Test: Alternator vs. no alternator = 10% MPG gain @ 70 km/h

[Nerys]

yeah I got a pair of em off ebay CHEAP. so might as well find a use for them :-) you can tell them apart as they are "red" like the ones on most calculators. designed to work in "low light levels" not as efficient but better for some circumstances.

[Cardinal Grammeter]

First, I confess I have not read the entire thread - it is quite long.

But just in case no one mentioned this strategy:

Set up an alternator Kill Switch like the drag racers do and then engage the alternator when you are using the brakes to slow down.

In olden times, there was a Variable Pitch Turbo 400 transmission used by GM in the 50's. The speedometer in those cars had a switch that was made under 5-7 mph. This engaged the high pitch setting in the torque converter. When you pulled out from a stop, you would be in high pitch until 5-7 mph and then it would disengage and revert back to normal pitch.

You would need something like this too so that if you are at a stop light with the brake on, the alternator should still be killed.

So if you could get the alternator to work when the brakes were one AND you were still moving, you could run the biggest 100+ amp alternator since it would act as "dynamic braking." You would want the biggest alternator torque load you could get your hands on.

Of course, the really skilled high mileage driver knows how to drive so that braking is kept to a minimum.

And then there is the condition when using engine braking - foot off gas, car in gear, brake off - as compared to coasting where you have the same except car in neutral.

Still in hilly terrain, this might work nicely and would definitely extend range.

Simplest thing would be a convenient button on steering wheel or shifter where you could hold in to engage alternator because you need the braking.

Tom

[yoyoyoda]

Originally Posted by Cardinal Grammeter

First, I confess I have not read the entire thread - it is quite long.

But just in case no one mentioned this strategy:

Set up an alternator Kill Switch like the drag racers do and then engage the alternator when you are using the brakes to slow down.

yes! I was thinking this myself tonight. but with a twist, instead of just a kill switch going to the alternator stator coil, (which has the trouble of telling the computer that something is wrong with the alternator). Instead of that using a relay to switch the output of the alternator which is then controlled by a computer (eg, arduino) or sensor circuit which detects when the starter battery voltage gets to below 12v and automatically turns on the alternator to charge the battery.

Then disconnect the battery when voltage rises to 14.0 v.

This is so when you drive 500 miles you aren't left with a fully depleted battery when you arrive, or break down on the side of the road from a completely flat battery which wont crank your engine.

So during the drive the alternator kicks in and out much like an air conditioner compressor, cycling the battery.

You could then replace the starter battery with a deep cycle one and have an alternator which automatically disconnects from the engine when you are driving and when it is safe to run from battery power while driving.

This should give you a 40-50 mile range on a deep cycle battery with the huge bonus of 10% fuel efficiency savings and the peace of mind of a system you don't have to worry about constantly.

THEN combine this wonderful setup with a 20-40 watt solar panel which charges the deep cycle battery when the car is parked, so you can start it again in the morning!

The solar panel system can then charge the battery even while driving, when using a cheap seperate charge controller off eBay, you could theoretically load the car up with 40-80 watts of solar panels on the roof of a wagon, provided you make it aerodynamic and then run the entire electrical system from solar.

= BOOM = a wonderful fully automatic alternator disconnect system is born!

I'm excited to implement it on my ride

[Frank Lee]

^Your car already has a voltage regulator.

[mechman600]

Originally Posted by Frank Lee

^Your car already has a voltage regulator.

I think what he is describing is a pulse and glide regulator.

[Cobb]

Depends on the car. Hondas use something called an ELD that turns the charging circuit off and on as needed based on voltage. Other cars constantly charge the battery to around 14 volts +/- the temperature, load and price of tea in China.

[steveo539]

That was the longest thread I've ever read on a forum. But good stuff. I'm up here in the pacific northwest (or southwest for you Canuks) so I get lots of rainy days (wiper motors) and foggy windows (defroster motor) and short daylight hours in the winter (headlights both to and from work). I'm chicken to go "alternatorless" and like the security of on-demand charging. Thinking my situation would benefit from reducing the electrical load as much as possible. LED lighting wherever possible, Create a "vent mode" so I don't have to run the fan as much, liberal use of Rain-X and either the alternator kill switch or electromagnetic clutch on the alternator. Use deep cycle battery(s) and take advantage of plugging in to the grid wherever possible to keep the battery charged. I do have a short commute so that works in my favor.

I am a tinkerer and do work for an air conditioning manufacturer. I can get as many electrical clutches to play with as I want from our warranty compressors. I read someone's thread about installing an A/C clutch on their power steering pump. Nice work there. Might be able to come up with an adaptor to use the stock smaller alt pulley and place the clutch between the alt pulley and alt. You would need to space the alternator back from the belt by the thickness of the clutch.
Do the same for the power steering or delete it all together. I've driven a similar car without PS and it wasn't bad.

[justme1969]

rite now and possibly already posted this but; I tackled this issue also.
My simple initial solutions were adding a toggle to activate alternator when I wanted it to be on. Added a toggle to Cooling fan to control the prolonged cycle run time on it.
Added Led fog lamps for dusk and dawn and alot of engine off glides that really sucked battery down.
These mods seemed to be an answer at the time

Cause: Air dam caused fan to run constantly.
Effect: I controlled by switch and gage:
Effect: after running engine really Hot 1x I installed a higher temp fan switch instead. This and an Led indicator to help me see how often fan came on and or stayed on till got switch as best case as possible. I removed switch and Led light. called it best possible.

Cause: Alternator drawing down MPG during Testing.
Effect: Added switch to alternator regulator wire for activation down hills and at stop lights.
Effect: Routine deep cycle charging cause death of batt and nearly left me at stop light 1x
Effect: Bought Biggest battery that I could fit with large reserve and seldom use switch regulator is much more efficient at maintaining battery. I still do use switch sometime at on ramps and stop n go.

Cause: Fast Battery discharge during morning commute due to excessive engine off glide in darkness. Excessive Alternator run time recharging on trip both directions.
Effect: Installed LED fog lights with toggle.
Effect: Nearly caused an accident from no use of tail lamps 1x till I touched brake pedal.
Effect: Tied fog light switch in as interruptor in parking light series. And bought cheapo digital battery maintainer mounted to batty and left plug under dr. fender.
Effect: trickle charge with conditioner keeps battery full every night so long as I remember to plug it in. Fog lamps only used dusk to dawn now not in dark. when using for actual fog all lights tied into circuit are brighter.

So you see nothing here is perfect but all help. but learn from my mistakes. Nothing like killing a $140 batt and $175 alternator and getting $30 for it credit when it shoulda been good for another 3 -5 years. But thats not as bad as sceeching tires behind you at a stop sign because you left lights off too long again.

All the doohickies we pay for have a best case purpose not purfect for eco modding but turning a switch on and off 50 times in 20 miles sucks in my opinion. just be glad for our solid state electronics.

[Sneakybassturd69]

Originally Posted by MetroMPG

When people read about this, one of the first questions that inevitably comes up is: "can you just use a solar panel?"

Short answer: not really (for reasons of cost & potential aerodynamic penalties).

If you drive a normal amount, it will cost you a lot of money to get enough panels to keep your battery topped up, and you'll probably destroy your car's aerodynamics mounting them on top .

The only reason I can get away with solar recharging is because I don't use my car very much (less than 200 miles in May). It could easily take a couple of days for my panel to replace the electricity I use from the battery in half an hour of driving.

The panel I have is equivalent to a 1 amp trickle charger, and it cost $160 CDN (I got it to keep a boat battery charged):

http://tinyurl.com/fw77y

A typical electric battery charger "trickle" setting is 2 A (twice the power of my panel), and they cost a fraction of what solar panels cost.

#
! Now they have boat solar panels that are just a few mm thick and can be glued on without any effect to your aero and they are 150 bucks for a 50 watt 20 amp one

[oil pan 4]

I have 4 little panels that are something like 7watts each.
When I was using the large lead acid batteries in my diesel those solar panels would hold the voltage right at about 14 volts and I could leave the solar panels on pretty much all the time. They were great to have in the winter.