I have a fleet of around 25-- 6000lb capacity 48 volt units, and the performance parameters are faster than the 36 volt stuff. 36 volt batteries tend to have a longer discharge cycle, (more plate surface area and less cell wall) than a 48 volt, but I have not seen any negative effects from using good condition 48 volts. If you want longer run times- go 36 volt. If you want increased hydraulic and travel performance, go 48 volt. Most operators prefer 48 volt.