Talk Morgan Forums Morgan Sports Cars Morgan Aero 8, 2012< Plus 8, SuperSports, Coupe & Aeromax Battery Drain Rate

After a new battery and charger I've been monitoring battery drain, possibly a bit obsessively.

So far it seems as if the battery looses 0.2v per 24 hours, or 1.2v a week.
The battery needs to be at 12.2v, minimum, to be certain of starting the engine, so 10 days is about the longest time it is "safe" to leave the car without charging, or using.
It is, of course, possible to turn everything off with the master switch, but then the radio station memory is lost.

What I want to know is what is drawing power?

It will be a whole host of items Peter.

The radio pre-sets , the ecu , the electonic modules around the car , various memories in the electronics, and probably many more.

That makes two of us Peter, please let us know if you find out.

My S4 does the same and also seems to dislike the Ctek charger I was using - which kept going into fault mode. Now using a Halfrauds unit which seems to do the job well. The boot opening button and hazard button both remain faintly illuminated, when the car is off. Techniques say this is "normal" and couldn't find any other obvious drain.

I have tried everything, even trying to talk Mrs R into getting in the boot to see if the light goes off when closed! It does, but I had to video the event myself as my powers of persuasion have obviously declined over the years.

I have a very sensitive clip on current ammeter and I went around my Classic Plus 8 checking a few residual drains and decided it was easier to throw the Red switch every time. I have left her for 8 weeks once on a holiday and she fired up straight away, the ECU soon relearns the temporary information so it makes no difference and out of interest the radio is the only remaining drain once the Red switch is thrown so I don't loose the memory on the Becker unit - this may not be the case with the Aero 8.

Difficult to comment sensibly without some more details - battery size for example. Does the car have an alarm? Does it have a tracker? Those two are the most likely permanent draws on the battery. You might expect an alarm to use maybe 40mA and a tracker a further 20 so 60 in total. Over 24 hours thats 1.5 Ah. If your battery is fully charged and is say 60Ah capacity then it will drop to 12.2 v ( half charged) in something like 20 days.

Your numbers are a bit odd. Fully charged your battery voltage is 12.7 or 12.8. 10 days to drop to 12.2 is 0.06 per day. 0.2v per day would have your battery down to 10.7v in 10 days. Are you being confused by the approc 14v voltage you can measure immediately after running the engine? This is surface charge and there is no power behind it - left to itself it will decay away failry quickly. to the normal 12.7.

On a modern "electronic " car, a stand time before you get issues of 15 to 20 days isnt unusual. Both my Ferraris have been in that bracket as is my wife's Smart Roadster

We had a friend with an Aero arrive here a couple of years back and it turned out that a seemingly good battery was going flat overnight however if he operated the inertia kill switch, thereby disconnecting the battery, it would start without problems the next morning. We went to the local auto electrician and discovered two things: 1) there was a constant drain on the battery that was enough to flatten any battery overnight, and 2) the battery was a little down on power and needed replacing.

It was too difficult to identify the source of the drain but when the battery was replaced the current drain dropped back to virtually normal for the various small items that had to remain live to some degree, central locking, radio, etc.

So it seems that if the battery is not fully up to the correct voltage some item in the car was not fully disconnecting when the ignition was turn off. With a fully charged battery the item turned off correctly.

I'm not sure how accurate (scientifically?) your conclusion is Peter (and I know you are not claiming it to be) but that is the best explanation I have come across of why Aero type cars' batteries drain excessively......

James

Can anyone advise if the close proximity of the keys to the car when it is parked could make any difference to the battery drain? I have heard that if the keys are stored close enough to the car, then the canbus (?) system doesn't shut down fully - hence more drain. My keys are usually stored indoors, but the cupboard is probably less than five feet from the fuse box of the car.

Also, I wonder could that also trigger my repeated fault mode on the Ctek charger?

I'll experiment further with key position and Ctek reconnected.

I am not aware of any proximity capability of the BMW/Morgan system unlike cars with keyless go/start. I would doubt this could be the issue.

My S2 had a trapped wire in the engine bay which was causing a consistent drain which a specialist electrician isolated and replaced. It was pretty good after that and would do a couple of weeks without a charge. It had no alarm and a Becker which retained memories. I was using the banner red bull back then. It did not have a tracker. The boot lamp is always lightly on even when parked and locked.

The Coupe does have the mother of all trackers and has never been able to do more than about 2-3 days without a drive or boost/trickle. Various lights have a mind of their own.

I still love it. Just like the wife loves a defective me. A little.

We are back from a weekend away, having driven the car about 200 miles. The battery us showing 12.9v, ignition off.
I've connected the charger, a "RING" brand device that charges, maintains, repairs and keeps a battery warm in very cold conditions. It is capable of charging at 12A in repair mode.
In maintenance mode it sarges at up to 0.5A.

The battery is new, a Yusa 60Amp device.

There is no tracker or other device and the USB adaptor is unplugged.

When the ignition is off the heated front screen with is partly illuminated for about 10 min before going out.
Also, as soon as the door is opened the footwell lights come on and the seatbelt, hazard flasher and heated screen come on.

The Radio is an Alpine device that does not have any ability to retain station information when disconnected.

This friend it was me .... Chanteclair

I wouldn't hold too much store (pun?) by measured off load voltages after charging or discharging Peter. Both situations take place at the battery plate to electrolyte interface, but the electrical storage of a lead/acid battery is chemically within the depth of the plates so it takes a while for the measured voltage to stabilise after either condition. See table below for a guide to battery condition, only relevant after resting for several hours from use.



Please note that specific gravity of the batteries electrolyte is a better guide to battery condition rather than off load voltage. This is measured with a hydrometer but only if you have access, i.e. no help with a sealed battery. Even then it gives no indication of the batteries capacity which can only be assumed as advertised when new or nearly so. Part of the ageing process is sulphation where the lead sulphate on the plates of a discharged battery can crystallise, effectively reducing their surface area in contact with electrolyte. This situation is greatly accelerated if battery is left unused in discharged state, hence importance of battery charger on float/maintenance mode when vehicle out of use for several weeks.

A sulphated battery will have a much diminished capacity, hence will charge and discharge quickly. It may show the full 12.7 volts indicating it's fully charged but only within the constraints of its limited capacity which even then may not be enough to turn engine over long enough for it to fire, especially mid winter, and hence my initial comments. The "repair" mode on your charger will be an attempt to reverse the sulphation by deliberately raising the charge voltage and often called equalisation. You usually get a warning in the chargers instructions not to have anything connected during operation in this mode since a 12 volt battery can hit up to 16 volts during such charging.

A lead/acid battery even left without load will still loose approx 5% of its capacity/month due to internal discharge. Having said all this I would be very dissapointed if a normally regularly used battery, in a new or old car, wouldn't start the vehicle after at least three weeks, in an airport car park for example.

Its highly unlikely that there is a battery fault. 12.2 v is a battery roughly half charged so you are saying that the car when switched off uses 30aH in 10 days or a constant drain of 125 ma. Without a radio or tracker and alarm / immobiliser (does it have one?) there should be no drain at all, or to be totally correct just the small internal drain that every lead acid battery has.

Finding what is happening is a tiresome ballsaching exercise involving putting an ammeter on the battery lead whilst in the garage , noting the current flow and then disconnecting various bits of the electrical circuit to see what changes. Personally I couldnt be bothered. I'd simply wire in a trickle charger and plug the car in every few days. For travel abrioad you can get solar chargers that put out that level of power.

The Morgan has lots of quirks - this is just another!

P.S. If you do decide to have a go, I would start with the items you have highlighted. The hazards shouldnt come on when you open a door and neither should the heated screen

I generally turn the electrics off using the master switch then have the battery on a Ctek attached to a timer which runs for about two hours a day.

The Speedster has a tracker - which I am required to have by all the insurance companies I contacted- has the usual floor-well lighting on shut down, an Alpine head unit - but other than that-not particularly problematic or unusual .

In the time I've owned - always started first time. Hope it stays that way.

Bulb warning - is , however, a " feature" when no bulb appears to have failed- and its intermittent. I just ignore it.

I have random lighting of the warning switches and the dials. Sometimes all - sometimes - just some. I just ignore it.

I work on the EE Lightning/SR71 principle.

If at least one of the dashboards lights is not on when it is at rest locked in the garage then this indicates the battery is flat or close to.

As Howard has said, a Morgan has lots of Quirks!

I solved this one by switching on the headlights after switching on the car.
Mine can anyhow stay 2/3 weeks without the CTEK connected, but I fear the moment when I want to use the car and it does not start, so recently I got the habit to always connect it. Before via the cigarette lighter plug in the glovebox, now I decided to connect it directly to the battery, in this way:

Much better way of connecting charger

My Ctek clone charger came with an optional extra charge lead. It allows permanent hook up to battery, terminating in non reversible high current plug to match chargers, just as yours appears to have.

Has the Plus 6 arrived yet

S5 would probably fail to start after 5 or 6 days so keep it on charge 3 days +

No point worrying about it - just a Morgan thing.

Plus fours have always been okay for 2 weeks plus.

Not yet Ihope on December the 1 th

Not yet, I hope December the 1 th

Peter would you like me to come around with my FLIR camera and see what is hot! It'll be the various instrumentation adaption modules along with the Immobilizer, you'll probably find a hot CANBUS or LINBUS chip or two.

Alternately remove the fuses and see when it stops then investigate what is hanging off the end of said feed.

Mark, that's a smart idea. May I ask what you are using for the FLIR ? Is it s bolt to a smart phone or some dedicated device.

I'd say Yes, if I had a car.
But it is still at Williams....
Should be back on Tuesday...... perhaps....

Just the FLIR one add-on for my phone

Last thing I used it for was searching for a wasp nest at night in the hedge at the bottom of my garden!

Give me a shout when it's convenient Peter, maybe one weekend.

Info at https://www.flir.com/flirone