Jump to content

Need Alternator Help

Recommended Posts

Usually the amp rating is marked on the alternator somewhere. To get a idea of what it's putting out take a amp meter,at idle 60amps should do it but 100 would be better.hook the negative side of the meter to the pos terminal of the alt.Hook the pos terminal of the amp meter to a carbon pile. Remove the pos battery terminal from the battery. The amp meter will be reading the alt output.

Link to comment
Share on other sites

Most alternators are hot rated, which means they are rated at a certain rpm like 2000rpm. If your truck idles at under 1000rpm you are not getting say 100amps it's rated for. The only way to do this at idle is to get a alternator rated 100A at that rpm or getting a smaller pully for it so it spins faster at idle.


Some trucks came with 60 or 85 amp units so check to see what one you have first.

Link to comment
Share on other sites

Could always get a pull throttle.


We have one on our old rescue truck to keep the RPMs up around 2500rpm to not drain the battery with the strobes and lightbars. It basicly is just a pull knob that has enough tension to hold a certain position on the idle cable. thought about one myself.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...