3 Cyl Metro Pull Start?
 

I had another crazy idea for my metro. To eliminate the battery and the maintenance that comes along with that, I was thinking I could install a lawnmower style pull start. I'd probably just use a small capacitor in place of the battery for the sake of current flow while running. This would eliminate the issue of of the alternator constantly working to charge a 12v battery to 14v. This also would mean no worrying about a dead frozen battery in winter.

Thoughts?

You would need a destroke lever so you could reduce the kick

You would also need a magneto to run the spark until ecu wakes up

That doesn't solve the problem of losing memory presets, which is among the reasons to have a battery. If you don't care about that, then you could just use a detachable battery or supercap. Heck, if the parasitic drain is extremely low, you could probably just leave the supercap in and it would hold enough charge to start the car even after sitting a couple weeks.

My truck is down to about 5 mA parasitic drain (radio), so it could theoretically run off supercaps alone.

I don't think the ECM runs the spark on these cars? maybe so but I figured they weren't as it has a distributor.

As far as presets....I don't even know how to turn the radio on in this car (very old aftermarket CD player.) I have 4 kids at home, my commute is my time to have quiet, aside from the drone of the 3-cyl.

I'd start by measuring your parasitic drain with a multimeter. If it's low, you could try a 6-series 350 farad supercap bank. Should work fantastic in your cold winters...

Of course, you'd want to disable your dome lights (or go LED) and be careful about anything else that might turn on when you open doors, etc. That will very rapidly drain a supercap.

bettery delete

I'd skip the "pull start" and consider one of the battery pack jump starters
still using a capacitor for your electrical load

https://www.amazon.com/GOOLOO-SuperS...=fsclp_pl_dp_2

Actually the dome lights is what made me think of it. Of all things this car does not turn on the dome light when the door opens, but it does have an idiot light to show the door is open if the key is on.

pocket jump starter
 

I think I like this one even better

https://www.amazon.com/dp/B07MNKH8PK..._t3_B076PR52Z7

https://images-na.ssl-images-amazon....L._SL1024_.jpg
they have larger ones too
800Amps
$49.99
1200Amps
$64.99
1500Amps
$79.94
2200Amps
$129.94

Those guys did a pretty lousy job of actually hooking things up, I just found some other videos of predator swaps in cars where they did things properly. Here is one:

5 speed transmission, centrifugal clutch, and the throttle is hooked up(duh!). You can shift on the fly!


https://www.youtube.com/watch?v=Baey...ge9nX&index=11

That belongs in a Mad Max film! :thumbup:

I need to be able to to use this on the interstate in 70-80 mph traffic

How about hand crank?

https://www.youtube.com/watch?v=1pnXaENvCKc

Hmm, that's an idea.

Or a usb powerbank with a boost converter.


Newer powerbanks can charge laptops aswell so they can output up to 20V.

Obviously not hundreds of amps.

You have to communicate with them over the data lines, the protocol was simple from what i observed on a youtube channel.

Those guys didn't even know what they were doing. The second video with the truck is much better. I can see this being handy around a farm or country home, but the engine lacks the power to cruise at 55mph+ and climb hills.

It wouldn't eliminate the alternator or starter, but I was searching batteries one time and found some amazing lithium-ion batteries that packed a helluva punch and only weighed like 7 lbs! Of course, they were very expensive - some over $1000 - but that would save a bunch of weight! Then solar cells on the roof, and....

Well to buy and fix this car I'm only in it for $450, so 1k for a battery ins't going to happen.

I have a friend who uses a little 2 pound mighty max battery from amazon to start his 40hp yamaha two stroke outboard motor. Its like 700cc so maybe you could try something like that. His battery was only like 19.99 and reduced weight by ~60 pounds.
Past that... Pull starting my yam 40 is a big pain in the ass. I wouldn't recommend pull starting a car engine.

I'm not so much concerned about weight, I drive 80 miles of interstate a day with ~3-4 miles of 'city' driving, which is basically just from my house to interstate. The reason I was thinking about this was to eliminate the constant draw of a battery that can't be charged further, yet the alternator is trying to do so.

does it have injection or carburator? when I was a kid, my dad adapted his Skoda 100 for hand cranking, but it was old-fashioned carburated engine with spark distributor.
As far as I remember, it also kicked hard so he started the car by hand only when batttery was too weak to power the starter.

Beside that, hand cranking mod shoul be relatively easy. you just need socket (preferably ratchet type) bolted to a crankshaft, handle with two pins at the end and thats all...

Once the battery's voltage is up to 'fully charged' the alternator will stop 'trying' to charge it :)

The problem is an auto battery only accepts ~12.5 volts, while the alternator is putting out 14.5 assuming it's healthy. The alternator is constantly working to make up this 2V difference, and it causes a significant load on the engine while doing so. People have seen I believe as much as 10% fuel economy increase by eliminating this load. That translates to another 4-5 MPG in my geo if it holds true.

The battery isn't what causes the majority of the alternator load, it's everything else in the car. The alternator will run at 14volts with or without a battery connected, so the load will still be there running all the various electronics in the car.

Another important note, I strongly suggest not driving any car without some manner of battery or capacitor or something to smooth out voltage, the voltage will jump around enough to damage electronics without one.

The lead acid battery is extremely inefficient at accepting a charge when it's nearly full; perhaps as low as 50% or less. The thing is though, wasting 50% of almost nothing is still almost nothing.

I don't even think 1% gain in fuel economy is possible by replacing the lead acid battery.

Interesting. I thought people had seen good gains by doing this previously? Or do they ditch the alternator and just bank on their battery lasting long enough to get home?

The alternator is very inefficient, and ditching it has shown gains of around 5% depending on how efficient the vehicle is in the first place and the electrical demands. That requires more battery capacity and a means of charging from the grid.

I think there are gains to be had by replacing the lead acid battery with another chemistry or perhaps a supercap, but they would be very small and likely not measurable. One of my projects is to measure the difference in efficiency between a lead acid and lithium ion battery someday by discharging it some measured amount, and then measuring how much energy is required to charge it back to "full".

Ok. This project will probably never get done on my car then. The old Metro is pretty fuel efficient as is, and a new O2 sensor will do far more than the maybe 1% you're predicting here.

Obviously my reading comprehension needs some help.:thumbup: