Reducing alternator drag- Would this work?
 

I was thinking of ways to drive my 2005 Civic without an alternator. Then I came up with the idea of installing a switch inside the car to shut the alternator off when not using accessories or when accelerating, and turn the alternator back on when coasting in gear, when slowing down, when using accessories or if voltage gets way low, like on a long road trip. Would that work? I have an Optima Yellow Top deep cycle battery with a 3 year warranty, so I am not worried about damage to the battery. I also have a new alternator, and I have a grounding kit and I upgraded the alternator positive wire. I have an idea for an automatic version of this that I will explain if this is a valid concept. Thanks, I am looking forward to reading your responses to this.

Yep, its quite possible. Several OEMs are doing that, but to a lesser extent since they don't use deep cycle batteries. A good practice would also be to throw a battery charger onboard and plug in when you're home.

I would plug in to charge when I get home, but my garage at the apartment I live in does not have electricity.

You'll have to make sure that you keep it adequately charged so your lead acid battery doesn't get sulfation problems. This means the resting voltage needs to stay above 12.5V or 12.6V, I forget, but you'll want to look that up. Lead acid batteries are best stored at 100% charge to avoid these issues. Ideally, this means at the end of each trip your battery is fully charged (as it would be with an active alternator). However, the guys running without an alternator usually plug in daily.

Here is some additional info on sulfation:
Sulfation and How to Prevent it - Battery University

Or use solar panels.

I don't think that solar panels would provide enough electricity to run the electrical system, even with no accessories on. I do not know how much power the ignition coils, fuel pump, ECU, sensors, and all the other things necessary to run the car draws, but probably a lot more than solar panels can provide.

He means in lieu of plugging in to charge.

You might be able to get away with keeping the alternator switched off if you don't drain your battery much during daily driving, and charge it back up with a solar panel during the day.

You'll want to keep an eye on voltage levels as you drive, perhaps with a cigarette lighter voltmeter, or from other gauges you might have.

Definitely install some kind of voltmeter and see if the alternator isn't already doing some sort of 'smart' charging behaviour.

My 1998 Civic HX already does that.

I think it is supposed to, but on my Scangauge 2, the voltage stays between 14.1 and 14.4 at all times. I think the ELD should be cutting voltage to around 12.6 under certain conditions though, but it is not. Great idea though.

It's easy to figure out how much power you need. Just use an amp meter and turn stuff on.
If you drive less than 30 miles a day a roof covered with solar and a real MPPT type charge controller would be more than enough.
Keep the alternative unbelted and powered down, most of the time, then put the belt back on for long trips.

Would it not hurt aerodynamics significantly and add weight to put solar panels on the roof? How many watts of power could I get out of a roof covered with solar panels on a bright, sunny day? What about putting a solar panel above the back seat so it gets light through the back window?

http://ecomodder.com/forum/showthrea...tml#post286419

I installed an alternator kill switch on my 1998 Civic DX for the exact purposes you describe. I also use it for a crude, mild regen braking tactic: slow-down using DFCO with the alt turned to "on" position. No fuel burned, no friction brakes used, electricity generated (though not a lot, and prolly not well absorbed in my deep cycle batt). :)

Not the way I do it. Just attaching a metal edge panel to the roof of a car doesn't work, it's already been tried. It increases drag so much that the car uses more fuel.

Forget putting a panel inside the vehicle being behind glass, it cuts panel current by 2/3. It's a waste of time and solar panels.

I don't know how big the roof on your car is but up to 200w of panels isn't out of the questions. Laying flat they produce about half of name plate watts.