03.5 p5 was driving in the rain and was a puddle about 20 feet long collected on the side of the road went thru it doing 25 and could hear the water hitting the floor boards. After the going thru it the battery light came on for about 20 seconds and went out, had no previous issues with the battery or battery light. Also noticed the dash lights starting to go dimm. Puddle was on the passenger side of car. Any suggestions on what to check?
battery light
- Thread starter slayne
- Start date
Jasonjames
Member
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- Mazda 2002 BJ Astina 323 1.8 L
Because the alternator is mounted quite low in these cars,..they're susceptable to water getting in and causing the slip-ring-brushes to lose contact with the slip-rings mounted on the alternator-rotor. This effectively stops any output from the alternator to the battery,...and therefore a battery/charge alarm-light.
No biggy,..the rings will dry out in a few minutes or less
JJ
No biggy,..the rings will dry out in a few minutes or less
JJ
Thanks Another Question tho. When crusing about 45 mph i will notice the headlights will dimm for about 5 seconds and return. when using the heater I can hear it slow down with the dimming, Im assuming it has something to do with the charging system, correct? How often does the alternator go bad in these cars? how are they to replace, seeing as its so low and near the firewall.
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- Mazda Protege 5
That is just the nature of the P5. There is nothing wrong with it.
Jasonjames
Member
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- Mazda 2002 BJ Astina 323 1.8 L
I think your alternator may need attention. IIRC they are around 80 amperes max output. This type of power should handle any load [ie lights, fans etc] that is demanded of it. The electrical equation here is Power [in watts] = Volts [12.8v or so *times** current [in amperes] As an example, 2,.. 50watt headlamps = total power of 100watts. Now re-arranging the formulae to make Current the subject Amps = Power divided by volts. Or to apply values,. amps = 100 divided by 12 = 8.33 amps. So it can be seen that with headlights on, the alternator only has to supply 8 odd extra amps,..plenty of current left [80A minus 8 = 72 amps left. If the alternator is running at less than full available power [due to worn brushes or power-diode probs or a fractured solder-joint in the windings] its available power may be well down,..giving the symptoms you have mentioned.
One rough test is to sit in the car while its idling. While watching the tacho, you switch on your headlamps. Now if the alt is working well,..it will immediately start supplying more current out which means the engine will get a higher load as the alt becomes more difficult to spin. This will show as a slight drop in engine revs. If the engine doesnt drop revs slightly, the alt needs attention... You have mentioned the dimming of your car's headlights and the fan slowing down. You're right,..it's not normal and maybe the alt or loose and dirty connections on the alt, or the wiring to the battery. Unless you can get a hold of a multimeter to check the alternator's output volts [nominally around 12.5 to 14v] you'll need to get it checked out.
As far as the battery goes, as long as it is showing full charge thru the spy-glass, and it spins the starter briskly,..its OK. However you need to remember the battery charge is only as good as the alt performance.
JJ
One rough test is to sit in the car while its idling. While watching the tacho, you switch on your headlamps. Now if the alt is working well,..it will immediately start supplying more current out which means the engine will get a higher load as the alt becomes more difficult to spin. This will show as a slight drop in engine revs. If the engine doesnt drop revs slightly, the alt needs attention... You have mentioned the dimming of your car's headlights and the fan slowing down. You're right,..it's not normal and maybe the alt or loose and dirty connections on the alt, or the wiring to the battery. Unless you can get a hold of a multimeter to check the alternator's output volts [nominally around 12.5 to 14v] you'll need to get it checked out.
As far as the battery goes, as long as it is showing full charge thru the spy-glass, and it spins the starter briskly,..its OK. However you need to remember the battery charge is only as good as the alt performance.
JJ
sorry to thread jack a little bit here, but i have a question...
i have a 1000w sound system in my car to the original battery and alt.
my headlights always dim while i play music and the alt drop happens as well. 4 times in the last 2 months i've "surged" and blown out my low beams and high beams, too.
should i get a more powerful alt and battery? or a capacitor.
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- Mazda Protege 5
capacitor
Jasonjames
Member
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- Mazda 2002 BJ Astina 323 1.8 L
That's some serious power . When we use the formula >> Amps = Power divided by volts i.e. Current = 1000 divided by 12,..we end up with 83 amps **at peak music power**. Because the alt can only output around 80 amps,..and the other circuits [eg ECU, injector-pump, injectors and ignition, any lights on plus fans and AC clutch] are pulling not insignificant current,..the alt cant handle all that load. So when this happens, the battery supplies the extra current. Hasten to add, when the music PPower drops, the alt will then provide more current to re-charge the battery.
Car batteries are like a huge capacitor, accumulating charge, and discharging charge,..so any additional capacitors wont do much at all.
If it was my car, I'd fit a more powerfull alt [say around 100 amps max output], or less ideally, fit a more powerfull battery which can provide that extra current when your peak music power hits 1000 watts. If money was no problem,..I'd up the alt power and up the battery size.
Another way would be to limit max audio power to say 750 watts. Turn the volume down
As to why your lights are blowing, seems to point to excessive system voltage. How that is happening when most alts are no more than 14v out,..is a bit of a mystery. It might just be, that when the power-amp goes from high output to near nothing out [eg music has quiet passages in it] there is an overshoot of volts from the alt due too slow decay time from the alt regulator. Just a theory
JJ
. When we use the formula >> Amps = Power divided by volts i.e. Current = 1000 divided by 12,..we end up with 83 amps **at peak music power**. Because the alt can only output around 80 amps,..and the other circuits [eg ECU, injector-pump, injectors and ignition, any lights on plus fans and AC clutch] are pulling not insignificant current,..the alt cant handle all that load. So when this happens, the battery supplies the extra current. Hasten to add, when the music PPower drops, the alt will then provide more current to re-charge the battery.Car batteries are like a huge capacitor, accumulating charge, and discharging charge,..so any additional capacitors wont do much at all.
If it was my car, I'd fit a more powerfull alt [say around 100 amps max output], or less ideally, fit a more powerfull battery which can provide that extra current when your peak music power hits 1000 watts
. If money was no problem,..I'd up the alt power and up the battery size.Another way would be to limit max audio power to say 750 watts. Turn the volume down
As to why your lights are blowing, seems to point to excessive system voltage. How that is happening when most alts are no more than 14v out,..is a bit of a mystery. It might just be, that when the power-amp goes from high output to near nothing out [eg music has quiet passages in it] there is an overshoot of volts from the alt due too slow decay time from the alt regulator. Just a theory
JJ
tweety2300
Member
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- 2001 mazda protege mp3
But the ecu runs the alternator and there have been a few people that have fried the ecu by putting h.o alternators because it sends too much power through it
I just ran into this issue a few weeks ago with my amp, after a year of runing too small of wire the ground wire eventually melted and took the amp out with it.
It won't happen immediately but over time it could fry the ecu or cause an electrical fire
I just ran into this issue a few weeks ago with my amp, after a year of runing too small of wire the ground wire eventually melted and took the amp out with it.
It won't happen immediately but over time it could fry the ecu or cause an electrical fire
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- Mazda Protege 5
How wont the capacitor do much at all? It will supply a constant voltage straight to the amp despite other electronics and lights etc being on. Key thing you said car batteries are "LIKE" capacitors, but in the real world they are not, if they where they would be labeled as such. Like tweety said you could run a higher alt but your run the risk of all sorts of junk happening when you could have just bought a $100 capacitor. Bottom line if your serious about your audio equipment and you turn it up very loud you should just get the capacitor to handle the extra voltage. You will notice that your headlights will no longer dim, they make these capacitors for a reason.
Jasonjames
Member
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- Mazda 2002 BJ Astina 323 1.8 L
Higher output alts have thicker windings to carry more current, thereby increasing excitation magnetic flux [from the rotor], and providing more *available* [if needed] current from its stator. Their voltage out is set by their internal regulator c/w brush-module. The ECU gets its power from the battery, which is kept charged by the alt. The ECU will most likely have a number of lower voltage regulators "on board" to supply its various circuits. If an 100 amp HO alt is somehow going to damage the ECU,..then an 80 amp std alt will do the same thing.
The ECU wants 2 things from the car's electrical system>> battery volts,..and enough available current to operate and drive things like fuel-injector waveforms. Whether its a 80 or 100 amp alt makes no difference to it. Having said that,.if a fault occures in the ECU [say a short, blown power-fet for example] the thing which will cause it to fry, will be the enormous current reserves in the battery. A starter motor draws 100,s of amps to operate, from the battery. It is the battery that has the real power,..not the alt. Sure the alt will recharge the battery after a start,..but it takes minutes to do this,..while the starting process takes seconds.
As an aside>
Modern circuit design, includes safety devices like power-zenerdiodes which will conduct if the alt/battery volts go too high. The zener, once conducting, can be used to protect the ECU BY "crow-barring" supply fuses OB the ECU thereby isolating the ECU from car's electrical system.
JJ
The ECU wants 2 things from the car's electrical system>> battery volts,..and enough available current to operate and drive things like fuel-injector waveforms. Whether its a 80 or 100 amp alt makes no difference to it. Having said that,.if a fault occures in the ECU [say a short, blown power-fet for example] the thing which will cause it to fry, will be the enormous current reserves in the battery. A starter motor draws 100,s of amps to operate, from the battery. It is the battery that has the real power,..not the alt. Sure the alt will recharge the battery after a start,..but it takes minutes to do this,..while the starting process takes seconds.
As an aside>
Modern circuit design, includes safety devices like power-zenerdiodes which will conduct if the alt/battery volts go too high. The zener, once conducting, can be used to protect the ECU BY "crow-barring" supply fuses OB the ECU thereby isolating the ECU from car's electrical system.
JJ
Jasonjames
Member
- :
- Mazda 2002 BJ Astina 323 1.8 L
tweety2300
Member
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- 2001 mazda protege mp3
Iirc our alternators aren't internally regulated and its done straight through the ecu and that's why they can get damaged.
Obviously I don't know for a fact but if you dig around on here for awhile you'll find a thread about it
Obviously I don't know for a fact but if you dig around on here for awhile you'll find a thread about it
Jasonjames
Member
- :
- Mazda 2002 BJ Astina 323 1.8 L
For the life of me, I cant see how mounting the alt-regulator in the ECU achieves anything,...but if you 're right, it *maybe* a measure to get the alt to respond to battery volts its experiencing. Why the differential in battery volts between the engine-bay battery volts and the ECU ? Less than ideal voltage regulation,...meaning the +ve rail in the ECU is one or two volts lower than at the battery. I'll try to check it out, as this situation is less than ideal,..because the alt is hitting the battery harder, which can cause failures in the alt and battery itself...
JJ
JJ
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- Mazda Protege 5
Its purpose is to maintain a constant output voltage when there are changes in current demands and the electrical system can not maintain the output required. In high output situations like a bass hit the capacitor will discharge into the amplifier and give you that added current that you need. In low current situations it will draw power from the battery and charge up to be ready for the next hit. The capacitor aids the battery in power delivery to the amplifier. Now if there is bad wiring such as ground, power and alt wires than those will have an affect as well. You could even run the whole system off another battery that is designed for audio systems like a deep cycle battery. I also have to disagree with you on the battery and capacitor shenanigan, how many times can a capacitor charge and discharge before its no good vs a battery? They both store energy in different ways, they both discharge differently etc. Clearly you see where i am going with this, But your right the similarity between the both of them is shocking. All i am trying to do here is give an alternative to the h.o alt. I mean even an electrical genius/mathematician such as your self cant completely dismiss it as an option. Im done going on about this, it bores me.
Jasonjames
Member
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- Mazda 2002 BJ Astina 323 1.8 L
" it bores me"
Yep
JJ
Yep
JJ
If you are running w/ heat setting at floor, floor+windshield, or windshield, the AC comnpressor operates. When it kicks on and off, the lights may dim momentarily. Might be the issue.
