C Series 6CTA – M3 Delco 28si alternator upgrade

[Paul Hampton]

Hi Guys

I have a 2000 model 6CTA M3, at the moment it has a Delco 22si alternator, J hinge, 12v, with sense wire. I think its 130amp or 145amp

I am looking at installing a 28si, preferably 180amp, 8600223, or 160amp 8600312, to give me more charge at idle.

I do a lot of drifting, engine idle or off and when wrecking idle & low rpm,s. on a night especially I have a a large load drawing from the plotters, radar, lights, heater etc.

I have 2 x FLA Trojan 6v, in series giving me 12v @ 415amp on the house batteries, 2 x Banner AGM for starting, hook up through blue seas isolating switches and a DVSR.

Has anyone upgraded to any of the models mentioned, have there been any problems, any detrimental effects on the serp belt/tensioner, etc. is it worth the cost ?

I think these are plug and play from what I can see.

Is it difficult to change the pulley from old alternator to new ? 

 

any advise is gratefully welcomed

Thanks in advance

Paul

 

 

Topic

[Rob Schepis]

Paul, are those two Trojans golf cart batteries or some industrial line batteries?  AH seems too high for golf cart. I have a series/parallel golf cart house bank David refers of.    

[David Marchand]

Paul:

I can’t help you with your 24-28si alternator upgrade, but I can suggest a few things that might help, one of which might suggest a different alternator.

First if you have two 6V golf cart batteries in series, you only have about 225 AH of capacity at 12V. When you hook them in series you double the voltage but not the current.

So if you were to add another pair of 6V batteries with the two new ones wired in series but also wired in parallel with your existing batteries, that will give you about 450 AH of capacity. That might get you through the night without doing anything.

If that doesn’t help, consider replacing your alternator with a large frame, high output alternator.

An internally regulated alternator like the 3 wire ones is designed to supply a fixed voltage in the neighborhood of 13.5-14.0 volts. When you are running a lot of loads while drifting at idle, you pull down the batteries voltage and that tells the alternator to put out more current. But that current is limited by the windings of the alternator and  at idle that might only be 20-30 amps. A higher amperage alternator like the 28si probably won’t put out that much more current at idle.

To put out more idle current you need a large frame alternator with heavier windings, better cooling and heavier diodes. These are physically larger than your current alternator and often would have to be added to the other side of the engine with custom designed mounting hardware and belts. But one would double or triple the idle charging current relative to your current alternator or even the 28si.

So, I would double up on the batteries first. If that doesn’t work, then consider a high output, large frame alternator.

David

 

 

[Tony Athens]

A Delco 22SI alternator is a fine unit, but it’s base design is maybe 30++ years ago.. Things have changed.. Both  the 24SI Delco and the 28 SI Delco will FIT where your unit is and both could could provide you with 50 – 100% + more charging at low speeds compared to what to have now….

But before I could really tell you what would be your best option may be, I need to know more as to your overall wiring of your DC POWER DISTRIBUTION  SYSTEM… Can your draw me a diagram and tell me about it?..

Just so you know, I speak this language very well.. Because you mentioned “3-wire”, that can add a twist to the adaptation or any upgrade.. –That’s why need to “see” how your are wired now..

 

Tony

 

 

[Philip]

24SI

I just did the 24SI upgrade and couldn’t be happier.

The install was super easy, just need to deal with the increased stud size of the 24SI.

 

 

[Rob Schepis]

Alt Upgrade Options

Have you considered the 24si?  See attached.

[Author]

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