Battery discharge whilst in motion

[baldrick_the_cat]

Help anyone !!
I have a 59 saloon, which is prone to battery problems.
On a couple of occasions in the last 3 months I have had a complete discharge of the battery whilst happily pootling along.
I've also had the ignition coil blow apart in the same period.
Any suggestions?
Tx
Matt

[Willie]

Re the coil....was it a correct type for the Minor? i.e. 12 volt type
NOT a 'ballast' later type? If it was a ballast type it would have been
running on too high a voltage which may have caused it to 'blow up'.
Re the battery discharge...obvious question,was the red charging
light lit up? Did it only happen once? How have you cured it?
( new battery, new dynamo, new regulator unit)?

[baldrick_the_cat]

Re the coil....was it a correct type for the Minor? i.e. 12 volt type
NOT a 'ballast' later type? If it was a ballast type it would have been
running on too high a voltage which may have caused it to 'blow up'.

Cheers, Willie........ how can I check this ??

Re the battery discharge...obvious question,was the red charging
light lit up? Did it only happen once? How have you cured it?
( new battery, new dynamo, new regulator unit)?

In the last 18 months I have fitted a new dynamo, ignition coil, regulator unit and battery, so they should all be OK
The battery is one recommended for a Minor, altho' I now gather that my engine is probably a 1275 cc from a Marina/Ital (Tx to Cam, elsewhere on this site), so I don't know if this makes a difference.
Don't know if this helps, but last night it conked out again........... I pulled up in front of my garage, and took out the keys to use the electronic garage tag. When I tried to restart the engine immediately afterwards, the battery was completely dead.
This was after a couple of 12 mile runs to/from work, with the headlamps & wipers on, but without the fan.
I'm beginning to suspect a loose wire somewhere, as the wiring loom is a mess, particularly where the previous owner attempted to fit a stereo and a flip switch for indicators/trafficators.
Most puzzling, not to mention frustating !!
Cheers
matt

[Andy]

I used to have a similar problem to this on my car (incidentally also a '59 saloon). I would very often fully charge the battery only to find it was almost dead after a long run. It turned out to be a poor earth between the engine and body. The original earth connection is via the back of the gearbox. This connection can become poor after time as it gets blasted by road dirt and salt.

I've fitted an earth strap directly between the engine and the battery tray. Connecting to a cylinder head stud and the battery earthing point respectively. This solved the problem

Earth strap are available from just about anywhere (even Halfords)

Hope this helps

Andy H

[newagetraveller]

Consider fitting an ammeter to your car.
Then you will be able to see what is going on.

[Alec]

Hello B the C,
if the coil is Lucas then often there are no markings to identify ballast or non ballast so it's a matter of buying a new correct type to be sure.
I would echo Andy's advice and the point is whether the battery is actually discharged or the starter motor won't turn the engine over; two different faults. If the latter, try the headlights or horn and if they work then it's almost certainly an earthing fault. (By no means a conclusive test, by the way, but one that often works.)

Alec

[Willie]

A good place for an additional engine to chassis earthing strap
is from one of the front engine tower/chassis bolts to the stud
which clamps the oil breather pipe below the exhaust manifold.
As stated if there is a dodgy engine to chassis earth then the
starter could fail to operate. If this happens you should jump
out and gingerly feel the choke cable. If it is unduly hot then it
has been trying to pass all the current to the starter motor due
to the poor earth. It appears likely that you have this type of
fault since you say you drive normally until you switch off the
engine and it will not then restart......the battery is not going
to go 'completely dead' in such a short time.

[baldrick_the_cat]

Thanks to all for your helpful replies...
I will take a look at the earth-strap idea across the weekend, and get back to you all after I've given it a go!
Cheers
Matt

[Cam]

If ever the car just dies like you described then you can check if it's an earth strap fault by connecting the engine to the body with a jump-lead. If that improves matters then you have an earth strap fault. If not (assuming you have got a good connection on the jump-lead) then it's something else.

[forbesg]

Consider fitting an ammeter to your car.
Then you will be able to see what is going on.

I second that!
I had the same problem a couple of years ago with my alternator, noticed that when I pushed the clutch in the ammeter would increase into charge and the drop into discharge when the clutch was let out. It was as everyone has already pointed to.. bad earthing of the (in my case) alternator.

[baldrick_the_cat]

I took a look & the earthstrap at the back of the gearbox is pretty gammy.
Is it OK just to fit an extra earthstrap from the battery tray earthing point to the cylinder head, or do I need to replace the one at the back of the gearbox as well ?
thanks again
Matt

[Cam]

As long as you are connecting the engine block to the body it does not matter where you put the strap. I have one either side of the front engine rubber mounting. One will do, but two is better.

[baldrick_the_cat]

OK folks !
The earthstrap has been fitted, but the problems continue.
Last night the car conked out again when I arrived home.
The battery was recharged overnight & I set off to work this morning.
Anyway as I pulled up at a set of lights after around 45 miles, the car conked again, and wouldn't restart due to a flat battery.
Admittedly I had been using lights, wipers & heater (intermittently), but it sounds like the dynamo is not recharging correctly.
This puzzles me, as the regulator, dynamo & ignition coil have all been replaced in the last 18 months ??
The battery is also around 18 months old, but is being recharged on a regular basis due to this recurring problem - could it be that the battery is shot ??
Has anyone had a similar experience ? Could it be a loose connection/wrong clearance on the voltmeter?
What is the best fault-finding approach?
As usual, any contributions most welcome
Tx,
Matt

[Kevin]

Admittedly I had been using lights, wipers & heater (intermittently), but it sounds like the dynamo is not recharging correctly.

I am a bit puzzled as you say you have a 1275cc fitted well that should have an Alternator fitted but you have a Dynamo.
I know the battery is not that old but have you had it checked to see if it will hold a charge.

[rayofleamington]

I am a bit puzzled as you say you have a 1275cc fitted well that should have an Alternator fitted but you have a Dynamo.

Why???? I can't see what difference the engine makes regarding alternator / battery.

Yes - if the battery is shot you could get these symptoms as running with lights + wiper + heater (and also spending time sitting in traffic jams) you won't add much charge to the battery so if it is poor to start with it could drain down. Various garages / service centres etc.. will be able to do a battery discharge test to see how poorly the battery is.
However for it to happen so quickly I suspect there is something drawing a LOT of current!

[Cam]

I am a bit puzzled as you say you have a 1275cc fitted well that should have an Alternator fitted but you have a Dynamo.

Why???? I can't see what difference the engine makes regarding alternator / battery.

Well, the 1275 Ital/Marina engine already has brackets on for the alternator, so it's unusual to convert to a dynamo as it's generally regarded as a downgrade. Some folks do it though.

[Kevin]

Why???? I can't see what difference the engine makes regarding alternator / battery.

I just asked in case an Alternator was fitted rather than Dynamo as they are prone to cooking battery`s when they are not working properly and it not often an Alternator is changed for a Dynamo, sorry for the confusion.

[baldrick_the_cat]

.. I really ought to turn this into a "blog"
As you might expect, the little sod wouldn't start when I got back in to go home, so I got a colleague to give me a boost. After about 10 miles, it conked out again, with a completely dead battery. This time I called out the Wegenwacht (equivalent to the AA here in the Netherlands).
After 2 hours kicking about in the freezing cold, he turns up (and happens to be a Brit!!). Anyway, he manages to get me the last 2 miles home after a couple of stops for further electrical shock treatments, and takes a look at the engine.
Turns out, he reckons, that the fan belt is loose, and not generating sufficient charge in the dynamo!!
Must admit, I'd not have suspected that in a month of Sundays : visually the drivebelt was turning fine, and there was no accompanying shriek to suggest slippage ??
I bow to a higher judgement: He swapped the fanbelt for my spare and tightened up the dynamo and starter motor attachments. Per his ammeter, it seems that the battery is now recharging
After another overnight charge, I did the 45 mile run to work this morning, and made it without hiccup.
There is now however a "squeaking" (I'll call it) when the car is idling, which wasn't there before, so I'll have to take a butchers at that. Ah well, the Lord giveth and the Lord taketh away !!
Will update this again if there are any new developments.
Thanks to all for all the helpful responses I received

[57traveller]

Was your red ignition/charge warning light extinguishing as engine speed increased when you were having battery problem? Does it illuminate when you switch on the ignition? This light is the first indication that your battery may not be charging. If it doesn't light at all then a new bulb might be the answer.
I wonder if the "squeak" is a consequence of the belt being too tight now? (water pump or dynamo bearings or even belt misalignment)

[rayofleamington]

There is now however a "squeaking" (I'll call it) when the car is idling, which wasn't there before, so I'll have to take a butchers at that. Ah well, the Lord giveth and the Lord taketh away !!

You need to oil the rear bearing of the dynamo (it is VERY easy to forget) - it can squeal if it gets dry and if that is the case it will soon be damaged