Virtual alternator delete.
 

I should introduce myself better as a new member, but I have been a mental subscriber to Ecomodder for a decade, trying out most advise only short of a full belly pan and a Kammback, never caring about giving anything back to the community, sorry! However I've "invented" a new mod, not mentioned here I would like to share: I do a lot of city driving and noticed than when my alternator kicks in, my steady 35mph consumption goes up from 98mpg (2.4L/100km) to 70mpg (3L/100km) and my idle goes from 0.6L/h to 0.9L/h (I'm European, trying to mix empirical units with ISO units for this international audience), so an alternator delete is a logical next step, but I don't wan't to carry additional AH to make up for the missing charging, as the weight penalty will cost dearly in stop and go traffic, so here is my Hi-tech solution: Loosing the 40AH battery saves 16 pounds, replacing it with a 4S5P Li-ion pack, the size of a grown man's fist. The observant reader have noticed that this gives me a 16V car electrical system, but in reality it is a 15V system as I only charge each cell to 3.9V for a long cyclic life and safety as only float charging at 70% charged is safe with Li-ion. My car works perfectly on this, no fried coil or bulbs or any error codes. I did check with my workshop manual and 16V is within specs. Such a pack does not start my car so I added a super capacitor bank in parallel over a shunt resistor to take care of this. However, all this does not save me anything besides weight, so I've added a 50W solar panel and a 15V charger to keep my battery and capacitor above the 14.45 my alternator would like to push, so it shuts down. 50W solar on the dashboard is too puny for low beams, but they are only on at night where the sun doesn't shine anyway, so I got plenty for systems and DRL and my power windows are really fast!! This saves me guestimated 0.8L /tank idling and around 25% in city driving in the daytime, which both are substantial savings, that avoids the extra bettery weight and plug-in charging and does not require unbelting the alternator so quite unintrusive. It could even be build into a battery sized box with two wires going to the solar panel, and be a simple battery swap procedure to install and un-install.

Very good first post Luno. Our community would very much like to see A-B-A testing results of alternator off, on, and then off again to compare fuel consumption to get a good idea of actual % improvement in economy.

One thing I like about your system is that the battery can be charged in temperatures below freezing, which LiFePO4 cannot. I'll have to consider replicating a similar setup someday.

Looks interesting. I would second redpoint on the testing idea. Could you just run the scenarios you ran with the stock system again?

Also, you have saved some weight but you have spent a lot more upfront. How much do your solar panels and other components weigh?

I did consider LiFePo4 batteries, but Getting them to Europe is expensive, there is no European reseller of the sizes relevant here. Studying Li-Ion batteries, it dawned on me that undercharging them increase cycle life to 2000-4000 range and they become a safe as LiFePo4 batteries as you never drive them near the the electrode decomposition voltage, so in effect you have the benefit of LiFePo4 and a capacity/weight around LiFePo. What I did not mention is that I have a 10A LiFePo4 BMS on my pack as a secondary protection cutting off the pack if any cell goes above 3.9V or current draw is higher than 10A. I do know that this is an relative expensive system having a long payback time, but I had most of the stuff from an electric bike project. I've driven around for a week with this and it is totally reliable so far. What I also didn't mention is that when driving at night the battery lasts for 30 minutes until the voltage drops below the alternator cutout and it resumes normal operation, and there are no more savings to be had, but this is totally self managing. I have an MPGuino in my 98 Fiat, so my numbers are just the observed drop in the instant usage, during the last few days and I do understand that outrageous claims need matriculate proof, but I'm seeing the same numbers as other people un-belting and switching off stator current, The reason I have a large improvement in mileage is because this is a very mechanical efficient car (I can push the 990 pounds of it with my thumb to jogging speed in neutral on slick level asphalt) My real life city driving consumption is in the 47MPG range with traffic, but I need to run a few tanks to have a solid average, but the savings overall, including idling is around 25% city driving on the MPGuino so far.

What car do you drive?

I am unaware of any cars that weight as low as 990 lbs.

I am sure he meant kilos, which is almost 2200 lbs.

A few of us have done the same. Around 10% is the gain.

Weight doesn't cost much.

My Kangoo averaged 6.7 city (16mph average speed) and on a really bad day 9.7 with a 500kg+ trailer.

If you work that out that's 0.006l/100km per kg, including the aero and rolling drag of a trailer.

I can't imagine 50W of solar in Denmark does much. I've got 340W in Australia and it's not enough to keep up with the injection and ECUs (diesel). My previous 100W panel barely made a dent in my Petrol Kangoo's electrical usage, but topped off the battery nicely when parked.

Oh God, A Kangoo. Been there, Get over 85 kM/h and it drinks a lot. 6.2L/100kM highway was the best I could get going at lorry speed. Spare parts are extremely expensive and special tools for everything. I drive a Fiat Seicento 1.1 SPI from 1998 now. This car is not known for great mileage, mainly because of a very low gearing and slightly wider tires and I seriously believe that the Fiat test driver doing the test tried to drive very Italian. Luckily Fiat have struggled for decades to reduce consumption to pass increasing NEDEC driving cycle demands, and as parts are interchangeable between models I've managed to create quite the hypermiler: In 1999 they made the Seicento Suite model, that either came with a cloth roof or AC, both of which used more fuel, so they changed the gearbox for a 12% taller one. I got one of those. In 2000 they made the 4 injector MPI version of the Fiat Punto, which had a bigger engine so worse consumption than the previous SPI models, so they used a milder camshaft with less overlap. I got one of those too. I drive Ecopia B381 tires on 4.5" wide 14" rims which also increased the gearing by another 9%. Driving 50kM/h (or 35mph) in 5'th now happens at 1300 rpm. Interior is gutted, including rear cushion frame. Weight with me in it on a lorry scale was 690kg with spare tire and everything, that is 1521 pounds, without me that would be 1345. Factory nameplate dry weight stamped in the trunk is 610kg. Weight saving include 40 pounds saved on lightweight (6 kg each) rims and tires. 100 pounds interior and spare wheel. also some pounds on unused spot welded brackets and superfluous auxiliary systems around the car, like rear wiper with motor and more than one outside mirror, the whole heater blower motor and associated plastic and cardboard moulding (now using 4 server 80mm fans and ducting straight from the front grille, with pwm control), A cheap after-market 4A radiator fan connected with strips directly to the radiator instead of the original heavy metal frame thing made by Fiat and a 300g crap radio instead of the 90' Sony head unit that weighted 4 pounds. BTW, Passes MOT every time.

Oh, what is this, I thought this was a boasting thread but every other comment is from someone doubting by my claims? I can see one caveat with my measurements and that is that running 0.5V higher shortens the open time of the injector but also increases the hang time after power is cut and that not by an equal amount, but I have explained already that I have not run a full tank yet, so my figures might need correction once I've done a fill-up!

City driving is 1/3 - 1/2 power wasted on auxiliary systems from water pump and alternator. Weight is very important in stop and go. When piston heads claim that 5 pounds saved in their hotrod is the same as adding a HP it is also the same as saving a HP when accelerating to the same speed at the same rate.

We do use the same sun on the northern hemisphere and whatever sun height we have here is equivalent to whatever angle the sun hits you at down under. With the added benefit that in summer it stays up for longer. But you are right in that 50W is cutting it close. Having it behind a windshield cuts a 1/3 of power received, ad to that the elevated temperatures in a parked car in summer. So lets say the gets me 40 kWh yearly at my latitude (from the solar energy tables), that's 105 Wh a day on average. So this is not an all year system, and if I need to ad more panels in the fall or for longer trips (load is shared between solar panel and battery now most of the time unless I drive South around noon), so be it.

Idling with everything else off takes 2.5A for the ECU, coils, fuel pump and the single injector (1.1bar fuel pressure). If You have a diesel, maybe a very fancy one with an electric high pressure booster pump your base consumption is much higher, what you get is better atomization which improves fuel economy, but if it takes 350W of electrical power to do that in your car the benefit is eaten up in city driving where you only need 2-3 HP for driving at constant speed, so 1 HP mechanical to make 350W electrically is insignificant on the highway and but bad in city driving. So I agree, putting 350W of solar on your car saves you more than me putting 50W in mine, because your base consumption is higher to begin with. 10% to you saved by omitting the alternator is the same as 25% for me, it is because alternator drag is a much higher percentage to begin with on a small car. The stator coil alone uses 2A when turned on. So when I say that my savings are comparable to what others are getting, I mean in absolute HP savings. If this is only 10% on your car it does not mean that the mods is less beneficial for you as we both save the same amount of fuel by doing this. The reason this takes 350W for you is possibly also because of more electrical loads, electrical power steering? Urea catalyst? or heated oxygen sensor? (I know almost nothing about diesels).

Cheers!!

I'll better do a proper writeup on this with pictures of my clamp meter on every wire and videoed A-B-A tests between fill-ups for some of you to take this serious And I should, Irrefutable numbers are always the best arguments.

That actually sounds like a cool idea, hadn’t thought to boost battery voltage to where the alt would automatically not charge, but it seems logical...

It’s also a ridiculously light car, which is helping you in city driving... my car weighs around 1200kg, so it could use for some weight to come out lol

Denmark gets 1200-1600 hours, Australia gets double that.

We get roughly double the panel output that Denmark does.

Global Solar Atlas

I saw zero measurable gains from 100W on the petrol Kangoo, just as I saw no gain from 40W on my Mercedes.

This was all with roof mounted panels. Mounted inside your car a panel would be shaded most of the time -it only works for that small amount of time that you can drive with the panel facing the sun. 105Wh assumes the panel is angled towards the sun. On a vehicle the ideal angle is zero degrees. So more like 85Wh/day - assuming you only drive into the sun, and park facing the sun.

That's a tiny amount of energy - if you drove all day that's ~8w that you're getting, roughly the same effect as replacing your tail lights with LED. You haven't specified the size of your battery, but by the sounds of it, it's tiny. A 7.4Ah battery has no problem starting my cars. The point being it's not even a case where you can store a lot of power while parked for use later in the day.

My Trafic uses 3.8/100 at a steady 74km/h (lowest speed in top - A/C on 3-400kg on board). 360W gives me 0.2-0.3/100km. Adjusted for a behind glass 50W panel that would be 0.02l/100km - smaller than you can reasonably measure. Bare in mind that 360W of solar panels will never produce 360W of power when mounted on a car -about half the rated output is what you'll see.

If you look at my side bar, I've got all sorts of cars. The LiFe is in the Proton, a very simple car (MPEFI). The improved charge efficiency saw a solid 10% gain. If I connect a grid charger/ solar panel it just switches off immediately as the alt keeps the battery 98% full. Solar panels are pointless in this situation as there's no where for the current to go while parked, same goes for a really small capacity battery.

On the Trafic, with a 120Ah battery, stop start, all city driving and low RPM hypermiling, I found that the alt really couldn't keep up with demand - meaning stop/start didn't work. So now when I park, the power is stored in a large battery - which means stop start works 90+% of the time. The alternator sits at 11.7 volts with the engine running.

I think because people drive in different environments experiences are different. Typical city driving in Copenhagen it is very sedate except for the 4 lane city rings, usually only one lane with double lines, so nobody are pulling stunts. When I drive in Berlin or Hamburg, it is a constant show of horsepower going from stop light to stop light, or so it seems to me, though this might be considered by Germans to be light driving? Likewise driving in rush hour congestion mostly my milage would be in the low 20's mpg or worse, so when I manage 47mpg in the city, it is when traffic is spaced out enough for me to accelerate slowly and coasting from around 30 mph, with engine off when possible, timing the lights perfectly every second or third time. And you are backing me up on this; weight is extremely important when accelerating. Driving alone compared to with wife and 3 children, two of them adult requires an acceleration 3 times as slow to have the same numbers on the display and likewise I would need to coast sooner, from a lower speed to counteract the larger mass Luckily I lose coasting speed slower with a heavier car, so I will still make it to the next light, by I'll be 10 times as annoying to other drivers, so getting rid of 50 kg, is measurable at the pump. As said, I'll get back with exact numbers on the solar panel contribution and exact measurements of my cars amp draw in different conditions. Before,when I still had my failing lead acid battery I drove 706km on 28L gas with gets me 3.94L/100km highway, Which is quite good but not extraordinary for a car this size, just to point out that there is no magic here beside low rolling resistance, few parasitic loads and hard core hyper milling to get these numbers I in city driving where alternator load is a main fuel cost.

Well, if you're comparing to a failing Pb battery then anything is possible. I gained 16Mpg tank to tank swapping lead for lead in my FIAT.

I have a 13W panel and an 18 Watt panel hooked up to my 92 VX and keep the panels in my hatchback area. When I park at work, I park so the back of my hatch face the sun in the morning. I open the hatch during this time and position the panels so they are facing the sun optimally for the next 3-4 hours. It always charges my stock battery fully within a few hours. In the colder months, I put my alternator belt back on and turn my switches back on that interrupt the alternator circuit. This has been very effective and my mpg's instantly start climbing when the alternator is out of the picture. I haven't done A-B testing, but as I said, my mpg's very noticeably increase. Probably 8-10% gain.
My drive to work is about 7 miles. I have driven my car a long as 90 minutes, but that gets into the battery being at a voltage that I feel could start damaging it. I don't let it go below 12.2 volts. Most of the time it doesn't go below 12.4 volts and typically I stay above 12.6 volts. I do have LED lights all around including the headlights. In the not so often case that I drive for an hour or so and can't charge by sun later in the day, then I'll hook up my car charger. I rarely use the fan in the car, NO AC.. never has had that.. manual crank windows,,,very basic car. MPGuino is hooked up as well. I have that thing calibrated so well it's impressive. Solar works great for me.

Found this on my walk this morning. Thought of this thread...

http://ecomodder.com/forum/attachmen...1&d=1528825027

Would auto start stop systems be effected negatively by this?

Great stuff, would love to see some pics, and maybe a diagram of how you have everything set up. Which BMS and caps etc you used. I've got hundreds of 18650s laying around. But I dont trust chinese BMS's and I dont want to float charge them. But you as saying that its ok because they are not going fully charged. Makes sense I guess. Keep it up I look forward to seeing results.

How do you stop the batteries from undercharging?

He doesn't disable the alternator. It's "virtually" disabled from the fact that the battery is charged above ~14v. When the alternator detects voltages above this, it freewheels instead of generating power.

Once the battery drains below some threshold, the alternator detects this and supplies power, keeping the battery from further discharging.

I'm curious at what voltage threshold the alternator kicks in, as it matters from a battery health perspective. Too low, and there is risk of damaging the battery.

I bought a 5 Ah Li-ion battery so I can experiment with this. At $30, it's fairly cheap to play with to get a sense of how well this setup works. If it works very well, I might consider stepping up to a higher capacity.

I don't understand the mystery surrounding this mod. The alt holds the same voltage it always did ~14v.

Everything from the various Li battery threads applies.

Except if your flammable battery sets your car on fire, you may not get an insurance pay out.

I'll never get an insurance payout since I don't insure my car (liability only insurance). I'd mount the battery in a fire-resistant bag away from flammable parts.

Oh ok. Makes sense.

Now all you need to do is get the alternator to charge the batt on deceleration.

You could wire a relay that puts a couple of diodes in series to the alternator voltage sense and wire the relay to brake lights or a manual switch.

That way when you brake the alt pushes 16v to the batteries.

I have been thinking about this for some time now, but can’t really get the formula in my head. I have read almost all of the threads on ecomodder. I like t calculate measure design prototype redesign and build which is probably why i never get anything done :)


%10 gain is mentioned. Also 0.3l/100 km is mentioned. Which would be correct for a car that does ~3l/100 km.

If i had a diesel car that consumed 20l/100 km in the city and 10l/100 km on the highway would i expect to see 2l and 1 l gain respectively?

Or would it be 19.7l and 9.7l.

If we could somehow find a better formula it would be much more informative.

Such as if a car uses 350W and sees 0.3l gain. That makes 0.085l/100Wh (i assumed a steady speed of 100kmh). Or 0.85l/kWh.

If that were correct then it would be very easy to approximate the potential gains in fuel economy.

You want to run your blower motor at 100W. Sure thing, that will cost you 0.85 liters of gas in 10 hours. If this is the case (and I do run the blower motor a lot) it makes perfect sense for me to stockup a couple of kwh of batteries in to my car.

Modern cars also have lots of electrical gizmos from fuel pumps to sensors to actuators to power steering. Then it would also be easy to calculate the gain in a more electrified car. This formula would also permit me to understand what the gains would be in city fraffic.

If we assume that the above figure is correct, the converion is terrible.

1l of fuel is roughly 10 kWh. In the units of the above formula, that makes 0.1l/kWh compared to 0.85l/kWh. Roughly 8.5 times less efficient.

10kWh costs 3.3 monetary units where I live and 1l of gasoline costs 6.3 monetary units. So roughly double for the same energy.

So electricity in the car costs 17 times as much. Which seems to agree with a felllow ecomodder who said it costs 20 times more.

Am I on the right track or am I completely out of it?

Can you tell me more about your resistor replacement.

Are you still using the standard controls or your own control buttons.

If the standard buttons how do the resistors work?

Each fan level is connected to the fan through a different value resistor? Or is there some logic where different resistors are switched on in parallel to get the desired voltage drop to the fan?

My blower just stopped working and i suspect it is the resistors. Might aswell replace it with something more efficient. Arduino based.

If the blower stopped, it's probably the fuse or blower itself. The high fan setting normally bypasses the resistor and connects the fan directly to battery voltage. The lower speed settings normally have 1 power resistor with leads connected at various points to give different resistances.

I'd check the blower fuse since that is easiest. Next check resistor to see if it looks burned out or otherwise corroded. Finally, disconnect the blower harness and connect directly to a 12v source to see if it spins.

https://ae01.alicdn.com/kf/HTB1kbDXM...pg_640x640.jpg

Will test the blower with 12v directly.
I did check the fuse and it appears ok. It did happen at a bumpy road so i am hoping something got lodged in the fan or the harness popped out.

Back on toppic,
Redpoint5,

I have a bank of 6 capacitors 500F each. Do you think they would be enough to start a 2L car? I will be using a boost converter to feed it to implement Luno’s implementation.

Capacitors instead of lead battery. Capacitor charged by lithium batteries. So alt is virtually disabled.

What is the Ah rating of your Li-ion pack? Do you know how many watts electrical consumption your car has at idle, with all the accessories turned off?

Your capacitor bank in series should be plenty enough to start the vehicle. I was able to start my 2.2L Acura using 350F rated caps.

One thing is you might need a low ohm resistor in series between the caps and battery to limit the current going to or from the battery to within safe limits.

Not sure what you mean by boost converter.

Here's my poor quality video showing a quick experiment I did starting my car with supercaps, and a LiFePO4 battery with current limiting resistor.

https://www.youtube.com/watch?v=LX_o3hl2Dv4

I have my 5 Ah Li-ion battery now, so when I get some time I'll connect it to my Acura. I think my best bet would be to put my supercaps where the original battery was under the hood, and then run some 12 gauge wire into the cabin to connect the battery, which I might velcro somewhere near the footwell. This way I could alternate between batteries, charging one on a charger while running the other in the car. Who knows how many Ah I can get from the 5 Ah battery before it drops down to the point that the alternator runs? I'd be surprised to get half the rated capacity.

The capacitor bank will be charged to 16V or a little less.

Whatever battery I use can be of any voltage and chemistry I want. Say a whole bunch of 18650 cells in 2 series configuration(less balancing issuses). That would make 8.4V and i can boost it to 16V. Or a lead acid which can also be boosted to 16v or whatever voltage I want.

With multiple converters i can have different The current does not travel back to the batteries. That will be the job of another circuit/converter/relay.


The idea is to replace all the power used in the car with 1-2 kWh of batteries.

Its basically a modified version of Luno’s setup, but I am trying to use all the capacity of the battery (without voltage drop and without using the alternator.

I can slowly increase the battery size untill i no longer use the alternator at all.

How would you initiate the alternator turning on when the battery has dropped too low?

Let me know what you use for a voltage converter since it sounds like an interesting idea. I'd probably need something capable of 300 watts.

Here's a spreadsheet I started putting together a while back. The last tab titled "Cap Calculator" is handy for estimating what a supercap bank alone can do. If you input the farad rating of the caps, it calculates the total series capacitance and if you input the parasitic drain of your vehicle, it can estimate how many hours/days the vehicle can sit before it drains too much to start the vehicle. Just an interesting thought experiment. The spreadsheet can be modified if you download it to your computer.

https://docs.google.com/spreadsheets...it?usp=sharing

I can cut off the voltage converter to stop the charging of the caps, after which the alternator will take over.

It is also possible to add another coverter to charge the batteries when decelerating.

FWIW, uesterday I drove to work without my 12v charging in my Insight. To charge the 12v I currently have the IMA motor hooked to a 3 phase rectifier (70-300v AC to 70-300v DC) and that to a Meanwell power supply to step the 70-300v DC down to ~14v DC. The difference in fuel economy between driving to work Wednesday morning with everything charging, vs Thursday with it unhooked and just using the battery's capacity, was less than 1%.

Interesting.

How many l/100 km or l/h was your consumption ?

Fuel quantity / distance or fuel quantity / time.

My commute is around 12 miles each way, and I consistently get around 3.2L/100km on the way there (uphill) and 2.9L/100km on the way home (downhill), not driving very conservatively either way lately. Travel to work is ~05:30-05:50 and trip home is 13:00-13:25.

I notice a consistent ~0.25L/100km increase when lean burn is disabled for this trip, but toggling 12v charging on and off disappears into background noise.

EDIT: Before I took my hybrid system out, I was getting the same ~2.9L/100km on the way to work, but on the way home, due to opportunities for EoC, I could see as low as 2.5L/100km depending on traffic.

And may one inquire your guesstimated electrical load?

The Meanwell power supply I have outputs up to 53 amps, and I currently have it set to ~14.0v. It's rated at typically 88% efficient, but I've bypassed its internal rectifier so it might be higher than that. The fan isn't supposed to come on until 35% load (+/- 15%) and for the most part it stays off, even when I'm blasting music. I often hear the fan pulsing when I run my turn signals (following the blink rate), roll down the windows, or have the HVAC system running plus headlights (low watt HIDs). So, if I were to guess, typically I'm drawing less than 20 amps during this drive, possibly less than 10 amps.

So 0.03 l /100 km for 120-200W

Roughly 0.2l/kWh.

No, not exactly. I haven't been able to measure a drop in economy. It disappears into background noise, it's zero within margin of error.

I'm sure it's not actually zero, of course, I just can't see it.

If those are the numbers it is not really worth doing for me.
Then again your converion ratio is close to optimal.