Images fixed
I have a factory 'smart' alternator so it automatically cuts back based on the panel input. If you have a 'standard' alternator, based on my previous panels installed on older vans, you probably won't see a measurable gain. My hope is with the second panel (360W) the alternator will only be providing a charge at night, lights on etc.
If that's not enough I have space to add a third panel across the front still.
I also have stop/ start, and with the panel it's able to activate about twice as often as it previously did. The second panel should mean stop start will work almost 100% of the time. I used to use an A/C charger once a week and that always gave me improved economy in the morning. Unfortunately the battery was already weak by the time I got into the city. I drive 90% city, 26km/h avg around 22km with 22 lights, so the stop start cops a beating. Renault say it's good for 400,000 cycles, I hope so. I do try to take the highway home once in a while.
Now when the engine switches off I can still see the battery holding about 12.6v with the A/C fan and radio, GPS, dash cams, drl's, stop lights etc running. Previously it would dip to 12.0 or slightly lower pretty quick.
The smart alt is pretty good, on a charged battery it will just sit on 11.7 volts while I cruise, only ramping up under braking, but as a hypermiler, there's not really much energy to recapture, so I find my battery is always pretty low. The solar panels seem to be helping at cruise I usually see around 12.0 now.