58 MPG by 2032

[Grumpycat]

kWh is independent of voltage. Amp-hours requires knowledge of the voltage to determine kWh. Amp-hours times voltage equals Watt-hours. Amp times volts equals Watts. I know, in this day and age math is hard, and racist.

And in support of @WinterDeere the CCA rating is hyped by starter battery vendors as a valid means of comparing starter batteries to the point consumers think they know everything about buying batteries and are smart with CCA. It is meaningful for comparing starter batteries but says almost nothing about capacity. Lithium “upgrade” starter batteries have astronomical CCA ratings but about 1/4 the amp-hours. So CCA doesn’t translate outside the starter battery realm, and then only to lead-acid batteries.

These same smart consumers ”know” batteries only last 3-5 years and therefore believe the same will be true for EV traction batteries. Sadly Nissan worked hard to make that come true with the LEAF.

 

[WinterDeere]

Amp-hours becomes important on a starter battery when you (a) have a vehicle that doesn't want to start, or (b) a vehicle that sees frequent starts (eg. UPS trucks). If you've ever sat cranking a stubborn car on a cold morning until the battery eventually goes dead, you've had a chance to display CCA and amp-hours, all in the same sitting!

 

[nickfank]

How do you figure out example a car battery has 800 cold
cranking amps = how many KWH how to figure this??
How long would a lithium 100 ah battery last drawing 15 amps?
My wife had the 6400 btu unit cooled her 17x12 room an the
8400 cools the kitchen. dining room and we keep the
temp at 75 F because the temps are close to 100+ here
no need to cool where we are not! I an usually outside with
no a/c working in the heat as I don't like going from 100+ to
75 degrees F when your soaking wet from sweating!

willy

Several good responses to this, but I'll add a little detail...

volts times amps = watts, so the 12V, 800CCA battery can briefly supply 9.6 kW. No telling how long it can do that though, unless they tell you the Ah rating as well.

If your battery (lithium, or any other chemistry) is rated for 100Ah, it will last 6-2/3 hours drawing 15 Amps. (100/15)



Watts tells you how much power you have right now, and watt-hours tells you how long you can maintain that power before your battery is dead or your fuel tank is empty.

A watt and a BTU/hr is a unit equivalent to horsepower. (1HP = 746 watts = 9,000 BTU/hr)

Watt-hours and BTUs are equivalent to gallons of fuel. (1 gallon of diesel = 38 kWh = 138,700 BTU)

Putting this into practice:

If I have a 35HP tractor, that tells me how hard the tractor can pull, but not for how long. If I also know I've got 3 gallons of fuel in the tank, now I know I can pull at the full 35HP for one hour before I run out of fuel.

We can do the same thing with watts:

If I have an electric tractor with a 50 volt battery that can supply 500 Amps, then by multiplying 50 times 500, I know it can pull with a force of 25kW (33HP). If I add the information that the battery can supply 1000 Ah, now I know the battery will need to be recharged after 2 hours working at full power.

Since BTU tends to be used for air conditioners, I can't come up with a good tractor version, but that 6,400 BTU air conditioner includes a hidden time component that the marketing folks left out. In air conditioning jargon, 6,400 BTU means that the air conditioner is removing 6,400 BTUs of heat from the room every hour. That means that if you turned on a 530 watt heater in the same room, or burned .05 gallons of diesel fuel each hour, it would exactly balance the air conditioner and the temp wouldn't change.

 

[Grumpycat]

Amp-hours becomes important on a starter battery when you (a) have a vehicle that doesn't want to start, or (b) a vehicle that sees frequent starts (eg. UPS trucks). If you've ever sat cranking a stubborn car on a cold morning until the battery eventually goes dead, you've had a chance to display CCA and amp-hours, all in the same sitting!

LiFePO4 "upgrade" batteries are popular in the motorcycle market for being lighter than AGM. They suffer at 50°F, and while they have spectacular lead-equivalent-CCA ratings, as you say, when the engine doesn't start quickly the battery quickly depletes for lack of total Wh.

LiFePO4 can't rate CCA at the temperatures lead-acid batteries are tested. So they do a Cranking Amps at a warm temperature and misguidedly quote that number and footnote in the fine print how lithium CCA is different.

 

[WinterDeere]

I believe they probably use Ah over Wh for most batteries because it is more a true measure if the stored chemical charge. Voltage will drop as battery depletes, making watt-hours a less consistent metric, for that application.

 

[Williy]

Thank's to y'all for the information.
I was thinking of getting a Jetta tdi but in 2015 no more vw diesels
for the USA too much garbage you have to put on machines.
However the Jetta with the gas engine is getting over 40 mpg
and I think its smaller so will make it easy t;o squeeze into a
parking spot. We are in the last days and IMHO fuel prices at
going to esculate

willy

 

[etpm]

Our power spiked from 11c/kwh to 17c/kwh, I didn't even realize it. I installed new equipment to cut power, and factored the cost of the equipment would pay for itself in about 15 months. The bill didn't go down the next month by any measurable amount so I went to verify that the usage recorded was lower. I have my own instruments for monitoring consumption as well. The reading was ~2500kwh, vs the forecasted 3500kwh on the old equipment. However that massive increase in costs just killed any savings I would have seen.

I will be pushing my solar array install up to as soon as possible to try and further offset the increased costs. It's really not a selling point for EV's when it's going to cost me more to run them. Once I have a big enough array in place I'll be ordering batteries and disconnecting entirely.

Which types of battery chemistries are you considering? Even though where I live in western WA gets much less usable solar than other places in western WA I am still considering solar. And I would like batteries to obviate a generator when the power goes out. I don't think, for me, that 100% solar would be economical at this time.
Thanks,
Eric

 

[bnold]

LiFePO4 "upgrade" batteries are popular in the motorcycle market for being lighter than AGM. They suffer at 50°F, and while they have spectacular lead-equivalent-CCA ratings, as you say, when the engine doesn't start quickly the battery quickly depletes for lack of total Wh.

LiFePO4 can't rate CCA at the temperatures lead-acid batteries are tested. So they do a Cranking Amps at a warm temperature and misguidedly quote that number and footnote in the fine print how lithium CCA is different.

Thing is absolutely amazing in my KTM.
Thing feels like a feather and is tiny.

 

[Grumpycat]

I believe they probably use Ah over Wh for most batteries because it is more a true measure if the stored chemical charge. Voltage will drop as battery depletes, making watt-hours a less consistent metric, for that application.

Wh is the true measure of the battery's capacity. It is a number one can use to compare batteries irrespective of voltage.

Short circuit amps (as with CCA) will taper off as voltage declines as battery discharges.

For many batteries the Ah rating is measured as a continuous amperage for 20 hours. Requires trial and error to determine. IIRC a 1 hour test is used for automotive starter batteries.

Wh is much the same but the area under the curve is integrated. Again "in a set time", and again one has to guess by trial and error how many amps to draw.

Many do not realize how hard it is to produce a S.O.C. meter for a battery, State Of Charge, to know how much is remaining. Can not just measure voltage and temperature. Am amazed at how well Tesla has calibrated the "fuel gauge" on my Model S.

 

[WinterDeere]

Wh is the true measure of the battery's capacity. It is a number one can use to compare batteries irrespective of voltage.

I'm not sure this is true, or at least I'm not used to seeing "Wh" ratings printed on battery casings, those I've checked have been nearly always expressed in "Ah". Again, I believe this has to do with battery chemistry and physics, as it's a stored charge (Coulombs) which translates to consistency in amps (Coulombs/second), and no consistency in watts under condition of diminishing voltage. I'm not a battery expert, and I hated all three terms of Chemistry I was forced to take, it would be good if we could hear on this from someone who actually designs batteries.

Wh is much the same but the area under the curve is integrated. Again "in a set time", and again one has to guess by trial and error how many amps to draw.

Again, EE here... you don't need to explain what watt-hours are, this is kindergarden stuff. If you want to get into skin effect and variation in effective conductivity due to surface roughness at higher frequencies, or moding of various conductor arrangements due to physical geometry and inhomogeneous dielectrics between them, I'm your man.

 

[Gator6x4]

I'm not sure this is true, or at least I'm not used to seeing "Wh" ratings printed on battery casings, those I've checked have been nearly always expressed in "Ah". Again, I believe this has to do with battery chemistry and physics, as it's a stored charge (Coulombs) which translates to consistency in amps (Coulombs/second), and no consistency in watts under condition of diminishing voltage. I'm not a battery expert, and I hated all three terms of Chemistry I was forced to take, it would be good if we could hear on this from someone who actually designs batteries.


Again, EE here... you don't need to explain what watt-hours are, this is kindergarden stuff. If you want to get into skin effect and variation in effective conductivity due to surface roughness at higher frequencies, or moding of various conductor arrangements due to physical geometry and inhomogeneous dielectrics between them, I'm your man.

AMP hours or AH is used on a battery to advise how many amps the battery can delivery in an hour.

Capacity – Amp hours (Ah):As the name suggests this means how many amps the battery can deliver in an hour. For example, a 12V lithium battery with a capacity of 100Ah can deliver 100A to a 12-volt device for one hour. The same 100Ah battery could supply power for 4 hours (100/25=4) to a 25 ampere device.

WH or KWH is used to provide information on the electrical flow and usage into a business or residential structure.

"Watt vs Watt-Hour"​

"A watt is a unit of power, while a watt-hour is a unit of energy."

"Watt refers to the amount of energy a device needs in order to function. It is equivalent to the electricity flowing at a rate of one joule per second."

"Watt-hour, on the other hand, measures the amount of work generated by an appliance. It calculates the total energy consumed by an electrical device or appliance over a period of time. It indicates how many watts are used in one hour."

"In short, watts measure power while watt-hours (Or KWH)measure energy used."

A lot of new vehicle come with a 110 volt converter. You plug a regular 110 drop cord into the receptable on the vehicle and operate a portable electric drill from example. You would need to know the ampreage use of the drill to know how many hours or minutes your could drill holes with the drill before the battery would stop producing amperage to power the drill.

 

[WinterDeere]

AMP hours or AH is used on a battery to advise how many amps the battery can delivery in an hour.

No, you got that backwards. You copied and pasted the right explanation, but drew the wrong conclusion from it.

Amp hours is amps times hours, not amps per hour. As already noted in the definitions you posted, it is a measure of energy. Energy is power times time, not power divided by time.

Let's pretend we have a battery capable of delivering 10 amps continuous, without thermal constraints. If the capacity of this battery is 75 Ah, it would be able to deliver that 10 amps (nominally) for 7.5 hours. Not per hour.

Because voltage wains below 40% or 50% capacity in a real (non-theoretical) battery, the actual delivery of current will vary, and thus power will vary by a square law (as voltage and current both drop correspondingly. This may be why battery manufacturers seem to prefer using Ah over Wh.

 

[Grumpycat]

AMP hours or AH is used on a battery to advise how many amps the battery can delivery in an hour.

Capacity – Amp hours (Ah):As the name suggests this means how many amps the battery can deliver in an hour. For example, a 12V lithium battery with a capacity of 100Ah can deliver 100A to a 12-volt device for one hour. The same 100Ah battery could supply power for 4 hours (100/25=4) to a 25 ampere device.

This is not true. Deep cycle batteries are rated for amp-hours on a 20 hour test. A current is drawn for 20 hours and if sufficient voltage is held at the end then it is rated at 20 times the current which was drawn.

This link says car starter batteries are tested for 10 hours:

How to Determine Amp Hr Rate - Lead Acid Batteries | BatteryStuff

Learn how “Amp Hr Rate” is determined and why it’s a more accurate representation of lead acid battery performance. Read the post today.

www.batterystuff.com

One will be disappointed if one tries to pull the Amp-hour rating in one hour.

Lithium chemistries have spectacularly low internal resistances which will source large amounts of current. The lithium industry may rate Amp-hours on a different time scale.

 

[Grumpycat]

Thing is absolutely amazing in my KTM.
Thing feels like a feather and is tiny.

Just wait until it gets cold.

 

[IXLR8]

I'm late to this thread, my mildly tuned 02 VW Golf TDI routinely got 57-58mpg in the summer, 52-54mpg in the winter. Had several tanks were I averaged 60mpg. I had 300K miles on it when too many Maine winters caused it to rust out and fail to pass safety inspections, otherwise I would still be driving it.

 

[Grumpycat]

I'm late to this thread, my mildly tuned 02 VW Golf TDI routinely got 57-58mpg in the summer, 52-54mpg in the winter. Had several tanks were I averaged 60mpg. I had 300K miles on it when too many Maine winters caused it to rust out and fail to pass safety inspections, otherwise I would still be driving it.

Gee, that settles it! Everyone build 2002 GW Golf TDI clones to solve all the world's issues!

VW couldn't/wouldn't clean up their diesels to meet emission standards which were laxer for diesel than gasoline. That is why the TDI died.

I tried to buy a new 2005 VW Golf TDI but the dealer was awful. I found via online forums that all VW dealers were awful at TDI diagnostics. That VW had browbeat all into being totally dependent on VW's diagnostic computer which wasn't smart enough to instruct the mechanic to try replacing the fuel filter before replacing the fuel injectors or fuel pump. If VW warranty is paying we don't care, but when one has to pay for this idiocy out of pocket it is something else. The mechanic who doesn't learn on warranty work will not know any better.

So what happens if "everyone" drove diesel automobiles (even if they were as clean as gasoline)? Where would we get the diesel from? Diesel and gasoline are symbiotic. Production of one depends on the other, and vice versa. A barrel of crude can not be made into either gasoline or diesel, you can get some of each and rubber the ratio a bit but when you deviate from the natural split costs soar. This is why decades ago when gasoline was in high demand diesel was dirt cheap. It was being given away as a byproduct of producing gasoline.

Today there is a high demand for diesel driving it's price to something much greater than gasoline. I bought 87 AKI today for $3.269 at a pump that offered ULSD for $4.079.

At these prices and 54 MPG ULSD one only has to get 43 MPG on 87 AKI gasoline to be equal. My lifetime actual miles divided by actual gallons in 2007 Prius was 51.16.

 

[WinterDeere]

I got stuck behind a person driving a Jetta wagon today. Maybe the person just had a light foot, but their 0 - 60 times could have been almost measured in minutes, it was so painfully slow following them. Maybe they were just letting the car literally idle up to speed, rather than pressing the damn gas pedal, I don't know. They would eventually reach a respectable speed, so not an issue of just a slow driver, but my God... they took an awful long time in getting up to that eventual speed. Made me think the car must just be woefully under-powered.

 

[Gator6x4]

I got stuck behind a person driving a Jetta wagon today. Maybe the person just had a light foot, but their 0 - 60 times could have been almost measured in minutes, it was so painfully slow following them. Maybe they were just letting the car literally idle up to speed, rather than pressing the damn gas pedal, I don't know. They would eventually reach a respectable speed, so not an issue of just a slow driver, but my God... they took an awful long time in getting up to that eventual speed. Made me think the car must just be woefully under-powered.

That‘s how one achieves those astronomical MPG. Of course they average things out. 35 mph on 2 lane highway and 75-80 on 4 lane highways.

One of the high miles per gallon will also not pass on a two lane road because they will have to go faster than the car in front of them. They want a four lane so they can travel along in one‘s blind spot. In racing they call that side drafting improves fuel mileage.,

 

[IXLR8]

Most VW dealers are terrible at repairing the TDI engines, which I why I did all my own work. Scan tools are available that would give you more access to more options than the dealers computers.

My TDI was known to spin the tires on occasion when pulling away from a stop, so slow accelleration is mostly a function of the driver.

 

[Grumpycat]

That‘s how one achieves those astronomical MPG. Of course they average things out. 35 mph on 2 lane highway and 75-80 on 4 lane highways.

Not necessarily. Peak MPG is somewhere higher in speed. Apparently you have never tried.

This is what I did this morning in the Subaru Outback. This is what the Fool Computer says.

This is what the gas pump says. Previously filled same station 2 weeks ago. Parked 2 weeks. This is lower than I would have expected based on previous Lie O'Meter results. Expected 34-ish. Possible I filled different, they changed the nozzles.