9 replies to this topic

[adgjl7]

Hi has any one used the aeroflow alternators. Was looking at a 140 amp one , at the moment im good with the vn 85 amp alternator as i dont drive at night and in trffic it works well at lower rpms.At night i have have a problem where my blinkers started to slow and lights dimm. So now i was thinking of getting an electric A/c unit and air conning the car so it would be more fun in summer, but the extra load at lower rpms is probaly to much for my current alternator.the add on the aeroflow looks like it maybe a solution if they are any good. Cheers

[76lxhatch]

I'd be asking for a copy of the current vs rpm graph to see if its capable of the low rpm output, or you might be going backwards. An OEM-spec (e.g. as fitted to LS1) 140A unit will supply 80-90A at engine idle rpm but a lot of generic aftermarket ones are nowhere near that.

[hanra]

Careful you don’t catch glossy magazine syndrome.

[Rockoz]

With an 85 amp alternator, I would be looking for the problem why you seem to be losing power at night.

What have you got running that isnt standard?

85 amps is a lot of current to be pushing through the standard wiring for long periods. Especially if it isnt keeping the battery voltage up.

Would find out what isnt quite right with what you are running before even looking at an electric AC unit. They draw lots of power.

 

Ive mentioned it on other posts.

Jaycar sell a great multimeter that also has a DC current clamp meter integrated.

It will tell you exactly how much your alternator is pushing out, and with a bit of fiddling it can determine the current draw of individual parts of your electrical system.

90 bucks is cheap for a reasonable meter which once you have it you will find many uses for.

Big name brands cost 4 to 5 times more minimum.

I have used one a lot over the years.

 

https://www.jaycar.c...f6eca5a9f44349d

 

Trying to chase down electrical problems without a meter is like trying to move a boat against the tide without some sort of propulsion.

 

Cheers

 

Rob

[adgjl7]

will have a look and check things out abit more. I have two au fans, not sure what they pull and 100w low 150 high beam h4 lamps (i know but the car is so low no one seems to notice with all these fourbys on the road now i never get flashed and their are heaps of roos hate driving at night) plus a stereo amp and ignition system but not to sure what it all draws. Will look at an amp meter and check it out. Thanks. PS is there a post on how to do the LS1-140A unit mounting wiring and pulley etc. thanks everyone for your replies

[76lxhatch]

There's not much to it, wiring is the same as VN and pulleys interchange. Bolts into the standard bracket with a spacer and will need a slightly different adjuster bracket, I made a small turnbuckle which you can kind of see here:

http://www.gmh-toran...16#entry1036183

 

If your current alternator has seen some work (as a lot of VN parts have) you may find the VN 85A unit is perfectly adequate, you just want one that isn't worn out.

[Rockoz]

7 amps each rough on low beam.

10 amps roughly each on high beam.

 

Lets say 30 amps roughly for lighting.

20 amps for ignition and stereo roughly

30 amps should go close for the fans, but they really should only be operating at low speed anyway.

An 85 amp alternator should be keeping up with what you already have.

I would think perhaps you have a blown diode in the alternator reducing its output.

 

But if you want electric air, then you will definitely need to go to a larger output alternator to keep up with everything.

Older alternators were rated at what they could give out all day. Newer ones probably not.

 

Alternators will give their rated output pretty much all the time over a low minimum RPM.

They arent like generators which had to be revved more to get more out of them.

 

What may confuse some about modern alternators, is that in modern cars they are controlled by the computer instead of the demand placed on them.

The computer will reduce the output so that the alternator doesnt load up the engine immediately after starting.

Starting the car is a big drain on the battery and spreading the recharge over a longer period has benefits on modern engines according to the makers.

It keeps available engine power higher initially, which improves driveability and keeps resultant emissions lower.

All about the numbers. Not cheating quite as much as VW did, but cheating a little anyway.

 

The clamp meter from Jaycar is very simple to use and will easily find your current (pun intended) problem.

It will show you how much your alternator is putting out, and how much various things are pulling from the system.

 

I like your lighting choice too.

I used to run 90/130W lamps for hi/lo, 150W aircraft landing lights for 4 light combos, or 150W large driving lights as a rule.

Country roads where I lived and I liked to be able to see well at night.

 

Cheers

 

Rob

[RallyRed]

All good info Rob.   A clamp/tong meter is a real handy tool for all sorts of applications. 

i keep a couple at home, one in the track day box, and one in the caravan.

Several times now it has been pretty easy to sort out a caravan/battery/solar type issue, that someone has been guessing at for months.

[adgjl7]

Hi thanks every one for your reply's a lot of info to take in an i think that maybe you are all right in saying that my vn alternator is on its way out,it was second hand when i got it many years ago. 76lxhatch don't suppose you have a model number or year for your alternator. also do i need a different plug to wire it up.May as well try to get one if im up for a new alternator anyway Cheers

[76lxhatch]

Alternators will give their rated output pretty much all the time over a low minimum RPM.

Yes but unfortunately its common for that minimum RPM to be somewhere around 1500-1600 engine RPM depending on pulley ratios, so at idle or low RPM cruise you can still be significantly short of the rated output. Possibly a side effect of the fact they don't want them spinning too fast at the other end of the scale, they ask questions about how many revs if you ever make a warranty claim.

Mine is a factory Holden LS1 unit, just make sure you get the last of the standard ones not computer-controlled as mentioned above. The plug is different but still only two pins, you can use mini spade connectors if need be.

At the end of the day all the advice to calculate and/or measure your requirements is the correct answer, then get something that is rated as capable of supplying it at the required RPM.