I got a 2010 montero foreclosed from a bank. Patay na ang battery kaya pinalitan ko. After a month of use, I noticed when the idling rpm is at 650 and when revving or when the rpm goes up to 850 when the compressor switches on, lumalakas ang headlight, blower, pati ang dome light sa loob at humihina pag nasa 650rpm. Pinatingin ko sa mitsu casa who connected the battery to a computer/digital battery tester. Wala daw problema ang charging at yung battery. Readings come to high 13 (13.8 or so) to 14. Ginawa na nila ito 6x na. The problem became more of a concern kasi on a few occasions, yung stereo headunit would reboot or trip off and switch back on when I press something: volume, change fm station. Pinatingin ko to several accessory stores and the battery shop where I bought the battery. Using their testers, we noticed the voltage would stay at the 14 level when the rev is high or none of the electrical loads are switched on. Pag binuksan ang headlight (on high beam), fog lights, stereo, (aircon blower without switching on the compressor to avoid the rpm from going up) eto na, slowly bumaba ang volt. I took a picture of the digital voltmeter registering 12.79 after several minutes of watching it go down. Naka timing naman ako may pumasok na 2012 glx montero sa accessory shop. The owner allowed me to check his ride's voltage and switching on the same electrical load, 13.9 yung kanya. Pinakita ko sa service manager ng mitsu casa yung pictures ng voltage readings. But still after 2 days of testing, sabi pa rin niya normal lang daw ito kasi they checked with 5 other monteros in the shop, nagfi-flicker talaga ang headlights ng montero but not on the Stradas.

Sabi ko sa kanya, di yan normal kasi pag na timing ka sa traffic at di naman naka on ang compressor mo sa gabi and the effect is lower rpm, dahan dahan mauubos ang battery ko. But because THEIR computer battery tester said its normal (yung may print out), they cannot make any repairs or warranty claims. I want them to open up the alternator coz 2 other shops (hindi na yung accessory shops na sinabi ko) told me nasa alternator ang problema.

Does anyone have any experience like this or any suggestions? The montero still has around 10 months under warranty to go. 20K mileage, 2010 GLS 4x2 A/T model. Kung hindi pwede iclaim sa warranty o hindi pwede ipaayos sa casa dahil nga sabi nila normal lang yan, ipatrabaho ko na lang kaya sa labas?

Yung accessory shops pala, refuse to install accessories sa montero (wanted to improve the sound system and horn upgrade) kasi nga bumababa ang voltage.