Alternator delete with regen braking modification for better MPG
So, now that I am commuting again, I am motivated to do some more fun stuff with the Mirage. The next mod I am currently planning an alternator delete.
What is an alternator delete? Well, in this case it simply means I am going to disable (not actually delete) my alternator electrically. This will stop it from putting a load on the engine. The effect is increases fuel economy (a very impressive 5-10% on some cars) and also increases available power to the wheels. However, the battery still needs to be charged, so you do that with a battery charger. Just plug it in when you get home, and its ready when you want to leave.
I already started preparing for this mod when I put a deep cycle battery in the Mirage when I accidentally killed the original battery (oops). You need a deep cycle battery so you can run the car off the battery. A normal OEM starting type battery does not have the necessary capacity, and also starting batteries die a quick death if deeply cycled. So, the only additional thing that I need to do is install a switch inline with the field regulator control wire. This will stop the alternator from charging the battery. Also, if you want to charge the battery with the alternator, all you do is flick the switch and it turns back on. This comes in very handy if you go on a long trip.
But, what about REGEN BRAKING??? That will be phase two of the modification. I will be doing that later on, but I'll outline what it'll do because it is pretty cool. Since we installed a switch to turn the alternator on and off at will, we can use that switch (or much more likely a relay or mosfet) to turn the alternator back on while braking. We can use the brake lights turning on as a trigger for that relay, so whenever your brake lights turn on, it turns the alternator on. I will probably use an arduino to control the setup because I like it, and it gives me more control and options for future mods. An arduino is a programmable micro controller for those who don't know, essentially a tiny computer that can do tons of different things. It will help if I ever get to phase three of this modification.
Phase three is essentially beefing up the regen capability of the alternator. By sending a false battery voltage signal to the alternator, whenever the regenerative braking comes on, I can max out the alternator output. This essentially just makes the setup work a little better than normal. Testing will need to be done to see if this is actually necessary, and I may never get to this phase. But, I'm laying it out here because it is being planned for.
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View my fuel log 2015 Mirage DE 1.2 manual: 47.2 mpg (US) ... 20.1 km/L ... 5.0 L/100 km ... 56.7 mpg (Imp)