Alternator problems

[Red82stepside]

Alright so here's what's happening.  I was having trouble with my battery dying while driving.  I had already checked for phantom draw and there was none (thought it might be happening overnight), voltmeter constantly looked like it was overcharging while driving, so I figured a bad voltage regulator.  I changed the alternator today, when I pulled the plug off the alt. It was REALLY dirty and kind of loose so I changed that out too (butt connectors and heat shrink).  Now when I start the truck I get readings at the battery of  between 10.6 and 11.  When I rev the engine the readings go up to 13.5 or slightly higher.  What the heck did I do wrong!

[Red82stepside]

Sorry, it's an 82 c10 305 auto

[Blazin]

New alt. bad??

[beastie_3]

i dont think alternators put out a lot at idle, so when the RPMs are up and your getting 13.5, you should be good. you could also check the resistance on that wire going from the alternator to the battery or where ever it is going.

[bake74]

     On a 12 volt system, at idle you should be reading between 13 and 14 volts at the battery with everything hooked up.  Like beastie said, check the resistance.  Start at the alternator wire and ground wire at idle, should be between 13 and 14 volts, then start tracing back to battery checking at everything wire passes through to make sure voltage is the same before and after each item.  If it drops, either the item is at fault or the wire between the two items has resistance I.E. bad connection, corrosion, or such.

[1980c10]

check volts at idle from the B+ on the back of your alt and neg on your battery. This should read between 13-14. If it doesn't your alt is bad.
If it does then check at B+ on the distribution block on the firewall to neg on the batt. (or any ground).
this should read between 13-14 volts.
if it doesn't that wire or those connections are bad
then check the b+ on the starter etc.
-just follow the circuit in reverse
-you can also test your grounds using the same theory
check from B+ on the batt to neg on the battery then move neg to the engine block and see if your voltage drops
-Also tighten all connections especially on your batt and alt.
a loose, worn or corroded wire or connection can read 0 ohms and still not be able to carry 13-14 volts required.
Like bake says but check voltage at idle.

[Red82stepside]

So I checked the connections today, apparently after one of the trips to the parts store to get the bat charged I stripped the positive connection on the battery.  Haven't got a new one yet but could that be causing this new problem?

[bake74]

     Do you mean that you stripped the bolt that holds the positive cable on the battery ?  What kind of connection do you have a standard clamp style that tightens with a bolt ?

[1980c10]

So I checked the connections today, apparently after one of the trips to the parts store to get the bat charged I stripped the positive connection on the battery.  Haven't got a new one yet but could that be causing this new problem?

yes, but wiggle it and watch your volt meter connected to the battery while at idle. You might need three hands for this.

[Red82stepside]

It is a side post where the bolt screws directly into the battery terminal, the connection on the battery side is lead or somthing soft, it is the female side of the connection.  Now the bolt won't tighten down

[bake74]

     As 1980c10 stated you can still check it by "wiggling" it to see if you have proper voltage, but if you can not fix that battery post you need a new battery.

[Lt.Del]

try a different bolt if the female threads are stripped.  Get an oversized bolt, or one with wider thread pattern.  It'll get tight.

[Red82stepside]

Finally got time to work on the truck, replaced the battery and it is charging correctly and everything appears to be fine now, thanks for the help everyone!

[beastie_3]

did you try fixing the old battery, or just go buy a new one?

[Red82stepside]

Battery was already four years old and after the post being stripped and jumped and recharged several times I decided to just get a new battery, probably couldve fixed it but would have had to replace it before to long anyhow