I’m linking a YouTube video for reference. In it, the man says that you can determine whether your alternator is bad or your battery is the problem by starting your engine and then removing the positive terminal on your car’s battery. If the car keeps running, your alternator is good. Sounds log…

Very bad idea. I can’t explain why, but especially bad idea with all the electronics in car. More like a parlor trick, or last words “hey, watch this!”

The guy’s a moron! http://troubleshooters.com/dont_disconnect_battery.htm Tester

This was an old method done when the electrical systems in cars were not as sophisticated. Now with modern electronics…which many use less than 5 volts…you can cause a voltage spike that can fry many components, including the cars computer. Granted, some people still say that it works, but it’s ju…

others are correct, this is a very bad idea, it could easily fry some electronics in your car. Without the battery, the voltage will jump to perhaps 40-50 volts. The electronics are supposed to be protected agains that, but are they? and how long will that protection last against such an overload? C…

This happened inadvertently to me once while I was driving - I hadn’t tightened the connector enough and it rattled loose. My battery ran down and I stalled at a stop, but nothing worse happened - to my '87 Toyota pickup.

Thanks very much for the responses. So, should I assume you would get the same result from driving with a dead battery that doesn’t hold a charge? (probably a dumb question but I’m asking it anyway)

No. Driving with a dead battery will just fry the alternator. [image] Fact: Alternators are not designed to charge dead batteries | OPTIMA Batteries Fact: Alternators are not designed to charge dead batteries Tester

Joe_Guy: you would get the same result from driving with a dead battery that doesn’t hold a charge? If you mean a battery with no resistance like an open cell and will not accept a charge, when jump starting a vehicle with a battery in this condition it can be difficult to keep the engine ru…

Is This "Simple" Alternator Test Correct?

Maintenance/Repairs

VOLVO-V70 July 4, 2018, 7:26pm 4

Frankly I think @Joe_Guy you should edit and remove the link. There are many places that will test an alternator and battery for free .

Topic		Replies	Views
Car battery disconnecting Maintenance/Repairs	11	992	January 29, 2019
Battery or alternator? Maintenance/Repairs batteries , alternators	8	1070	December 20, 2008
Battery check & alternator frying Maintenance/Repairs	4	2022	May 28, 2009
Bad alternator? Help Maintenance/Repairs	6	512	November 23, 2018
Jumpstarting...can it kill alternator? General Discussion	77	102452	September 8, 2021

Is This "Simple" Alternator Test Correct?

Related topics