voltage ??????

[dsmricer1200]

Ok my 01 mountaineer with 5.0l awd. The voltage is sitting low so I got a new one its still low what's going on?my old.one passed the test at advance auto but was only pushing 2 amps out of 130. I'm going to get new one tested tomorrow but.what could be causing it to sit low? Just have factory amp an sub that's it any help would b great

 

[koda2000]

Ok my 01 mountaineer with 5.0l awd. The voltage is sitting low so I got a new one its still low what's going on?my old.one passed the test at advance auto but was only pushing 2 amps out of 130. I'm going to get new one tested tomorrow but.what could be causing it to sit low? Just have factory amp an sub that's it any help would b great

what's the voltage? it should about 14.6 V with the engine running, accessories off. the battery voltage with engine off should be around 12.6 volts.

 

[dsmricer1200]

It's at 13.1 v running an 12.3 v off

 

[koda2000]

It's at 13.1 v running an 12.3 v off

that's a bit low. s/b 14.+ and 12.6 V for a fully charged battery. get that new alternator and the battery load tested.

 

[J_C]

If your bad alternator caused the battery to drain it may need to run for a while to get the voltage back up. Did you do the test right after the replacement or after driving it for a while?

 

[wifes2011xlt]

Was 13.1v what you were getting when yu had the rpms above 2000? Sounds like you took a reading at idle.

 

[koda2000]

Was 13.1v what you were getting when yu had the rpms above 2000? Sounds like you took a reading at idle.

yes, should have been at idle w/everything OFF.

 

[dsmricer1200]

I did the test at idle an at 2k I still need to get the new one tested tomorrow but some times the.volts jump up to normal then back down again I put battey on charger an it still did same so I don't know if there's something causing it to read low or what

 

[wifes2011xlt]

Could be that your battery was drawn down so low that it is drawing so much current trying to recharge itself that it draws the voltage down and spike. Give the battery a nice overnight trickle charge (2amps) and take readings again.

Under normal conditions, you won't get ~14.6v at idle. The battery is not being drawn down enough at idle for the alternator to start producing that much current. Only at above 2k rpms will the battery start to get drawn down enough that the alternator will start producing more current.

 

[koda2000]

Could be that your battery was drawn down so low that it is drawing so much current trying to recharge itself that it draws the voltage down and spike. Give the battery a nice overnight trickle charge (2amps) and take readings again.

Under normal conditions, you won't get ~14.6v at idle. The battery is not being drawn down enough at idle for the alternator to start producing that much current. Only at above 2k rpms will the battery start to get drawn down enough that the alternator will start producing more current.

i disagree, and i've got 5 Explorers to prove it. they all produce 14.3-14.6 volts at idle.

 

[wifes2011xlt]

i disagree, and i've got 5 Explorers to prove it. they all produce 14.3-14.6 volts at idle.

Really? Well, I'll defer to to the generation owners. Just curious, are you getting these voltage readings from the alternator gauge or a handle held voltmeter?

 

[koda2000]

Really? Well, I'll defer to to the generation owners. Just curious, are you getting these voltage readings from the alternator gauge or a handle held voltmeter?

from a high quality VOM measured at the battery posts.

 

[dsmricer1200]

Getting it from volt meter well had new one tested at advance auto same thing came up. Said alt was good but only was making 2 amps so I'm lost here an have no idea. I got a new battery an still same

 

[koda2000]

have you tried measuring the voltage at the alternator's "B" terminal with your volt meter?

 

[dsmricer1200]

No. What should it read

 

[koda2000]

No. What should it read

the alternator's output uninfected by wiring and poor connections. 14.3-14.6 volts.

 

[dsmricer1200]

I'll check in morning but.if that's.good what else could it be

 

[koda2000]

I'll check in morning but.if that's.good what else could it be

if it turns out the alternator is putting out good voltage, then the wiring and connections become suspect.

 

[dsmricer1200]

Ok it was a wire that was dry rotted but fixed that an still when I turn on heater the truck will bounce rpms from 600 through 1500 rims y is this an when I turn it off it stops an today I turned heat on the truck was slacking bad when I was at a stop sig but when u shut the heat off it stoprd. When the rpm bounce it's only when it's in part. Could this be from like a voltage problem or not. Also too it can b hard to start like it cranks an the starter stops but hits 1 sec later an starts any idea. This problem started when the voltage was low the first time when I thought it was the alternater

 

[SoNic67]

i disagree, and i've got 5 Explorers to prove it. they all produce 14.3-14.6 volts at idle.

Correct if the idle is around 750-800 rpm.
Any voltage less that 14V at 1000 rpm means a bad alternator.