Logo

AQ131a New Alternator Wiring

brian_zim

New member
I am attempting to replace my old Paris Rhone alternator with a new API Marine alternator. The Paris Rhone had 3 wires, Red (+), Black (-), and a purple wire with a resistor on it that went to a terminal labeled 61 (which looks like it's just 12V from the key that also goes to the coil from the wiring diagram on the volvo website). The new API alternator has a screw terminals that are red, black, and one that's white that has a tag on it that says "AC TAP-Tachometer caution hot lead." Is the purple wire no longer needed with this new alternator? Should anything be hooked up to the "AC TAP"? Also, the new alternator has what seems to be a grounding screw on it's case, does something need to be connected to that terminal on the case?
 

Attachments

  • DSCF0006.JPG
    DSCF0006.JPG
    67.1 KB · Views: 577
  • DSCF0008.JPG
    DSCF0008.JPG
    36.7 KB · Views: 5,903
What you have now is a single wire alternator. You don't need the purple wire, and you just have to connect the red wire to the red post and the black to the ground post. Check this link.

http://www.ebasicpower.com/charge/alternatorwiring.htm

The only setback with your new alternator is that it won't charge the battery with the engine at idle or even at fast idle, but this is not a problem in most applications. An exception would be if you were using the boat for trolling at very low speed and your boat had a lot of electrical and electronic equipment being run at the time (radar, sounder, GPS, downriggers, a stereo, etc).
 
This appears to be a Delco 10 SI set up for what is called "single wire"!
I use these..... they seem to be fine.
attachment.php


Eduardo...... you are correct with regard to the RPM required to self excite! Often they require being bumped up to 1,200/1,500 rpm or so to excite!
But once excited, they should charge at idle rpm.

.
 
Thanks guys, I should have thought of that, I've read about people using single wire alternators on this forum. Just to make sure I have it correct, the ground wire from the boat should connect to the ground terminal on the new alternator case, not the small black terminal next to the AC-TAP? My new alternator looks lust like the middle one in the top row pictured on the above link, except it has the two additional terminals at the bottom, the AC-TAP and the terminal with the blade connector that is marked black. If that terminal is also unused, or should I connect the ground there?
 
There should be a Negative cable (small one) one the engine that takes the alternator case to Negative.
Do not use the slip connector.... use the screw down connector.
I'm not sure what that push-on connector is for, if this is a 10 SI.
If negative, then make that secondary to the more important screwed down cable connection.

.
 
Here is the exact model info. It looks says it replaces a Valeo part number. It says it's 12V negative ground ignition protected. So, you think the black screw terminal (next to the AC-TAP) should connect to the engine ground (black wire) rather than the screw terminal on the case?
 

Attachments

  • DSCF0007.JPG
    DSCF0007.JPG
    89.1 KB · Views: 120
I can't tell you that for certain.

Here is a one wire Delco 10SI on e-Bay. It does not offer this terminal!
None do that I have seen.
It may be something specific to how this company is building the 10SI.

One of the four case screws would be used for the Negative cable connection screw bracket.

5b16_1.JPG



5f2c_1.JPG
 
I think I've got it figured out. I checked API Marine's website, and looked at their catalog. This alternator is a 3 wire, although it looks like the Motorola single wire. I called API, and they confirmed the lower terminal marked with black plastic is for excitation voltage. They make a 50 amp alternator that looks exactly like the Paris Rhone that my 1986 AQ131a had when I got it. This alternator is the high load step up, and meant to be a drop in replacement, so it has the same four connections, but they look different on this version, and the black wire not going to the black terminal was quite confusing, and the alternator didn't come with any schematics to clear it up. I'll let you know if it worked in a couple of days. Thank you both for your help.
 
Last edited:
I finally got the boat running, and the alternator works great. It was really confusing, since the ground wire on the new API alternator goes to the terminal on the case, not the black terminal of the back of the alternator. Thanks for all of the help. I wouldn't have got it right if it wasn't for this board.
 
I finally got the boat running, and the alternator works great. It was really confusing, since the ground wire on the new API alternator goes to the terminal on the case, not the black terminal of the back of the alternator. Thanks for all of the help. I wouldn't have got it right if it wasn't for this board.

Great thread. I have a boat with a Volvo KAD 44 diesel and another with an AQAD 31A diesel. I tried to make this type of alfernator work properly, but could never stop the low voltage alarm from going off and on at idle speed. The aftermarket alternators just do not excite enough at idle Speed to prevent the alarm from going off. I eventually found a distributor for the OEM Valeo Paris Rhone unit at less than half the cost Volvo asks for them. Finding work arounds to source OEM parts without going through Volvo is key to saving significant money and keeping these engines going.
 
I think I've got it figured out. I checked API Marine's website, and looked at their catalog. This alternator is a 3 wire, although it looks like the Motorola single wire. I called API, and they confirmed the lower terminal marked with black plastic is for excitation voltage. They make a 50 amp alternator that looks exactly like the Paris Rhone that my 1986 AQ131a had when I got it. This alternator is the high load step up, and meant to be a drop in replacement, so it has the same four connections, but they look different on this version, and the black wire not going to the black terminal was quite confusing, and the alternator didn't come with any schematics to clear it up. I'll let you know if it worked in a couple of days. Thank you both for your help.

Hello, I’m new to boats but I picked up one to try to restore. It has a Volvo aq131a in it and I’m having the same trouble with the alternator wiring I think. I bought a new engine that I thought was exactly the same but turns out it has a different alternator. The old engine has an alternator without the purple wire and the new engine has a Paris Rhône alternator with a purple wire. Right now the only thing that works is my cb radio. I think if I got the right alternator without the purple wire it might fix everything, but I’m not sure. Any help is greatly appreciated!
 
Back
Top