Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Poor battery life

The battery in my 2009 Roadster becomes flat if the car isn't used for 2 weeks or more - totally flat, will not even light the ignition lamp.
It now has a new battery but the situation hasn't changed. Is this normal? Are there known causes of battery drainage?

I always use a conditioner and the battery stays fully charged. There's a demand from the immobiliser (and clock if you have one) but you may have a leak. I would test with a multimeter and if there's a current drain you should be able to isolate it by pulling fuses. If you're not confident to do this, get an auto electrician to look at it. A new battery should hold charge longer than two weeks.

Take out the various fuses for the instrument module and see if that improves matters while not being used

My ECU draws very little, sub 10mA just sat with the immobiliser LED flashing. Not enough to drain the battery as you describe. I did have to fix a very similar problem on one of my son’s cars recently. I traced it back to his fancy wireless. He refused to part with it so ended up fitting a separate power switch. If you have one and have no way of checking it I would suggest perhaps disconnecting it for a week or so.

My 1999 +8 will discharge a fully charged battery in about 2 to 3 weeks if left alone with no use. I have always assumed that this is the immobiliser circuits, but don't have any measurements to quantify this.

If I isolate the battery from the all the circuits (except my SatNav charge point) by removing the red isolation key , it keeps its charge for considerably longer (again not quantified but would suggest at least 2 months) However when I do this it appears to take a few miles before the ecu "relearns" my driving habits, so I don't like this a method of preserving battery life.

Like Dave W I keep the car on a trickle charger all the time it is in the garage. That way I have not had any problems.

Note to self: remember to hook up battery minder. Now three weeks since I last used the car.

My car has a switch to switch off the clock, I've no ecu to worry about,I use a solar charger to trickle charge the battery.
It will start normally after 2months (eg winter storage) but it is on a new battery this year
normal "moderns" can suffer discharge in about 1month, of enough charge to not be able to start (cold weather)

Started my 1972 4/4 last night after 3 months in store. Started first turn of the key. On a 5 year old Halfords battery too!

Arwyn

My +8 starts whenever needed,if i remember to give it some choke. amount varies with air temperature. Battery about six year old.

Oh for the pre ECU, immobiliser, clock and electronic thingies.
You don't need batteries for your twin forties, SU's, Strombergs etc.
However a new battery should hold charge for longer than that, something is on.
The Morgan connection for the radio on mine had a live feed so was on standby all the time. If you have one it is worth checking what it is drawing from the battery.