Originally Posted by soontobesrt
Hey J, you said stock is 136 or 160, do you know how much it delivers at idle? Would love to know some more specs of the factory Alt in the 3.7!
Mine seems to be good for my system all in all, on big bass hits ill notice the idle dropping so I know I could probably use a cap or a better alt but no issues once cruising so I dont worry to much, just at stops i have to make sure im not pushing it too hard lol.
I would guess that the stock piece is putting out somewhere between 75 and 90 amps at idle. Now, that's an extremely healthy system, IF it were consuming that entire amount. You've got other draws, too.
If your headlights are dimming on healthy bass hits, a capacitor or doing the "big 3" is going to help more than a bigger alt. Alternators just can't "respond" instantaneously to a huge bass hit. They just don't work that way, especially at idle.
The big 3 you need to do anyways, and you should do it before adding a cap. Oftentimes, the big 3 will preclude the need to add a cap.
When you need to think about adding a bigger alt is when you start getting into 1000W RMS
or larger. Basically, a bigger alt is necessary when you are CONSISTENTLY drawing more than your alt can produce. In these cases, you are actually drawing down your battery even though your alternator is spinning. This will eventually ruin your battery or alternator (or more likely, both). I don't know the specs on your system but if you are fine while cruising, I would say the big 3 and possibly a cap is all you'd need.
Just remember, even big systems only draw big current for a fraction of the time. Your battery evens out these spikes and the alternator replenishes your battery. If you build your electrical system with an alternator big enough to handle all these spikes, you are going to be way overbuilt and have way more money than you need to spend into it.
Take care of the big 3 first, as it is ALWAYS a good investment. If that doesn't fix the problem, you can always add the bigger alt later. And besides, if you were to add a bigger alt, you'd need to upgrade the big 3 anyways.
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