This schematic from another project shows the way I hook up my capacitors for a BoostPack.  On my car BoostPack I have been using 6 capacitors instead of eight but the hookup is in series and exactly the same. 

 

This update goes over my latest research with the BoostPack auto battery replacement project.  BoostPacks are now for sale on eBay for $100-$200 Buy It Now.  Coupled with a small solar panel my setup has been working flawlessly.

Actually, the solar panel is a 1.8 watt panel:
http://www.amazon.com/Sunforce-50012-1-8-Watt-Battery-Maintainer/dp/B0006JO0KG/

 

Untested eBay capacitor packs:

 

15V 233F   US $118.00

http://www.ebay.com/itm/15V-233F-Ultracapacitor-Engine-Battery-Starter-Booster-Car-Ultra-Super-Capacitor-/181238407266?pt=Battery_Chargers&hash=item2a32a6a062

 

15V 380F   US $165.00

http://www.ebay.com/itm/15V-380F-Ultracapacitor-Engine-Battery-Starter-Booster-Car-Ultra-Super-Capacitor-/181238407262?pt=Battery_Chargers&hash=item2a32a6a05e