Battery Discharge

[gonecrazy]

Hi, i have a toyota carina e 1.8 Since having an o2 sensor installed i have been experiencing rapid Battery discharge, (charged Battery friday, started car saturday and on sunday the Battery was depleted again) i have replaced the battery 3 times and each time making sure all electrical items (radio, lights, heater) are turned off, the alternator was replaced at the same time as the the sensor was installed so am pretty sure it's not that, my only other guess is the voltage regulator. Can anyone else suggest what may be causing this and the best way of testing the regulator, have checked the wiring under the bonnet that all seems in order.

[Richard KM]

Hi, i have a toyota carina e 1.8 Since having an o2 sensor installed i have been experiencing rapid battery discharge, (charged battery friday, started car saturday and on sunday the battery was depleted again) i have replaced the battery 3 times and each time making sure all electrical items (radio, lights, heater) are turned off, the alternator was replaced at the same time as the the sensor was installed so am pretty sure it's not that, my only other guess is the voltage regulator. Can anyone else suggest what may be causing this and the best way of testing the regulator, have checked the wiring under the bonnet that all seems in order.

I wouldn't be surprised if it is the alternator, as the Nippon Denso internal fan alternators do have the odd problem with the rotors shorting to ground. The rotor (the internal piece that spins in the alternator)is permanently fed from the main alternator terminal. If the rotor shorts to ground (and they do sometimes), they usually draw about 2 amps. If you can hook up a digital ammeter to the negative Battery terminal, set it to the 10A range, or whatever the meter has, not the mA range. If you have 1-2 amps showing with everything switched off, try unplugging the 3 pin plug in the alternator. It'd probably still be drawing 1-2 amps, so disconnect the alternator main terminal carefully not to short to anything metal. If the current draw drops to 0.03 amps, it's in the alternator. Usually the rotor with that sort of drain, could also be the rectifier, also in the alternator.