Drawbacks to rewinding alternator for higher output? (1 Viewer)

[toadshade]

I am in the market for a new alternator. Even though I really don’t need more amperage I was thinking of having my current alternator rewound. Since I was going to go that route, I could also get it wound for higher output. Are there drawbacks to making the alternator put out more than it was originally designed to do? Are there inherent wires, contacts etc that are designed only for the loads for what it was originally built to handle? I have no problem rewinding to original specs but if it doesn’t matter then I would like to get as much out of it as I can.

 

[LandLocked93]

What is the regulators' factory rating for current?
Is a custom wind really so economically advantageous over just swapping in another higher-amp factory alt?

 

[toadshade]

My alternator is the stock 60 amp in my HDJ80. And I am debating that. There aren't many factory alternators out there for my truck with exception to an early Tercel and some other Land Cruisers (As far as I can tell so far). That is what got me thinking about a new wind. My alternator is actually working fine but I traced a possible small electrical issue back to it so I just thought it was time since it is also the last "consumable" on my truck that is original. I don't really need more amperage. My load is not something that needs a larger alternator. More than anything I wanted to see why not? I wanted to know if winding for higher current was like adding a turbo to a car. It will work, but blow a head gasket or something else down the line that ultimately wasn't made for the added pressure. And having a stock alternator rewound to a higher current will be a lot cheaper than the high amp aftermarket alternators (that I really don't need). And a lot cheaper than getting a new OEM Denso replacement.

 

[LandLocked93]

I see. Well it would make sense that there has to be a limit to how much the 60A regulator can handle. It may even have clipping capabilities to limit the flow regardless what the wind produces. I prob wouldn't go much beyond ~25% of original capacity with a custom wind. But have nothing to point to in terms of a hard stop. It's just a hunch that much headroom was built in.

 

[ducktapeguy]

Aside from any component limits and cooling issues, I'd also make sure to look at the alternator output curves to be sure that the added output is actually in a usable RPM range. Just like an engine, some of the high power alternators only reach that peak power at high RPM's. If you need power at idle, for something like winching or running other items at camp, then having a high peak output isn't much of a benefit and could be a disadvantage. Personally I would prefer an alternator that outputs the most current at idle, because that's when I would probably need it the most.

This is just a random alternator output chart I found on the web that illustrates the point, I don't know if you'd be able to find something similar for your particular alternator. If your engine idles around 600-700 RPM and you have a 2:1 crank/alternator pully ratio, then at idle a 100amp alternator would be spinning around 1200-1400 rpm and putting out ~75A at idle, while a 145A alternator would outputting 0 current. It's not until after 2500 rpm (alternator RPM) that you'd begin to see an advantage to the higher output alternator.

 

[toadshade]

Thanks for the info. I think no matter what size alternator I get I am sure it will be fine doe my rather small loads. The original alternator would work fine at 60 amps. But if I am going to have it rewound. It will cost the same amount for me to wind it at the original 60 or go up a certain percentage. I haven’t found out what that is but to be honest it really isn’t important. I have been wondering if there are any other parts in the alternator that would be placed under increased stress as a result of a higher current wind. If it doesn’t affect any part of the alternator then I would just give it as much of a boost as possible just for possible future modifications.

 

[cruiserpilot]

So what year is your 1HDT? 12V?

High Output Alternator 12V 150A E-Coated Denso Type Suits Toyota LandcruiserDefault Title

Vehicle Application MAKE MODEL ENGINE FUEL TYPE LITRES YEAR Toyota Landcruiser 100 Series HDJ100 1HD-FT Diesel 4.2 2002-04 Toyota Landcruiser 100 Series HZJ105R 1HZ Diesel 4.2 1998-00 Toyota Landcruiser 105 Series HZJ105 1HZ Diesel 4.2 2002-04 Toyota Landcruiser 70, 75 Series HZJ70, HZJ75 1HZ...

www.nationwideautoparts.com.au

 

[toadshade]

‘92 and standard 12v with a dual battery 24v start. But that alternator would work fine. I ended up rebuilding mine although the regulator was downright impossible to find so I had to reuse it. Luckily it was in really good shape so I just got new brushes. I am sure it will give me a good bit of mileage as is till I need to figure out a new solution.