I have seen similar setups cheaper. For example. https://www.aliexpress.com/item/100W-Solar-Panel-Monocrystalline-Taiwan-Solar-Cell-Folding-Solar-Fabric-Charger-Bag-Portable-Solar-Panels-for/32597702650.html?spm=2114.01020208.3.148.9Fjlnw&ws_ab_test=searchweb0_0,searchweb201602_3_10065_10068_10084_10083_10080_10082_10081_10060_10061_10062_10056_10055_10054_10059_10099_10078_10079_426_10073_10103_10102_10096_10052_10050_10051,searchweb201603_1&btsid=cc8497ff-b5c6-45ca-a63e-7ef9e6f04023
As for charges any battery, of course they can arrange the panels to put out whatever voltage they want, and make it as big, as many watts, as you can afford.
I was just this week seriously looking at what a 200w in 12v size, 48v setup would cost. Best I could find was about $350-400 for 4 12v 50w panels. The math gets a bit confusing, but this would still put out potentially 200w max, (watts is watts) but strung in series, the output would be about 3 amps of "48v". Size about 22" by 88". I was looking at panels like these but more square vs rectangular.
http://www.ebay.com/itm/2pcs-x-50W-Solar-Photovoltaic-Panel-100W-semi-flexible-Poly-silicon-panels-12V/282092137372?_trksid=p2141725.c100338.m3726&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20150313114020%26meid%3Dec7666a6fb2f40d1bd8e5403b24f4e00%26pid%3D100338%26rk%3D12%26rkt%3D30%26sd%3D351856876150
48v charge controller would be great, but I was thinking just ride enough to have partially drained battery, then connect direct. Pack voltage charged 58v. Output of the panels anything from 48v to 72v depending on the sun strength. A voltage converter or charge controller to 58v would be best, but if you are pulling 500w and generating 200w, you won't overcharge.
The use I had in mind, I'd generate at best 1600wh a day, and be using 3000 per day, so again, like that, can't possibly overcharge a huge battery with not enough wh to do it.