Alternator replacement -- opinions?

[dcyrilc]

I have an older JD2240 diesel tractor. Factory alternator was 33 amp. The factory setup had 3 ~50W lights, 2 flashers, and the guages in the instrument cluster. I'm going to be increasing to 5 ~50W lights, 6 flashers, plus the instrument cluster. My alternator fried Christmas morning and I'm going to have to replace it. My options for a factory alternator are 33 amp or 55 amp.

The lights should draw 3.5 amps or less each... so 17.5 amps. 6 flashers (IE backup lamps) can't be more than an amp each... so another 6 amps. I also can't see the cluster drawing more than 2 amps for the guages. This would total 25.5 amps... probably less.

Anyone have opinions on if and why I should spend the extra money to upgrade to a 55 amp alternator? Currently I'm figuring on just replacing with the 33 amp, but it never hurts to get other opinions before committing. The price difference is about $50.

TIA

 

[tcartwri]

You're forgetting the current required to top up the battery after a start.

 

[dcyrilc]

You're forgetting the current required to top up the battery after a start.

True, I didn't list that, but again would it charge at more than 8+ amps??

 

[brin]

Cyril...I had an alternator go bad on my JD 3020 and I saved a bunch of money taking it to a local auto electric repair shop and having them rebuild it over the cost of a new one...I am sure you know that...I don't know aobut the amp part of your question but I wanted to be sure to remind you of the rebuild part...

 

[tcartwri]

True, I didn't list that, but again would it charge at more than 8+ amps??

It depends on the voltage drop on the battery. It could use the entire 30A if the battery is drawn down enough, or if the battery isn't in good shape.

 

[brandoro]

Cyril...I had an alternator go bad on my JD 3020 and I saved a bunch of money taking it to a local auto electric repair shop and having them rebuild it over the cost of a new one...I am sure you know that...I don't know aobut the amp part of your question but I wanted to be sure to remind you of the rebuild part...

I agree with this. I have never had an alternator fail that needed more than bearings and/or brushes. Both quite easy to change yourself or have a shop do for a reasonable price.
If a new alternator really is required then I would go with the bigger one if it is a straight forward swap and you don't need to modify brackets, wiring or anything else. Might be you will want to add more devices in the future and will have need of the extra output.

 

[dcyrilc]

I'm going to get a rebuild price to compare with. I had a hydraulic line blow off under the hood a couple of months ago and dumped around 7 gallons of hydro fluid on and into the alternator. The regulator is integral to the alternator and is what fried in the alternator. Complete meltdown.

As for the lighting, the most I can see runnig at one time would be 4 lights. The new configuration will have the factory work light on the rear, 2 flood work lights on the front canopy and 2 spot driving lights on the canopy. I'm going to use a switch on the headlight circuit which gives me either both floods or all four at once. I'm not likely to have the rear work light on if I'm using the driving lights. The factory light switch gives me the following options; off, flashers, headlights, headlights and flashers, headlights flashers and rear work light. Not neccessarily in that order.

At this time, I'm only mounting the front work lights. I'll add the driving lights later if I need them. I try not to have to run after dark if I can avoid it.

 

[mscheer772]

I upgraded my 4310 from 40 amp to 55 because of additional light , winch, accessory outlet, etc. If 40 amps will do you, I've got one for cheap.

 

[dcyrilc]

I upgraded my 4310 from 40 amp to 55 because of additional light , winch, accessory outlet, etc. If 40 amps will do you, I've got one for cheap.

It would do me fine. Now my only question is will it fit a 30 year old 2240 tractor? We might have to do some investigating to check.

 

[Soundguy]

as a rule of thumb.. I like a loade to be 80% of an alternators rated capacity for constant use. sound slike you are right there.

I'd see no problem going back stock 33 safely. on the other hand.. 50$ ain't much probably compaired tot he price of the alt.. and it WILL give you extra capacity.. and that almost never hurts.. as engine load is based on electrical load.. so a 55 vs 33 will not be seen any different to the engine unless you are using more than 33.. etc.

soundguy

I have an older JD2240 diesel tractor. Factory alternator was 33 amp. The factory setup had 3 ~50W lights, 2 flashers, and the guages in the instrument cluster. I'm going to be increasing to 5 ~50W lights, 6 flashers, plus the instrument cluster. My alternator fried Christmas morning and I'm going to have to replace it. My options for a factory alternator are 33 amp or 55 amp.

The lights should draw 3.5 amps or less each... so 17.5 amps. 6 flashers (IE backup lamps) can't be more than an amp each... so another 6 amps. I also can't see the cluster drawing more than 2 amps for the guages. This would total 25.5 amps... probably less.

Anyone have opinions on if and why I should spend the extra money to upgrade to a 55 amp alternator? Currently I'm figuring on just replacing with the 33 amp, but it never hurts to get other opinions before committing. The price difference is about $50.

TIA