Caps work great. I purchased the six pack awhile ago, & connected to 1 of two Orion 4000.1. Then I bought 6 cells separately & assembled them myself in order to save some $. For the second Orion 4000.1. The caps do make a difference. Also be aware of the high current draw when they need to recharge. For instance,... when engine is off, the voltage will gradually decrease to 12.5 volts before battery starts to take over. When you start engine, the caps will need to recharge which will draw high current( 30-70amps per capacitor bank depending upon how low the voltage level goes) Yes, I have done all electrical up grades; 250 amp alternator, two deep cycle batteries independent of stock electrical system, ( factory alternator, & 250 amp alternator)