It's was I who was fabricating brackets and installing larger alternators for our Ram's. I haven't been around much due to business and family matters (5 kids !! and a full time auto business),but I was emailed by another member about this post,so I just dropped in to offer some advice.
We have very high electrical requirements on our trucks (plow and service trucks) and was going through batteries and alt's like crazy. I ended up trying several different styles and sizes of alternators and batteries,and finally found one that worked very well,and was very cost effective.
First of all lets go over the different styles of alternators available to us,and what purpose they are suited for.
1-stock,a decent unit which will usually last for a while under normal use. Not very good for corrosive or wet use (ie salt and water),and requires a fair amount of engine speed to create good output,usually around 75-90 amps,but no where near the rated 136 amp rating.
2-modified stock,usually "souped up" by a rebuilder with larger rotor and stator windings. Will put out a little more amps at high RPM,but same as stock at low speeds. They usually don't last long as the extra amperage usually creates more heat,which the stock case is to small to dissipate. It will also usually kill the stock rectifier assy in short order.
3-redesigned stock,usually made by aftermarket companies with better components,but still in a stock case. A step up from above,but still suffer with heat and durabilty problems due to small stock case being used.
4-large frame (case) alternators,by utilizing a larger case,ALL the components are larger and built better to deal with the heat created by more amperage. They have much better low speed output,as most are made to be used on a low speed diesel,and much higher amperage ratings. Most of these style alt's are used on the larger diesels used in tractor's,buses,etc,so they are meant for the long haul,and will withstand the extra vibration. Some of the aftermarket stuff,like the Hehr units are based on these style alternators,but are very expensive. By using a "stock" large frame alternator,you get the high output,at a reasonable cost. Most truck shops have a fair number of these on the shelf,both new and rebuilt,very cheap.
I used a Leece-Neville 140 amp unit which uses a standard J180 "ear" type mount. With a few spacers,a longer bolt,and a bracket extension,it's a direct bolt on. A longer belt is also required. This is a brand new unit and my cost was $230. 00 Canadian. Odd parts to install (pulley,belt,etc) was less than a $100. 00 Canadian. I now have a unit which puts out almost 100 amps at base idle,and WELL OVER 140 amps at cruise. The alt tested much higher on the test bench. It solved all my charging system problems. I was actually looking for a higher amp unit,but this one puts out plenty,for a great price. It also runs very cool,and I have seen these alt's go many many years on larger OTR trucks. You will have to upgrade the charge wire (from alt to batt),as well as the alt fuse,as it will blow the stock 120 amp fuse in short order. I also don't have as much of a problem with the grid heaters pulling down the voltage and dimming the headlamps.
More info on these alternators at
www.prestolite.com
Regarding batteries,I use two group 31 batteries (used on diesel trucks and tractors) from Interstate. Brand is not as important as size and reserve capacity. They will require a little "massaging" of the battery trays,but they do bolt in. The are rated for 950 CCA,1370 HCA,and have a reserve capacity of 200 mins each !!. Stock is only 750 CCA,and 90 min reserve I think. These things are also very well built to deal with excessive vibration. We were lucky to get a year out of the stock size batteries,but these have been going strong for over 3 years. They would work great for winching as they have a huge reserve. I used to run separate batteries,with an isolator,so I wouldn't get stranded when I ran down the batteries. These are almost impossible to run down.
Will run the stereo,strobes,and all my lights all day,and start the truck like nothing happened. I no longer need the isolator and extra batteries. It also takes the load off the alt some during high amperage draws (ie winching),as the batteries can keep up longer.
Sorry about the rant,just passing along all the info I have learned in my quest to build the perfect truck,or charging system at least. Don't throw away your money. You could probably do this upgrade for $200. 00 US.
Here is a link to my previous thread for more info. Hope it still works. It has all the info and pics.
https://www.turbodieselregister.com/forums/showthread.php?s=&threadid=34554
I have been away from here for a while but will try and follow this thread if anyone wants more info on how to do this. Hope it helps someone.
Chris
Auto Proformance Services
www.autoprofomance.com
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