I will begin my review by stating: I am your average Joe who likes to read automotive manuals, BMW blogs and watch BMW X5 do-it-yourself YouTube channels. I do 95% of the work on my 2003 BMW X5 4.4I. First and foremost I attest: I have no relationship to anyone at POWER BASTERS. I am not receiving any royalties, favors or free equipment from this company. I don't even know where they are located. I will attempt to relay to you my pain and the leap-of-faith I took in buying a high performance alternator from POWER BASTERS.

Anyone who owns a late model BMW X5 4.4I; in particular the do-it-yourself-er who understands the work the time involved in replacing a part below the the air filter on these X5's. For those relying on mechanics-the expense is mind-blowing. There are always issues like removing other parts directly blocking the part you want to replace. Then there is the need to purchase a variety of specific tool and/or a particular OBD2 scanner. I realized I couldn't trust big chain auto-parts store for parts without first doing the research to verify the exact part. Their data bases regarding BMW X5 part are for the most part lacking in relevant information. Like any other merchant. They just want to sell you a part and off you go. If its the wrong or it fails bring it back-easy for them to say!

AT ISSUE: The 160 amp water-cooled alternator in my 2003 BMW X5 has been replaced 5 times FROM 2012 TO 2020. When auto-parts store alternators began to fail me. I went to a machine shops specializing in rebuild alternators and starters. The re-builds after a longer interval failed as well. I had the electrical system checked twice-their diagnosis good battery, good wiring system but it had a bad alternator-tell me something I don't know already!

THE FIRST SIGN THE ALTERNATOR WAS GOING BAD WAS A PARASITIC LEAK I FOUND BY LUCK. I did numerous FLUKE METER parasitic leak testing-I couldn't find the power draw. The new battery was slowly losing its charge while parked. WHEN THE ENGINE WAS ON THE FLUKE METER INDICATED THE ALTERNATOR WAS CHARGING THE BATTERY. HOWEVER THE BATTERY GAUGE LIGHT OFTEN TURNED ON. Whenever I charged or changed the battery the battery gauge light would turn off. Only to turn on again later on. This was my 4th alternator replacement. I was wasted I didn't want to work on the X5 anymore. I got so fed up I put the X5 into storage for two years.

Seven months ago I was at a bar on Staten Island NY where I ran into the tech who rebuilt my alternator twice. He remembered me and after a few beers. I told him my water-cooled alternator was going bad again. He said "yeah I figured that much." I asked him why. These are his exact words: "I have been rebuilding starters and alternators for 30 years and ever since CHINA began mass producing ALTERNATOR DIODES ALTERNATORS HAVE BEEN FAILING. HOWEVER AIR-COOLED ALTERNATOR-NOT SO MUCH. They all had one thing in common he explained-cheap Chinese made diodes inside the alternator that can't withstand the heat so they fail."

In laymen terms he explained that cheap diode failure rate is highest in water-cooled alternators due to heat in certain LATE MODEL BMW'S and LAND ROVERS. The fried diodes causes the battery current to start leaking power backwards. THUS CREATING A PARASITIC LEAK. When most or all of the diodes are fried the alternator no longer charges the battery. HE INSTRUCTED ME TO DO A SIMPLE TEST. (1) DISCONNECT THE NEGATIVE BATTERY POST. (2) DISCONNECT THE POSITIVE CONNECTOR FROM THE ALTERNATOR-TAPE UP THE POSITIVE CONNECTOR REALLY GOOD. THE FINAL STEP WOULD BE TO RECONNECT THE NEGATIVE POST TO THE BATTERY. Two days later I used my fluke to check the battery and the power loss was negligible and the battery held its charge. AS HE PREDICTED!

For whatever the reason BMW engineers believed it would be better to place the alternator inside the engine to be cooled down by the circulating coolant from the radiator. I had already replaced the radiator and the water pump with expensive high-performance parts. The elderly tech explained the following:

THE PROBLEM: Aftermarket water cooled alternators you buy new or refurbished at your neighborhood auto-parts stores start to fail slowly but surely-DUE TO HEAT. Re-built water-cooled alternators are a little better-maybe 2 year later they go bad too. A new water-cooled alternator from the dealer will definitely last longer. However the new original equipment 160 amp alternator can cost between $1000-$1200. For me its the work; the constant struggle replacing these hard to get install heavy alternators and taking everything apart again and again-it is exhausting.

My new friend gave me some advice.
He said I should buy a higher performance water-cooled alternator in the 240 to 300 amp range-brand new no refurbished or rebuilt. Since the these high performance alternators have regulators. I shouldn't concern myself with the extra power destroying my wiring system-as long as the problem isn't the wiring. The alternator will run between $400-$700. He recommended 5 companies and after an doing my research. I decided to take a leap of faith based on his recommendations. I chose POWER BASTERS because the reviews were stellar-the best.

I purchased a brand new 240 amp water-cooled alternator in May 2020 from POWER BASTERS. The alternator cost me $544 tax included. I immediately noticed the difference. My 2003 BMW X5 Felt peppy. The battery warning light shut off. The alternator endured the summer heat with the air conditioning and the electric fan constantly running. Almost 7 months later it is still working fantastic. Yes it did cost me $544 but the price was way better than what the dealer would of charged me for 160 amps. I am happy having higher amps-240 amps. I am very happy with my purchase. So happy that almost 7 months later I decided to share my experience with POWER BASTERS and anyone who may have the same X5 problem. I apologize to POWER BASTERS and the reader for this long and drawn out review. However if this review helps even one tired out X5 owning soul I believe it was worth it. KEEP UP THE GOOD WORK POWER BASTERS

You were not kidding when you say these are high output. Wow. So much better than I was expecting. 2 enthusiastic thumbs up!