Acceptable Voltage?
 

I've been tracing down some charging system issues lately. On the advice of some Barners I checked the voltage on my 6v battery. I measured a whopping 2.65 volts. Not trusting my multimeter I measure the other A and got a similar 2.51 volts. "Impossible," I thought. So I measured a small square Alkaline battery and got 4 volts. The battery in the Coupe is 2 1/2 years old, but the battery in the truck is only 8 months old. My now properly working alternator runs a 15 amp charge upon start-up, but is back down to zero within a minute. And the car, even with a high compression head turns over, and starts quickly.

Hope I've given enough background. So, do I have two failing batteries? Surely, a 2.6 volt reading is low. Any thoughts?

Re: Acceptable Voltage?
 

Are you using a "digital" meter?

Re: Acceptable Voltage?
 

I like my Sperry SP-152A analog multimeter. Menards used to sell them, but don't anymore. I found some on Amazon and on ebay. It's an excellent meter and under $20. Your meter looks to be no good.

Re: Acceptable Voltage?
 

Okay, you guys nailed it. I just went out and got a new multimeter and immediately all reading are right. 6.36 volts on the car batt. Sorry, I'm an idiot.:o

Re: Acceptable Voltage?
 

No, an idiot would have just bought two new batteries and not consulted these good folks.

Re: Acceptable Voltage?
 

You should have about 6.3 to 6.5 volts with a good battery if it starts or even turns over your meter is bad 2.6 wont turn it an AA--C D battery will be 1.5 to 1.7 if it is good

Re: Acceptable Voltage?
 

'Dirty' electrons from an old car can drive a digital meter to pull its hair out. But, with the engine shut down/off it should work for checking how many there at the battery. With the readings you're showing I'd say there is something wrong, but, not necessarily with your batteries, or even the meter. Don't take this the wrong way as I don't mean anything by it, but, is the meter set correctly ? Sorry, but had to ask it. Stranger things have happened.


OK, sorry. You guys type fast !

Re: Acceptable Voltage?
 

Legitimate question. It's a cheap meter I got a long time ago, so maybe something is wrong with it. Of course, I believe I've got the meter set properly. 20v DC range selected, Comm and V/ohms ports used on the leads. In any case, the new meter I just purchased it's Auto Ranging, which I think means, Idiot Proof.

Now I'm off to see what trouble I can make for myself by putting vinegar in my car for a month. No doubt, I'll be back wasting your time on that topic.

Re: Acceptable Voltage?
 

I have had occasion to use a cheap yellow or red Harbor Freight meter that seemingly had a "problem."

It turns out the push-in banana terminals where the banana plugs fit into the meter can mechanically "work" the solder connection to the board inside the meter, leading to increased resistance and inaccurate readings.

The soldering is small and the meter not easily disassembled to work on the hidden surfaces of the circuit board. So with discretion and calling upon the better part of valor, I pitched the meter in the trash (it broke my heart!) - and bought a new one which I don't remove the plugs on - ever.

They are pretty cheap - but useful when they work.

Joe K

Re: Acceptable Voltage?
 

Glad Joe mentioned that. I was doing some checking a few years ago and things just weren't adding up. I finally removed the meter's rear cover and found a bad connection at the socket, just as Joe mentioned. I've seen this problem a few times on meters.

Re: Acceptable Voltage?
 

yea if you come across a junk meter get rid of it immediately so you dont accidentally pick it up and use it again or forget and use it on something a tad more lethal.

ive got a few of those harbor freight throwaway meters, they are useful to have around like a light bulb continuity tester and can tell you crudely whats going on but i wouldn't rely on it.

Re: Acceptable Voltage?
 

I was using my twenty five year old digitaL SPERRY Dm 3010 the other day when I was getting erronious readings', new set of test lead's took care of the trouble.

Re: Acceptable Voltage?
 

If you want a good digital meter that will work just fine in a noisy environment, purchase a FLUKE, a older FLUKE 77 or 87 can be found in the $50 or less area. They are professional test equipment and last a long time. My original Fluke 77 that I purchased in 1985 still works as good as it did when new. Trust me it has had a lot of use, including very high voltage from high power transmitters. Dropped off heavy road equipment....... Menards and Harbor Freight test equipment is a poor choice... you get exactly what you pay for...

Re: Acceptable Voltage?
 

My voltmeter requires a 9v battery. When that is low it gives erronius readings. Have you checked the battery in your meter? Ron W

Re: Acceptable Voltage?
 

On my meter that was the first thing I checked , Batt. was good.