two wire plug on top of alternator

Forum for both AC and DC electrical components. From engine alternator to dashboard, inverter to batteries, and everything electrical in-between.
mikeoc
Posts: 20
Joined: Sat Mar 07, 2020 7:49 am

Re: two wire plug on top of alternator

Post by mikeoc »

Thanks for getting back to me Mel, I am going to have to consider doing this, I can't find out why these lights are coming on. Thanks again Mike
TDJohn
Posts: 552
Joined: Sun Oct 27, 2019 11:34 pm

Re: two wire plug on top of alternator

Post by TDJohn »

Mike,

I don't know if you received my reply via email, if you didn't, check the spam folder. Or better yet, give me a call tomorrow, and I will do my best to help you resolve this.
John
'95 Serengeti, Cummins C8.3-300
Allison 6spd.
TDJohn
Posts: 552
Joined: Sun Oct 27, 2019 11:34 pm

Re:Alternator Back-feeding Solution

Post by TDJohn »

Mike,

The reason your are having back feeding issues with your new alternator is because they sold you an alternator that was not outfitted for remote sense wire capability. It took me some serious digging, but I finally found the document that should help you resolve your problem, and I will give you a few different options that you can choose to do, depending on your comfort level.

Option (1) Attached is a document that you can fallow in step one, to be able to do an easy modification so you could be able to wire your alternator as your previous one was. This involves snipping the small bridge on the voltage regulator, that ties the two terminals of your top plug together. By having those two terminals tied together on your new alternator, the remote sense wire is back feeding power to your ignition circuit. So if you want your alternator to be wired as the old was, and for everything to functioning properly, you have to snip/cut that bridge. See the red arrow on the attached photo and also option #1 instructions in the document. If you have a pair of small skinny snips, you should be able to snip that bridge without opening the alternator up.

Option (2) If you are not comfortable with snipping that bridge, the other simple option is to cut and tape off the wire on the top plug that is closest to the drivers side of the coach (terminal #2 right side looking from the back of the alternator). When you cut the wire, leave a long pig tale, in case you need to reconnect that wire in the future (ex. use of a different alternator style).

Option (3) Another option can be to return the alternator because it is the wrong one for your application (meaning it is not set up for remote sense capability that your coach needs), and instead, buy a Delco 28SI style alternator, that has remote capability and it is a much better and more powerful unit. The 28SI series have much better cooling ability, more power output at idle and low rpm and has a longer lifespan. I upgraded to a Delco 28SI three years ago, and the difference compared to the old 22SI I had on there is day and night. If you do decide to upgrade to a 28SI be sure to get the stud terminal style not the plug style. See this Delco link (below) in section four to see the difference between the two. Your mounting body style is J180. They offer J180 long hinge or short hinge, I would guess that it is the long, even though the difference between the two is very small, but the long hinge does help keep the belt tighter. (I installed the long hinge style and it works well)
If you do decide to upgrade, give me a call and I will be glad to assist you on how to correctly wire the alternator up, it is fairly simple.

Link to Delco 28SI alternator:

http://www.delcoremy.com/documents/alte ... -28si.aspx



Remote sense capability modification
Remote sense capability modification
013708416_1-e1429696e52fd1dd129ec2990b62d206.png (211.82 KiB) Viewed 2096 times
Photo of the bridge that needs to be snipped for remote sense capability
Photo of the bridge that needs to be snipped for remote sense capability
Delco_21SI_V_Regulator1.jpg (12.34 KiB) Viewed 2096 times
John
'95 Serengeti, Cummins C8.3-300
Allison 6spd.
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