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

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.