Talk Morgan Forums Morgan Sports Cars Morgan Aero 8, 2012< Plus 8, SuperSports, Coupe & Aeromax Electrical Issue or Another Quirk?

OK Stephen. The click you heard is the solenoid and this suggests either a flat battery with only enough power to activate the solenoid or a duff starter motor / bad connection. That the car now works with a fresh battery suggests that it was a simple flat battery.

A flat battery can be one of three things. No 1 is a duff battery. No 2 is a good battery not being charged by the alternator. No 3 is a steady discharge whilst parked and turned off.. You can get a very good idea of which with a simple digi voltmeter. The alternator should charge the battery at somewhere round 14.5v so step 1 is to start the engine, get someone to rev at say 2000rpm and check the volts at the battery terminal. If the volts are 12.8 or even less then alternator problem. If 14.5 or thereabouts then alternator likely is OK. Lets assume the alternator is OK then stop the engine and turn on the headlights for 20 sec or so to burn off any excess charge on the plates. Let the battery sit for 5 mins and measure the voltage. Take a not - likely its something like 12.8v. Let the car sit for half a day and again measure the volts. In an ideal world it wont have dropped even as much as 0.1v showing nothing draining the battery. But if it has dropped then go straight to that windscreen heater button. It should not show any light at all when the car is parked up and the light it does show indicates its using up your amps.
The whine is likely to be irrelevant - after all it can only be there when the engine is running since stationary there is nothing to generate the AC voltage you are hearing. It could possibly be an indication of a duff alternator but see above.
Last comment. Take the car to an auto electrician and not your usual garage. The average mechanic knows sod all about electric circuits and their testing.

Glowing buttons are rither indicative of a bad earth with the live circuits trying to return to the battery via alternative paths

Or the circuit board that the indicators are driven by is faulty.



If you want to know what state your battery is in have a proper battery load test performed on it that would show up a week battery no problem but that wouldn't make your window heater glow?

Later Aero based cars, the ones with the 4.8L motor, have a digital voltmeter available to display in the small LCD in the bottom of the speedometer. I'm not sure exactly when this started, possibly the Aero S4.

I checked Tarka, following the process you descrived, and the results were spot on: 14.7v charging, 12.3v after a few hours sitting. Turning on the lights, heated screen and seat heater each drops the voltage by 0.1v, so with all on it showed 12.0v.
This suggests that the battery is good and being properly charged.

The switch pannel with the Warning lights and the strip of warning lights below are prone to internal corrosion if they get damp. On Tarka the row of warning lights failed one by one until nothing worked - but the button for the heated screen glowed very slightly and all the switches worked.

All replaced by MMC under warranty.

12.3v is somewhere around 50% charged Peter - cant be precise because voltage depends on load. However a battery that is left 50% charged isnt going to be happy for long so you might like to attach a trickle charger.

The common problem is that it takes quite a long run for the alternator to fully charge a 50% discharged battery. On my boat it takes 6 hours because the current flow into the battery falls significantly as the charge state of the battery rises.And thats with the alternator running at 14.5 v

Howard,

thanks...I possibly need to use the Optimate more.

At 12.3v the car starts without any issue. I wonder how low it has to fall before the car will not start?

It's not just poor starting that tells you the battery charge is slightly below par. On my Aero, some of the CANBUS sensors seem very sensitive to voltage differences, for example bulb fail warnings. The lights work OK, but warnings are triggered unless the battery is fully charged. Quirky things these Morgans.

So an update - all appears well with the car. I followed the advice handed out here (thanks again) and the alternator is charging the battery and I've had no further issues.

I suspect the previous battery had gone bad although I'll get the heater light issue looked into as a priority. I also plan to have the non-standard equipment removed too.

Thanks again!