Morris Minor Owners Club

i have just changed my battery for the third time in around 12 months, free of charge under the guarantee, but now i'm wondering whether it's not simply a case of being unlucky with faulty batteries, but that something under the old moggie bonnet might be draining it. This time, for example, I had the new battery fitted on a friday afternoon, and on the following morning it struggled to turn the engine just like the old one. It hadn't been an especially cold night either.
Has anyone any ideas of what might drain a battery while the car is standing idle? I don't have any add-ons or conversions, like an alternator, just a standard 948 engine on a 1958 moggie.

Really any guarantee claim on a battery should have the suspect battery fully charged and then load tested to confirm it's condition.
It's not unknown to have a faulty new battery as they are stored charged up sometimes for many months.
We recentley have have fitted 3 or 4 seperate vehicles with batteries theat where confirmmed duff. These where all motor spares suppliers own brand (Lion if your interested) we now only fit Exide or bosch batteries (We prefer Exide as they make em)

To discharge overnight would be quite a current draw. Take key out ingnition and put a charged up battery on the car. Look for any sparking on the terminal as youput it onto the post this would indicate a current draw. Best w ay is to connect a multimeter set on DC amps in series with the battery and car and observe what current is flowing backwards it should be zero or VERY low assuming all assesories and equ is OFF

Can we assume the red IGN light is going off ok - and the interior light??

No radio or extra lights under the bonnet or in the boot?
That's quite a big drain overnight, about like leaving the headlights on, I'd expect the culprit to be getting quite warm.
Regulator points stuck maybe?

I had this problem and it turned out to be the dynamo. Now replaced it with an alternator, and dont have this problem anymore.

Dynamos just arent up to it in todays stop start traffic.

The dynamo could not cause this problem because it is isolated when the Ign is off. But a faulty regulator (sticking in) would certainly do this - but the red light will be glowing if this happens. It is by far the most likely culprit.

If you dont find the source of the problem you could fit a battery cut out switch as shown below, for those extended garage lay ups.
http://www.moss-europe.co.uk/Shop/ViewP ... ortOrder=2
Not cheap though.

a Battery Disconnect Switch Isolator would be cheaper (£5.95 + £1.75 postage)
see ebay item number 121062207902 are check for similar
I have one fitted to my traveller without the bypass fuse and always disconnect when car not in use

andy.pointeer wrote:a Battery Disconnect Switch Isolator would be cheaper (£5.95 + £1.75 postage)
see ebay item number 121062207902 are check for similar
I have one fitted to my traveller without the bypass fuse and always disconnect when car not in use

I too use one of the above, coupled with the solar trickle charger the battery stays in fine fettle. An added bonus is that the isolator can be used as a security device.

Though you do need to find the source of the current drain, as roy says check the regulator if you have no lights that are staying on with the ignition off.

was talking to my local factor the other day about batteries,he says that non of the batteries are tested before being distrubuted,they just send them out and wait for customers to take them back if they are faulty,he says that over the last 5 years or so he has seen a big increase in returns. Typical modern way sell us rubish and let us do the running about.

I recently bought an exide one and the first cold night and it died. they will exchange it no problems thankfully. just havent got round to it yet.

the guy at the tyre place says he thinks the dynamo must be us/worn out and is not charging the battery.
any thoughts on this?

Go and get it properly tested with and without load ,thinking it might be this or that is for the bad weather

He 'thinks' - wow - he is a real expert then.... The only way to tell is with a voltmeter - Maplins do them inexpensively. With engine running at decent revs and headlighst on and heater fan running - the battery should be showing ~ 13 volts with a dynamo charging. If only 12 volts - it's not charging. Simples !