down after a certain amount of time. Usually engine driven DC charging is best for bulk charging. I used to run an engine driven alternator for my first 12volt system. Worked great but you don't have any of the control features of the built in charger on the inverter so it's up to you to control it. There are expensive marine alternators with standalone charge controllers but they are pricey.