12 volt conversion issue

[Scott Limbourne]

I have a Super M that has been converted using a delco three wire. The voltage at the battery was 16-17 volts while running. I thought I had a bad regulator inside the alt so I replaced with new alt. Same issue. I had alt tested and it is good but why am I getting 16 - 17 volts in the charging system? Battery is at 12.7 when everything is off. I will boil the battery putting that many volts into it.

 

[Don Norris]

Scott,

Yes, you will boil the battery if the voltage stays that high too long.

It's possible your battery is low on charge and the regulator is trying top it off. Let it charge a while and see if the voltage goes down.

Or you might have a bad cell in your battery and again the system is trying to charge it up. A battery with a bad cell can still produce enough voltage to give a good voltage reading with no load.

Try a different battery is possible.

 

[John T]

FWIW I agree with the gents who think the voltage sensing circuit/lead isnt getting a good connection to the battery.

1) Try a jumper wire connecting the little No 2 terminal up to the big rear main output stud on the alternator n see what happens?????

2) Try a jumper wire connecting the little No 2 terminal on the alternator direct to the batteries Pos post n see what happens???

Take two aspirins n call me Monday at the office.

John T

 

[old]

Sounds like you do not have it wired as it should be like John said the #2 wire from the plug where is it hooked??? It should be hooked to the bog post on the alternator so it sees the voltage coming form the alternator.

 

[Scott Limbourne]

Yes it is jumped to big post on alt and jumper is good.

 

[old]

Is the wire from the big post going to the amp gauge or some such place so it goes to the battery with no switches etc in line with it??

 

[Scott Limbourne]

I will try that.

 

[Scott Limbourne]

Amp guage but let me double check that.

 

[old]

Not likely but you may have an amp gauge that is going bad and has a high resistance to it and that would make an alternator put out more volts then it should due to trying to push power threw it but as I said not likely

 

[Scott Limbourne]

Yes it is a about a 4 inch jumper from big post to plug terminal 2.

 

[Don Norris]

Scott,, Did you get it fixed?

 

[Scott Limbourne]

I did! There was a bad connection on the sensing lead. Now charging 13.8 volts. All is good and thanks for your help.

 

[JMOR]

(quoted from post at 11:32:19 12/13/11) I did! There was a bad connection on the sensing lead. Now charging 13.8 volts. All is good and thanks for your help.

ell, you have my curiosity up now! The long run of postings made it sound as though you had checked & re-checked & confirmed that #2 sense went to big alternator output stud a week ago, .....so, please give us details. What, where, how was the connection bad? Might help someone else down the road to know what, where to look. Thanks.

 

[Scott Limbourne]

It was intermittant...I cut off connector and soldered better
ones on. It appeared fine but when i rolled alt back up to
bolt down it would break connection. You cant see the posts
when alt is in position it is against motor.

 

[JMOR]

(quoted from post at 13:01:42 12/13/11) It was intermittant...I cut off connector and soldered better
ones on. It appeared fine but when i rolled alt back up to
bolt down it would break connection. You cant see the posts
when alt is in position it is against motor.

hanks. Those intermittents will kick your _____ & mine too.

 

[Jon Hagen]

Just to add, If you do not have a stock type plastic regulator plug in place in the alternator, Please, please put one on.
The alt repair plug with two 6 inch pigtail wire in a safe plastic plug is only about $2 at an auto parts store.

I have seen so many SI series alt conversions done with uninsulated crimp on terminals plugged into the alternator. The regulator blades are not very sturdy and the push on terminals are only 1/8 inch from shorting to the alternator case. If a tug on the #2 sense wire shorts the terminal to the alt case, you have full battery current, unfused, in a dead short situation. This will cause an electrical fire and destroy the wiring harness, possibly the tractor and shed.
That $2 harness repair plug not only eliminates the chance of a short, but also makes for a much more professional looking wiring job.

 

[Scott Limbourne]

I will get one...what exactly would I ask for at autozone? An SI repair plug?

I am safety consious so paranoid about fuel leaks with needle sticking and forgetting to shut off fuel that I installed a 12 volt cutoff valve in the fuel line wired to ignition. I can just see gallons of fuel dripping from carburator and igniting from hot water heater or spark.

 

[Jon Hagen]

Alternator plug repair kit. Likely shown under GM in the 74-85 range. or possibly for the Delco SI series GM alternator.


A Google search for GM alternator repair plug kit turns up a lot of hits like this.

A good partsman at an auto parts store should know what to pick off the rack.
Alternator repair pigtail.