EA alt question

[mobeious 10+ year member]

just got my 300a alt on my explorer and seems a lil weird like going doin the road it charges at 14.6 but if i slow down to stop the voltage drops to like 12.9 and if i just sit there at idel its stays at like 12.9 and if i tap the gas pedel it will jump real fast to like 14.9 -15 v then go back down.. if i keep the rpms around 1200-1500 it stays at 14.2 or if im at idle (12.9) and hit the window switch it will jump up to 14ish then go down..... its like it doesnt get to voltage unless a load is applied .... is this normal?? when i first got the alt on it was idle at 14.7 for around 3mins then started to go down and got to around 13.2 then took it for a drive and thats when it went down to 12.9 at idel

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[xclusiv3 10+ year member]

well im pretty sure they dont do rated output at idle, u do have to get ur rpms up a bit.....

 

[mobeious 10+ year member]

i know that but 12.9v at idel? my factory alt was 14,7

 

[_JaY_ 10+ year member]

id ask nate personaly u do big 3?

 

[mobeious 10+ year member]

oh ya

iv had that done.... just been on stock alt the hole time

g34 up front and stinger 2150 in the back all 1/0 on the big three

 

[mrwigglezdj 10+ year member]

that might be a pully issue? might need a smaller pully so it will up the rpm of the alt while at idle to get the voltage up, but 12.9 wouldnt cut it imo

 

[mobeious 10+ year member]

ya i thought i might need a smaller pully ill take to nate on monday see what he says

 

[94Mazda626 10+ year member]

that might be a pully issue? might need a smaller pully so it will up the rpm of the alt while at idle to get the voltage up, but 12.9 wouldnt cut it imo

x2 on the pulley, are you using your original pulley or a smaller one?

 

[Lakota 5,000+ posts]

You get what you pay for with EA. I could have took the cheaper route and gotten a 250A EA alt for the price of my 200A MG. Maybe you need a smaller pulley.

 

[SHOemup233 10+ year member]

You get what you pay for with EA. I could have took the cheaper route and gotten a 250A EA alt for the price of my 200A MG. Maybe you need a smaller pulley.

I suppose. My EA has been good to me so far with absolutely no problems.

 

[mlstrass 5,000+ posts]

Same here, EA going strong on 2 years now. HO alts don't kick in as fast as stockers, so you need a smaller pulley if one is available. But 12.9 at idle isn't bad at all.

Also it will put out more volts when the car is cold, common for most alternators, then drop down when it's warmed up...

 

[pawn man 10+ year member]

i am pretty sure most of the high out alts at idle are slightly lower. call nathan and see if he has a smaller pulley so it will turn faster at idle. this should solve the problem.

 

[audioarsonal 10+ year member]

Same here, EA going strong on 2 years now. HO alts don't kick in as fast as stockers, so you need a smaller pulley if one is available. But 12.9 at idle isn't bad at all.
Also it will put out more volts when the car is cold, common for most alternators, then drop down when it's warmed up...

How do you figure!!That is practically all battery power running your car and system and with any significant bass your going to dip into the 11-10's.That shit should be at the charging voltage of the alt at all times(idle or driving)otherwise theres a problem.

I would guess its a pulley issue as eveyone else has stated.Cut in rate for most HO alts is 2400 alt speed.

 

[audioarsonal 10+ year member]

just got my 300a alt on my explorer and seems a lil weird like going doin the road it charges at 14.6 but if i slow down to stop the voltage drops to like 12.9 and if i just sit there at idel its stays at like 12.9 and if i tap the gas pedel it will jump real fast to like 14.9 -15 v then go back down.. if i keep the rpms around 1200-1500 it stays at 14.2 or if im at idle (12.9) and hit the window switch it will jump up to 14ish then go down..... its like it doesnt get to voltage unless a load is applied .... is this normal?? when i first got the alt on it was idle at 14.7 for around 3mins then started to go down and got to around 13.2 then took it for a drive and thats when it went down to 12.9 at idel

Hey this is probably cause your vehicle was cold.When you first start up your vehicle will idle slightly higher as it warms the idle RPM wil drop slightly.You are probably just below the cut in point of your alt.Get a smaller pulley and that should take care of it.

 

[mobeious 10+ year member]

ok i didnt some testing today and heres what i found... first start truck in morning voltage = 14.5 tell truck gets to temp...thats idle voltage then it drops to 13.2 then to 12.9 running down hwy it stays around 14.2 tell i go to slow down like to a redlight and drops down to around 13.4 if i stay at the light drops down the 12ish and when i hit the gas to go the mids cut out cause voltage gets to low and the alt spikes from 12.7 to 15ish when i hit the gas.. so i guess the amps cuts out cause of the voltage spike ill try to get some vid....