Will the Next Mooney Be Electric?

[Pinecone]

Lithium batteries charge on Constant Current/Constant Voltage curve.  You start charging a desired amperage, typically a multiple of the capacity.  So a 100 amp hour battery would charge at 100 amps (1C) or 200 amp (2C), etc.  The higher the charge rate, the faster it charges, but the hotter it gets.  And the lower the number of cycles.

Once the voltage gets to the maximum for the type of cell (4.2 volts (edit) for the lithium polymer cells), the voltage is held, and the charge rate goes down.  That changeover point is 80% capacity. 

So, charging to 80% does 2 things.  It increases the number of cycles the battery will last.  And, it makes the charge time shorter, as you are charging at a higher amperage.

Due to being life limited by the number of charge cycles, for longest life, it is best to run them down to no lower than 20% and then charge.  A charge from 60% to 80% counts against the life.

[A64Pilot]

Where you say 4.2 amps I believe you mean 4.2V as 4.3V is generally considered 100% charge, amps are depending on cell size of course voltage is not.

‘The term Li-po means Lithium polymer, that’s the pouch cells we used in models, Li-ion is the same battery, just in a metal can.

But there are honestly so many chemistries now that are all called “lithium” it’s about as descriptive as “plastic”

Tesla I believe uses a doped Lithium Nickel Cobalt Aluminum battery, doped means they add their own proprietary chemicals to a base recipe if you will. Like probably Manganese and who knows what else.

But they are also now using Chinese made LifePO4 batteries, AKA Lithium Iron 

The cycle thing is also open to interpretation, Apple for example quite logically states that 1 cycle is full capacity of the battery, so three 33% discharges is one cycle, while most everybody else says any discharge and recharge is a cycle, but doing that it leaves cycle life claims wide open for the marketing dept.

This is relevant because if you only discharge 20% and call it a cycle, then you have to have 5 times the cycle life to equal the energy of 1 full discharge.

But yes lower depth of discharge and shallower charge greatly extends pack life, generally using the middle third is accepted to maximize pack life to its limit. There are diminishing returns.

‘People who don’t know anything about EV’s think that one with a 300 mile range means they can regularly go 300 miles before recharging, which isn’t really correct, because they are murdering the battery if they do so. You should pick a car that has a range at least three times your usual daily use, and charge it every night up to a point that puts 50% as half its use. Wife currently only uses about 15% daily, so I charge the car to 60% every night.

Use the higher charge limits for travelling.

So, I feel with this airplane if you charge to 100% and suck it down to near zero, the pack will degrade rather quickly, pretty soon your hour is 45 min, then 30 min etc.

I think full cycle life is about 500 cycles, where 1/3 cycle is tens of thousands

This chart shows that but it doesn’t show the effect on stopping short of full charge, which also extends life about the same as shallow discharges

https://www.researchgate.net/figure/Depth-of-discharge-versus-cycle-life-of-the-lithium-ion-battery_fig4_318292540

[carusoam]

Yikes…. Anyone study electro-chemistry?

Some people don’t like chemistry…

others don’t like electricity…

This one depends on both…

Throw on rates for charging… and limitations at the top and bottom…

Transition Training is going to be an hour longer, just for battery technology…

 

Keep both eyes open, the whole time…

Best regards,

-a-

[Pinecone]

12 hours ago, A64Pilot said:

Where you say 4.2 amps I believe you mean 4.2V as 4.3V is generally considered 100% charge, amps are depending on cell size of course voltage is not.

‘The term Li-po means Lithium polymer, that’s the pouch cells we used in models, Li-ion is the same battery, just in a metal can.

But there are honestly so many chemistries now that are all called “lithium” it’s about as descriptive as “plastic”

Tesla I believe uses a doped Lithium Nickel Cobalt Aluminum battery, doped means they add their own proprietary chemicals to a base recipe if you will. Like probably Manganese and who knows what else.

But they are also now using Chinese made LifePO4 batteries, AKA Lithium Iron 

The cycle thing is also open to interpretation, Apple for example quite logically states that 1 cycle is full capacity of the battery, so three 33% discharges is one cycle, while most everybody else says any discharge and recharge is a cycle, but doing that it leaves cycle life claims wide open for the marketing dept.

This is relevant because if you only discharge 20% and call it a cycle, then you have to have 5 times the cycle life to equal the energy of 1 full discharge.

But yes lower depth of discharge and shallower charge greatly extends pack life, generally using the middle third is accepted to maximize pack life to its limit. There are diminishing returns.

‘People who don’t know anything about EV’s think that one with a 300 mile range means they can regularly go 300 miles before recharging, which isn’t really correct, because they are murdering the battery if they do so. You should pick a car that has a range at least three times your usual daily use, and charge it every night up to a point that puts 50% as half its use. Wife currently only uses about 15% daily, so I charge the car to 60% every night.

Use the higher charge limits for travelling.

So, I feel with this airplane if you charge to 100% and suck it down to near zero, the pack will degrade rather quickly, pretty soon your hour is 45 min, then 30 min etc.

I think full cycle life is about 500 cycles, where 1/3 cycle is tens of thousands

This chart shows that but it doesn’t show the effect on stopping short of full charge, which also extends life about the same as shallow discharges

https://www.researchgate.net/figure/Depth-of-discharge-versus-cycle-life-of-the-lithium-ion-battery_fig4_318292540

Yes, volts, edited.

The lithium can cells are different.  They have a max voltage of 3.7 volts IIRC.

I think for airplane use, the 20% - 80% cycle is sustainable for max cycles with reasonable performance.  And starting duration for pattern work, should be at least 90 minutes.  That allows a 1 hour lesson, with some slack, and taxi out and taxi back without pushing.