APU Tri-pac not charging batteries

His size reference is not accurate. 13mm is the size of the wrench that fits the bolt head. It's more like an M8-1.5 x 20mm. That translates to a bolt 8mm in diameter, 1.5 threads per mm, and 20 mm long. It's a short bolt. You might be better off getting a longer one and hacksawing it to size (what I did). Use a lockwasher.

I didn't measure the length of the 3/8" bolt that goes thru the tensioner bar and adjuster tab on the alternator. Reading back, mwerner apparently didn't either. Just measure with a tape and buy one 1/2" longer. I didn't buy fine thread, but did get a stainless bolt and locknut to avoid rust issues.

Try an Ace or Tru-value hardware store for your bolts. They usually have a much better selection that's easier to find stuff in.

 

Ok thanks for your input. Will give it a shot .
Another question...is it difficult to connect the wires with that new pigtail?

 

No. I used heat shrink butt splices to avoid corrosion problems.

Another variation from mwerner, I re-used the short ring terminal wire from the old connector on the S lead of the pigtail harness, and stacked it on the output terminal with the main battery + lead. Delco's are usually internally sensing, so yeah probably redundant to do that.

The other wire goes into the main harness and I spliced it to the L lead on the pigtail.

In other words, hooked up the same way as the old TK alternator. Just using the pigtail to adapt the Delco.

 

Thank you very much for the info.

 

Just hooked up the new alternator and connected L from pigtail connector to old L wire and S pigtail wire to alternator output. The result : not working....still 12.3V with apu on and off. Anyone any suggestions why it's not working? Maybe it's not the alternator?? No clue what to do now.

 

The bench test procedure, after verifying your battery connections with a volt meter. I would connect a voltmeter to the apu harness side of that L wire (disconnected from the alternator) and look for just below battery voltage with the unit running. If that checks out, you may have gotten a bad alternator. Most parts stores can check them too.

If the alternator checks good, you'll need the service manual. I downloaded one from somewhere, but am on the road and do not have it on this laptop. Might be a fuse or circuit breaker somewhere. I don't know, since I didn't run into this and did not need to troubleshoot further.

You'll see on that link that the alternator is self sensing. That is, the S terminal connection is indeed redundant and not required for the bench test. The bench test only requires faking a lamp circuit with a resistor.

 

I found out that the old L wire was cut and that the 50A fuse was a little bent and I had it replaced. I fixed the old L wire and connected to the L wire from pigtail and the S write from pigtail to the alternator output. Turned the apu on and the alternator started to smell and to smoke just a little bit and the pulley to get really hot. I also checked the output and was the same 12.5V. On the L wire I had about 10V when I checked it. At this point I don't know what the problem could be...probably as you said...a bad alternator...I don't know. I took the new alternator off and I'll try to replace it.

Here are some pics I took:

 

Ok I did the conversion it came out OK i am getting 14.4 v at the alternator when running I am only showing 13,6 at my inverter ??? any thoughts? can anyone tell me ware the wire with the mega fuse goes to? batteries or inverter...or control under bunk???? in one of the other conversion pix it showed a alternator adjustment turnbuckle does anyone have a part number for that mine is a flat bar with a oblong hole at the alternator for adjustment...thanks in advance

 

That all depends on the installer.

The main power to the engine case should be direct to the batteries. Same with the inverter leads. Depending on how long the run is from the battery box, as well as what gauge wire was used to connect your inverter, you will see some voltage drop. Bad connections, faulty or crusty crimps will cause voltage drop too. So there probably isn't a simple answer.

You should also check the condition of the terminal ends on all the power cables. Over time I have changed out all of mine. The first ones to go were crimped with a hammer by either the installer or previous owner. Next went the ones that got green stuff growing inside the crimp. Use a proper hydraulic crimper, and self sealing heat shrink with the adhesive inside for a water tight seal. You can find the crimpers cheap on eBay.

I am not positive, but I believe the turnbuckle style adjuster is found on older units and may have been superseded by the bar/slot style adjuster. You'd need to ask a Thermo King dealer. Have your unit serial number handy. I have one of each, both units converted to GM alternators. The turnbuckle style is easier to adjust, but they both get the job done. I won't bother with changing out the bar style, as it's never given me problems.

 

Thanks i will try and follow the battery wires and check all my connections i would like to get a turnbuckle ajuster i will contact TK