15 volts in my commuter Sundance!!!

[90Spirit2.5]

I recently bought a 92 N/A Sundance for a commuter. I had to replace the alternator on it when I got it, the original was bad. I had a unit from an 89 LeBaron I parted out, so I swapped it in along with the earlier mounting through bolt and sleeves and tensioner. It fixed the problem by my immediate observation, gauge read ~14 volts while running instead of the ~12 I noted upon test driving the car. Well I noticed while driving to work that while cruising at about 2800 rpm, the gauge read ~15 volts. So I broke my multi meter out when I got to work. I got readings of 14 volts at idle and 15 volts while maintaining an engine speed of about 3k rpm. The previous owner claimed to have switched the SBEC out with a 92 N/A 2.5 unit. My car is a 2.2 so I have another SBEC tracked down for that issue. I have no way to verify what SBEC he installed in this thing. I think the voltage regulator in the SBEC may be bad. Any ideas and should I avoid driving it in the meantime? Will 15 volts damage my batt? Thanks

[1BADVAN]

My volts ran high when the battery voltage signal wire to the ecu was corroded and cut part way through. It only saw a part of the voltage so it cranked up the alternator to make up for that.
Just something to check

[turbovanman²]

What's wrong with 15? If its charging at 12 volts then something is wrong, it should charge on the high end of 14 so if its 15, its fine.

[90Spirit2.5]

If you think that 15 volts is a totally safe voltage to be running on the system when the car is running than that is great news. I have noted that when I shut the car off, even right after reading 15 volts while running, the battery voltage is never higher than 12. This tells me the battery isn't being overcharged. And no wires (battery or otherwise) are getting hot. I was only worried due to never having seen over 14 volts in any of my FWD Mopars over the years at any point of their running. Thanks

[iangoround]

Check all your grounds and battery connections, then check the connections at the SBEC for corrosion. Couldn't hurt to hit them with some contact cleaner.

If that all checks out, 15 volts isn't too much to worry about. My car with an external regulator runs at 14.89v. On the internal regulator it runs at 14.65v or so. Nothing has blown up yet.

[Reaper1]

Most TM's that *I* know of only charge around 13.2-13.7V on the stock regulators that are internal to the PM, SMEC, or SBEC.

The computers have internal fail-safes to protect it from overcharging...*if* it knows it's being overcharged. First it'll set a code. If it goes above a certain point I *think* they will shut off. (Shel-Game or 5Digits might know for sure on that).

I'd check your codes first, make sure you aren't getting an overcharging condition. Also, as suggested, check the field and reference wiring to make sure there are good connections all the way.

If all that checks out, have the alternator checked (most auto parts stores will do this for free...off the car is best, but they usually can do it on the car as well).

You also might want to stick a volt meter on the connector at the back of the gauges...maybe the gauge is off.

If everything is good...run it, I'd say.

[Khajjathefang]

If it goes full field you'll know it. Radio will shut out, lights on the dash will get super bright. Etc

[iangoround]

If it goes full field you'll know it. Radio will shut out, lights on the dash will get super bright. Etc

Full field is close to or more than 20v I think. Had that happen to me once when I was running an external voltage regulator and something shorted or came unplugged on the wiring harness. No damage was done, but all the electronics in the car shut off and it started running like crap.

[85boostbox]

Have your battery checked for a dead or dying cell. I bet that is your problem.

[85boostbox]

Let me add to my statement actually lol. It is not charging enpugh to be a bad regulator. So that tells me that you have excessive resistance somewhere in the charging system telling the computer to put more volts out. I have experienced this first hand with a going dead battery. It may seem to hold volts according to a voltmeter, and start fine, but in relaity it is starting to lose its charging capabilities and holding the charge. Easy way to find out is to swap to a different battery and see what your charging at.

[90Spirit2.5]

The battery is brand new. I have ran codes several times since buying the car and I have never got an overcharging code. Sometimes the radio won't turn on and it appears to not have power, but I thought the unit to be defective. And the voltage is never higher than 15 when this happens. In my experience with all my other FWD Chryslers, I have also noticed that they charge in the high 13's and the gauges read a sliver under the 14 line. I still haven't checked all my grounds and wiring etc. I will do next week and report back. Thanks for all your replies.

[Reaper1]

I just noticed you're in Seattle. I'm in north Everett. Right now I don't have transportation, but am willing to help if we can work out how to meet up.

[Vigo]

I have noted that when I shut the car off, even right after reading 15 volts while running, the battery voltage is never higher than 12.

What exactly are you getting when you check batt voltage after turning the car off? It should be OVER 12.6 volts. If it's charging ~15v and going down to low 12s as soon as you turn the car off, you have a dead cell in the battery. If i charge a battery with 15v and it measures below 12.6 when i turn the car off, brand new doesnt mean jack crap anymore, i just 100% diagnosed it as a bad battery.

It would actually be normal to see a little over 13v at the battery right after turning the car off. Letting it sit for a minute, you should see it drop into the high 12s and EVENTUALLY settle around 12.6x volts, if it's a good battery.

[90Spirit2.5]

What exactly are you getting when you check batt voltage after turning the car off? It should be OVER 12.6 volts. If it's charging ~15v and going down to low 12s as soon as you turn the car off, you have a dead cell in the battery. If i charge a battery with 15v and it measures below 12.6 when i turn the car off, brand new doesnt mean jack crap anymore, i just 100% diagnosed it as a bad battery.

It would actually be normal to see a little over 13v at the battery right after turning the car off. Letting it sit for a minute, you should see it drop into the high 12s and EVENTUALLY settle around 12.6x volts, if it's a good battery.

I received my 1992 2.2 SBEC today. As I suspected, there was a problem with the voltage regulator in the SBEC that came with the car. And by running the part number after removing it, I can confirm it to be a 1992 2.5 SBEC. My voltage problem is solved now, the volts never rise above 14.1 regardless of engine speed. The battery reads 12.8 after shutting engine off. Battery is fine. Thanks for your responses everyone.

[Vigo]

Sounds good. I had that happen to an 89 SMEC car. On the SMEC cars the logic module and power module are separate even though they are in the same case. I swapped just the power module and fixed that one too.

Also, since ive had over-charging situations in my k-cars about 3 different times, i can tell you that ~18v is about where your headlight filaments will pop when you're driving at night.