alternator problem?

[Lucky 76 5]

i upgraded my alternator to an iraggi 260 amp .... i had an excessive amperage 300 amp in there but it was not charging correctly ... it was only charging at 13.9 and would get voltage drops into the low 10s ... i sent it back because i thought the alternator was bad ... i sent my stock one to dom to build me one to work for my car ... i just put it in and am getting similar readings ... this time i am getting around 13.8 (best) and drops to the low 10s .... i understand my t40001 draws 400+ amps of current but i dont think the voltage drop should be that bad (drops like that within 3-4 seconds) ... i am pretty sure the battery is good ... i only have the front battery in right now but i dont believe the voltage drop should be that bad ... could it be my belt even though i have a tensioner spring? ... the pully is considerably smaller than the stock one

[slim2fattycake 85]

what battery do you have?

[Lucky 76 5]

what battery do you have?

its an autocraft from advance auto parts

[Lucky 76 5]

it could b the battery now that i am thinking about it ... it is not a deep cycle and has been in my car for over a year ... ill have to charge it over night and see the float voltage in the morning ... what should it b reading at float?

[jcarter1885 995]

Just my .02, it seems to me like it is your battery (you got two different alternators put in the vehicle and still have the same problem). That amp is drawing a lot of power and a H/O alternator by itself will not cut it.

[Lucky 76 5]

i measured the voltage and the battery was readying 12.71 floating ... i did not charge the battery yet ... it seems to be good as far as that voltage goes ... is it possible that the battery can still be bad ... some weird things were happening today ... i was driving up the hill and the rpms were low and then it suddenly shifted up and then the battery light came on for a second ... also when i come to a stop the voltage will drop to what seems battery level (around 12.8) and then it will rise back up to charging level... the voltage has been all over the place ... this morning it was at 14.4 with no accessories ... then i turned it off and back on again a half hour later and it reads 14.1 ... turned it off and back on again another half hour its reading 13.8 ... this is all with no accessories on just running the car with nothing on ... i have not attempted to turn my music up yet

[jcarter1885 995]

i measured the voltage and the battery was readying 12.71 floating ... i did not charge the battery yet ... it seems to be good as far as that voltage goes ... is it possible that the battery can still be bad ... some weird things were happening today ... i was driving up the hill and the rpms were low and then it suddenly shifted up and then the battery light came on for a second ... also when i come to a stop the voltage will drop to what seems battery level (around 12.8) and then it will rise back up to charging level... the voltage has been all over the place ... this morning it was at 14.4 with no accessories ... then i turned it off and back on again a half hour later and it reads 14.1 ... turned it off and back on again another half hour its reading 13.8 ... this is all with no accessories on just running the car with nothing on ... i have not attempted to turn my music up yet

Well the reason for the small voltage drops is the heat from outside(the later you go in the day the hotter it gets) and your engine components heating up after be running for a few minutes will cause this. Were not saying your battery is bad (the battery can be excellent for a normal car just for starting purposes) but your trying to run an amp that draws over 400amps, the group size battery you have is probably to small for that application. What size and what kind of battery do you have(just because you add a H/O altenator does not mean it will be ok for you to try and draw 400amps or more from it and be okay without upgrading your battery.

You have been having alot of voltage problems, how about taking your car to someone who knows what their doing and maybe then can guide you in the right direction (check all your wires and connections, especially your grounds-thats what could be causing all these voltage leaps and bounds).

Edited July 31, 2009 by jay-cee

[Lucky 76 5]

alright ill give that a shot thanks

[Lucky 76 5]

so for some reason when the music is playing pretty loud (over 75% max) and my rpms are in excess of 2000 rpm the check charging system light flickers on and off like i stated in my first post ... it only does this on some songs ... what could be the cause of this

[shizzzon 461]

you can't run a large amplifier with just a high output alternator.

What happens is 2 things-

1 - voltage regulator does not react as fast as a battery does so first sense of a massive current draw will come from battery. If it's like a quick bass hit, it will pull out of battery then alt will attempt to charge batt back up.

2 - alternator has exceeded it's duty capacity.

Like the first example, if a bass note came in that was more constant, it's first source would be the battery since it reacts first... Then the alt will try to take over but it has a problem. It must attempt to supply power to the 4000w amp AND recharge the batt at the same time so it splits it's current dispersion. What happens now is it runs out of capacity to keep the amp running straight off the alt and starts digging into the batt full force just as if the car was off!

When this happens, the larger the current draw, the lower the voltage will dip and i mean severe dip.

It is VERY BAD to try to run an amp of that power with just a high output alt and no batt(s) next to the amp to help.

This is the reason your voltage drops so low. Now, onto what might happen soon...

You will need to make sure that your starting battery is kept charged. If it's discharged, then the more current that is supplied to the battery, the lower the voltage will be.

don't keep your batt in a discharged state if it is and stop wangin on it for the time being until u get some batts back there.

[KU40 173]

You need extra batteries.

[Lucky 76 5]

alright then this is understandable ... let me just make sure this is acceptable as welll ... i was driving today with the music turned 30/35 on a techno song so quick bass but not that hard ... the car normally will charge cold at 14.4v with no accessories on ... the voltage would stay at around 13.8 and then shoot up to maybe 14.8 and then go back down again shoot back up to around there and then all of the sudden my check engine light came on ... i reset the system and the light turned off ... what would cause this? i was coasting downhill as well

[KU40 173]

In my old car the check engine light came on when the alternator was starting to fail. When you're coasting, the RPMs are down so the alternator isn't putting out as much current. Don't beat very long if your foot isn't on the gas.

[shizzzon 461]

get an ammeter and check and see if the alt is outputting what it suppose to be outputting at a given rpm.

Due to lots of manufacturers rating idle at 2400rpm... newer vehicles will have idling alt issues if your vehicle idles below 800rpm which most new ones do anyway...

I'm sayin this so if u meter alt current at idle, don't expect idle output ratings until u hit at least 800rpm engine.

So, because of this, expect alt output range between 800-2600rpm. Anything higher is pointless and anything below 800 is just enough to run the car.

My 250A alt i tested was putting out in between 47-69A at 1800rpm Alternator speed(600rpm engine) so just enough for the car.

[Lucky 76 5]

ok so then the current draw could also have caused the check engine light to turn on ... it said the charging system was fine when this happened ... if the check engine light did come on is it possible that i damaged the alternator? ... is there n e where i can get the code red for free? ... i would like to know if that happens again exactly what the code reads ...

[jcarter1885 995]

autozone or anything similar should check it for ya.

[Lucky 76 5]

autozone or anything similar should check it for ya.

thanks ... how many d3100s should i buy for my system ... i am not replacing the front battery ... i was also thinking about getting the c and d technologies 100lb batteries instead ... which would be a better choice ... i have heard good things about the c and d batteries and i can get them for about 220 a piece

[shizzzon 461]

good luck at autozone....

some of them dont even believe high output alts exists and then some of their machines cant read their output either...

Autozone for testing alts is about as bad as asking a crackhead to do it, i'm serious.

Don't let them take your ground cable off the batt either...

I've seen them want to do that before too, i was ready to bitch-slap some automotive sense into them but i figured it was a waste of muscle.

[Lucky 76 5]

shawn i meant the code for my check engine ... i asked advance auto and they couldnt even test my alt with it off the car ... too them a half hour and they gave up ... struggled to figure out how to mount it on the bench tester lmao ... i want to find out exactly what the code is that way i can look it up and check out what happened

[Lucky 76 5]

k so today i noticed that when at a constant rpm my car will start chopping and shaking with the music on ... is this also a cause of the battery ... i just want to make sure before i go buy some batteries and then come to find out that that is not even the problem

[Bdunn23 0]

k so today i noticed that when at a constant rpm my car will start chopping and shaking with the music on ... is this also a cause of the battery ... i just want to make sure before i go buy some batteries and then come to find out that that is not even the problem

Ok first off you definately need a extra battery or 2 if I were you thats the first place I would start because there is no way a single battery is going to be able to keep up with a 400 amp current draw therefore the alternator cannot keep the battery charged if you get a single 3100 that should help a lot but just to make sure you have enough I would put a powermaster battery upfront as well such as a 3400 and that should help now you will still have voltage drop but it shouldnt be nowhere near as much I have a 6000 watt amp and I was running it at 2ohms instead of 1ohms which is half the power so you can say 3000 watts and I have 2 stinger 1700's and 2 stinger 680's and a powermaster 3400 up front and a 250 amp mechman alt and I still see voltage drop.

[Lucky 76 5]

i should note that the music was playing techno ... my voltage drops were not that bad ... maybe to 12.8 .... i had my subwoofer set on -6 and i have it tuned at 0 on the deck so it is not seeing more than 2000w

[shizzzon 461]

u got a big engine so i doubt it's this but u might be losin too much horsepower... only way that's possible is if u already have mechanical problems.

[Lucky 76 5]

u got a big engine so i doubt it's this but u might be losin too much horsepower... only way that's possible is if u already have mechanical problems.

it will not shake with the music off ... i remember it did it slightly with my stock alternator and my bxi2006 but no where near as bad

[Lucky 76 5]

i got the readings at advance today ... the code says

ignition coil a,b,c,e,f,g, and h primary

secondary ckt

is it possible that these are not bad and the check engine light went on when the voltage dropped? ... i reset the system and all seems to be well (no check engine light)

Edited August 4, 2009 by Lucky 76