Energy Draw to Charge

[zolorin]

Has anyone put a KillaWatt on the slow 110 charger to see how much does the energy it takes to charge the car fully?

I have and was terrified
So to charge 10.6 kWh of battery capacity I have used 14.5 kWh which means it is 73% efficient.
This is quite bad. I hope that this inefficiency is only at low 120V. Now would be interesting to measure using a high speed charger. I have just installed solar myself on my house and all of the electrical componentry was 95% and higher efficiency. Now I don't know if the efficiency is being lost in external charger, internal charger or both. My bet it is mostly internal.

 

[jmueller065]

First question: Where was the FFE parked when it was charging? Was it hot? It is quite likely that the thermal management system (TMS) kicked on to cool the battery (which consumes a lot of juice).

So far with L2 charging the best I've seen is about 85% efficient--this was overnight, though, so I don't know if the TMS turned on or not.

 

[mcowger]

Has anyone put a KillaWatt on the slow 110 charger to see how much does the energy it takes to charge the car fully?

I have and was terrified
So to charge 10.6 kWh of battery capacity I have used 14.5 kWh which means it is 73% efficient.
This is quite bad. I hope that this inefficiency is only at low 120V. Now would be interesting to measure using a high speed charger. I have just installed solar myself on my house and all of the electrical componentry was 95% and higher efficiency. Now I don't know if the efficiency is being lost in external charger, internal charger or both. My bet it is mostly internal.

Might be different with the 240V - I found it to be 85.9% efficient with my power monitoring hardware.

--M

 

[WattsUp]

Has anyone put a KillaWatt on the slow 110 charger to see how much does the energy it takes to charge the car fully? I have and was terrified
So to charge 10.6 kWh of battery capacity I have used 14.5 kWh which means it is 73% efficient.

Might be different with the 240V - I found it to be 85.9% efficient with my power monitoring hardware.

Even at Level 2, the "typical" EV charging process is about 80% efficient (if it's about 85% with the FFE, them we're ahead of the game).

Supposedly, Level 1 charging is always somewhat less efficient than Level 2, so 73% would seem to be in line with that expectation.

 

[zolorin]

This was 120V charging scheme. So I will measure more and check the temperature in the garage (the car is parked inside).

I am going to get the 240 volt charger and see what will happen then

 

[WattsUp]

This was 120V charging scheme.

Understood. I was pointing out that, even at Level 2, one can really only expect about 80% charging efficiency, and, at Level 1, it is even less. So, 73% is not surprising at all.

You mentioned that you were "terrified" with the energy required to charge your car, but this is simply the reality of Li-ion battery charging. What you should really be terrified about is how much energy must be put into a gasoline-powered car (and how much it utterly wastes) to make it go the same distance as your EV.

20% overhead may seem like "quite a waste" of energy. But, even with this overhead, EVs are still about 4 times more efficient than gasoline-powered cars at turning the energy put into them into useful work.

 

[zolorin]

It is actually really bad.

Solar cells get inverted at 95% from DC to AC. Some of the new power supplies for computers (really high end stuff) is 90+% effiicient (platinum grade). I just installed solar panels on my house and I have read all of the specs. So 70% for electrical to electrical conversion is fairly bad. Mechanical to electrical of 70% is ok -- most newer alternators that are brush-less are 75% or better

 

[WattsUp]

It is actually really bad.

You seem to be comparing the efficiency of the entire battery charging process to just the power conversion efficiencies of these other scenarios (solar panels, computer power supplies, etc.)?

As an industry-wide norm, the typical EV battery charging process is about 80% efficient. The energy required to charge an EV includes not only the energy lost in the power conversion (the scenarios you're comparing to), but also the energy lost as heat generated by the current flow within the system, the energy consumed by the thermal management system (like the FFE has) to regulate the battery temperature (which is affected both by generated heat as well as the ambient temperature), and the fact the charging a Li-ion battery itself is not a zero-sum game. It always takes more energy to place a charge into the battery than the battery ends up holding and is then able to discharge. The best Li-ion cells are about 90% efficient.

For an EV, I think you'll find that the overall charging efficiency of the FFE (someone just quoted about 85% at Level 2, slightly better than the industry norm) is actually quite good.

 

[zolorin]

The battery cells are 97 to 99% efficient (any lower and they would blow up and they used to blow up) at a charge of 0.8C

http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries

I have a lot of experience with the Lion and LiFePo batteries from my work and my side projects I have done. The batteries are charged at a constant current (till about 80% of battery capacity). The rate of this current is non dimentionalized by the rated battery current. So 1 amp-hr battery at 3.7Volts has energy density of 3.7W-hr. It has a efficiency of 97-99% if it is charged at 0.8 amps.

Now lets see where the ford batteries are

23 kw-hr. One of the persons here on forum said that they use 98 cells to get the voltage. Thus nominal voltage is 362.6V and thus each cell is 63.4 Amp-h. Level 2 charging is 6.6Kw at 4.2Volts (near the cutoff to the trickle charge, which ford seems not to use) this results that each cell is only 16 amps. Which only 0.25C, that is the charging of these cells is a 97+% efficiency.

Now for the battery managment system -- it is all depends on how they built the internal charger. If they used old style transformer to raise the voltage first then I can see it being 70-80% effiicient. If they went with solid state components, then we should see efficiencies much higher.

 

[WattsUp]

The battery cells are 97 to 99% efficient (any lower and they would blow up and they used to blow up) at a charge of 0.8C. I have a lot of experience with the Lion and LiFePo batteries from my work and my side projects I have done.

I stand corrected. I was going by wikipedia.

So you're saying EV charging could achieve efficiencies in, perhaps, the mid to high 90 percent range, "if they really wanted it to"?

 

[zolorin]

essentially yes,

Maybe not mid to high 90s, but low 90s defenetely doable. 97% on batteries plus 95% on inversion of the voltage, 90 to 93% depending on a situation.

The reason I am harping on this is that I have installed solar my self. I know what I am producing, I expect certain efficiencies from other people and I get pissed off if I don't get them. Because they cut into my bottom line. I promised my wife and my soul mate that we can be nearly energy free and this cuts into my promise.
:evil:

 

[unplugged]

I promised my wife and my soul mate that we can be nearly energy free and this cuts into my promise.

I'm curious, does your wife know about your soulmate?

 

[hybridbear]

I promised my wife and my soul mate that we can be nearly energy free and this cuts into my promise.

I'm curious, does your wife know about your soulmate?

Lol :lol:

 

[zolorin]

:lol: :lol:

OOOPSSS

I meant to say

I promised my wife who is my soulmate ...

 

[EVA]

OK I love what this forum does to certain words.

Soul ends up with a link to here:
http://www.mykiasoulev.com/

So Zolorin your soulmate is a Kia?

Sorry you are upset about the charging efficiency. I guess I always just figured, the efficiency is 80-85%, it's a loss, it goes somewhere, and there's nothing I can do about it.

Here's the way I looked at it, and why I'm not messing with time of day charging. I used to spend $300 a month on gas. I now spend maybe $20 on electricity. I don't know, that sounds like a heck of a lot more efficient than anything I was doing before. So if I lose 20% while charging, it doesn't matter, my bill would have been $16 if the car was 99% efficient. For $4 I'm going to worry?

So you could look at it, your electric bill before solar panels was $500 a month. Maybe your gasoline bill was $200 a month. Because the FFE is only 80% efficient, your total electric bill will be $5 after the solar panels, and zero for gas. Gosh to me that sounds like a $695 savings a month.

How efficient are other BEVs?

 

[zolorin]

BEV? what are those, I am new to this stuff

But you are right on the gas being replaced with electricity.

However it is not that easy to say 300$ = 20$, well not in CA. The dreaded state. Our electricity tiers are outrageous.

Tier 1 = 15 cents (up to your baseline which is about 11 kwhr a day) so 330 kwh per day on a 30 day month
Tier 2 = 17 cents for the next 30% over base (next 99 kwhr)
Tier 3 = 36 cents and this is for up to 2x of the baseline (next 231 kwh)
Tier 4 = 38 cents afterwords

heating is usually gas, but AC kills you
basic house burns minimum of 400 kwh (no matter what you do)
Then if you have pool pump (variable speed) that is another 300 kwh or 600+ if it is older school.
AC is a cherry on top of that. My woman is happy that she can be relatively comfortable with our cooling needs

Solar makes sense if you install it your self I did a 10kw system for about 1.55 $/W capacity after the tax rebate.
However I am trying to upgrade the HVAC, water heating and try to live off the the 10kw system. I am fed up with paying to the util company. They are a bunch of crooks.

Next is winter and I am trying to get us ready with heat pumps. I hope that they can come up with ways to store energy long term

 

[WattsUp]

BEV? what are those, I am new to this stuff

Battery Electric Vehicle

The FFE is a BEV.

 

[v_traveller]

Did a really quick search for net wisdom... Here's a glossary, albeit woefully incomplete - doesn't have FFE in it... WTF? :evil:

Found others, but they didn't even have BEV in them...

http://www.environmentfriendlystore.com/ebike-glossary.html