Mickey_928S

Question: Is it strange that I am getting 25V reading from my battery?

I have had some oddities lately. My voltmeter would fluctuate with my tach. ie: accelerate V would go up to 12, at idle would hover barely above red. With lights on would dip into red and light would come on.

Had some work done on my girl so she sat for a few months. Old battery died so I replaced it. NOW voltmeter STAYS at barely above red and never moves.This is when i decided to find out what the heck was happening and discovered 25V at the battery.

PS: Checked the alternator and 25V there too. Charging voltage is 11 - 13 volts.

Odd? Any comments, questions or insults would be appreciated.

83 928S

Normy

DO NOT TRUST THE DASHBOARD VOLT METER!

This is a device that is flaky at best. Since the contacts in the dash pod can weaken with age, it is common for this to not read correctly.

-The dash volt gauge is good for monitoring trends, however. If it has suddenly started reading 25 volts...then you best get your voltmeter/multitester out right now and find out exactly what your system voltage is! 25 volts is going to do damage to several components if it is true, most likely your battery. IF you do have 25 volts- then your voltage regulator is bad. I'd not run the car until I worked this out!

www.928international.com
www.928specialists.com
www.devek.net

All the above have the parts ready to ship, and they will all spend hours on the phone with you helping you work your problem out. Good luck!

N!

Mickey_928S

The 25V is on a multitester. The dash reading is barely above red. Even with the car off the battery is reading 25V. ??

Normy

Where are you testing the 25 volts? Battery terminals? Alternator leads?

N!

FlyingDog

Get/borrow another multimeter.

ErnestSw

replace the battery in your multi meter.

Mickey_928S

25V Reads at the battery terminals, jumpstart point and at the alternator. However, alternator charge reads around 12V.

Normy

25 volts with the engine running, but 12 when it is off?

N?

Mickey_928S

Nope, 25V running and off. When I turn accesories on, like lights, etc voltage drops a little (as expencted) by about 1V.

Changed battery in multi-meter- still 25V.

Normy

So your 12 volt battery is supplying 25 volts when your engine is off. Is that correct?

That can't be. If that is true, I'd suspect my voltmeter. Here's a test: Disconnect the wires from your alternator, and start your engine. You are now running your L-Jetronic computer and your fuel pump off of your battery. It's going to run down in a while- test it while this happens. If you don't see a drop- your multitester is bad. A better idea is to test your multitester. Move the dial to AC and 250 volts, and test it in a wall socket. I suspect that your car is happy. Your multitester isn't. Best of luck!

N!

worf928

Another test: Take your voltmeter and test a household battery. A 9v or something like that.

John Struthers

Norm, Mickey,
What are you two smoking?
Mickey,
if Ern's suggestion doesn't pan out opt for the suggestion from the flying dog.
BTW
If those readings remain at 25v with a refreshed Multi-meter batt. and a different multimeter we probably won't hear from you unless there's an outside line at AREA 51.
There is a link around the Renn somewhere that'll hook you up with a Multi-meter operation tutorial, not saying you can't read one just explains readings,
and reasons for possible glitches/errors on the test equipment as well as the item being tested.
FWIW
You Voltmeter/voltage fluctuations sound like:
1. Regulator is on the way out.
2. Battery is on the way out.
3. Battery, alt. chassis/frame grounds could use a cleaning.
4. Might just need a good overnight trickle charge -disconnect batt ground-.
5. You might also be suffering from the dreaded "draw" syndrom.
Which means 'something' is drawing juice after you put the sHARk to sleep.
If the latter (5) is the case I finally resorted to disconnecting the batt every time I stop ... haven't needed to charge in months whereas I was charging every 2 - 4 days before.

ErnestSw

Your multi meter batteries produce a reference voltage. If the reference voltage is too low all of the voltage readings will be too high.

Mickey_928S

Thanks for all the suggestions guys. If I still get the 25V readings after trying a new multi-meter, I'll send greetings down from the Mother Ship!

ErnestSw

Just change the batteries!!