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

[Daox]

Well, nominal voltage for 4X lithium batteries is 12.8V, max charging voltage is ~14.4V. As long as your alternator doesn't exceed 14.4V I'd say you don't need any buffer or anything, the alternator should charge the lithium pack very well.

[Nerys]

I thought lithium needed a CONTROLLED charge? I am pretty sure you can't just shove raw power into a lithium pack and expect to survive the encounter :-)

also what about balancing the pack? lithium is 3.7v so that 14.8v is made of 4 cells that need to be balanced.??

So I very much doubt you could "charge" the lithium pack directly off the alternator like you can a lead acid battery.

then you have the problem of how well will a lithium (and charger) handle the pack being charged "AND USED" at the same time? most battery charger arrangements do "NOT" like this at all.

so you might need 2 packs. one to charge one 2 "use" and alternator between them to keep the packs happy.

now if you go sans alternator no problem since you will only use or charge and not both. but now the lithium pack gets a lot more expensive since you will need a much larger one :-)

[sidebar78]

There was a Nascar car builder and Indy car builder named Smokey Unick. in his book The Best Damn Garage in Town,it stated that in the 60's Smokey put a propeller on an alternator and mounted it behind the grill,did it work? it worked so well Nascar out lawed it.Smokey discovered that at 60 mph it charged the battery as well as the engine did. Smokey had a real dislike of engine driven components..they steal power ,his next invention was to have the alternator driven by the drive shaft. he put a pully on the drive shaft and made a bracket to hold the alternator. it was belt driven. not as efficient as the propeller driven one it still saved power.he had ideas that the water pump could be electric and driven by his air powered alternator.this was really advanced thinking for the time, when gas was 32 cents a gallon.he made a car that got 78 mpg with air cond, and ran 80 mph,he tried to give it to the U.S. auto makers, they turned him down saying his little diesel car wasn't efficient enough. boy, I sure wish I had one!

[Hauki]

Smokey sounds like a great guy. But I'm sure the savings were not so significant because any saving you make from one area is counter-acted by the energy required in another area. Much like if you put a wind generator on top of an electric car, any electricity gained is cancelled out by the increased drag. I suspect the same issue's Smokey faced. He should have just made a grille block and kept his alternator standard

[Frank Lee]

He made the prop alternator because he was having a problem with the engine throwing belts. That's it.

[Christ]

I'll add to that, as well. A prop driven alternator can't be more than about 24% efficient from wind to battery... It would take a prop the size of the frontal area if the engine block, or a very high wind speed to make any useful power.

There is also not alot of need for an alt on cup cars... Not alot of lights and stereo/climate control, ya know? That being the case, it might have produced enough power to keep the battery charged and keep the ignition system operating, but likely not much else.

Use search function "squirrel cage alternator". I did some math in that thread to explain exactly this.

[sidebar78]

alas,Smokey has long passed away, some of the things he made was the first workable flow bench for cylinder heads,and fuel systems. he built the first engine dyno, you can take a tour through his shop in Florida. his flow bench was so good, many Nascar engine builders say it is more accurate than the modern one they have now.the guy was a bonifide genius,none of us had the right to be in the same room with him,that said when asked a question,Smokey would explain things till you understood it.a rare man

[sidebar78]

one other thing the little car that got 78Mpg and ran 80 mpg with Air! was not destroyed. Smokey was disgusted with Detroit and Washington, so when he got back to his shop he just shoved the little car to the back of his shop,it is going under restoration, I want to see it when it's done, I know it's a Ford and has a 3 cylinder diesel eng, to get 78 mpg this diesel has to be running at the top of it's game,almost no wasted energy

[Moriene]

Hello Friends,
I am new over here

[electricman]

Originally Posted by MetroMPG

Today, with two 6v "junk" batteries (from the forklift company) in series to make 12v, then in parallel with the existing 12v starting battery, I did a 46 mile / 74 km alternator-less round trip.

Starting voltage: 12.68
Ending voltage: 12.40 (batteries resting for 1 hour)

11.7v is "empty", so I used 26% pack capacity in that trip, with light accessory load: wipers occasionally; heater fan occasionally; lights; occasionally; plus engine overhead, turn signals & brake lights.

Assuming similar electrical loads, my total range to 100% depth of discharge is about 177 miles / 285 km.

It is currious - the Two 6V Forklift batteries would each weigh (in my guess about 66lbs each) 132 lbs!

So - if you tried this with 4 x 60 Ah Thundersky Batteries at about $64.50/$75 apiece, for a $300 total - but - a total weight of about ~10 Kg, or 22 lbs, I wonder how that 110 lbs weight saving would change the energy used, and since they handle deeper discharges even better (1C x 100% DOD = 1000 Cycles - vs Lead Acid .05C x 80% DOD = about 450 cycles) the cost in the long run could actually be cheaper than free! (Free Beastly batteries)

If you did not seem to need the 60Ah sizes, myabe just use 4 x 40 Ah cells for $200? Alliance Renewable Energy = $43/$50 China/USA.

Consider - if the forklift company gave you 'expired' Lithium Iron Phoshpate cells - that has just 80% of original rated power - you cold get the best of both worlds - free and LiFePO4!

Someday!

Robert