Well today I got to play with the cap and see if it makes a difference, and it does help about 80% of the time. I can hear when the pump kicks on, there is a split second of hesitation from max amp draw, and 9 times out of 10 it works just fine, but the 10th time it sticks and hangs. The volts drop down to about 8v. Which is better than the 6v it used to drop down to. Now my other 12v equipment doesnt shut of due to low voltage which is good.
I shouldve gone with the 18 Farad model instead of the 8 farad. I'm going to see if Amazon will allow a return, even though I threw away the original box. We'll see.
Bottom line, I think I shouldve gone with the 13.8v model and this 8 farad probably would have been just fine.