Delco 10SI Alt overcharging even after new regulator

[Mac]

The volt gauge in my dash is reading 16V and more most of the time while driving. At idle, with some accessories running, it will be down to 12.5V. This is verified by a volt meter also.

Approx. 6 yr old red top Optima that cranked well this AM @ -8 deg.

8ga. lead from battery to Bat terminal less than 16 inches away.

#2 alt terminal jumpered to Bat terminal

#1 alt terminal wired thru firewall into 10 ohm resistor then to keyed power.

I replaced the regulator because of this condition with a "Standard" brand T-Series and it seemed to fix it, but only for a few days.

Is my wiring wrong, do I have a defective regulator or what am I missing?

Please help.

[enjenjo]

Was the alternator bench tested after the regulator was replaced? 12.5 sounds a bit low at idle, and 16 is too high while running.

[Mac]

No, not bench tested....and tonight it thru a worse fit and stopped charging. I limped home watching the volt gauge fall farther and farther below 12v.

I'm buying a new unit. This one was only an AdvanceZone cheapie and had a ratty sound early on.

Thanks

[1800guy]

Had a similar thing with the Suburban last summer, and decided to just replace the alt. with a rebuilt.  My NAPA said they had 3 on the shelf - come and get one.  When I told them it was for my own truck and that I planned to keep it at least five more years, they said they would order me one for the next day.  Does that mean there are different qualities involved?  

[wayne petty]

The volt gauge in my dash is reading 16V and more most of the time while driving. At idle, with some accessories running, it will be down to 12.5V. This is verified by a volt meter also.

Approx. 6 yr old red top Optima that cranked well this AM @ -8 deg.

8ga. lead from battery to Bat terminal less than 16 inches away.

#2 alt terminal jumpered to Bat terminal

#1 alt terminal wired thru firewall into 10 ohm resistor then to keyed power.

I replaced the regulator because of this condition with a "Standard" brand T-Series and it seemed to fix it, but only for a few days.

Is my wiring wrong, do I have a defective regulator or what am I missing?

Please help.

print and perform this..  perhaps the problem is on the negative side..
http://i.imgur.com/WMDprhm.jpg  it has helped me in so many places..

you may also want to perform a few additional tests.. alternator housing to the negative battery post.. should be close to 4/100ths.. 0.04 with the meter setting at 20 volts or set at 2 volts. depending on your meter..

can you pick up some components and assemble. them.. a spare alternator connector.. some kind of side marker light bulb socket that has 2 wires and uses a 194 bulb... a pair of gator clips..   unplug your existing connector...  plug in this new one for testing..   hook the #2 terminal just like you have to the output stud on the alternator.. and the #1 terminal that has the 194 bulb in circuit also to the  alternator output..  or with a longer wire over to the positive battery post or positive terminal block..  or try it in all three places.  this bypasses the 10 ohm resistor.. some stuff i have says to use a 6 watt resistor others say a 2 watt 10 ohm.. which did you use???

you might want to order a few of these... http://www.wagneralt.com/products/D08-03.asp so you have some in stock..  these are SELF ENERGIZING.. only the case needs to be grounded thru the mounting and the alternator output hooked to the positive battery..

either the black or the orange diode trios..  http://www.wagneralt.com/products/D04-02.asp

these used to be available with six 50A 200PIV diodes instead of the stock generic six 25AMP 100 PIV diodes..  http://www.wagneralt.com/products/D06-07.asp

if you change to the one wire voltage regulator. some models have a RESISTOR  across 2 of the voltage regulator brush hold down screws. remove that resistor with a self energizing regulator.

sorry to be so late to the party..

warning.. if you have a battery cut off switch.. and it disconnects the alternator output from the battery completely.. you can damage the alternator diodes and the voltage regulator.