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Thu Feb 19, 2004 3:52 pm

how can I find out wdat the output of my altenator.I want to put a second battery in my bus and use an isolater.Its a newer amp is there somthing to look for on it that tells me what amperage it puts out.

Thu Feb 19, 2004 4:35 pm

Bosch alternators have the amperage rating on the label. Under the oil/dirt/dust and in a hard to reach place you'll find the label. It's a volkswagen.

Thu Feb 19, 2004 5:59 pm

If you can't find/read the label, you can get the amperage with a multi meter...or you can go to most any auto parts house and they'll test it for free...just get them to tell you how many amps its puttin' out...

Thu Feb 19, 2004 6:22 pm

Most multimeters have a limit of 10A with a dedicated jack and the fuse inside will go pop unless you have the time to wire a shunt and do some math.

You usually need to get an inductive style ameter to measure alternator current. The ones that measure DC are more expensive the the AC variety. FYI.

Sun Feb 22, 2004 9:51 pm

Unless someone has put in a larger alternator, you can guess around 55Amps. It shouldn't really matter though. You are really only interested in the amount of voltage you can get from your alternator to charge the batteries.

First do a search for batteries, charging, isolator, etc. There has been alot written up on it.

For the quick and dirty:

Buy a 90Amp rated isolator from the auto store ($25). If you think you have some huge alternator, get the 120Amp model for another 10 bucks. Then get 2 or 4 O/T cable to run to the batteries. There was just a post on that, and one of the guys got a set made for him at a battery shop for around 45 bucks. Then go get a deep cyle Marine RV batter (Group 29) is going to have the most juice and still fit in your car ($80).

Plug it all in and have fun. Seriously, do a search on this, there is tons of stuff out there already written up in detail.