They are way over priced for what you get.
Price a couple solar panels on eBay and a charge controller. Even 1 100 watt panel will only give you 4.5 to 5 amp of charging capabilities and with an average of 5 hours good sun per day you will want at least 200 watts of solar to give you 9 to 10 amps of charging capabilities. You can also find solar kits on eBay and Renogy panels are nice and efficient. Always use fusing and a charge controller so you don't over charge your batteries.
2014 Palomino Columbus 3650TH
435AH 12V VMax Charge Tanks, 520 watt Monocrystilline Solar Array, Morningstar MPPT TS-60 CC,Morningstar Remote,Cotek True Sine Wave Inverter,Cotek Remote Controller,50amp Progressive Hardwire Surge Protector
2015 Dodge 3500 6.7L 4X4
2011 CanAm Commander XT 1000