High Output Alternator options

And also don't forget that the pulley size determines how fast it spins, the larger the pulley the slower it spins. Mainly an issue at idle, some alternators will not be spinning fast enough to charge much if at all if the pulley is too big.

The most important thing that differentiates alternators is their idle output. All well and good having a high current alternator, but if it's not charging at idle - and you are winching you are screwed. Some high output alternators have very poor low speed currents.. (Or maybe it was just the ones I happened to buy in the past to upgrade a 65A alternator to 120A. Those were a major dissapointment - damned noisey and worse than the factory 65A at idle)

Have a look at this PDF for some current curves vs RPM - [ame]http://www.dieselusa.com/productinfo/Bosch%20longhaul%20alternators%20160a%20to%20200a. pdf[/ame]

Anyone know what the 100amp disco one does at idle? Pointless me putting in something that only puts out decent power at high revs

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Originally Posted by thrower78

Anyone know what the 100amp disco one does at idle? Pointless me putting in something that only puts out decent power at high revs

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RE: pulley size, you can choose to run with the disco pulley which comes with the alternator which is what I did or put your defender pulley onto the disco alternator

I run 2x100A disco altenators on my 300TDI.
Not because I feel I need a max of 200A but for multiple redundancy.
The altenator in the standard position charges the start battery, the second altenator sits up next to the A/C pump (coverted to an air pump...) on a custom bracket and feeds my auxilary battery on a completely isolated system (except they have a common 0V)
If one of my altenators fails, I can change the system to a very conventional dual battery system with a 13mm spanner in about 5 min.
Of course I also have a large isolator switch between the batteries so the two systems can be joined for jump starting a flat starter battery.
The Auxilary battery also charges from 2x 100W solar panels hard mounted on the roof bars......

Early and late 300TDI defenders have different size pulleys (and a different length serpentine belt) - I think Disco 100A altenators have the same pulley as late 300TDI Defender altenators...?

Scott

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Originally Posted by thrower78

Anyone know what the 100amp disco one does at idle? Pointless me putting in something that only puts out decent power at high revs

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God, don't sweat it, it'll be fine, these aren't race engines.

The Deefer had a pulley size change in about '96 from large to small pulley too, just like the Disco.
The new Disco one I bought had the 'wrong' pulley for my 11/98 version so I just swapped the pulleys as;
a)I didn't have a long belt
b)I can see an advantage in a higher speed alternator for off road winching stuff too.

I too have the Disco 100A alternator. My 130 is '95 so I used the belt and the smaller pulley that came with the alt. Couldn't see the sense in putting in a bigger alternator and running it slower than necessary.

The D1 100amp alternator isn't just higher output, it's better quality with a sealed rear bearing.

I've got one of these and my next consideration would be a regulator from Sterling Power Products Australia

They do a unit for $200 that acts as regulator and a 12V to 12V smart charger and charges batteries faster and to full capacity. I recently had what I thought was a dodgy reg on my alternator and inquired about bypassing the internal reg and using one of these - that would work fine, would require a solder though. In the end I had a loose wire, but this unit would give me some built in redundancy and better battery recovery after camping and running fridge and lights.

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Originally Posted by scottvdw

I run 2x100A disco altenators on my 300TDI.
Not because I feel I need a max of 200A but for multiple redundancy.
The altenator in the standard position charges the start battery, the second altenator sits up next to the A/C pump (coverted to an air pump...) on a custom bracket and feeds my auxilary battery on a completely isolated system (except they have a common 0V)
If one of my altenators fails, I can change the system to a very conventional dual battery system with a 13mm spanner in about 5 min.
Of course I also have a large isolator switch between the batteries so the two systems can be joined for jump starting a flat starter battery.
The Auxilary battery also charges from 2x 100W solar panels hard mounted on the roof bars......

Early and late 300TDI defenders have different size pulleys (and a different length serpentine belt) - I think Disco 100A altenators have the same pulley as late 300TDI Defender altenators...?

Scott

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I'd guess those alternators are costing you 10 or more HP at the wheels. :p. Pat

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Originally Posted by PAT303

I'd guess those alternators are costing you 10 or more HP at the wheels. :p. Pat

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Why? I've spun up alternators with a power drill and they only draw power when they're doing some actual charging. The rest of the time they just freewheel.

Disco alternator was an option until my local independent Landie place wanted 500 bucks for one. What a joke. Have to find a non genuine one or something else