# Ultralight Battery Powered

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#### blane.c

##### Well-Known Member
HBA Supporter
Would current rules allow the use of eight of these in a electric ultralight? And if so considering 40hp of efficient motor for takeoff and about 20hp for cruise how long would they give you in flying time (approximately or range of estimate)?
[h=3]Product Specifications for EarthX ETX680 Lithium Battery for Experimental Aircraft & Race Car with 60 Amp Alternator[/h] Specifications:
BM Part #: LTX680 12 Volt 12.4 Ah LiFePO4 6.5" 3.1" 6.6" 320 CCA / 680 PCA 4.10Lbs 2 Year Factory Direct

Features:

• Due to shipping regulations regarding shipping lithium batteries, the EarthX batteries can only be shipped via FedEX or UPS Ground.
• Designed for a 60 amp alternator or less
• 12.4 Ah of reserve power with an amazing 680 cranking amps!
• LED battery fault light indicator
• The indicator can be plugged into your control panel.
• Battery Management System (BMS) redundancy accurately monitors cell voltage, state of charge, and resistance.
• The ETX680 meets the requirements from Rotax engines as an approved lithium battery for use.
• Engineered and assembled in the U.S.A.

Thank you.

Specs
Description
Cross Reference

Free Standard Shipping

Order today and receive free standard shipping on your EarthX ETX680 Lithium Battery for Experimental Aircraft & Race Car with 60 Amp Alternator. Only valid in the continental 48 states and not valid with any other offer. Physical address required (No PO Boxes).

The EarthX Lithium batteries (LiFePO4) are designed to be a light-weight, maintenance free replacement of your standard lead-acid battery.

These batteries will work with any vehicle charging system and "modern" lead-acid battery chargers, thanks to the exclusive built-in electronics (Battery Management System, BMS).

No other motorsport lithium battery manufacturer offers a battery with built-in electronics to protect it from over-discharging, over-charging, plus keep the cell's charge level balanced.

Engineered and assembled in the U.S.A.
Nominal Voltage 13.2 Volt
Ah (1 Hour Discharge Rate) 12.4 Ah (1C Rate)
Pulse Crank Amps (PCA) 680A (3 seconds @ 45°C voltage > 9V)
Cold Cranking Amps (CCA) 320A (modified SAE test, 3 seconds @ 0°F, voltage > 7.2 Volt)
Max Continuous Discharge Amps 100A
Standard Charge Voltage 13.9 - 14.6 Volt
Maximum Charge Voltage 15 Volt
Recommended Charger / Maintainer Amps 0.8 - 15A
Max Charge Amps 60A (from vehicle charging system)
Life (Charge cycles, 80% depth of discharge) 4000 cycles @ 1C discharge rate 25°C
2000 cycles @ 10C discharge rate 25°C
Life (Years) 8 Years
Environmental Rating (Resistance to water intrusion) IP 66 (wash down with a high pressure washer)
Operating Temperature -30°C to +60°C
Storage Temperature -40°C to +70°C

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#### BBerson

##### Light Plane Philosopher
HBA Supporter
Note, the specs say max continuous discharge 100 amps.
So 100 amps times 12 volts is 1200 watts. That's about 1.5 hp. (746 watts = 1hp)
So eight of them is 12hp continuous for 6 to 8 minutes (12.4 amp hour total each)

How much do they cost?

#### Tiger Tim

##### Well-Known Member
Would current rules allow the use of eight of these in a electric ultralight?
I don't think there are any rules against it, but be aware that batteries are considered part of the airframe weight of a Part 103 UL. It sucks, but for the time being that's how it is.

#### lr27

##### Well-Known Member
Each one is 148 watt hours.

At least LiFePO4's are supposed to be safer than Lipos. But their capacity per lb is lower. Current capacity can be right up there, though.

#### blane.c

##### Well-Known Member
HBA Supporter
380 dollars each
pretty spendy for maybe 8 minutes.

#### blane.c

##### Well-Known Member
HBA Supporter
So I guess a better question may be what is the best option for electric power in an ultralight? Is there anything that works for long enough to be seriously considered? To refine that last question a little I think most people are getting their "fix" in about 20 minutes so having some reserve for the unexpected probably 40 minutes of flight time would be a minimum I am guessing. Also the way I am currently understanding the regs interpretation is that (double whammy) battery's are included in empty weight of aircraft and cannot exceed 5 gallons of capacity (they are considered not fuel for weight and considered fuel for capacity).

#### blane.c

##### Well-Known Member
HBA Supporter
So the cycle times on the batterys are 2000 times at heavy duty and 4000 times if you only use 80% of charge or less. figuring 8 minutes (for now) and 2000 charge cycles and approx. 3000 bucks for battery's that is around $11.50 per hour at around 266 hrs total operating time. That is spendy compared to gas and does not include cost to charge battery's. Not knowing the ratio of how much the battery's life would be compared to engine maintenance (assuming that battery's are not just considered fuel but also an element of the motor) and how much would be compared to fuel, nor what it would cost to charge the battery's 2000 times and also figuring that it is another$3000 for new battery's after the 266 hrs of operation, it is really difficult to gain a realistic perspective of the true cost differential to IC but at the moment it seems rather staggering?

#### BBerson

##### Light Plane Philosopher
HBA Supporter
Can't really trust the 2000 cycles estimate. Just BS.
The only thing you can trust is the two year warranty. But I doubt they would warranty them for this extreme use. They are made to crank an engine 15 seconds in normal use.
Very smart of you to calculate lifetime cost.

#### blane.c

##### Well-Known Member
HBA Supporter
Can't really trust the 2000 cycles estimate. Just BS.
The only thing you can trust is the two year warranty. But I doubt they would warranty them for this extreme use. They are made to crank an engine 15 seconds in normal use.
Very smart of you to calculate lifetime cost.
It is interesting to speculate about electric, but the one thing that always nags at me is how are they recharging the battery's, because if the recharging energy is coming from a fossil fuel powered source then how is it better than IC? And as one of my electrician friends once told me if we all powered on solar the planet surface would really heat up, as one of the byproducts of solar is heat dissipation, heat that is normally reflected (as light) not stored or dissipated at the earths surface.

#### pictsidhe

##### Well-Known Member
if you want to fly electric, you want a really efficient airframe. Sticking a bigger engine to compensate for drag doesn't work when it runs from batteries.
Plenty of span and low drag.
Theres a recent thread on electric aircraft, I think its in the light stuff section.
Solar wont heat the planet much, unless you panel the snowy parts. The darkish parts already convert almost all the solar radiation into heat.

#### BBerson

##### Light Plane Philosopher
HBA Supporter
It is interesting to speculate about electric, but the one thing that always nags at me is how are they recharging the battery's, because if the recharging energy is coming from a fossil fuel powered source then how is it better than IC? And as one of my electrician friends once told me if we all powered on solar the planet surface would really heat up, as one of the byproducts of solar is heat dissipation, heat that is normally reflected (as light) not stored or dissipated at the earths surface.
Well, we could be charging batteries with nuclear now, except Bill Clinton and the other Greens halted modern nuclear in '93.
I have a booklentiful Energy by Charles Till. All about the Integral Fast Reactor, that unbelievably is 100 times more efficient and burns up it's waste. Maybe things will change.

#### lr27

##### Well-Known Member
BBerson:
There's always fusion. It's only 20 years away and always has been.

LiFePO4 batteries ARE supposed to survive considerably more cycles than Lipo. Don't know how that works out in real life, but it at least seems plausible to me that a different chemistry could have a longer life. It probably also makes a difference who's making them.
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It's my understanding that charging, at least for electric cars, is cheaper than gas. Also that a vehicle charged with electricity from anything but coal fired generators has a smaller carbon footprint than using a gas engine. Or, at least, I've read that in several places.
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In the time it takes to design and build an ultralight, it seems likely batteries will continue to improve. At least if one has a day job.
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A clean ultralight ought to take off on 20hp and cruise on a quarter of that. It does, however, raise the issue of how you're going to limit the aircraft to the legal top speed.

#### Aesquire

##### Well-Known Member
You are limited in pt 103 by the weight, the 5 gallon limit is for fuel, not batteries. You can have as many batteries as you want, as long as you are under the 254 pound dry weight.

The problem you face is 2 fold.

One: batteries that are light and have a good capacity are expensive. With mass production the price goes down, but it's early days yet.

Two: with arbitrary weight limits, you are very range limited with electric. Gasoline just has more energy per pound, and until super capacitor tech gets scaled up, that's true of all batteries today. ( and the promise of high density power storage is matched by the built in hazards.

That said, by all means explore the numbers and see what you can do. I'm waiting for cheaper, better power storage. I figure they'll have perfect batteries for airplanes, and immortality about a week after I'm gone.

#### BBerson

##### Light Plane Philosopher
HBA Supporter
BBerson:
There's always fusion. It's only 20 years away and always has been.
.
The Integral Fast Reactor (version two)is real and has been operating in Idaho flawlessly for decades.

#### BJC

##### Well-Known Member
HBA Supporter
The Integral Fast Reactor (version two)is real and has been operating in Idaho flawlessly for decades.
BB:

Could you point me toward a source for that?

Thanks,

BJC

#### BBerson

##### Light Plane Philosopher
HBA Supporter
BB:

Could you point me toward a source for that?

Thanks,

BJC
The book: PLENTIFUL ENERGY, (2011) by Charles Till and Yoon IL Chang. Both nuclear engineers that spent entire careers at Argonne National Laboratory
Charles Till was interviewed on a recent PBS Nova about future of nuclear.
The Integral Fast Reactor burns almost 100% of the fuel. So thst's 100 times better than current plants.
And the residuals are only dangerous for about 300 years and can easily be sealed in glass.
And it's passive sodium coolant makes meltdown impossible by design, no matter from operator error or inattention.
Enough fuel for centuries, or forever if they get the uranium from seawater. It doesn't need much fuel.

#### bmcj

##### Well-Known Member
HBA Supporter

What, you say? You don't want to be around a bunch of radioactive diamonds? No problem! They can just put a protective case around them to block the radiation. But what should they cover it with? The answer to that is to encase it in another manmade diamond that is not radioactive. The outer layer blocks the radiation AND generates its own current in the process, adding to the current from the inner diamond. The beauty of this is that the core is being protected by the hardest material available, and the battery last a long time (with a 5,700 year half-life).

Will it fly a plane? Probably not, but it will power microelectronics like watches and cell phones.

#### BBerson

##### Light Plane Philosopher
HBA Supporter
Got a source for that?
I doubt they use carbon much anymore, because it burns, but I could be wrong.

#### BJC

##### Well-Known Member
HBA Supporter
The book: PLENTIFUL ENERGY, (2011) by Charles Till and Yoon IL Chang. Both nuclear engineers that spent entire careers at Argonne National Laboratory
Charles Till was interviewed on a recent PBS Nova about future of nuclear.
The Integral Fast Reactor burns almost 100% of the fuel. So thst's 100 times better than current plants.
And the residuals are only dangerous for about 300 years and can easily be sealed in glass.
And it's passive sodium coolant makes meltdown impossible by design, no matter from operator error or inattention.
Enough fuel for centuries, or forever if they get the uranium from seawater. It doesn't need much fuel.
Thanks.

BJC

#### Dana

##### Super Moderator
Staff member
It is interesting to speculate about electric, but the one thing that always nags at me is how are they recharging the battery's, because if the recharging energy is coming from a fossil fuel powered source then how is it better than IC?
For an aircraft, the only advantages are mechanical reliability, lack of vibration, noise, and the ability to put a small electric motor almost anywhere you want. For a car, where the extra weight can be tolerated, the idea is that an engine burning fossil fuel at a constant rate (an electric power plant on the grid charging an all-electric car or a steady running engine in a hybrid car) is more efficient and less polluting than a conventional car IC engine that is constantly varying rpm and power output. Of course, the environmental costs of making and later disposing of batteries are conveniently swept under the rug.

The big problem, particularly for aircraft (other than cost), is the mass energy density... batteries are heavy, and there will never be a battery with anywhere near the energy density of a tank of gasoline. That's not "wait until batteries get better"; never. The basic physics of electrochemical reactions is well understood, and none of them (even theoretical ones that could never work in the real world) come close to the energy released by burning liquid fuels. And safety... puncture a gas tank and it might catch fire if an ignition source is present, but it might not. Damage a LiPo battery, and you can expect bad things to happen.

Supercapacitors, I dunno. Capacitors are limited by dielectric strength, but I don't know what the theoretical limits are. But supercapacitors large enough to power an aircraft are a long way away.

What we really need is Shipstones (for the Robert Heinlein fans out there).

Dana