My frog batteries are rated at 8.5aH (8.5 amps for one hour, or 4.25 amps for 2 hours, etc). So, when you say "Your frog batteries can give about 15 amps - maybe 20A max." , do you mean that I would have to use both of them to get this result? A round of golf (at least the way I play it!) lasts...