HSH Energy calculations
These are some rough calculations for the hybrid system based
upon information gathered on the internet and from the
Owner's Manual.
From the Manual:
Battery pack consists of 72 cells arranged in 9 modules of 8
cells each.
Battery pack voltage is 270V (nominal). This means all 72
cells are arranged in series since a single cell has a
nominal voltage of 3.75V.
Battery pack system weight is 42kg (92.4lbs).
From the internet:
netcarshow dot com slash hyundai/2011-sonata_hybrid
Battery pack capacity is 5.3Ah. Therefore 270V x 5.3Ah =
1.43kWh, which is how much energy the battery pack can store.
Drive motor produces 30kW, which is almost exactly 40HP.
I found a similar LiPo cell at bananahobby dot com for $21
each. The specs are:
Capacity: 5500mAh This equals 5.5Ah.
Max Charge Rate: 8C
Max Continuous Discharge Rate: 55C(302.5A)
Max Burst Discharge Rate: 80C(440A)
Weight is about 150g.
Volume is about 80cc.
Now we can do some calculations and see how close they come
to real life observations. First some assumptions:
Motor efficiency is 75%.
Inverter efficiency is 80%.
Power required to maintain 62mph on level roadway at standard
temp and pressure is 9kW. This is not quite a WAG and should
be fairly close to the actual.
Power required to operate all other vehicle systems at normal
conditions no more than 3kW.
First, for the motor to output the max power of 30kW or about
40HP, the battery will see a load of 50kW.
50kW * 80% = 40kw from the inverter to the motor.
40kW * 75% = 30kW mechanical power to the tranny.
For the battery pack to output 50kW will require an amperage
of 50kW =50,000W / 270V = 185A. Including the other vehicle
systems the amperage required would be 196A at max
conditions. This is well within the stated specs of the
above LiPo cell, especially since max conditions cannot be
maintained but for a short time due to battery capacity.
Second, for the motor to output 9kW or about 12HP, the
battery will see a load of 15kW. You can do the calculations
to see if that's accurate. Now we add in the other vehicle
systems load of 3kW to get a total of a 18kW load at the
battery pack. Remember this is about what we are estimating
is required to maintain 62mph. So the burning question is
how long can this EV mode be maintained. This is answered by
calculating how long a 1.43KWh capacity battery pack can
output 18kW. This is a simple calculation.
1.43kWh / 18kW = 0.08 hour or 3.3 minutes.
But it seems we have overlooked a critical item of
importance. The Hyundai engineers apparently decided to use
only about 20% of the total battery pack capacity under
normal use. Apparently they are limiting the system to use
only the third quintile, or from about 40% to 60% of total
battery capacity. This is done to lengthen battery life so
there will be few if any claims on the battery warranty.
So the actual available battery capacity is only 1.43kWh *
20% = 0.29kWh. Let's redo the EV mode endurance calculation.
0.29kWh / 18kW = 0.016 hour or 0.95 minutes or about 57
seconds.
How does this matchup with real world observations. Please
post your observed results. And if you have information that
is more accurate than that above we can redo the
calculations. Just for fun, you know.
Using the above data for weight and volume the battery cells
themselves would weigh 11.2kg (yes I know this is really a
mass unit) or 24.7lbs. The additional weight would be
electronics and packaging as well as the fan cooling
equipment. Any additional info here would be appreciated.
The total volume of the cells themselves would be about 6
liters or about 0.2 ft^3. But the cells are probably spread
out some for cooling purposes. So assume double that volume.
It would appear that there would be plenty of room in the
trunk to double battery pack capacity by installing another
72 cell unit in parallel. This would double or more than
double practical pack capacity since amperage requirements
would be cut in half, reducing degradation of the cells. Of
course, it has to be properly tied in to the system. Perhaps
in a few years when prices of cells come down and battery
packs start to need replacing it will be possible to increase
capacity at a reasonable price.
As an aside, at $21 each, 72 cells would cost $1512. I would
suspect that Hyundai would get a much better price than
internet retail. But quality and specs can also raise the
price. Still I doubt that Hyundai has more than $1000 cost
in the battery cells. Of course, you also need an integrated
9 module by eight cell microprocessor controlled voltage
balancing charger. Each of the nine chargers would
individually charge and monitor the eight cells in a module
and also balance the voltages. This is also done to lengthen
battery life. Then you need to monitor temp of the pack and
protect it from overloading when being discharged. All these
electronics add up along with assembly and testing. So we
just cannot know from here what Hyundai's cost really is.
However, I do know this from the Fitzmall dot com site:
HSH Premium Sonata Limited w/nav
MSRP $32,435 $29,600
Invoice $30,662 $27,783
selling $29,507 $26,838
Taking the difference between the invoice prices:
$30,662
- $27,783
diff $2,879
This $2,879 must cover the cost of the battery pack,
inverter, HSG, added cost of the electric air compressor and
all other hybrid specific additions, as well as the R&D
required to bring it all to market. I don't know if they are
breaking even on all this. They probably see it as a good
policy to penetrate this market which is new to them, even if
they don't break even on the hybrid upgrade. If this is true
a potential buyer would be well advised to buy a HSH now
before they get established in the market and raise the price
so they can earn a profit on the hybrid specific upgrade.
Please post any info you may have that would refine these calculations.
These are some rough calculations for the hybrid system based
upon information gathered on the internet and from the
Owner's Manual.
From the Manual:
Battery pack consists of 72 cells arranged in 9 modules of 8
cells each.
Battery pack voltage is 270V (nominal). This means all 72
cells are arranged in series since a single cell has a
nominal voltage of 3.75V.
Battery pack system weight is 42kg (92.4lbs).
From the internet:
netcarshow dot com slash hyundai/2011-sonata_hybrid
Battery pack capacity is 5.3Ah. Therefore 270V x 5.3Ah =
1.43kWh, which is how much energy the battery pack can store.
Drive motor produces 30kW, which is almost exactly 40HP.
I found a similar LiPo cell at bananahobby dot com for $21
each. The specs are:
Capacity: 5500mAh This equals 5.5Ah.
Max Charge Rate: 8C
Max Continuous Discharge Rate: 55C(302.5A)
Max Burst Discharge Rate: 80C(440A)
Weight is about 150g.
Volume is about 80cc.
Now we can do some calculations and see how close they come
to real life observations. First some assumptions:
Motor efficiency is 75%.
Inverter efficiency is 80%.
Power required to maintain 62mph on level roadway at standard
temp and pressure is 9kW. This is not quite a WAG and should
be fairly close to the actual.
Power required to operate all other vehicle systems at normal
conditions no more than 3kW.
First, for the motor to output the max power of 30kW or about
40HP, the battery will see a load of 50kW.
50kW * 80% = 40kw from the inverter to the motor.
40kW * 75% = 30kW mechanical power to the tranny.
For the battery pack to output 50kW will require an amperage
of 50kW =50,000W / 270V = 185A. Including the other vehicle
systems the amperage required would be 196A at max
conditions. This is well within the stated specs of the
above LiPo cell, especially since max conditions cannot be
maintained but for a short time due to battery capacity.
Second, for the motor to output 9kW or about 12HP, the
battery will see a load of 15kW. You can do the calculations
to see if that's accurate. Now we add in the other vehicle
systems load of 3kW to get a total of a 18kW load at the
battery pack. Remember this is about what we are estimating
is required to maintain 62mph. So the burning question is
how long can this EV mode be maintained. This is answered by
calculating how long a 1.43KWh capacity battery pack can
output 18kW. This is a simple calculation.
1.43kWh / 18kW = 0.08 hour or 3.3 minutes.
But it seems we have overlooked a critical item of
importance. The Hyundai engineers apparently decided to use
only about 20% of the total battery pack capacity under
normal use. Apparently they are limiting the system to use
only the third quintile, or from about 40% to 60% of total
battery capacity. This is done to lengthen battery life so
there will be few if any claims on the battery warranty.
So the actual available battery capacity is only 1.43kWh *
20% = 0.29kWh. Let's redo the EV mode endurance calculation.
0.29kWh / 18kW = 0.016 hour or 0.95 minutes or about 57
seconds.
How does this matchup with real world observations. Please
post your observed results. And if you have information that
is more accurate than that above we can redo the
calculations. Just for fun, you know.
Using the above data for weight and volume the battery cells
themselves would weigh 11.2kg (yes I know this is really a
mass unit) or 24.7lbs. The additional weight would be
electronics and packaging as well as the fan cooling
equipment. Any additional info here would be appreciated.
The total volume of the cells themselves would be about 6
liters or about 0.2 ft^3. But the cells are probably spread
out some for cooling purposes. So assume double that volume.
It would appear that there would be plenty of room in the
trunk to double battery pack capacity by installing another
72 cell unit in parallel. This would double or more than
double practical pack capacity since amperage requirements
would be cut in half, reducing degradation of the cells. Of
course, it has to be properly tied in to the system. Perhaps
in a few years when prices of cells come down and battery
packs start to need replacing it will be possible to increase
capacity at a reasonable price.
As an aside, at $21 each, 72 cells would cost $1512. I would
suspect that Hyundai would get a much better price than
internet retail. But quality and specs can also raise the
price. Still I doubt that Hyundai has more than $1000 cost
in the battery cells. Of course, you also need an integrated
9 module by eight cell microprocessor controlled voltage
balancing charger. Each of the nine chargers would
individually charge and monitor the eight cells in a module
and also balance the voltages. This is also done to lengthen
battery life. Then you need to monitor temp of the pack and
protect it from overloading when being discharged. All these
electronics add up along with assembly and testing. So we
just cannot know from here what Hyundai's cost really is.
However, I do know this from the Fitzmall dot com site:
HSH Premium Sonata Limited w/nav
MSRP $32,435 $29,600
Invoice $30,662 $27,783
selling $29,507 $26,838
Taking the difference between the invoice prices:
$30,662
- $27,783
diff $2,879
This $2,879 must cover the cost of the battery pack,
inverter, HSG, added cost of the electric air compressor and
all other hybrid specific additions, as well as the R&D
required to bring it all to market. I don't know if they are
breaking even on all this. They probably see it as a good
policy to penetrate this market which is new to them, even if
they don't break even on the hybrid upgrade. If this is true
a potential buyer would be well advised to buy a HSH now
before they get established in the market and raise the price
so they can earn a profit on the hybrid specific upgrade.
Please post any info you may have that would refine these calculations.
