Best battery for my flying bike?

Hey guys,

I've been trying to find a good solution for my flying car battery and honestly can't make up my mind. I don't like to ask for help when I know the information is out there, but hopefully you guys can weigh in. This is not something I can afford to get wrong

Requirements:

-3 to 5 kWh
-90 volt maximum
-80 kw peak output
-35 kw continuous output

For a 3 kWh battery that's 12 C continuous and 27 C peak. The peak power requirement is more of a nice to have... if all I can get, for example, is 50 kW peak I can live with that (no pun intended).

Multistar won't work well. Other hobbyking batteries might, but I don't trust the specifications they provide or the overall quality. Tesla modules don't work because the voltage is too low to work with. I don't want to get into spot welding individual cells together. Other EV batteries might work but I can't find a good source.

Thoughts?

What you're asking here is almost similar to a full power ev. Those power requirements are stupid high... You really need 80,000W burst and 35,000 maintained? What the heck is a flying bike?

Bike which flies, through the air!

Yes, they're high power requirements. That's why I can't use Multistar, unless I get way more of them than I actually want.

So where can I find a 3 kWh EV battery that can do 35 kw continuous?

A huge pile of Lipo. That's what I have seen used on the quad copters big enough to lift a person.

80kW is enough to make almost anything fly.

you need 400A at 90 volts continous or 900A peak. those are stupid numbers. just in cables the drone/bike would weigh 50 kilo's in copper cables alone. for reference: you would need a wire 1 inch thick to handle that current without melting. just to give you a idea: that would mean 10 kilo's of copper wire per METER.

this is a dead end. you must up the voltage by at least a factor of 5 to make it viable. or have each motor its own power pack and controller bolted next to it on the frame. having a central battery at these voltages is just plain stupid.

Quality hi power cells are available for those outputs ..30-100+C rating...suggest you contact John Metric at Ampahaulic for details and costs.
http://www.ampahaulic.com
But, as others have said, your voltage range seems unrealistic for the power you plan to use.

This crazy contraption: https://www.facebook.com/TodayTonight/videos/1173124852726969/

Only flew because of the massive pile of LiPo I built for it. It was about 6 kWh of 40 C peak cells. The system was powered by six separate motors and controllers, each running on a 100 volt bus. In hindsight higher voltages would have meant less copper mass, but we were punishing these cells at 30C continuous.

30C continuous cells will work nicely.

dozentrio said:

Thoughts?

Click to expand...

Hi dozentrio,

You forgot to mention one thing which seems pretty important to me: the weight.
If your project is to make some kind of flying machine, then your battery will need to be as lightweight as possible.
That basically rules out most of the choices and you're pretty much forced to use LiPOs here.

Why do you have a 90V maximum specification? Do you already have a specific controller in mind?
If you plan on saving mass you will need to go up in voltages, copper is heavy!

Good luck in your project!

Have you got money to burn?



33S of these = 89.1v max 79.2v nominal, 792wh, so 33S4S = 4kwh roughly.

Capable of 237kw for 10S

Unfortunately, it'll also weigh 67kg.

One of my dreams is to build an electric hovercraft. Less... Fatal, if I screw it up.

10 seconds of flight time seems a bit "short". and it does not solve the current issue with those low voltages.