Thinking hard about replacing my 136 with a higher amp alternator, I’ve read a lot of good info on here, but seems like the last info I found was from 2018. Is there anything new I should check out for a good drop in replacement option with some more amperage? It snowed here in TN a few weeks ago on Christmas Eve, I spent the entire night winching tourists and holiday visitors from Florida out of ditches and creeks and one guys trout pond. Pretty sure the  old 1981 Ramsey worm gear along with the 100W KC Halogens fried my diodes, figured I’d just upgrade it instead of replace. 

 

8 hours ago, Andyba20 said:

Sounds like healthy batteries, clean terminals, and good cables along with a healthy stock alternator works for you.

 

The biggest thing was I been reducing loads (mechanical and electrical) on the vehicle completely. Electrically, I switched over to HID headlight which are half the load (35 watts - 2.9 Amps) but 4 times brighter lighting (4,000 lumens vs 860 lumen halogen) and my driving lights are 4,000 lumen LED which draw a mere (18 watts - 1.5 Amps). The rest of the exterior lights are swapped over to LED. I've got the interior light for cab done but not for the cluster yet. Hence I don't need a monster alternator now being most of the electrical loads have been reduced. Heck just the red LEDs in the taillights are only 0.5 Watts for a mere 0.041 amps...

 

What do I need a monster alternator for? 

 

 

I use to run four 100 watt aircraft landing lights. These draw a bit over 20 amps. Then it was set up for 2 on hi beam and 2 on lo beam. Then got into the silverstar headlights which were pretty hoot and draw quite a bit of power on hi beams. 

 

Just remember bigger alternator, bigger loads on the engine. Again I'm aiming to reduce all loads on the engine and electrical system not add to it. Less loads at any time mean better MPG's and going farther on a gallon of fuel.

 

Edited January 13, 20214 yr by Mopar1973Man

22 minutes ago, Mopar1973Man said:

 

The biggest thing was I been reducing loads (mechanical and electrical) on the vehicle completely. Electrically, I switched over to HID headlight which are half the load (35 watts - 2.9 Amps) but 4 times brighter lighting (4,000 lumens vs 860 lumen halogen) and my driving lights are 4,000 lumen LED which draw a mere (18 watts - 1.5 Amps). The rest of the exterior lights are swapped over to LED. I've got the interior light for cab done but not for the cluster yet. Hence I don't need a monster alternator now being most of the electrical loads have been reduced. Heck just the red LEDs in the taillights are only 0.5 Watts for a mere 0.041 amps...

 

What do I need a monster alternator for? 

 

 

I use to run four 100 watt aircraft landing lights. These draw a bit over 20 amps. Then it was set up for 2 on hi beam and 2 on lo beam. Then got into the silverstar headlights which were pretty hoot and draw quite a bit of power on hi beams. 

 

Just remember bigger alternator, bigger loads on the engine. Again I'm aiming to reduce all loads on the engine and electrical system not add to it. Less loads at any time mean better MPG's and going farther on a gallon of fuel.

 

 

 

Doesn't do much good for the OP when he's concerned about winching. Not much you can do there to reduce the draw, so that's what he needs a bigger alternator over. 

Yup. I know. But just showing why... 

 

 

 To add to @Mopar1973Man's  post, if the OP were to switch over to all LED lighting it would free up amps to help run the winch. That way the load of the big alternator isn't a constant mechanical load on the engine. If one used the winch frequently yes then a bigger alternator would be the ticket but for a few times a year it may be a wiser choice to reduce load in other places to free up some amperage to operate the winch plus enjoy the brighter output of the LED lighting and the safety factor it also adds as well.

Great info from all of you, I appreciate it. I have some Rigid Led cubes on the front bumper that throw plenty of  yellow light so I can always turn off the headlights and KC’s. I tried an H3 type led in the KC housing and it just wasn’t near as bright. I’m a huge fan of LED technology but I will say I haven’t found an LED yet that will outshine that 100W halogen spot light pair (for the size). I’ll also go ahead and swap out led bulbs in the tail lights and blinkers. I have the Daniel Stern kit for my headlights and I have been extremely happy with that, one of the best mods I’ve done to this truck so I’ll probably keep it as is. 

Search for “cheap factory 160 amp alt.” on this site. Good information. 

Here it is

https://mopar1973man.com/topic/17066-cheap-factory-160a-alternator/

 

@01cummins4everthank you. I don’t know how to do that!

I’ve been running a Nations 180 amp alternator for about 3 years now. Switched to it because of high AC noise from the factory unit. Was having TC lockup issues. I don’t have a winch. My Pacbreak does run off a small air compressor. I haven’t had any issues with it. Just FYI. 

3 hours ago, Doubletrouble said:

 To add to @Mopar1973Man's  post, if the OP were to switch over to all LED lighting it would free up amps to help run the winch. That way the load of the big alternator isn't a constant mechanical load on the engine. If one used the winch frequently yes then a bigger alternator would be the ticket but for a few times a year it may be a wiser choice to reduce load in other places to free up some amperage to operate the winch plus enjoy the brighter output of the LED lighting and the safety factor it also adds as well.

 

While that would technically help, it would be such a small effect that it would likely be imperceptible to the alternator. 

 

While you're drawing 350A a change of 5-10A isn't going to do much for the alternator as it will be at 100% load either way. 

Will a larger alternator put that much more load on the engine if in dailey driving? I know it will using a winch or other large draw devices.

11 minutes ago, dripley said:

Will a larger alternator put that much more load on the engine if in dailey driving? I know it will using a winch or other large draw devices.

 

Within reason, no it won't. As long as you're not talking a much heavier rotor, which is likely not going to happen  at a perceivable amount on these trucks. 

I think you should try to isolate the winching battery from the alternator.

 

When you start winching, it will pull amps from where it can get them.  If for some stupid reason (or the batteries are too dead) it will start pulling directly from the alternator.    (I have my dump trailer set up with a relay that disconnects the truck aux power that charges the battery.  when I power the dump up,  it disconnects the truck aux)

 

The best set up I did on most of my 4xs was add a battery with diode isolation.  It would charge the extra battery but would not creep back and directly load the truck battery or alternator.   Since we start with two batteries.... it is gonna be tougher, though you might be able to do the relay (it would be a starter solenoid for that many amps) to separate the battery from the system.

 

Good Luck

Hag

18 minutes ago, Haggar said:

When you start winching, it will pull amps from where it can get them.  If for some stupid reason (or the batteries are too dead) it will start pulling directly from the alternator.  

 

Yup exactly. Hence why my landlords truck blew the 150 Amp alternator fuse I installed while running his winch. Even though the alternator is only 136 Amp. As the batteries dropped in voltage being totally wore out it increase the current from a already tapped out alternator and blew the fuse out. Again batteries have more of the role of "storage of energy" to be redelivered to the electrical loads. Alternator is only to recharge the batteries NOT to sustain high loads. Being like myself got two WalMart batteries at 810 CCA that is 1,620 CCA if that can't sustain a winch for a time of pulling then I would say batteries are not doing there job. Even stock was 750 CCA for 1,500 CCA total.

 

 

 

Yup, Even with 136 Amp stock alternator and weak batteries you can blow a 150 Amp fuse or circuit breaker. Just because the batteries are weak or no longer have the capacity for said loads. Again like even the rebuilder down in Nampa, ID told me the alternators are not to blame but weak connections, bad grounds, and weak batteries. 

 

 

Edited January 14, 20214 yr by Mopar1973Man

There is likely something else wrong with a truck blowing a 150A fuse on a 136A alternator. It may have occurred with a high amp draw but that just allowed the other failure to manifest. 

 

I've done lots of winching over the years with amp draws that have been 2-3x higher than the alternator rating on rigs with 1 or 2 batteries and never had a alternator fuse blow. 

 

I would not disconnect the alternator while winching as that will result in even lower voltage and higher amp draw. 

 

High amp draw will reduce voltage even on good batteries. When you're talking 400A draws you want as much voltage retention as you can get and that means an operational alternator. The grid heaters are also a great example of voltage drop at high amp draw. 14V to 11V with 180A of grids AND supplemental alternator. Just think what a winch will do to voltage. 

 

If the alternator was ONLY to recharge batteries they wouldn't offer high amperage alternators, high amperage power points, and dual alternators for sustained high amperage loads.

 

The way 12V electrical systems work the alternator is providing 100% of the used power while driving, 100%. The main function of the batteries is starting, not supplying power while driving. A shunt on the batteries could easily prove this, if they are charging, even at 0.001A, then there is no draw on the batteries. The driving voltage of 13.4+ V also indicates the alternator is the main source of power while driving since 12V batteries cannot hold that voltage on their own, even the best 12V batteries only sit at about 13.1 fully charged without a load and most sit at 12.7. The only time, aside from rapid power changes while the alternator catches up, you would see the current move out of the battery is when the load exceeds the alternator output.. think grid heaters for most of us Cummins owners.

 

A Group 27 810cca battery has 76 amp hours. Two of them in parallel have 152 amp hours, with 76 of them being usable. A 9000lb Warn winch pulls ~280A at 50% load. That pair of G27's would only allow for 16 minutes of use before damaging the batteries. At 100% load it's less than 10 minutes. That is a lot of winching, but with a 136A alternator that time increases to 30 minutes at 50% and 13 mints at 100% load. A 136A alternator will take 2 minutes to recharge the batteries for every 1 minute of winching at 50%. That may seem like a lot of winch time but that fully depends on the scenario. 

 

CCA's are just that, and not relative to battery capacity for high amp loads. Really good deep cycle batteries have high amp hours and low CCA's. 

 

On my previous off-road rigs I ran stock alternators, 9000lb winch, and a deep cycle battery. This was because the alternator couldn't keep up with the winch loads and neither could starting batteries. It was a small 4cyl engine so I didn't need a lot of CCA's and made the sacrifice for better winching performance. Still never blew an alternator fuse.