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High Output Alternator recommendations

Gent

Active Member
Messages
25
Location
Canada
Hi gang, I have an Warn M8000 winch tucked inside a Defelice winch mount. I've noticed that the Warn dips into the battery under load, and I'd like to get a high output alternator to help with the issue. I've searched the forums, but I haven't seen any posts about this upgrade. Anybody have input?

3.5 I5 2006 H3
 

alrock

El Diablo
Staff member
Messages
10,092
Location
Scottsdale
I haven't seen one, but maybe others have. But have you noticed any issues so far, or are just trying to head off something you think might appear? I've seen a fair amount of H3 winching and no issues so far. My winching is usually pretty limited to a few minutes of pulling. It might actually be easier to do a dual battery setup than getting a higher output alternator for these I5 H3s.
 

Gent

Active Member
Messages
25
Location
Canada
I don’t like the load dipping into the battery. I like to keep the battery fresh n full for starting the SUV.

I did a full day recovery course, and it was ok, but you could see the lights dim out when I was pulling heavy loads.

I’ve seen some out there, but I’d like to hear reviews.
 

JPaul

Well-Known Member
Messages
2,351
Location
Way up north, UT
You'll always see the headlights dim when pulling heavy loads. You need some massive power out of the alternator to never "dip into the battery." And that is with your RPM's up to at least around 2500 or higher to actually see the rated output, if you're just letting it idle while winching then the alternator is barely putting anything out.

The M8000 (like most winches that size) can pull over 430 amps at full load. Even at half load it's nearly 300 amps. The factory alternator on the 3.5L is rated at 140 amps if I recall but that would only be that much at probably 2,500 to 3,000 RPM engine speed. You'd need at least a dual 200-250 amp alternator setup to not need the battery for supplemental power if you plan on winching at full (heavy) loads. Those alternators are stupid expensive though (starting around $350 for the cheap ones and up from there) and I don't think it'd be very easy to add a dual alternator setup to the 3.5L since you'd need to make custom brackets most likely, and the 5.3L which you can find actual kits for leaves little room to actually fit them in with our tiny engine bay (the 5.3L barely fits by itself!).

The whole purpose the battery serves is two fold. One is obviously to start the engine. The other though is to act like a reserve of power for when the power requirements are higher than the alternator can provide. Mainly when sitting at idle at stop lights and drive through's when the people inside are taking for bloody ever. But then you get moving again and the RPM's go up and the alternator can go back to providing the power and recharge the battery. And if you're like us it's to provide reserve power to get your sorry butt out of a sticky situation while winching out.

Your most cost effective option is a 2 battery setup. Or even cheaper (and better in my opinion due to versatility and simplicity) these days is to just keep a lithium jump pack in the truck (basically a 2 battery setup but the 2nd battery is MUCH smaller and it's portable!). And to reduce the load on the winch you can run a pulley block to half the load on the winch/double your pulling power for the same amp draw.

How much winching are you actually planning on doing? I run a group 31M AGM deep cycle (though I hear it's better to use a regular starting battery for winching due to the high amp draws) and have never drained it dry while winching, though I don't really do much winching at all since I just don't get myself into situations it's necessary. It's an insurance policy, not a ticket to be careless. More often you're better off doing a strap than a winch, unless you're by yourself but then you have to deal with finding something to actually hook to. Might be easier up in Canada with all them trees, but I bet as most of our luck tends to be, you'll end up stuck in a spot with nothing to hook to. Maxtrax are a better investment with that regard.

Doing a course every now and then is not something I feel warrants sinking $500 at a minimum for a single 250 amp alternator (because don't forget you'll need to update the wiring to handle that amount of draw without melting anything) and if you want to go dual 250's to have sufficient power to not use the battery then you're looking at well over $1000 once you get done with brackets, belts, alternators, wiring, etc. And that's just for the parts, labor is going to cost you a good amount more if you have to have someone else do it for you.

If you're going to winch competitively, which is the only time I could see this level of investment being justified, then you need to be looking at a different rig entirely for that in my opinion. I don't think the H3's frame rails could handle repeated heavy winching on a frequent basis. Something will definitely tear out after a short while without reinforcing the frame horns substantially.

All that being said, it's your rig so if you want to go that route and have the coin for it, by all means do. Just make sure you post it all here for everyone to see! It's always neat to see what ideas people come up with and how they make them a reality.
 

JPaul

Well-Known Member
Messages
2,351
Location
Way up north, UT
Another thing I forgot to mention is that when I have looked into these high amp alternators in the past is that too many times the alternators end up dying after short order. Not sure if it's due to faulty builds or the manufacturer not really being able to get enough cooling through them to keep them from melting down at such high outputs or what. Maybe they've gotten better over the years, but I'd be reluctant to put anything other than OEM grade or better in for something crucial like that, and those get real pricey. Alternators always like to go out at the worst times.
 

Gent

Active Member
Messages
25
Location
Canada
You'll always see the headlights dim when pulling heavy loads. You need some massive power out of the alternator to never "dip into the battery." And that is with your RPM's up to at least around 2500 or higher to actually see the rated output, if you're just letting it idle while winching then the alternator is barely putting anything out.

The M8000 (like most winches that size) can pull over 430 amps at full load. Even at half load it's nearly 300 amps. The factory alternator on the 3.5L is rated at 140 amps if I recall but that would only be that much at probably 2,500 to 3,000 RPM engine speed. You'd need at least a dual 200-250 amp alternator setup to not need the battery for supplemental power if you plan on winching at full (heavy) loads. Those alternators are stupid expensive though (starting around $350 for the cheap ones and up from there) and I don't think it'd be very easy to add a dual alternator setup to the 3.5L since you'd need to make custom brackets most likely, and the 5.3L which you can find actual kits for leaves little room to actually fit them in with our tiny engine bay (the 5.3L barely fits by itself!).

The whole purpose the battery serves is two fold. One is obviously to start the engine. The other though is to act like a reserve of power for when the power requirements are higher than the alternator can provide. Mainly when sitting at idle at stop lights and drive through's when the people inside are taking for bloody ever. But then you get moving again and the RPM's go up and the alternator can go back to providing the power and recharge the battery. And if you're like us it's to provide reserve power to get your sorry butt out of a sticky situation while winching out.

Your most cost effective option is a 2 battery setup. Or even cheaper (and better in my opinion due to versatility and simplicity) these days is to just keep a lithium jump pack in the truck (basically a 2 battery setup but the 2nd battery is MUCH smaller and it's portable!). And to reduce the load on the winch you can run a pulley block to half the load on the winch/double your pulling power for the same amp draw.

How much winching are you actually planning on doing? I run a group 31M AGM deep cycle (though I hear it's better to use a regular starting battery for winching due to the high amp draws) and have never drained it dry while winching, though I don't really do much winching at all since I just don't get myself into situations it's necessary. It's an insurance policy, not a ticket to be careless. More often you're better off doing a strap than a winch, unless you're by yourself but then you have to deal with finding something to actually hook to. Might be easier up in Canada with all them trees, but I bet as most of our luck tends to be, you'll end up stuck in a spot with nothing to hook to. Maxtrax are a better investment with that regard.

Doing a course every now and then is not something I feel warrants sinking $500 at a minimum for a single 250 amp alternator (because don't forget you'll need to update the wiring to handle that amount of draw without melting anything) and if you want to go dual 250's to have sufficient power to not use the battery then you're looking at well over $1000 once you get done with brackets, belts, alternators, wiring, etc. And that's just for the parts, labor is going to cost you a good amount more if you have to have someone else do it for you.

If you're going to winch competitively, which is the only time I could see this level of investment being justified, then you need to be looking at a different rig entirely for that in my opinion. I don't think the H3's frame rails could handle repeated heavy winching on a frequent basis. Something will definitely tear out after a short while without reinforcing the frame horns substantially.

All that being said, it's your rig so if you want to go that route and have the coin for it, by all means do. Just make sure you post it all here for everyone to see! It's always neat to see what ideas people come up with and how they make them a reality.
Hey, thanks for the comprehensive answer!

You’re right - 9 times out of ten, I’ve just used a strap to get my buddies out. I’ve been lucky and never gotten stuck yet.

I’m going to be doing more solo stuff so that’s why I was looking at beefing up the system. I’ll grab some traction boards. I have a lithium pack already.

Good advice, thanks again
 

Bigunit

Hammer Down!
Staff member
Messages
6,557
Location
Arizona
I have dual battery setup on my H3T and always keep the engine running whenever I use my winch. Never had any battery or alternator issues.

Sent from my moto z4 using Tapatalk
 

Guerrero

Well-Known Member
Messages
121
Location
Spain
Another thing I forgot to mention is that when I have looked into these high amp alternators in the past is that too many times the alternators end up dying after short order. Not sure if it's due to faulty builds or the manufacturer not really being able to get enough cooling through them to keep them from melting down at such high outputs or what. Maybe they've gotten better over the years, but I'd be reluctant to put anything other than OEM grade or better in for something crucial like that, and those get real pricey. Alternators always like to go out at the worst times.

You are right JPaul, I usually see the same, aftermarket alternator always failing after short time, then reducing the overall reliability of the truck. That is not the way...

I am upgrading the cooling system, doing lot of little things to the Alpha and want to do a Built thread because interesting findings. Amr is helping me with everything, and he is super knowledge, thanks to him I am going to upgrade the efan to a Jeep Wrangler JL EFan that put more than 6000 cfm, that combined with good thermostat and some coolant tricks, the Alpha with stock radiator would maintain 1/2 of gauge even in desert..

Well because of that fan upgrade, I am looking about upgrading alternator (my stock alternator have more than 140000 miles and its time to refurbish it too).

Stock oem alternators in the Alpha are a 145 amps unit. I can see that 2008 H2 alternator is a direct fit (same connectors) and have an output of 160 amps (15 amps upgrade and maintaining GM reliability parts).
There is another upgrade that is a 170 amps alternator from some 2020 GM models cars. And with same connectors (almost sure), So there is upgrades from GM for our alphas, more difficult for i5s, and keep the GM parts
 

Gent

Active Member
Messages
25
Location
Canada
Well, the alternator crapped out on me the other day just as I was going to do the Whipsaw trail with a bunch of H1, H2 and H3 guys. Major bummer. I'm guessing it was weak and my winching practice gave it a death wobble. I've put in a new OEM one for now.
 

crwalkerasla

Well-Known Member
Messages
264
Location
Corinth, MS
Tread with caution where you get your HO alternator. I had one installed from AutoZone and it wound up having a bad voltage regulator out of the box. Pushing upwards of 20volts. Through the dash gages into spasms, blew out the headlights and fog lights, and now the odometer doesn't work. Went back stock after debugging the problem.
 

Exodus

Active Member
Messages
41
Location
Alaska\Philippines
I had a TA that i needed higher amps output once,,buddy of mine was really good mechanic
so what he did was replace th factory regulator inside the alternator with a higher amp regulator, never had a problem and all it cost me was 17bucks
not sure if this option is even still possible but worth looking into
 
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