Alternator In Place Of AC Compressor

[dasnoboarder]

Hey guys,

Have my alternator out at the moment, taking it to sparky tomorrow to get it charging again as I need to be driving the car on Wednesday.
As I've ripped out my aircon pipes, I'd like to put an alternator in the compressor's place at a later date.
I'd like to leave the current alternator in place with the vacuum pump on the back and no electrical wires connected.
Is there anything I should do for this? Like take any internals out?

Also wondering if anyone has any ideas for which alternator to use up top.
To make wiring easy it must be 12V, internally regulated. My current one is the 3 wire system.
I'd like a 80amp or bigger unit, and can't be massive so it fits in fornt of turbo.

Only option I've seen so far is the "GM 10si style 94 Amp Chrome" unit on TradeMe for around $200,

Cheers,
Andy.

[mulover]

You can mount the alternator up there with the vacume pump still mounted on it, you just have to extend all the pipes. If you do it the way you are planning, take out all the brushes and anything else that touches the shaft except for the bearings and seal of course.
I know the 80 amp alternator was going to be a squeeze with the vacume pump on it, but if your dropping the vacume pump then you should be able to fit a pretty big one up there. try to find one that works around the air con units mounts, as this will save you alot of time.

[dasnoboarder]

Thanks for the info!

I hadn't thought putting the alt with vac pump up on top.
You think the 80amp unit from the 3.1L and or the 120amp unit from the Isuzu trucks would fit up there with vac pump attached?
I think I want more than the standard 55amps for my dual battery setup.

[mulover]

If you still have the standard air intake pipe to the turbo, then I think so, I have a custom intake that comes straight out from the turbo, doesn't have that sharp 90 degree bend in it.
55 amp is ok for a "normal" turck, no winch or big driving lights, but when you start running a winch, driving lights, power inverter, etc, etc, you definatley need a bigger one.
I have a 80 amp Hitachi unit (part number lr180-501c 897134-8660) and its handled all of the above. the old 55 amp used to drop down to 12 volts when i turned the spotties on, but not the 80 amp.

Dont know the piping set-up on a 3.1, but i'm sure it would be possible.

[dasnoboarder]

Been to Auto Electrical Spares Ltd in Henderson today.
Searching for an alternator to put up top as my standard one has fried again.

They've recommended a BXU12121 Unipoint unit (Bosch copy unit that fits Bosch parts).

It's brand new, and the same price as a second-hand MU one from the wrecker.

On the Unipoint website it's described as a 14V, 120A unit.

However on the Bosch catalogue the BXU12121 is a 14V, 2-120A (depends on revs), and is described as being for Agricultural constant speed engines.

Any thoughts/opinions?

[geeves]

probably ok. Cant see why an alternator would be designed for constant speed

[pig75]

I put one of those 120A bosch alternator's on my gemini was never happy with the voltage 13.8v max i needed 14.4v and above

[dasnoboarder]

Thanks for replies.

Can anyone help me out with approximate current draws?

I need to know the following amounts:

3x electric radiator fans (one for intercooler)

3x spotlights (hella 2000 series)

normal operation, headlights, wipers, interior heater

winching - very approximate, say for a 9000lb winch?

Didn't know charging a battery could be so difficult!
Stupid mud! Hehe.

[pig75]

I jus did a test ignition on hi beam with 2x55w spot lights and 2 10” fans running = 40A

[dasnoboarder]

Thanks Pig, very helpful.
Hopefully I'll have a suitable alternator being couriered tomorrow!

[geeves]

9000 pound winch at full load is close to 400 amps. Luckily you rarely run it for long. Most winches state in there manual that after 1 minuite running at full load you should let it cool for 10. Ive run mine 5 minutes straight and the paint on the motor changed colour. (dont you hate it when a nissan gets stuck)

[mulover]

You need a big alternator and a very big battery to hold enough current to operate the winch under full load.

[dasnoboarder]

I've seen a few people saying not to go for the Universal BXU12121 unit, and one or two saying they've had good experience.

I was a bit unsure of it's low down charge capacity (engine idle), and Pig's warning, so I gave them all my requirements and see what else they came up with.

They've recommended a:
A13705
1996 Nissan Pathfinder/Mistral TD27
100amp
Internally Regulated

Which they say has low speed charge capacity.

BUT, it's $526 (incl GST)! Rebuilt unit.

Anyone have any thoughts/opinions on this? Are they durable, easy to replace parts on? Too much to pay?

Andy.

[mulover]

IF it comes off a nissan...... , have no idea, only had a hitachi unit, if it has good low down charge capacity which is what you need for winching, and you can't find anything else, then it could be worth a look.
Have a look on trademe, I picked up my one brand new for $300, normal retail $800??, right place right time i guess.

[mulover]

IF it comes off a nissan...... , have no idea, only had a hitachi unit, if it has good low down charge capacity which is what you need for winching, and you can't find anything else, then it could be worth a look.
Have a look on trademe, I picked up my one brand new for $300, normal retail $800??, right place right time i guess.

[dasnoboarder]

Haha thanks for advice. I couldn't see anything on TradeMe, so I've bit the bullit.

The unit is sitting on the floor. Truck's going in tomorrow morning to get a bracket made to fit this monster where A/C pump is.

They said that when they rebuild these units they get up to 130amps on test bench. Gonna' need a big wire!

[dasnoboarder]

All fitted and charging again!

For anyone who's interested, here's a photo of the alternator and it's new bracket made up by MotorTech4x4.



They had to modify the original alternator bracket below to get it to fit.

Andy.

[geeves]

looks nice. Does that have a vac pump or are you still useing the old one on the old alternator

[dasnoboarder]

Old broken alternator is still down the bottom, all wires disconnected, only running the vacuum pump.

As my new alternator is right up against the turbo intake pipe, I don't think you could put an alternator with a vacuum pump up top without modifying the turbo manifold or belts setup.

My setup does waste a little space, but I need brakes and I think having the alternator up high is worth it .

Andy.

[mulover]

That was the main reason why I didn't move my alternator up, there is just not enough room to have a big alternator and vacume pump up the top in front of the turbo.