Inliners International Forums General Discussion Electrical Basic GM alternator questions?

The alternator on the 153 in my old CJ2 has given it up after many years. It's a regular 3 wire GM from the 70's. I thinking of replacing it with a higher amp output alternator due to the electric winch which can draw 200 amps under load, and maybe going to a marine deep cycle battery at the same time.

Is there any downside to that thought? Harder to spin? Over charges something? Battery life? I'm only working with about 90 hp here and I really don't have much of any running electrical load, but the winch can draw the battery down in one minute and I don't really have anywhere to put a second battery. I don't use the winch often, but when I need it, I may really need it.

The stock alternator produces 63 amps. I see alternators that would fit that make 140 amp or even 200 amps. Any advice?

you can change over to a 2 Or even a 1 wire and it shouldn't be a problem. As for a marine deep cycle battery they are ment to be drained then re-charged Not a continues charge, But I have known people to still use them like any other battery.

I have a good generator that came out of a '46 Chevy 3100. Unfortunately it's on the opposite coast from you...

I think it may have been rebuilt, but not sure. It seems to have a new chrome strap on it which is why I believe it's rebuilt.

It was working in my truck before I converted it to 12v.

Not sure if it will fit in a Med./Lg. flat rate box, I can check if you're interested in it. You can have it, just pay for postage.

As far as conversion, if you decide to go with an alternator and convert to 12v, figure about $50-$100 for an alternator, and you can get a bracket to mount it for about $20, a coil is about $25. You need to keep your flywheel with your starter though, the 6v and 12v are different (I think 6v is 139 tooth and the 12v is 153 tooth. The pinions on the starter are also different, the intention was so that the starters were not mismatched. You can use your 6v starter with a 12v battery, but not the other way. You also need to replace your bulbs and add a resister on the fuel gauge. Oh, and I think I had to get some type of harness for the alternator electrical so I didn't have to hack up the wiring. I got all the stuff from Jim Carter.

IMO it really depends on what you plan for your truck. If you want to have a radio and/or navigation system, or charger for your cell phone, that stuff if better suited for 12v, it will be able to handle it better. With 6 volt you can still have an inverter to convert 6v to 12v, that's another solution to get a 12v cigarette plug. Kind of funny, smoking is taboo, but we use those plugs a lot, heh? (I know I do! LOL)

Pretty sure he is already 12v there aren''t many 6v winches and I think his 153 in a Chevy 4 that came out in '62
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There are two styles of deep cycle marine one is really a dual purpose that does a pretty good job of cranking and powering moderate loads over a longer time. Read the description and get the most powerful battery that can fit in your space. Also use the largest cables you can afford from the battery to the winch. DC loses a lot if cables are too small.

Although the higher output alternator will draw more power from your engine when it is putting out it's maximum amps when will that be? It should act pretty normal with your regular light loads and just keeping the battery topped off. It won't normally put out 140-200 amps unless the loads are drawing the battery down. At times when it may be assisting the battery run the winch you probably won't be using the engine to move the jeep so the full 90 hp can run the alternator. I have a big Miller welder that came with a 4 cylinder Jeep flathead four. The welder can be used as a 10KW power plant plus another 1100 watt auxiliary generator. No where near the 90 hp of your 153. I think you would be fine with a 75-100 amp alternator. On a long hard pull you might want to give the winch a break and let the battery charge a few minutes.

I ordered a 140 amp Tuff Stuff alternator, (made in the US). They told it should be fine in the 153 as long as I run a #6 charging wire and #10 ground. They also told me that it can be set up as a one wire. or three wire, but that for my use the 3 wire setup would likely be preferred as it will excite as low as 800 rpm with the 3 wire set up. I'm running #2 wires for the winch to both ends of the jeep through a marine battery switch so they won't be hot until I need them. I set the winch up on a Reese type mount so I can use it on whichever end makes sense at the time. I still have some thinking to do about whether to ground through the frame, or run ground wires to both ends from the block ground. And whether and how to fuse any of this stuff.

I think you are on the right track with your alternator & cable choices. Your pan sounds almost identical to what I did on my '06 Silverado. I was just able to get the front receiver hitch from CURT a couple of weeks ago and have not tested it yet, My winch is a 12,000 lb Bad Land from HF. It has very good reviews on several sites and a friend has one. It can not be beat for the price and availability. So far my one issue is weight. I can only imagine packing it to the hitch in country so rugged that I would need it, Synthetic cable would make it much lighter. I have it to put on. I have only used it a few times, once to test it by spooling the cable and pull the Silverado up the road. I used it to pull a 2500 4x4 Suburban to a spot my tractor would not pull it and to move my Blazer out of the line of fire of the ground squirrel range. It did those with ease with only the parking brake set and all four wheels chocked. I learned not to use 'Park".

I bought a 2 gauge cable kit with quick connectors & wired the winch to match. It has a large T handle switch for the power cables so they are only hot when needed. There is a circuit breaker between the battery & switch. The ground cables are full length to both ends of the truck and share the stock battery ground connection. I don't like having more than one major ground connection especially with all the electronic circuits on the truck. So far I am very happy with it. I'm ready now to rescue the Ford tractor that has been stranded on the hill above the house for a few years due to the rough terrain.

I bought a Smittybuilt 9,500 lb winch, (the CJ2a weighs less than 3,000 lb), with synthetic cable. The choice was primarily based on online reviews, weight and amp draw at full power. I have the Reese receiver on the rear but I am building one through the front bumper as well. I am considering adding the wiring to my plow truck as well.

That is supposed to be a very good winch.
I started this when my son and I picked up a '55 Studebaker Station wagon a while back and the trailer we used had a winch. Though I always wanted a truck with a winch the trailer winch made things so easy. I may still put one on the trailer or just use a receiver hitch with a second mount for use with the trailer. Thinking of being able to mount it on the tractors too. if the Ford had a mount it wouldn't be stuck on the hill!

No way, they're a real piece of garbage. They have 2 big problems, the solenoid going out and the motor going out.

Very cheap Chinese motors inside, it's kinda like a motor shaped object. The biggest reason people buy them is that they're cheap. I'd almost rather go with an HF Badlands winch than a Smittybilt. Here's one on Ebay for $340 w/free-shipping. (9500 lb)

BD1, yeah, it sounds good on paper, but here's a video of a Smittybilt 9500 with a new 10k motor and look how it struggles to pull my '46 up the tilt-top, although it did work out well for me to take it over to the weigh station and DMV, I did have to get the '46 running to drive it to the DMV for final inspection with the DMV folks. The winch did get it up there, but after I watch it later it didn't seem like 9500 lbs. of pulling with a 3000 lb. load.

https://www.youtube.com/watch?v=mYbE4OIKFpc

This winch came with my trailer that I just FUBAR'd. I think the seller was glad to get rid of it. I will never buy another one.

If the current alternator is external regulator, Tuff Stuff has a 100 amp version that is pretty good. I installed one on my 57 when my stock 63 chevy alternator could not keep up any longer. the rub, you cannot use a mechanical regulator, you have to use a heavy duty electronic regulator, which Tuff Stuff also sells. Mine has been installed for a couple of years now, not a single issue.

Having to use higher output alternators to run the new electronic doodads on our cars makes me wonder how much engine hp is used. It has to come from somewhere. It reminds me of the picture of the electric car being charged by the diesel generator.

Well just because they had the brains to build the car But not enough Brains to put a alternator on it. go figure that one.

Good laugh Larry!

I thought this was an interesting question. A little digging, and I was shocked to learn that most automotive alternators are lucky if they are 50% efficient. I found a site with some good info on the topic:

Alternator Efficiency

If you use a 100 amp alternator:

Watts = Volts x Amps. If we assume the alternator when charging puts out 14 volts, then 100 amps times 14 volts is 1,400 watts. Double that to 2,800 watts of power needed from the engine to make 100 amps (because the alternator is only 50% efficient).

1 horsepower equals 745.7 watts. If 2,800 watts from engine is needed to make 100 amps, divided by 745.7 watts per horsepower gives you 3.75 horsepower.

I think I got my math right...

And then there are watt hours, the time the watts are needed to do whatever needs to be done. So added fuel consumption over that length of time. There is also a loss caused by inefficiency & friction every time we change from one power source to another. I guess that could be part to the alternator efficiency rating.

I think that to fully understand modern energy needs we will have to return to the Stone Age because every advance from there required greenhouse gas producing fuel. With today's population deforestation issues wipe out the oxygen producing plants very quickly. No fossil fuels = no metal. We are in a pickle!

The way the Tuff Stuff tech explained this to me, the internally regulated alternators only produce the amount of amps that the draw on the electrical system requires. Like a generator which will loaf along all day, but needs to "throttle up" when a real load is put on it. So I will pay about 4 hp to get the 140 amps out of it at +/- 1,200 rpm. But when that happens the jeep will be barely moving, (stuck), or not moving at all, (moving a log, or pulling someone else out), so I will have hp to spare. Driving down the road it should cost me less hp than the one I'm replacing, because the amp draw to run the inline 4 is very low and the new alternator is more efficient that the old one. Added bonus: If wired as a "3 wire", the new alternator makes amps as low as 850 rpm, (idle) so the battery amperage used to start the engine is being replaced immediately, leading to less load when I start driving.

I spent some time researching these before I bought one. The new Smittybuilt looked to me like the best bang for the buck, with lower amp draw/rating and has better reliability ratings than the competition. Time will tell.
Most of the major complaints I looked into regarding motor and solenoid failure related to undersizing the wiring to the winch. Mounted on a trailer, (12 to 15 feet from the battery?) it looks like there would need to be at least 1/0 wire all the way from the vehicle battery to the winch to avoid "browning out" the electrical components. With all the connections and plugs rated accordingly. Even heavier cable if you are running it at full capacity.
The way around this is to mount a separate larger battery on the trailer right next to the winch and then run a charging wire appropriate to the alternator output from the truck alternator to that separate battery. Maybe that was your issue?

I agree with everything you said here. Doing some looking around it looks like the new Smittybuilt winches have a good rating. Cable size & length is a big deal especially with DC current. Jumper cables won't do it. As I said earlier I started this because of a winch on a friend's trailer. Now I have a killer setup on my pickup and still none on my trailer. I like the idea of a separate battery & winch on the trailer so if I'm towing with another vehicle I still have a winch. Close short runs of big cable + a big battery would allow a smaller winch to roll something no the trailer. No need for a 12,000 lb winch. I need to check out my alternator and next time I replace my battery go for the most amps that will fit in the space.