Extending the Life of My Car's Alternator.





Introduction: Extending the Life of My Car's Alternator.

About: As of April 2017 I have decided to no longer post on instructables. The fact that several of my published works have been removed without my consent is inexcusable. Also the insult of an author having no co...

I once had my 1999 civic alternator fail on me while driving on the highway. Symptoms?
Radio malfunctioning.
Steering wheel becoming very stiff.
Fuel gauge showing a fast decline.
Battery voltage to 9volt? What the hell! I Hope paddington bear was not giving my car a hard stare.

I had my alternator replaced with a used unit but how to maximize the life of this one?

A lower amp load means the alternator has to work less hard and this will help maximize the service life (new or used). How is that even possible? Lower amps means lower thermal stress on the winding insulation (believe it! Heat kills insulation integrity) and rectifiers. Also a lower workload can translate to longer bearing and belt life (provide the belt is properly installed).

Read on for tips to do this.

Step 1: Led Headlights.

Gas bulb headlamps are power hogs. Switching to leds will help decrease the load. For me I went from 55watt oem to 20watt led. I made sure to adjust the headlamps to put the light on the road and not drivers' eyes.

Step 2: Led Signaling and Indicator Lighting.

I used full leds for my external car indicating lights. I had to change the turn signal relay to the led compatible type to prevent hyper flashing.

Also for the dashboard indicators, again led type.

The dome light, yes you guessed it. Led.

Step 3: Using Lifepo4 Battery for Engine Starting.

Lifepo4 is a smaller battery but cranks my engine better than any lead acid ever did. It's been in service for 19 months and has not let me down. I installed Mine in the glove box. Check out my Instructable on it.

This battery charges much faster than lead acid and needs far less current to be recharged.

A special note on conversion to Lifepo4. Since the amp hour rating a quite small, the one I have is actually 6 amp hour, using electrical loads without the engine running is a bad idea. If you love to pull up at the beach, turn off the engine and play loud music then Lifepo4 may not be for you (without incurring high cost for multiple batteries). I had inserted a relay that turns off all lights when the engine is off. I have no use of my electrical loads (except the hazard lights) when my engine is off. Your application may be different.

Step 4: Enjoy Longer Service Life on the Alternator.

Failing alternators are no fun. It's not safe, will leave you stranded and costs money. Reducing the electrical load equals a happier alternator!



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    Well for rxcample H7 light in led gives rather week ligh.. but placeing 2 of them in one place may do the work... second thing is homologation. Dunno how it works in US but here in europe you can have a HUGE 'mandate penalty' for it.

    1 reply

    Yes I think the H7 light are weak but the newer ones have a higher lumen output. I'm not from the US but I'm just into this because I love LEDs and energy efficiency is my way of life.

    Nice info.. If you can post a pic of that turn signal indicator relay that you replaced it would be helpful.. thanks

    2 replies

    It looks identical to the stock relay. On Amazon I searched for led turn signal relay. Just make sure it's the right type for your car since they come in several pinouts and shapes.

    I've been thinking about replacing the incandescent lights on my motorcycle with LEDs to lighten the load on it's puny 60 watt alternator. This will give me the motivation I need to get my butt in gear and do it.

    1 reply

    I had measured the output of my alternator while having engine running, radio on and high beams burning. Wattage was approximately 118watts. Every amount of reduction will help.

    I'm curious as to what the fault was with the old alternator, worn bearings, worn brushes, blown diode in the rectifier pack? My experience with failed alternator bearings has always been that the seals have failed letting out the small amount of lubricant and a dry bearing has caused the heat not the electrical load .

    1 reply

    Beats me. Yes failed bearings are yet another mode of failure however the best that can be done is to properly tension the belt at installation. The electrical part is something that can be managed after.

    Im sorry to be the typical naysayer, but the alternator is going to last the same amount of time regardless of how much current is being drawn. And your ideas only save less than 100 watts and the alternate battery onky protects the battery, not the alternator.

    6 replies

    Less current draw improves the service life of any alternator, small as vehicle ones or up the the 10megawatt unit I had commissioned several years ago. Also no alternator protects any battery. It has a large part to the with the insulation of the windings. It's an power engineering issue that is only understood by power engineers. Feel free to load up your alternator. Go strong.

    Do you have any proof of your claims? Citations? And someone who is not a "power engineer" could easily understand such a concept...

    Gosh I was talking about how I earn part of my Living. Insulation on generators and motors fall onto several classes. Certain classes have higher thermal ratings. Also contamination due to dirt, water ingress, oil, airborne pollutants etc will decrease the service life of any insulation. Insulation fails and of course the alternator fails. Mind you this is only one mode of failure but it's a common one. People like myself having the training and experience to design, install, commission and maintain such equipment (although much bigger units). Reducing the load on your alternator whilst keeping it clean will go a long way to its service life. Online sources I can't recommend since there are a couple paid standards and guidelines for folks in this field.

    in his case it wouldn't be much of a noticeable difference in how long the alternator lasts because its not much savings in electricity but he's heading in the right direction. with that being said reducing the load on the alternator will help it to last longer also reducing the electrical load that you're asking from the alternator helps to save fuel

    I agree with very modest fuel savings when one starts to really cut down on amperage due to less drag being produced, however, the difference in life would be more likely affected by manufacturing than anything else. The alternator in my Mazda is the original with 154k miles on it and I have a 500 watt subwoofer in addition to an upgraded head unit, whereas my wife's alternator went out at 130k in her mustang with everything stock. Both alternators are made by Ford.

    Very well said. You are a knowledgeable person.

    I have a car that has some serious electrical issues (1988 mazda rx7) I've replaced both the battery and the alternator. However whenever I drive it any additional electrical use is a strain and the volt meter reads lower. Do you think full led conversion would eliminate this problem? Any other sugestions?

    1 reply

    Lower as in when you have your sound system on full with subwoofers gulping juice? Lol. Do you have fog lights, hid kit, incandescent lighting on the rear? Your alternator is in good condition (bulk charge around 14.4v and float around 13.5v)? Also if any non oem wiring was performed then if the size is not large enough then depending where you measure that voltage, it's gonna come up lower than expected. There are several factors but once your battery properly charges and your devices work then don't worry.

    Do you think this battery would be enough for an on/off road Jeep Wrangler YJ? How many cranks do you get before it starts to fail? Reason I ask is I've had to use my battery and starter to drive me out of rough spots when my fuel pump failed.

    1 reply

    I don't know much about the life pro batteries, but if you were to do that, and already having experience "drive by starter", I would recommend duals if you don't already have that set up. I have built several Jeeps old and new for off road. having a geared starter ( recommend Mean Green) also helps.