Alternator overheating??
My issue is that even after a short drive, say 5 miles or so, If I pop the hood the alternator is so hot you can barely touch it for a second.
Now, I am also having a drop in voltage(drops to low 11 volts at idle) after a few minutes of warm up. I think this is because its getting so hot. Im not sure if there is too much load on it, or if I need to put a smaller pulley on it, because I do have an underdrive pulley as well. When im driving it and keep the rpm's up above 2000, then the voltage gauge will start to go back to around 12-13 volts. Once I come to a stop sign/light and sit for a minute, it draws the volts back to the low 11's.
This is a brand new LS1 alternator.
Recent mods electrically are:
Battery relocation to spare tire area (2 g wires)
2 x 340lph pumps on a BAP
Versa Fueler
2 interior gauges and an electronic boost controller.
The wires going to the alternator are also very very hot, almost melting off the plastic wire cover, not sure if the load is on them or if them are hot because the alternator is so damn hot.
Any input would be helpful.
Thanks
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most new cars have rear mount batteries and the neg is terminated at the chassis
also they dont have a neg post, just a positive post and tell you to put the jumper cables to chassis ground

also did you remove any pulleys with a ac delete? if its getting really hot and low voltage maybe its not getting enough RPM for a full voltage? (shot in the dark with this one) which would make it hot if the car is demanding more voltage than its producing
not saying having a dedicated negative line wouldnt help but i ran mine staight to ground as well.
I did not have this problem when its was h/c with alternator in factory location, and it also had an underdrive pulley then as well
I did not have this problem when its was h/c with alternator in factory location, and it also had an underdrive pulley then as well
Your heat is created by the fact that even though it left the battery it will return....but the difficult time it has makes heat because it has such a shitty path to take causes friction.
Hope my analogy makes sense. Basically to make a continual circuit work it has to be continual. All the ****, paint, body panels, car body, all add resistance. Resistance=heat which is caused by requiring higher amperage to get though the resistance back to the battery.
Make sense? Might not be your whole problem but a good contributor.
Your heat is created by the fact that even though it left the battery it will return....but the difficult time it has makes heat because it has such a shitty path to take causes friction.
Hope my analogy makes sense. Basically to make a continual circuit work it has to be continual. All the ****, paint, body panels, car body, all add resistance. Resistance=heat which is caused by requiring higher amperage to get though the resistance back to the battery.
Make sense? Might not be your whole problem but a good contributor.
the voltage didnt change with a battery in the stock location either so im not thinking its a ground issue. if he is he can clean off both grounding points and call it a day. if hes really concerned he can check continuity with the negative terminal to whereever his chassis ground is.
maybe the UD pulley slowed the rpm of the alternator and its finally taking a crap.
the voltage didnt change with a battery in the stock location either so im not thinking its a ground issue. if he is he can clean off both grounding points and call it a day. if hes really concerned he can check continuity with the negative terminal to whereever his chassis ground is.
maybe the UD pulley slowed the rpm of the alternator and its finally taking a crap.
Having the battery in the trunk and not having a dedicated ground to the engine block, the alternator is trying to charge the battery through the chassis, motor mounts, and can even use ground wires in your harness to back feed. Its like taking jumper cables and putting the + on the battery, then throwing the - one out and using a speaker wire.
Ever use a set of jumper cables? If you use a small thin cheap set they heat up, take forever to work. Use a thick heavy gauge wire set and the car jump starts much faster.
Last edited by pwrtrip75; Sep 10, 2013 at 01:16 PM.
i completely agree that a dedicated ground is best, im just saying its not necessary. if the OP drove around with the 2nd battery and the alt didnt get hot then i would consider the ground. imo.
i completely agree that a dedicated ground is best, im just saying its not necessary. if the OP drove around with the 2nd battery and the alt didnt get hot then i would consider the ground. imo.
Run a ground cable before you burn the thing down.
Run a ground cable before you burn the thing down.when i did my relocation i had zero issues with grounding my battery to the crash bar bolt underneath the car and the alternator to a ground on the front of the car, i was running 2 amps and a 160 amp truck alternator. but like you said i agree that the ground wire would be best but its not necessary for a car to perform properly
The ground wire could be the issue with the overheating alternator, and once the alternator is that hot, then it can't run to its potential and put the right voltage out?





