Classic cars forum & vehicle restoration.

[Ray White]

The TC battery is charged up. It reads 12.5 volts which - although not as good as perhaps it should be - I would have thought would be enough to turn the engine over.

What is happening is when I pull the starter knob the engine turns over once then all I get is click click click.

The starter worked O.K. a few weeks ago (when I last had the engine running) but now it is not playing ball.

I don't know if it is me (I am jinxed with electrical stuff) or just bad luck ...but the starter is a new high torque unit and the solenoid is the second new one.

Not being much good with electrical things I can only assume the starter is duff.

What else could it be.?

[consul 57]

bad earth?

[ukdave2002]

Where is the volt drop? Measure the battery voltage when operating the starter, if it drops below 9.6v then either the battery isn?t charged or it?s on the way out, if it?s above 9.6v measure the cranking voltage at the starter, if that?s low chase the voltage back to the battery to see where the drop is.

[Ray White]

If I get a new battery then hopefully that will fix the problem.

I don't see how it could be a bad earth. It was fine before. I haven't changed anything.

[ukdave2002]

[Ray White]

This is why I get befuddled by electrics. The light in the battery is green and it has read 12.6 volts steady for two days now.

When I pulled the starter knob with the multimeter connected to the battery, the voltage dropped to 2.5 volts.

From what you say, the battery is duff regardless...
The battery is 5 years and 1 month old. It has lasted two years more than it's warranty (although it is virtually impossible to successfully claim) so I guess it is time for a new one.?

[ukdave2002]

Almost certainly that battery is sulphated, its internal resistance will have gone high, hence the larger volt drop when a load is applied, you may recover it with one of the "smart" chargers that have a de-sulphation mode, but its never going to recover its full capacity.

Sulphation occurs when batteries are left for a few weeks without being charged, and are not covered by warranty.

[Ray White]

Thank you Dave. I didn't know that.

[petelang]

You can often restore a sulphates battery but it's a slow tedious process. First, fully charge it, then discharge with a small load like a bulb for several hours, then recharge. Repeat several times. It will make the chemical proces work and convert the sulphate which is grown on the plate surface, back into its constituent sulphuric acid.

Similarly, if you accidentally leave something on, and your battery goes dead flat, you can't just connect a charger and charge it.
First, connect another battery in parallel, then connect the charger to the parallel links, leave until next day, and bingo, you have two fully charged batteries!
_________________
Daimler Fifteen 1934 (now sold)
Armstrong Siddeley 15 Long 1933
Daimler V8 250 1969

[Ray White]

The problem was the battery after all. I replaced it with the same YUASA item because although I prefer the look of the original rubber case style - I have had problems with them in the past. This modern battery also has a carrying handle which makes it a lot easier to lift out of the battery box.

[ukdave2002]

[Ray White]

The old battery still reads 12.5 volts and has the green light showing. I guess the voltage is there but insufficient amps.

How long, if kept charged, should a battery last these days? This one was 5 years old.

[ukdave2002]

[Ray White]

Just as an aside; the 12 v battery in my Wife's 2022 Lexus hybrid failed the other day. She uses the car on a regular basis and has it routinely serviced by the Main Dealer.

The battery had a three year warranty and it died literally overnight... virtually to the day of the warranty expiry!!

[Penman]

+Ray: there is probably an AI chip in the battery which is programmed to sulphate the battery at 3 yrs +1 to 5 days. Or it might just trigger a dead short.
_________________
Bristols should always come in pairs.

Any 2 from:-
Straight 6
V8 V10