fluctuating voltage on a 2010 montero

[Retz]

Pa check-up mo muna sa Casa kung under warranty pa.

[miko101130]

I'll try to help you sir...
Dapat pag naka idle ka at walang load ang vehicle, usually 13.5-14.5 ang voltage at the battery...

The minimum voltage at idle speed should be 12.5 volts at the battery... This means that the battery is not discharging and also not charging...
Any drop below this voltage at idle with no load is attributed to alternator problem..

The capacity of your alternator, found on the alternator on a sticker, will determine how many AMPERES it can produce..

Example, an alternator rated at 90 amps, with a 13 nominal voltage will produce 1170 watts.... If your total electrical load reaches more than 1170 watts, then the alternator cannot charge the battery even at full capacity simply because the demand is higher than what can be supplied...

The alternator in your car is designed to provide electricity and still be able to charge the battery even if all your "stock electrical accesories are open"....

If the alternator will drop its voltage even without much load, probably at 50% load only, then the alternator or the PCM is at fault!
That is if the battery are 100% ok and grounding is ok..

Usually the charging inside the alternator is ruled by the diodes, 6 of them, 3 pairs... Then the voltage is controlled by a voltage regulator built inside, so that voltage will not increase above 14 or more even at full speed...

On newly built vehicles, the PCM, powertrain control module, also has the function of controlling the charging of the vehicle...

If the pcm is ok, then it will most likely be the alternator, assuming that the battery is ok and no other electrical issues at hand..

I'll give another example,
On my vehicle, my alternator is rated at 75 amps... Therfore at full capacity my alternator can produce 975 watts if the system demands it... At idle my alternator probably produces 20- 40 amps... Suffecient for normal use with vehicle accesories.
Aircon,headlights,engine...

At idle my voltage reading via a digital volt meter at the battery terminal is at 13.9 volts...
Every electrical load you switch on will lessen that 13.9 volts.

Headlight = 10 amps
Aircon= 10amps
Brake lights=5 amps
Parklight= 5 amps
Stock sounds= 10amps
Abs/ecu/ etc= 20 amps

Total is 60 amps... So there is still a 15 amp reserve still available for other accesories...
Total is 780watts... There is still 195 watts reserve capacity...

My voltage reading at this point will be at 13.1 to 13.2 volts...

If i use my auxilliary lights which consumes 400 watts
I will be at 12.3 volts.. So im discharging... Because im over the capacity ans the battery is supplying the extra power the accesories will use hence it will drop its voltage...

[miked]

isa pa, ano ang mga previous PMS na ginawa sa sasakyan nyo po bago nangyari ito? kasi baka simpleng maluwag na serpentine belt or some other simple things na hindi masyado napapansin. start with the basics first ika nga.

[miko101130]

one things pala TS... according to your statement, the same electrical load was applied on a similar montero that was also there at the time you are at the accessory shop... your reading with your montero at load is 12.7, while the other montero reads at 13.7... granting everything else equal among your units....

if the vehicle is still under warranty, try to pursue that path...
vehicle headlights should not flicker.... kasi pag nag flicker it signals that there was voltage drop that occured in the electrical line...
pero before you go and isolate the problem on the alternator, be sure that the battery, battery terminals, grounding, are all ok...

try to put the vehicle in high beam and see if the dome lights will dim... or if the gauges will dim/blink then return to normal...

[bambino]

ask mo yung casa kung meron sila ng AUTOMOTIVE LABSCOPE . dito makikita kung meron diode problem ang montero mo.
mode ng scope AC RIPPLE /DIODE TEST . i have seen a lot of these at my shop.

all loads on at idle =13vdc minimum

[altec]

casa service manager said yung ibang montero may flicker ang headlight when other heavy accessories switch on. I have my doubts about that kasi yung naabutan ko nga na GLX sa accessory shop na pumayag magpatest ng kotse niya, walang flicker, plus I also checked my friend who has a 2010 gls, and another friend who has a 2012 gtv. Walang flicker. Yung GLX, switch on high beam headlight with foglights, stereo, aircon blower without the compressor switched on, yung reading niya steady at 13.9. Yung sa akin will drop to 13.3 and continued to drop hanggang na picture ko yung voltmeter reading at 12.79, but actually, it continued to drop slowly.

Meron pa siyang warranty kasi July 2010 unit ito, so I have around 10 months warranty to go. Yun lang nga, sabi nga ng casa, walang problema ang battery at alternator according to their computer print out, kaya there is nothing to claim versus warranty. Yung battery ko, after market battery na, 3smf or N70. 2-3 months old, but the battery supplier agreed to replace it. Yung last check up sa casa, 3 days old pa ang replacement battery. Yung mga 2012 models ng Montero, naka 2smf or N50 na lang. The Mitsu service manager already ruled out that it is the battery. The casa electrician has already cleaned the grounding.

I also have a 2010 Strada with the original GS battery still connected. Sinubukan ko rin iswap ang battery nila. The GS battery installed at the Montero will still cause the voltage reading to drop, while the after market battery installed in the Strada, steady ang voltage reading. Same scenario: switch on high beam, fog lights, dome light, stereo, and aircon blower switched on. The only time the Strada's voltage reading drops is when I blow my horn, which is 2 sets of hella supertones, plus yung stereo niya may upgrade na rin. Yung Montero is still all stock.

Yung flicker is now happening more often, maybe at least 75% of the time na. Last month, it comes and goes.

Will ask the casa tomorrow about the labscope. Will also bring an electrical shop's battery voltmeter to show to the casa. Yung casa kasi insists on their computer which always show the reading at over 13, while if using a voltmeter, makikita yung "slow discharging".

[miko101130]

im suspecting the alternator diodes is somewhat involved...
the flickering headlights and the dropping voltage, plus the increasing instances that the headlights will flicker...

the alternator may not be sensing the load, and therfore does not provide the needed charge...

as to what the casa is insisting," that the unit is ok because there is no error yet happening..."
its because the vehicle is still within the range of charging (12.7 volts) but lets put that into perspective;

if a water pump is designed to pump at 100 liters/ hour, if it only performs at 70 liter/hour? does that constitutes as "walang sira o diperensiya"

just point out sir to the SA, na with other montero even with load, charge rate is at 13.7 volts....
that, being in the range of 12.7 volts of charging is not acceptable.!!!