Alternator Elimination on 1998 Civic EX

[Energy Miser]

I have been trolling the forums and have read several posts about people removing the alternator (through various methods). My Civic got smashed by a plow truck last month. I got paid for the damages ($3400), and I was able to keep the car. It runs and drives great but the trunk is crushed and the taillights are broken on one side. When I installed new bulbs in the holders, they all light and function right, so the car can be driven in good weather with no problems. It will now become a test mule for all the mods I care to try. I am going to start with the alternator removal first. To experiment with the idea, I unplugged my alternator so that it would not charge and I drove the car home on my normal commute (26.2 miles), with the lights off. When I reached my house my battery would still start the car, albeit weakly. I plan to approach the modification as follows;
1. Install toggle switch and relay to turn the alternator field windings on and off on demand.
2. Install a battery pack in the trunk area that is comprised of 33 – 4500 Mah Nimh batteries. The batteries are soldered together to create a cell that consists of 3 sets of 11 batteries wired in series, wired in parallel to create a 13.2 volt cell with a capacity of approximately 1.48 Ah.
3. Install a 750 watt fan cooled inverter, wired directly to the auxillary battery. The inverter will be turned on and off with a relay and a toggle switch from the dash.
4. Install a 6 amp battery charger that will draw it’s power from the inverter. This charger will be connected permanently to the cars starting battery.
5. Install a disconnect switch that will join the auxillary battery to the starting battery when desired. I envision tying the batteries together for plug-in grid charging, and leaving them disconnected for operation so that the charger, powered by the inverter, which in turn is powered by the auxillary battery, maintains the charge on the starting battery while driving.
6. Install a pair of 5 watt solar chargers, one for the auxiliary battery, one for the starting battery, to help maintain both batteries during the day on sunny days.
I have all of the components needed to make the modifications to the car, so the cost will not be a factor, but I think all the components I intend to use will run less than $350 total if purchased new. I believe it will work quite well, albeit in a somewhat Rube Goldberg manner. It should maintain the voltage required to keep the electronics in the car happy, at least until the auxiliary battery falls below 10.8 volts and the inverter shuts off automatically. With a pair of voltage gauges I will be able to monitor the voltage on both batteries and will be able to figure out how many miles can be driven with this setup before charging is required. The auxiliary charger, the inverter, and the aux battery weigh less than 25 pounds so the increased shouldn’t hurt FE too much. I have kept track of my mileage carefully over the years so I should be able to quantify exactly how much this will increase FE. The next step will be to shed as much unnecessary electrical load as possible to extend battery charge life.

[Ryland]

Why bother with the inverter and battey charger? a DC-DC converter would work better, be cheaper and waste less energy.
As it is your alternator cuts out under some conditions, check the battery voltage while driving and you will see.

[Energy Miser]

I don't have a DC to DC converter. I have an inverter and a charger. This is only experimental, not a permanent solution. It is merely to prove the concept. I have all the stuff to do it the way I described above, all free. Where can I get a DC to DC converter for free?

[RobertSmalls]

That's a big NiMH - twice as big as the one in a Civic Hybrid, iirc. Where'd you get the cells?

I'm pretty sure you'll need a BMS. You need to keep an eye on every cell to ensure it doesn't get too close to 100°C - Honda does this by monitoring twelve cells at a time with a PTC resistor. You also need to ensure that no cell has a polarity reversal - voltage less than zero. Again, Honda keeps an eye on the voltage of 12 cells at a time, and stops discharging at some predefined voltage around 1 VPC.

You can get a dirt-cheap DC/DC converter out of a wrecked Insight or Civic. In fact, I'm using a Civic DC/DC + Inverter as a decoration on an end table in my living room. There's also a great selection of MeanWell DC/DC's in the Jameco catalog, but they're not free either.

You said your whole array weighs 25lbs... by my math, your battery alone should weigh 90lbs just for the cells, plus more for a housing for 90lbs of battery.

[YukonCornelius]

I'm curious what kind of mpg gain you'll see from this.

[Energy Miser]

I'm hoping to get a 4-5 MPG gain. If I can get those results in a 2 week (1 tank) trial, then I will look at how to make the mod a reliable, permanent addition.
I guess the main reason I want to try this is because I have a memory from when I was a kid and rode a bicycle. I remember wanting a generator driven light for my bike, you know the friction type that rubbed on your front tire. When I finally got one, I remember how disappointed I was when I went to use it the first time. It made peddling way harder, and used up what seemed like a lot of the energy to barely light my way with some dim lights. To me an alternator on a commuter car is like the stupid little dynamo rubbing against the tire on my bike. I would like to ultimately take any load off my cars ICE that isn't directly responsible for forward motion and make it manual or electric.

[Varn]

I see a lot of users here remove them. IMO it takes a lot of utility away from your car, night driving, weather driving, cold weather starts. I figure that the regulator circuit reduces the rotor current to the minimum that it takes to keep the battery charged. I could understand putting a booster on it when parked but beyond that you have a car that has some of the range limitations of an electric vehicle.

[Energy Miser]

I don't have a problem with imposing limitations on the vehicle, as the car is driven for one purpose, commuting back and forth to work, 26 miles one way, 26 miles back, then it's parked from 4:30 PM until the next morning. I have vehicles for every other purpose so I use them for the other stuff. I use the commuter car just for that, no other use. I seldom even makes stops in it.

[Frank Lee]

In that case just throw a big deep-cycle batt in there and forget about all that other gook.

[RobertSmalls]

Originally Posted by Frank Lee

In that case just throw a big deep-cycle batt in there and forget about all that other gook.

There's an idea. Hook the NiMH pack directly to your 12V rail. Make sure it won't catch fire while you're cranking the engine, though.



And as I hinted at above, you don't have a 2kWh, <20lb NiMH battery. What do you have, and what's it sourced from?