23 replies to this topic

[KernowCooper]

Well I have never seen one blow like that, in an instant. Running with a dead shorted battery or one that has no circuit would be just the same, ive seen cars showing a few volts at 2000 rpm with a good alternator as the damaged battery is making the readings go to pot.

So you would check the battery as I described and once either found as faulty or fully charged and healthy, then you would connect it and then proceed to check the charge rate. Thats the correct way, why would you change the battery with the engine going? its asking for electrical problems

[CityEPete]

I would not change it with it running, id just drop the positive lead off for 2 seconds and glance at the voltmeter, if it shoots up to a healthy voltage without the battery then the battery is not only flat its knackered and causing problems for the alternator.

[KernowCooper]

Sorry thats not the way to test a alternator Pete, the change a battery was in reply to cals post sorry

[CityEPete]

Sorry yes I just spotted his post between ours! No problem. I know not to do it that way anymore then.

[KernowCooper]

No probs Pete just trying to save a lot of grief and money mate.

[CityEPete]

Years ago I had a project mini, I used to jump it off my van then drive it around with the leads loose in the boot! Alternator was fine, ended up on my brothers mini for years, the project sadly died

[cal844]

I do it on modern jap euro boxes,(i should have said, sorry!!) These have surge protection in the alternator wiring

[BenCoul]

Please excuse my ignorance on this subject, but I've just had a similar starting problem with mine.

Turned out, my alternator and battery were fine.

However, it was just simply the engine earth that was bad. Bad earth meant that not enough current could pass through. Even after a long run, I'd turn her off, back on again, she'd turn over once, slowly, and that was it.

 

After cleaning up connectors to the alternator, getting a new battery and starter motor I just tidied up the engine earth, and she's been 100% bob on ever since.

Hope this was more help than hindrance

Ben

[KernowCooper]

Hi Ben no probs mate anything which helps is good, a charging system check would have pointed out your issue and saved  bit of time and money, you can do volt drop tests which help identify those problems as well, but its good to find problems like you did on yours.