After installing a Volvo e-fan in my YJ I noticed that there was quite a bit of voltage fluctuation when the fan engaged. The e-fans take quite a bit of voltage on start up and I figure that must take a toll on the stock alt and wiring so what better project than a full electrical upgrade, right? The following contains some info I found on various sites as well as what I did. This will be a pic heavy thread and is not intended to be a be all end all but rather a what worked for me kind of deal. Disconnect your battery before starting any of this! After completing this makeover I can flip my headlights on (hi beam) and see no deflection in the voltage. When the fan kicks on the needle BARELY moves a tick and resumes its normal position at 14v.
Actual mileage may vary.

First off, the parts:
9' of 1/0 cable (red)
4' of 4ga welding wire (black)
#1 Bussmann fuse holder with rubber cover
#1 150a fuse
#7 1/0 copper lugs
#4 4ga copper lugs
#1 kit Marine terminals
Various size shrink tubing
#1 136a alternator
Solder, flux and map gas torch



I used a new 136a alt for a 98' Jeep GC w/v8. That unit fits a few different models and years and is a direct drop in for my YJ. It should fit these:



The 136a case was a bit larger in diameter than my stock unit but posed no problems with fitment.



The only mod I found necessary was the plastic lug on the alt faces the wrong way. Since I used such large gauge cable I had to trim the shield to fit the lug. No biggie. I used the shield from the old alt, trimmed it and installed it on the new unit. Also worth mentioning is that the new alt has a 7 row pulley vs 6 on the old- no problem. Just put the belt toward the back of the pulley or swap your old one over to the new unit. I left it.






The fixed post connectors on the bottom of the old alt will transfer directly to the new unit. I disconnected the hot lead to the old alt and clipped the terminal end off. I opted to put a rubber plug on the end and heat shrink to seal it. I may go back and remove that lead from under the fuse block or I may not...It's safe either way. It's tucked back into the corrugated loom.




Next up, new feed cable. I like 1/0 wire. Probably overkill but hey, I like it so there. First I flux the connectors then install the bare cable end and strike it with a punch to get the end to hold itself on. Soldering come next followed by heat shrink for both protection and support. I like building my own cables because it gives me the latitude to have them turn whichever direction I choose.






Next stop- 150a fuse:





From there we go to the top of the battery. I mention top because mine has front posts as well. From what I've read the front posts are not good for heavy loads ie: Winch, OBA, etc. I did repurpose my old smaller gauge positive cable to feed the fuse block via new connectors from the front lugs. This alone was a substantial gauge change from the little stock wire that fed the block previously.
Here's a shot of the old vs new. Beef!



Here's a shot of all of the cables intact. Included on the top positive are my winch lead, the feed from the alt and the new cable going to the starter. On the neg side is the winch neg, the welding wire going to the block and the welding wire going to the firewall. All connection areas scraped clean prior to making the connections. On the front lugs I have the feed to the fuse block and the feed to my front and rear lite relays. My e-fan is tied directly to the side of the fuse block and is protected via fuses and relays in the adjustable Hayden controller.


I think that about covers it. This job took me about 3 hours and I wasn't moving too quickly. It's definitely a doable job for anyone with some mechanical know how. Take your time, pay attention and have fun!

Looks great, one of the better upgrades I did to my old YJ when I had it. Nice writeup.

1) 1/0 (0AWG) wire is overkill for a 136A alternator - 4AWG is just fine (and still an upgrade over the OEM 6AWG.)

2) I may be missing something, but what did you do with the 4AWG wiring you mention in your parts BoM? If you used it to replace the primary ground, you shouldn't have - the main ground should be the same size as the main feeder lead (meaning that, if you use 0AWG feed wire, you should use 0AWG grounds - even though you won't pull enough power to tax either, most likely. 2AWG feeder? 2AWG ground. The ground may be larger than the feed if you like, but the feed being larger than the ground is bad design.)

No doubt the 1/0 is overkill. I had it leftover from the big block we just finished. As for the 4ga, I did use it for the grounds. One to the firewall and one to the block. I also considered that they should be of the same gauge but reconsidered due to the sizes that I chose. A 1/0 ground is mere minutes away.

Looks like a nice install...that is some hefty wire!

Quick question...do you know what series the alternator is that you purchased? CS130, CS144? What alternator size (12si?) was on there previously?

I'm still trying to sort through all of the alternator swap info out there...

The stock alt was on. I'm not sure about the series you are referencing. I simply asked for the alt that fits a 98' Grand Cherokee w/v8. Here's the data sheet, hope it helps.

Great write up.
One thing though, you left out how you powered the PDC.
You showed how you capped the wires off but did not show how you powered it.
I am assuming you left the feed that goes from the battery to the back of the PDC. Which works fine.

Thank you. I did reference the PDC only I used 'fuse block' instead. Here's the quote: I did repurpose my old smaller gauge positive cable to feed the fuse block via new connectors from the front lugs. This alone was a substantial gauge change from the little stock wire that fed the block previously.

great document.......thanks!!!!!!

Seriously. Thanks for this. I'm on the hunt for parts now.

Awesome write up! Much easier to read than other threads!! For the fuse, I used an inline circuit breaker instead for quicker fix if it ever popped on the trail.
*edit* I used 150a not the 50a posted...

blitz, the "series" of alts you're referring to are the AC Delco brand of alts, used in the YJ from 87-90. the one Dirt used in this write-up is actually a Nippon-Denso which started being used in the YJ when they switched to the newer engine designs in 91. totally different animal from the Delco's. in your case, go for a CS144 to replace the jeep's stock 12si.

If it was the 136A ND upgrade, it was probably a 70A, 90A, or 117/120A ND on there before.

If you've got a CS130 (like the RENIX XJ/MJ,) you can source a 140A CS130 and drop it on - you'll just need to swap the front case half, probably, to get the mounting right. The 140A CS130 can be found on GM vehicles with plenty of power accessories of similar vintage (also on some trucks, but the trucks usually got the CS144.) The Delco alternators (all of them) can be upwound by any competent shop for a nominal fee, they're the most commonly used alternators for conversions, kitbuilds, and custom projects anyhow

Hey Blitz- You threw me with the 'series' reference. Yes, as 5-90 said, I believe that my stock unit was a 90a.

Sentinal02 and 5-90- Thanks for the assist on the correct cross reference models for him and anyone else that may need it.
The ability to fill in the blanks is one of the best things about this forum!

Thanks for the follow-up guys. Having an older YJ, I wasn't aware that the newer models had the Nippon-Denso units. I imagine this is also when they did the swap from internally to externally regulated units.

Now that I have done some more digging, I plan to go with a 105 amp CS130 unit. Should be enough for me, seeing that I currently have a 76 amp 12si model.