Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Battery charging

If it's anything like my roadster then it's the instrument panel, I remove fuse 17 in my case.

Remove that and the rate of drain is drastically reduced.

It's easier to load the battery from time to time than removing a fuse in the fuse box under the hood.

Maybe somebody with a similar car can check this to confirm that such a current is normal? I pulled the fuse (I think it's the 3rd one of the bigger ones from right)and checked the current with a Multimeter between the two contacts.

Have to be careful not to let the battery get to low as it does them no good in the long run, it's why I use a ctek battery monitor on the mog it let's me know when it is getting lowish

The various MX5's which are also left over the winter like a Morgan are designed not to run a dark current of more than 20 mA.

The very latest Mk4 cars from 2015 on are in certain cases using more than this but not all cars and the battery is smaller to save weight and say 10% are getting flat batteries after a week or so.

The latest cars also have lots of sensors compared to the earlier cars. No doubt Morgans are similar in some use more dark current than others.

My car is a little older than yours but the drain is very low indeed and I believe of the same order of magnitude as the batteries natural self-discharge rate (say 5%/month). The car has always started easily if left for 2 or 3 weeks without charging. Also the cars total drain measured at the battery terminal is the same as just the ECU powered up on the bench (and yes sadly I have done that). The sleeping ECU draws a couple of milliamps max spiking up to around 7 or 8 mA as the PATs LED flashes for a few milliseconds each second. So the average drain is well below 10mA.

Ian

1998

Chris

Had a glitch with my battery in November 17. Car failed to start on ramp during MOT. Diagnoses low battery charge.
Funny old thing a few weeks before had decided to leave aircon (not fitted) button pressed in as doing this means when you put the heater fan on a tell tail light illuminates as a reminder you have the fan on.
Well switched it off and charged the battery. No problems since (touch wood) even after leaving the car without trickle charge for in excess of 6 weeks.
Coincidence maybe, not sure if mot bod attempted to start the car with one turn of key, rather than on 1st position wait for the vibration tach reset etc to finish then start. Someone can explain but the “system” does some sort of reset in those few seconds. He may therefore tried to start it 1/2 way through the reset.
Having said all that, batteries can be fickle things.

I use a CTek conditioner on my Mog if it’s not going to be driven for 2 or 3 weeks because it struggles to start after that long, no immobiliser, alarm or anything else to drain the battery. I fitted a cigarette lighter socket directly fed from the battery.
For a variety of reasons SWMBOs 2004 Porsche 911 was left in the garage untouched for a couple of months over the winter, went to get it out and the 3 year old battery was completely dead. The problem was that the battery is in the boot (at the front of the car where most people’s engine is) and the boot opening button on the key, nor the “manual” release, work when the battery’s dead . To open the boot you have to connect another battery to a contact in the fuse box and a ground position to be able to power the boot opening switch I’m sure that sounded like a great security idea to whoever designed it, but what a faff.
Bought another CTek so that the Porker will be connected as well as the Mog if left for any time in future.