M915A1 Alternator - Transformer Meltdown

[martinwcox]

Well this is the second one that failed over the last 12 months.

So, replacing with a bigger 12V 160A rather than the 100A alternator and ditching the transformer rectifier fiasco with a 12v to 24v converter.

 

[agazza2]

Keep us informed on the manufacturers & part numbers of the parts you use. I may want to do the same thing to my M915A1 before I have a failure.

 

[R Racing]

I did mine when I added my ac. my system charges much better. It used to idle at about 11volts. But now it now it's closer to 13v at idle. With everything on.

 

[CBR Metalworks]

I put a 200 amp dual voltage alternator off a HMMWV on mine. VERY tight fit, but seems to work well.

 

[Wildchild467]

There are new alternators out there that put out 130 amps at idle and 200 amps at speed. Very, very impressive.

 

[martinwcox]

Well now the snow is finally melting I will be finishing off my 12v to 24V installation.

I have decided to keep the 12V Alternator and add one of these to replace the transformer \ rectifier.

http://www.ase-supply.com/Sure_Power_12040E00_Battery_Equalizer_p/sp-12040e10.htm

Also found these to add the required protection https://www.bluesea.com/products/category/Fuse_Blocks and https://www.bluesea.com/products/category/Marine_Rated_Battery_Fuses

If you search for MRBF (Marine Rated Battery Fuses) your will find them on Amazon etc.

Will take some pictures of the installation one completed.

Martin.

 

[acme66]

Can I ask what sort of load you are drawing or do you think it is failing under no load?

Ken

 

[martinwcox]

Can I ask what sort of load you are drawing or do you think it is failing under no load?

Ken

The T\R is used to charge the cranking batteries, http://www.prestolite.com/literature/tech/alts/partslist/trans_rect_parts_list.pdf.

I have no other added 24V loads, the M915 and family are all 12V other than the starter. I have had 2 T\R's fail. I suspect that as the only over current protection is a thermal resetting fuse, the T\R is rated at 15A, if the batteries go low voltage and start drawing a lot of current the thermal fuse cycles and eventually the transformer gets hot enough to burn-up. I did try a 12V to 24V unit rated at 25A and in the warm weather all was good. As soon as winter set in and the temperatures dropped so did battery voltage and therefore current went up and the 25A fuse kept blowing. I hope that the 40A that is going in will be enough, to be fair its all so designed for this application.

 

[R Racing]

The m915-m920 are a dual voltage truck . With the majority of the load being 12v. The alternator is only rated for 18 amps of 24v.

 

[painter paul]

Is there any new info on replacement parts or replacement alternators available. I took mine to my rebuilder and he says the T/R unit is $700.00 yikes!

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[camoyj7]

Is there any new info on replacement parts or replacement alternators available. I took mine to my rebuilder and he says the T/R unit is $700.00 yikes!

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Talk to Alan (postman515) He has the new set up.
http://www.steelsoldiers.com/showth...Series-Alternators-With-LED-Voltage-Regulator

 

[deuceman51]

I have a few gov rebuilt units for $400 if anyone is interested. I think I also have a spare regulator assy around also. PM me if you would like a shipping estimate.

 

[74M35A2]

I don't think we are allowed to use threads as classifieds (posting prices), but I do offer the 12v alternator as WildChild indicated. It is brand new not a reman, rated at 200a, spits out 130a at idle, and is brushless. Rated for 1 million miles of usage. I will warranty it for 3 years. It is the same price as the post above this. . Is 4 bolt pad mount, so you would need to fab a simple bracket or have hinge type ears welded onto this case. Both are easy ways to solve that problem.

 

[painter paul]

So the starter and some wiring needs to be changed???

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