Driving in France and may have an electrical problem. Advice please.

[Ian Cooke]

Hi All

We are driving in France and I noticed today that the battery gauge is permanently in the red zone at 16 volts. It hasn't been like this previously as it's usually in the 'normal' zone.

The reading drops a little when we are moving at slow speed and also when we had the headlights on and the windscreen wipers going during a heavy downpour.

Being neither mechanically or electrically educated I 'm not sure if this is something that I should be unduly concerned about. The car seems to be performing faultlessly and we head home tomorrow so hopefully it's something that can wait until we are back in the UK?

Any advice you can give will be much appreciated.

Thanks

Ian

[Heuer]

Sounds like the voltage regulator (4TR) has failed which means the battery is over charging. Happened to me near Lille and it destroyed the battery which fortunately did not explode or boil acid out over the engine bay ( it was an SBS aviation grade battery thankfully).

The charging system should be limited to 14.3 volts so your 16v, if the gauge is to be believed, is not too far out (mine was charging at 21v). Check the battery for signs of boiling acid - there may be wetness around the top - and temperature. It should be cool to the touch. Check the electrolyte level before setting off tomorrow.

If it is getting hot best stop to give it chance to cool down. It is quite likely you will ruin the battery but the object is to get home. Try and keep the revs down and the headlights on. Watch the gauge and be ready to pull over if the voltage rises higher than you saw today.

Worst case scenarios:
1. battery will die and take the alternator diodes out
2. overcharging could cause the battery to spew acid out with damage to paintwork
3. boiling causes fumes which are highly combustible and could cause a fire

Best case scenarios:
1. battery will cope and you will get home
2. boiling will simply evaporate the electrolyte so keep adding water (mineral water will do)
3. fumes will be blown away by air flow; there are no sparks in the area to cause combustion

If you intend to continue touring in the E Type, on your return fit a modern Denso lightweight alternator with integrated regulator - full detailed instructions in the Upgrades Forum.

[Ian Cooke]

Thanks David - much appreciated.

The battery doesn't seem to be getting hot and there is no sign any wetness around the top.

We haven't got far to travel tomorrow so fingers crossed we'll be ok.

My gauge only goes up to 16v and the needle appears to be at the max so perhaps it's charging at a higher voltage than that?

Ian

[Heuer]

Very probably charging higher than 16v but as long as the battery remains cool and no electrolyte loss you should be OK. Check the electrolyte levels (if you can - depends on battery) and add mineral water so the battery does not become dry.

Good luck, you should be OK.

[politeperson]

Why don't you put a volt meter over the battery and see what the charging voltage is?

Then you will know.

[Heuer]

It is an S2 and already has a voltmeter which is showing overcharging. At this stage by how much is fairly irrelevant.

[politeperson]

Yes, David I see what you mean. 21v.

The alternator or the regulator is knackered. Needs fixing immediately.

Or it will all end in tears.

[Heuer]

The aim is to keep going because the hassle of being stuck on the side of the road, especially in France, is not worth contemplating. I always try to figure the odds and play them and in my book Ian has a very good chance of making it home. He should then fit a Denso and will probably need a new battery as the plates will be shot. The faulty 4TR can remain in place as decoration.

I am sure we will all be rooting for Ian to finish his tour successfully!

Note:
Anyone who is reading this and contemplating taking their E-Type abroad this year should seriously contemplate fitting a Nippon Denso alternator (from a John Deere tractor actually). Easy to do viewtopic.php?p=48278#p48278 or Angus will do it for you as he seems to have bought up the World supply of John Deere alternators and has had the correct brackets made.

[Ian Cooke]

Thanks again David for your wise words. I will definitely be fitting a Nippon Denso alternator upon my return.

We only have about 50 miles to do tomorrow to get to Cherebourg and have the whole day. We plan to do it in stages stopping at St Mere Eglise, Utah Beach and Barfleur on the way so plenty of opportunity for the battery to cool down if it starts getting hot.

I'll let you know how we get on!

[Hugo]

If the battery isn't getting hot, you may not even have a problem (other than with the gauge). If it's kicking out that much voltage, it will boil the water and buckle the battery plates. But before that can happen it has to get hot. I don't think you'll have a problem.
I'm not familiar with these regulators, but is it possible you have just lost a ground connection or something (on the regulator) that would cause it to become un-regulated?
Keeping the revs down won't hurt, but it's not likely to help much either, as alternators are designed to give high output at low revs.

[christopher storey]

I suggest that you disconnect the wires from the regulator and run the car on a no charge state for perhaps 1 hour . This will get you 40 miles or so. Then reconnect the regulator for perhaps 15 minutes running which will bring the battery back up to charge, disconnect again for one hour . This should prevent damage to the battery and get you home safely

[Durango2k]

Yes and why not try this: start the car, warm up, disconnect battery, drive home ? Should this not do it ? Of course if the engine dies re-connect, but pure driving should work without the battery connected.

Carsten

[Hugo]

You will cook the alternator if you disconnect it from the battery. Mind you, if it IS charging at the rate your gauge says, it's probably cooked anyway! You should be able to drive all day - several days in fact - on the battery alone, providing you don't use headlights, blowers etc.

[Heuer]

Agree with Hugo. Disconnecting the alternator and running the car is the worst thing you can do as it will blow the diodes which means you will only get as far as the battery will provide juice, which may not be far if it has been overcharged. Notionally you could drive quite a way on a fully charged battery but stopping for fuel, ferry, traffic, rain etc is going to drain the battery rapidly. IIRC the ignition draws about 3amps but starter motor, alternator (which uses power to energise itself), lights, wipers, fuel pump and cooling fan make that figure unrealistic in normal driving:
Lights (full beam and sides) = 16 amps
Heater motor = 7 amps
Wipers = 5 amps
Ignition = 3 amps
Alternator energiser = 3 amps
Cooling Fan = 6 amps

If we assume the car has a 60 AH battery then with fuel pump, ignition and alternator drawing current you can expect about 10 hours of life. Lights will be the biggest killer which will reduce your driving to a couple of hours.

As regards the 4TR regulator the ones now available from the usuals appear to have a very high failure rate so if you are wedded to your standard charging system carry a spare 4TR. They are plug in so can be swapped in minutes.

As regards the alternator, allowing it free rein to over-charge should not cause it to die as the diodes are specified for its full potential rated output. What will kill it is disconnecting it with the engine running or, in certain circumstances, a faulty battery. Also a standard Lucas alternator only outputs 40 amps when hot.

[Hugo]

When I was a student I drove all the way from Exeter to Sussex in a 6 volt Ford popular with no fanbelt! (Those old crates didn't even have a water pump so you could do that). By the time I got near to home it was getting dark and if I turned the lights on the engine would quit, so I tucked myself in behind a country bus and followed him home. Every time he stopped, I had to pull in behind him & wait! If I could make it all that way on a puny 6 volt battery, you should be able to get a considerable distance on a modern 12 volt. I'd give it a couple of days, with nothing else but ignition.

[Heuer]

Yes Hugo, but you need to add in energising the alternator and fuel pump so divide you battery capacity (assuming it is fully charged and healthy) by 7A which will give you number of hours driving. Each time you hit the brakes or need to stop/restart the engine they will drain significant current and the cooling fan(s) will also kick in adding to the loss. In practice, with modern traffic conditions, my own experience is about 2-3 hours of driving in an E-Type.

[Ian Cooke]

Thanks Guys

We arrived at Cherbourg without incident having left everything connected. The gauge was at the top end of the red zone pretty much the whole time ( about 2 hours in total today) and it only moved down a bit when driving v slowly.

We stopped on several occasions and each time I checked the battery and it didn't feel warm let alone hot. So I'm wondering if perhaps the gauge is the problem and not the regulator. Any suggestions on how best to check them both bearing in mind that I have little or no practical experience but am keen to learn?

Just a short journey home when we get to Portsmouth so hopefully we'll get back ok.

[Heuer]

Get yourself a multimeter and connect it to the battery terminals. It should read just above 12v but maybe lower depending on battery age and state. Then start the car and blip the throttle to make sure the alternator is energised, the meter should read no more than 14.3 volts. If it does and the car voltmeter still reads high then it is faulty although I think this is unlikely as it's normal failure mode is to read low or zero. If the multimeter reads higher then the regulator is at fault and a new one will be required as there are no service items in the 4TR, at least for the hobbyist.

One of these would be ideal: http://amzn.eu/3bvX2hj

[Ian Cooke]

Thanks David. I'll follow your advice and post my findings!

[Hugo]

What does the voltmeter read when the ignition is on but the engine not running? Should be somewhere around 13 if you have just switched off, dropping to 12-ish after a rest. Is the alternator getting very hot? Is there an acidic smell coming off the battery when it is running? There should be - and it should be getting hot! Only two minutes and a few quid on a voltmeter / multi-meter to find the answer.
As David said, the electric fans will soon kill the battery - I had forgotten about them - but only 2 or 3 hours of battery life without charging sounds very poor to me, unless the fans are on all the time.