Typical electrical load

[jalopi]

Hi Guys,

Wondering if anyone knows what the typical electrical load is on our cars i.e. what kind of charge the alternator puts out to keep things running. Did some research and found out that the stock M20 alt puts out about 90A max. When I was looking up how to wire up the alternator for my swap, I found out that since I bought a 2g alternator mine will only be putting out 75A max.

Anyone think this could be an issue? I don't have a modified stereo system, no A/C, ect. The only things I need electrically are:

*Radio (not necessary, yes, but I would really like to use it)
*Electric fan
*Current for spark
*Lights, gauges
*Fuel pump
*Power windows, although intermittently
*Blower for heat (winter use obviously)

The only variable here is the fan. Per the manufacturer it's supposed to pull roughly 10-12A. Aside from that, electrically, the car will be like any other stock e30. Input? Think I can get away with the 75A alternator?

[FLG]

As long as you have a good battery you won't have an issue.

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[jalopi]

False. If the alternator is putting out a max of 75A and your vehicle is using, lets say, 90A at full load, you're losing a constant 15A. New or good battery, it's not going to be good for very long in that kind of situation.

I don't think my car is going to pull that many amps though... newer cars pull 50 or so with the radio on, lights on, running and putting all four windows down at the same time. Hopefully it'll be OK.

[FLG]

False. If the alternator is putting out a max of 75A and your vehicle is using, lets say, 90A at full load, you're losing a constant 15A. New or good battery, it's not going to be good for very long in that kind of situation.

I don't think my car is going to pull that many amps though... newer cars pull 50 or so with the radio on, lights on, running and putting all four windows down at the same time. Hopefully it'll be OK.

Then whyd you ask the question?

All I was saying was assuming your battery isn't crap you'll be fine. If you had a battery that wasn't charging fully or discharging quickly it wouldn't matter what size alt you had.

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[jalopi]

Two reasons:

1. My battery is new. Granted, it does have a warranty, but I'd rather not have to deal with replacing it.

2. I don't know what the typical duty cycles are on alternators, but if you run any electrical/mechanical device near/at its maximum power output for too long, it will burn out or break. It's alot easier for me to sell a pretty-much-new alternator on craigslist than an alternator that's been burned up due to consistent overcharging.

[TobyB]

Stick an ammeter on it and find out.

If you idle in the winter with the lights, rear def, fan, etc all on high,
you might have a problem.

Otherwise, you won't.

t