You can get a shorter belt.

I think the only way to really go without an alternator is to have a number of deep cycle batteries in the trunk. Of course each of these will weight around 30lbs.

I think energy is better suited in finding an alternative to an alternator, like the turbo alternator idea.

I hate those big serpertine belts, but thay prolly make more sense. I have 1 belt for 1 task, though the only task that really exists is a/c and alternator.

I'm liking this turbo alernator idea, We have restrictions in our eshaust either way to reduce noise output, a turbo is slightly less efficient than a regular muffler, but if it's doing work... The only problem I see is the exhaust is VERY hot...

If you want, I have a T3 turbo that should be rebuilt, but I doubt Ill ever get around to doing it. You or anybody on this forum could have it for dirt cheap to experiment with. I think it would be awesome to create an exhaust powered alternator and save 10% of gas :thumbup:

gas improvements experments
 

Has anybody copiled a list of all the things that they tried showing the gains/loss, good and bad of each try, and lessens learned with each try???
that would be a great building tool for everybody passing out the information

One thing I am curious about is if disconnecting the alternator without removing the belt would show the same gain in mileage. The alternator isn't really that heavy and most likely would not be much drag if it had the power disconnected from it.

The advantage would be you could put a switch on the dash so the alternator charges the engine when you need it, but can turn it off for the most part. Like if you had to go somewhere on a long trip and would otherwise not be able to make it without the alt.

Taking this discussion in a strange direction. Maybe make a regenerative braking system by epoxying a bunch of super magnets to the brake drum/rotors and getting a coil near it so when you want to slow down you connect the coils through a bridge rectifier to your battery so it can help make up for the missing alternator. I think the extra weight of gluing 10 neodymium magnets to each rotor and a series of probably 6-8 coils on the backing plate would not be bad, maybe 10lbs total for all 4 wheels. It might be able to get 10-40 amps of current when the coils are connected. The noise generated from the coils when they are on would definately kill your radio reception though. This could be wired to a button or 4 so when you want to slow down faster than normal coasting you hit as many as you need to slow down with. An alternate way of activating them would be raise your brake pedal a half inch or so and set it so the extra travel trips the switches in sequence so you could use your brake pedal lightly to slow down/regen braking and if you need real brakes just push it farther.

I know, I know, I'm nuts but at least I sound like I know what I am talking about :)

Hi Coyote X

You could use regen braking , and do it a much simpler way.(an alt wont provide much braking effect)
By placing a pulley on a driveshaft you can run an alternator easily.
They do this on rear drive prop shafts in RWD hot rods when they want the alt out of the engine bay.
They put them down near the diff's and run a small belt off the propellor shaft diff flange.
Works fine , but the alt is in a more hostile envornment (no bush bashing) so they can get damaged a little easier.
But assuming you have a FWD car the alt can be mostly still in the engine bay , nice and safe.
You can also switch the alt on and off when required manualy , but if you had it switched by a vacuum switch it could be set to charge only when idling , of course no charge when your sitting still , but there would be when your coasting up to a stop light for example.

During the day not much charge time would be needed.

Overall , probably not much benifit over having it driven off the engine and switched in this manner tho.

Hey guys I have an idea. Are you familiar with Peltier junctions? They are usually used as thermoelectric coolers for computers and 12V coolers. When you pass a current through it, one side absorbs heat (gets cold) and the other side rejects heat (gets hot). Well they also work in reverse... if you heat one side and cool the other they generate electricity. You could attach one to the underside of your catalytic converter and attach a heat sink to the cold side which would be exposed to the flowing air under the vehicle. I know they are not very efficient as heat pumps, so as heat generators they are probably not good either, but if the heat is free any recovery would be good. I will do some research on efficiencies and report back here.

The Peltier idea would work but it would be very expensive and you would need a lot of Peltier modules. This one: https://www.tellurex.com/power_modules/p219.html
Generates only 5.7W max and it costs $43. It is about the same as photovoltaics per watt but only works while you drive.

They're 4.8V at 1.2A so you'd need 3 in series to get 14.4V (good enough to charge a car battery) at about 17W for $131.85, which might be enough power given that it can run continously*.

If you put 3 of those strings in parallel, you'd get 51W for $395.55, with 4 you'd get 68W for $527.40. I think that's comparable to a new alternator, (though I haven't priced one at a dealer lately) but that may be overkill.

*Well, to continue the photovoltaics analogy, PVs work whenever light hits them, Peltier junction devices should work whenever there is a temperature differential across them. So, if one side is heat-sinked, and the other side is still hot from the engine block, they should still work while the engine is off.

First you guys are great. I have a 2003 VW diesel TDI and have been messing with the alternator and most people over on the TDI forums think I am nuts. I have found I get about a 5-7% increase in mileage with the alternator disabled. I leave the alt in there and just pull the main fuse so it basically sees’s no load. I am sure if I removed the alt or belt it would help a bit but if my wife takes the car to work I can just pop the fuse back and everything is back to normal.

A couple of things I have found out. The car once warm pulls about 100w or 8 amps. Having a solar array on the house solar is not really an option.

The car will "throw codes" because it sees something is wrong. So I had to find a way to keep the main battery topped off.

When I start the car it runs glow plugs and then coolant plugs (even in summer) until the coolant temp hits 120F. These glow plugs and then coolant plugs use 80 amps and 60 amps respectively. So again I needed to keep the main battery charged.

So what I did was took some parts I had laying around, 6 6v deep cycle batteries (golf cart) put two of them in series behind the passenger seat. I ran that in turn to a 1500w inverter which in turn feeds an iota DLS 55 amp charger set at 14.4v. The voltage will slowly drop until the coolant heaters shut off then quickly come up to 13.8v. I haven’t thrown a code since I tried this setup.

I originally tried just paralleling the batteries but the voltage under those loads would just drop too far, usually about 12.4v and the car didn't like it.

But getting back to my testing. I ran a set route, 3 miles there and back 6 times, 3 each way. On my test runs I got 87 mpg with the alt on and 92 mpg (according to scangauge) with the alt fuse pulled about 5% better. I ran a whole tank last spring and saw about a 5% improvement on the entire tank as well.

Nice work, man!

It's amazing to think that the fuel economy improvement from grid-charging the battery and not running the alternator offsets the FE hit of the added battery weight.

Just 10 minutes ago, I came in (from a de-belted alternator local mostly pulse & glide trip - 104 mpg), and thought to myself: "I need to add some extra batteries for longer trips."

Just out of curiousity, why did you have floodies laying about? You either have a cart, or you're an EV builder...

LOL, close they are from my last battery bank from my solar PV system. My old battery bank had 8 Trojan T125's, my new bank is 8 AGMs for a total of 2000 A/H at 12v or 24kw total.

Oh no doubt the electricity is cheaper then the fuel burnt. Especially since I make some of it, and I charge off peak when my electricity rates are 1/2 the normal rate.

We have the makings a MPG beast here!

Wow
 

What a great idea!

So, did the added weight effect drivability and stress the rear suspension? Also, do you know the approximate weight and cost if someone where to set up something similar -- perhaps a write-up?

RH77

GM might say that, but I wouldn't. GM called its full-size pickups with autostop, an extra battery & an inverter for running power tools "hybrids". Silly marketing.

Doesn't a hybrid have to provide motive power from an electric motor to be a hybrid? Have to draw the line somewhere.

If you forget to push the clutch pedal in when you start a regular car and it moves via the starter, is that a hybrid? :D

The 6 batteries (even if 50 lbs each) would still have the car within its weight limits.

Thoughts
 

That's 300-pounds of extra weight, which I would say could account for a reduction in that 10% savings.

The question that next needs to be addressed is the range. Since the Diesel engine doesn't have a distributor, spark plugs, etc., then a battery isn't needed to run the engine. On a gasser, I'm thinking that the ignition system would drain the batts more quickly. I was also thinking about fewer batts for a short-trip commuter, but for a gasser, that might not be possible.

RH77

The diesel may have a higher electrical overhead for the fuel pump, though, since they're high-pressure units. I don't really know for sure though. Just a guess.

Frame of Reference
 

The only frame of reference I have is a personal experience: driving an E-350 Diesel Ambulance back from a 100-mile round-trip transport. The charge cable to the battery busted loose (unknowingly at the time). Meanwhile, the digital electrical charge display was dropping like a rock. We were able to drive it for a ways, but it was storming and raining too hard to see (no wipers or headlights and tree limbs in the road), so we pulled into a gas station and had it towed back to base.

I think the alternator keeps things going -- in this case it was a heavy-duty alt.

RH77

I thought the fuel pump in a diesel is mechanical driven on the engine (injector pump) and it draws the fuel from the tank. Thus no power required except for the control of the injectors via a ECU?

It sounds like the best solution is still solar panels on the roof to lighten the alternator load when driving in bright sunlight and then the cost of the solar panels comes into play but at lease they will last the life of the vehicle and not require additional expendature. Plus on a bright day you can crank up the radio and use the excess energy!

Note: split the discussion of weight into its own thread, because there's some good info in the weight thread deserving its own spotlight:

"Effect of weight on FE: estimates from online sources"
https://www.gassavers.org/showthread.php?t=2003

Note: I'm not saying the effect of extra batteries in a no-alternator set-up is inconsequential. But the weight discussion can affect everyone, not just the alternator experimenters.

It's a good point. 7 or 8 amps worth of solar would cost me roughly $700 though :eek:

You are getting the wrong cells - raw cells with 5.5 amp output crate of 50 for $450 last time I checked was over a year ago. 22% efficiency!!! 22 in series and 2 sets in parallel would give you about 14.5 volts at 11 amps and cover the hood in area 125mm square cells jet black no markings on them back side is an aluminum plate and contacts. As far as I know theses are the best cells on the market that anyone can buy.

OOPS!

https://www.sunpowercorp.com/solarcells/

In my case my car already weighs in at 3200 lbs. Throwing an additional 120lbs in the back is nothing to the car itself. It's like another person in the back seat. My typical commute is 11 miles to and from work, 1 stop sign each way so the added weight likely wouldn't affect me the way it would in normal stop and go city driving where weight really kills mileage.

For cost if it were all new
2 golf cart batteries - $150
1 Xantrex 1500w inverter - $100
1 Iota DLS-55 charger - $150
#4 wire from the back to the starter battery - $25
$425 total. I already had the heavy wire run for the inverter in the back, I just run the power back the other way in this case. I had the used batteries so I don't care if I run them in to the ground. The charger is one of two I use to charge my home battery bank in a power outage from a generator. So it was really just my time to set it up. I would not recommend this to “save” money. I highly doubt it would every pay for itself.

With solar I would need at least 2 KC120's to offset my load, at least $1200 and if I spend that much on solar panels I want to get the most out of them, that is to have them have them aimed correctly at the sun and use all the power they make. Oh and the wind drag from the solar panels would likely cause me to use more diesel then I am saving with the alternator disconnected. Maybe if you bought laminar (flexible) solar cells at twice the cost of regular flat panels cells, but that would be at least $2400.

Again my car once warm draws about 100w or 8 amps with nothing on, no radio, no DRL's, no fan or AC. That all just adds to the base 100w load.

And yes the fuel pump is mechanical driven off the engine. I am not sure what the car is doing with the 100w, but it uses it for something.

Linky?

You know if you tapped into the inverter and the charger you could increase the efficiency a lot - the inverter pumps up the 12 volts to about 120-180 VDC then chops it into a square wave - the charger takes the AC and rectifies it into 180 VDC and chops it back down to 14 volts. You should be able to jumper into the inverter internal high voltage DC and connect it directly to the caps in the charger and eliminate the fet switching and rectifier losses. Actually if you ran more about 18 volts and used a switching regulator power supply to drop it down to 14 for the vehicle it would be most efficient. And that could be done with a single FET or power transistor good for plenty of amps.

Metro you have a 10% gain with an unbelted alternator do you had any data if you just removed the load from the alternator and not the belt. Maybe install a kill switch to remove charging when not needed. Any thoughts on if that would give a noticeable increase in FE may 2-3%

JanGeo this is true, but I wasn't as worried about efficiency at first since I was really just seeing if it made a difference and if so how much. Probably the easiest thing to do would be to go with a 24v battery bank and a 12v charge controller and let it do it's thing, the trick is getting up to the 50 amp range, well that is easy, it's just how much it costs. For instance I use an Outback MX-60 charge controller and it will take any voltage up to 140vdc and charge either 12v, 24v or 48v battery banks and you can set bulk, absorb and float voltages and times. Very nice, but they run $550.

The thing I really like about the iota chargers is you can feed them anything from 90 volts to 180 volts, AC or DC and they put out a rock steady 13.4 or 14.4 volts DC. I didn't believe it at first but someone who dug in to the unit tried and now uses it on his electric truck to charge a 12v battery from his traction pack for all the old existing 12v items.

I'd wager the belt doesn't represent *most* of the gains I measured. Maybe a couple per cent of the 10 total. But I wouldn't know unless I tested it.

I've been waffling between rigging an electric water pump (so I don't have to worry about any belts at all), and putting the full belt back on and rigging a switch.

We'll see what winter brings. I'll probably be a lot less likely to be tinkering (adding/removing the belt for long/short trips), which may encourage me to use the fuse/switch.

I bet a 35 amp switching Vector charger will operate over such a wide range of input voltage as well and they sell for about $65 - I have a bunch of them. My point is that with a $3.00 transistor and a decent core with a bunch of turns of wire and a few bucks of components you could build a switcher to drop any DC battery voltage down to 14 volts at a pretty decent current. That iota charge controller doesn't list any current levels but it looks like it should work pretty well in bulk mode while you are driving.

Nice thing about an electric water pump is that you can continue to get heat from the heater with the engine off like when stopped at a light with engine off and regulate the pump speed (wasted energy) increasing it when it is needed like when you are burning a lot of gas and not a function of engine RPM so that lugging it on a hot day you could run the water pump faster for more cooling etc.

Thanks for the link, but that's the manufacturer (no info on the site about purchasing). I'm curious where you can buy the cells retail. Do you still have a link for that?

If you contact them directly you can purchase them by the crate of 50 cells - they gave me pricing but didn't get to the final "take my CCard number please".

On saturday I replaced the battery in my Swift.

I had know it was bad since I bought the car a few months ago , and as its getting colder (and batteries dont like cold) the big block 1 litre engine has been getting slower and slower to crank up and fire.
The battery's capacity is suitable for engines over 2 times that size , so for it to be struggling to turn the small engine I knew it was dead.

I have been noticing the car was a little down on power as well compared to when I bought it.

Amazingly when I repalced the battery engine power is back to normal again.

Ime supposing that the dead battery was always under volatage and wanting a full charge and that the power loss was from a full loaded alternator.

Unfortunately it will probably show up in this tank full FE test. :mad: , but interesting anyway the effect of the alternator on power and FE.

Oh, one thing I use a lot is a Deltran water proof battery tender. It charges at a lowly 800 mA up to 14.6v and then drops back to 13.2v float. I would strongly recommend one of these (or a larger version) if your messing with a disconnected alt. The battery will die a quick death cycling it without a good true full charge. I use this charger on our van, I suspect the alternator is a bit off in the van and never full charges the battery.

On the wagon the Deltran will show a full charge in 30 minutes and the van takes 4-6 hours.

Even running the alternator as normal the cars starts much quicker in winter and I figure it doesn't have to run the alternator as hard to get the battery charged back up after sitting a while since it starts ?full?.

Even a solar charger would likely work in most cases for this "topping off" of the battery

Definately Brock - most electrical systems if not run for hours will not charge the battery as much as it needs. A new battery should be charged at a slow rate for about a week before it really gets the self discharge down to under 0.1 amps. Deltran makes some really great chargers . . . just wished they made a really high output current version.

For those following this thread, I've updated metrompg.com with an article on this topic, summarized and describing my experiment in more detail:

https://www.metrompg.com/posts/photos...ternator-s.gif

https://www.metrompg.com/posts/alternator-optional.htm

Thanks to Brock for corroborating the results with his Jetta.

You seriously have a bungee cord as your water pump belt!
Arent you worried a bit (I guess it's better then a bike innertube).

Great article metro!

Yep, bungee. Bungee kicks *** compared to bike inner tubes. I'm thinking of making a second one as a backup. There's room on the pulley for 2, side by side.

I'd rather have a smart electric water pump, but I only know how to make a stupid one. And I'm lazy. So bungee it is!