testing a capacitor

Hello,    I bought a capacitor on ebay a while back. I'm not sure if it works or not. I just ordered a Kinetik 800 to store some extra power but I would like to put the cap back in as well (to keep voltage at 14.4v likes its suppose to). The problem is I don't know how to test it. I know that you can put a multimeter across it and if it reads the right voltage after being disconnected you should be ok. I tried the microwave capacitor method and it showed that the cap was faulty. I don't know since the microwave is made for a high voltage capacitor if that is different from a car audio capacitor. If you could tell me how to test a car audio capacitor that would be great because I can't find anywhere online that shows how to do it. (side note: the capacitor appears to be in great condition no dents and it isn't blown) Thanks for your help! Daniel

OK, first off, a cap WON'T "keep voltage at 14.4 like it's suppose to". Except that it IS "SUPPOSED" to, exactly. Supposed, as in ASSUMED to. It doesn't. Read the second definition, here... You need an HO alternator, period. Secondly, "Microwave capacitor method"? WTH is that? Thirdly, if it's not dented, leaking, scorched... whatever, most likely it's fine. I know of no readily available (EASY) method of testing a 1F (or larger) cap. You COULD use the DeltaT method, but you will only get results as good as your test bench, but it'll at least say "good" or "no good".It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

yeah...a cap will NOT keep the voltage up Read this and learn Why you don't need capacitors