Thread: 300TDI Charging and Starting

Originally Posted by isuzu110

Hi All

I've been battling an intermittent starting issue with my '95 defender over the last 18 months. Over that period, I've done the following:

* Replaced the alternator on Christmas eve. All that was available in the timeframe was another 65A unit
* Had the starter motor reconditioned and the faulty solenoid replaced
* Replaced the ignition switch
* Replaced the starting battery

The symptoms are that you turn the switch but the starter does not crank. After successive retries, the starter cranks healthily with no sign of voltage drop.


I have 3 key questions:

1. When I drive with the aircon on, the starting battery voltage sits at about 13.8V. When I turn the aircon off, the starting battery voltage rises to 14.2V. Is this a sign that my alternator is struggling with the aircon load and that my starting battery is not charging as quickly/fully as it should. I'm running a calcium based Supercharge starter battery.
   
2. I have 100ma of parasitic drain from the starting battery with the engine switched off. The vehicle has an isolating type of dual battery system installed. The aux battery runs the clock and radio. The only load on the starting battery is 12ma for the turbo timer and 20ma for the dual battery system. Any clues on there the other 68ma is going ? I can hear no relays clicking in when I connect the starting battery to the vehicle.
   
3. Sometimes I only see 10.5V on the starter terminal on the ignition switch, despite changing the ignition switch. The voltage comes up about a volt when the glow plugs time out. Any ideas on why this is so low ?

Thoughts anyone ?

Hi isuzu110

How are the batteries coupled?
I am about to throw out the smart relay that refuses to disconnect my start and auxiliary batteries, then I am installing a manual switch.
I have found that the older auxiliary battery is pulling the newer start battery down in voltage whilst the motor isnt going.
Cheers Arthur