Hi new guy with a 69 fastback in need of your wisdom

Come here to ask for technical help and advice
Post Reply
User avatar
Speeddemon078
Posts: 5
Joined: 3rd October 2016 - 6:26pm

Hi new guy with a 69 fastback in need of your wisdom

Post by Speeddemon078 » 3rd October 2016 - 6:33pm

My battery keeps dying after a short drives, I charged it to 100% but still any ideas what could be causing this ? Thank you for your help in advance

User avatar
purplepeter
Posts: 2338
Joined: 8th August 2006 - 4:41pm
Location: Bath, Avon

Re: Hi new guy with a 69 fastback in need of your wisdom

Post by purplepeter » 3rd October 2016 - 7:26pm

It could be that Your regulator is sticking- whip the top cover off & check that the points are not welded shut
or it could be that Your Dynamo has lost it's polarity if it's been stood up for a long time?

Sensible answer is probably to put a multimeter on Your battery with Engine running to check charging voltage
How old is Your Battery?... They don't last forever

User avatar
937carrera
Posts: 1190
Joined: 7th June 2013 - 11:54pm
Location: North Yorkshire

Re: Hi new guy with a 69 fastback in need of your wisdom

Post by 937carrera » 3rd October 2016 - 9:08pm

Alternatively, if you don't have a multimeter (usable ones are less than a tenner on ebay), charge the battery up and check the voltage after charging and at 24 hour internals thereafter (not connected to anything). If the voltage doesn't drop by any significant amount then you don't have a bad cell.
David
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon

User avatar
Speeddemon078
Posts: 5
Joined: 3rd October 2016 - 6:26pm

Re: Hi new guy with a 69 fastback in need of your wisdom

Post by Speeddemon078 » 20th October 2016 - 5:48pm

purplepeter wrote:It could be that Your regulator is sticking- whip the top cover off & check that the points are not welded shut
or it could be that Your Dynamo has lost it's polarity if it's been stood up for a long time?

Sensible answer is probably to put a multimeter on Your battery with Engine running to check charging voltage
How old is Your Battery?... They don't last forever
So the battery is not that old a couple of years I will try the regulator and I will check the points, I do have a multimeter what kind of voltage am I looking for?
Thanks for your help purple Peter

User avatar
Speeddemon078
Posts: 5
Joined: 3rd October 2016 - 6:26pm

Re: Hi new guy with a 69 fastback in need of your wisdom

Post by Speeddemon078 » 20th October 2016 - 5:50pm

937carrera wrote:Alternatively, if you don't have a multimeter (usable ones are less than a tenner on ebay), charge the battery up and check the voltage after charging and at 24 hour internals thereafter (not connected to anything). If the voltage doesn't drop by any significant amount then you don't have a bad cell.
Good to know I will try that too, is it possible to be the generator and not the battery? How can I know ?
Thanks for the help guys

User avatar
purplepeter
Posts: 2338
Joined: 8th August 2006 - 4:41pm
Location: Bath, Avon

Re: Hi new guy with a 69 fastback in need of your wisdom

Post by purplepeter » 21st October 2016 - 9:30am

Charging voltage should be between 12.6- 14V at the Battery

http://www.speedyjim.net/htm/gen.htm

User avatar
Speeddemon078
Posts: 5
Joined: 3rd October 2016 - 6:26pm

Re: Hi new guy with a 69 fastback in need of your wisdom

Post by Speeddemon078 » 23rd October 2016 - 12:58am

So I purchased a new battery and it wouldn't start what else can be?

User avatar
Speeddemon078
Posts: 5
Joined: 3rd October 2016 - 6:26pm

Re: Hi new guy with a 69 fastback in need of your wisdom

Post by Speeddemon078 » 23rd October 2016 - 1:01am

purplepeter wrote:Charging voltage should be between 12.6- 14V at the Battery

http://www.speedyjim.net/htm/gen.htm
Great info thanks

User avatar
Editor
Posts: 5515
Joined: 10th October 2004 - 8:52pm
Location: Pensford, Bristol
Contact:

Re: Hi new guy with a 69 fastback in need of your wisdom

Post by Editor » 25th October 2016 - 11:24am

Speeddemon078 wrote:So I purchased a new battery and it wouldn't start what else can be?
Would the engine turn when you tried to start on the key?

1) No? - Do the 'idiot' lights in the speedo dim when you tried to start?
Yes? - Starter sticking or problem with main battery lead or gearbox earth strap. No? - starter switch dodgy.

2) Yes? - Ignition or fuel system problem.

Not a full flow-chart, but may help!
If a new battery didn't fix the problem when fitted, it's probably not a charging system fault as such.
Dave.

Post Reply