Search found 52 matches

by Solarsail
Jan 07 2021 1:42am
Forum: Electric Aircraft
Topic: Suggested battery capacity for 30 min flight?
Replies: 24
Views: 710

Re: Suggested battery capacity for 30 min flight?

If your motors need 30kW to hover, then you would need 15kWh. As I have explained in a previous reply, each kWh weighs 4.4kg or 10lbs if you use 21700 Samsung 50E - 5Ah, 2C (about $3.50 each cell or $200/kWh), and your pack is absolutely minimalist in design, e.g. the BMS stays on the ground with th...
by Solarsail
Jan 07 2021 12:48am
Forum: Electric Aircraft
Topic: Help needed for manned VTOL
Replies: 25
Views: 500

Re: Neutronics 80 series motors for manned VTOL?

No problemo. Counter rotating top and bottom props may work, but the props would need different pitch because the lower one is running in moving air. In this case, get two motors and two props and test them. Again I suggest making a hub that would let you change the blade pitch. In my calculations, ...
by Solarsail
Jan 06 2021 10:09pm
Forum: Electric Aircraft
Topic: Help needed for manned VTOL
Replies: 25
Views: 500

Re: Neutronics 80 series motors for manned VTOL?

One question comes to mind.......Why are you trying g to lift 1200lbs? Because I want to put a huge battery in it and have a proper cockpit and floats. Let's say you want 350lbs MTOW and thus 440lbs thrust. That is 200kg. With 8 30" rotors that is 25 kg/rotor. According to the KDE table, this ...
by Solarsail
Jan 06 2021 8:52pm
Forum: Electric Aircraft
Topic: Help needed for manned VTOL
Replies: 25
Views: 500

Re: Neutronics 80 series motors for manned VTOL?

iven these motor specs, how much run time do you think one motor would run on a 60v 50Ah lipo pack? Motor: KDE1828-120 I think you mean the KDE8218-120? I am impressed by their website and the fact that they specialize in heavy lift drones. And they offer ESC and props. However, they do not differe...
by Solarsail
Jan 06 2021 7:57pm
Forum: Electric Aircraft
Topic: Help needed for manned VTOL
Replies: 25
Views: 500

Re: Neutronics 80 series motors for manned VTOL?

Wow, thanks again for the detailed information. 300 volts, what the heck are you building...a flying city...lol? Well, I am trying to lift 1,200 lbs. That is half a ton. Each motor is 30kW and rated to 550V. If I had a 30kW 60V motor, it would need 500A !! The battery pack would have to use busbars...
by Solarsail
Jan 06 2021 5:19pm
Forum: Electric Aircraft
Topic: Help needed for manned VTOL
Replies: 25
Views: 500

Re: Neutronics 80 series motors for manned VTOL?

BTW, to measure current, use a hall effect sensor. Such as

https://www.ebay.com/itm/ACS758LCB-050B ... 3687370502
by Solarsail
Jan 06 2021 5:15pm
Forum: Electric Aircraft
Topic: Help needed for manned VTOL
Replies: 25
Views: 500

Re: Neutronics 80 series motors for manned VTOL?

Great -- You are ahead of what I had thought. In theory 2 blades are the most efficient, but then they would require a higher RPM and generate more noise. If the BLDC efficiency drops at higher RPM, you will find out that a 3 blade or 4 blade is more efficient. Remember your DC amperage is a combina...
by Solarsail
Jan 06 2021 5:38am
Forum: Electric Aircraft
Topic: Help needed for manned VTOL
Replies: 25
Views: 500

Re: Neutronics 80 series motors for manned VTOL?

Okay, here's an update. I am going with eight 30" or 30.5" props. I do have a couple of questions though. Is there much, if any difference in thrust, between a 3010 prop, and a 30.5"x9.7? Also do noise reducuction props with angled ends have as much thrust as non noise reduction prop...
by Solarsail
Jan 06 2021 5:10am
Forum: General Discussion
Topic: Adding pictures?
Replies: 223
Views: 404114

Re: Adding pictures?

You will be super happy with our next platform as it does away with all of this early 2000's thinking that does not make sense to anyone today. It is very good looking, performing, and functioning :bigthumb: That is a great idea, and the forum does need a facelift. For example reaction emoticons to...
by Solarsail
Jan 06 2021 4:44am
Forum: Electric Aircraft
Topic: Help needed for manned VTOL
Replies: 25
Views: 500

Re: Neutronics 80 series motors for manned VTOL?

I would not rely on what the manufacturer or reseller tells you. Best is to order one of each and measure the thrust. Measuring the thrust is not so difficult, and I can show you how. Okay, here's an update. I am going with eight 30" or 30.5" props. I do have a couple of questions though. ...
by Solarsail
Jan 05 2021 3:41pm
Forum: Electric Aircraft
Topic: Help needed for manned VTOL
Replies: 25
Views: 500

Re: Neutronics 80 series motors for manned VTOL?

l came across ten KDE 8218-120 motors, really cheap. Do you think that they are a good choice for my application? From my calculations, they should work fine. They are more efficient powering a 24"-27" prop, vs a 30" prop. Please always specify the voltage in addition to the amps. Wh...
by Solarsail
Jan 05 2021 3:36pm
Forum: Electric Aircraft
Topic: Help needed for manned VTOL
Replies: 25
Views: 500

Re: Neutronics 80 series motors for manned VTOL?

Stealth_Chopper wrote:
Jan 05 2021 9:47am
Safety factor ~=0? :lowbatt:
With a massive 10 motor bi-plane you might live through this pipe dream flight.
He is not building a plane - but a drone to hover. Besides, you don't need 10 rotors for a plane to survive.
by Solarsail
Jan 05 2021 5:38am
Forum: Electric Aircraft
Topic: Help needed for manned VTOL
Replies: 25
Views: 500

Re: Neutronics 80 series motors for manned VTOL?

Thank you for the responses....they do help. As far as doubling the thrust needed for the weight, l always thought that you should only be flying at 50-75% throttle, and not at 100%, so l was doubling the nedeed thrust accordingly. Is that not correct? Electric motors can be driven over 50% of thei...
by Solarsail
Jan 05 2021 5:17am
Forum: General Discussion
Topic: Adding pictures?
Replies: 223
Views: 404114

Re: Adding pictures?

amberwolf wrote:
Jan 03 2021 1:42am
One is Attachments.
Thank you so much Amberwolf -- I was going mental. The web designer for ES should know that inline graphics, quotes, equations, etc. are not attachments, but part of the text, albeit a different object.

So at ES to insert a graphic, one has to attach it first.
by Solarsail
Jan 03 2021 5:03pm
Forum: Battery Technology
Topic: Open source BMS for 48V to 400V lithium-ion battery pack
Replies: 236
Views: 40228

Re: Open source BMS for 48V to 400V lithium-ion battery pack

I will order PCBs for a 15S-SS version this week. This would be better suited for your 14S modules. The 18S & 15S board will share 90%+ of component & design. Thanks, I would be interested in one or two 15S boards for testing. Can you put tabs on the board to allow for a discharge IRFS7530 ...
by Solarsail
Jan 03 2021 1:44am
Forum: Electric Aircraft
Topic: Help needed for manned VTOL
Replies: 25
Views: 500

Re: Neutronics 80 series motors for manned VTOL?

Regarding prop size, larger props are more efficient and will give you a better fly time. In regards to power pack, I would suggest Samsung 21700 50E cells (no liabilities accepted). They are about 15% lighter than lipos for the same energy, smaller than lipos, and far safer than lipos. If you are a...
by Solarsail
Jan 03 2021 12:55am
Forum: General Discussion
Topic: Adding pictures?
Replies: 223
Views: 404114

Re: Adding pictures?

How does one upload an image? It says in this thread "use the Browse button to upload". But I can't find the Browse button. And the [img] tag just takes a URL and assumes the image will be hosted elsewhere. I want the image to show up in my comment. I know it can be done, and everyone is d...
by Solarsail
Jan 03 2021 12:33am
Forum: Battery Technology
Topic: Open source BMS for 48V to 400V lithium-ion battery pack
Replies: 236
Views: 40228

Re: Open source BMS for 48V to 400V lithium-ion battery pack

If there is one BMS for every 14s module, what stops you from putting modules in series to achieve higher voltages? A full solidstate BMS array can only be possible if each unit has FET rated for the total string voltage and designed to operate at such high voltage which is not the case with the ac...
by Solarsail
Dec 31 2020 5:27am
Forum: Battery Technology
Topic: Can you see anything wrong with this pack build?
Replies: 21
Views: 907

Re: Can you see anything wrong with this pack build?

If they're the Battery Hookup 6Ah cells, then he has about 1150 Wh (but also about 8.5kg of cells). I don't think a 32650 LiFePO4 cell can deliver 6Ah. If it does, it probably is one of those mislabeled Chinese cells. I have assumed 4Ah per cell. Is the 6Ah cell a brand name like A123? Or one of th...
by Solarsail
Dec 22 2020 5:03pm
Forum: Battery Technology
Topic: Can you see anything wrong with this pack build?
Replies: 21
Views: 907

Re: Can you see anything wrong with this pack build?

Cells appear to be LiFePO4 32650, for a total of about 750Wh -- which is too little for a trail/mountain bike. At 115 Wh/kg, they are 2.3x heavier than 21700 NMC, and 3.1x larger. The thing weighs 6.5kg :o and takes up 3.5L in volume. By choosing 21700 NMC, he could have saved 3.7kg (8.1 lb) and 2.4...
by Solarsail
Dec 21 2020 9:06pm
Forum: Battery Technology
Topic: Open source BMS for 48V to 400V lithium-ion battery pack
Replies: 236
Views: 40228

Re: Open source BMS for 48V to 400V lithium-ion battery pack

Thanks ENNOID. I just visited your website and was not aware that you were doing other stuff too. It is a very nice website and more success to you. I am thinking of an Emrax 208 motor. When would your motor be available? As for your inverter, would it work with the Emrax? I will take a closer look ...
by Solarsail
Dec 21 2020 4:41pm
Forum: Battery Technology
Topic: Open source BMS for 48V to 400V lithium-ion battery pack
Replies: 236
Views: 40228

Re: Open source BMS for 48V to 400V lithium-ion battery pack

The application is for electric flight where weight and efficiency are critical. Efficient lightweight PMSM motors are HV and can be up to 600V. I assume your BMS can accept 14s and not just 18s? If there is one BMS for every 14s module, what stops you from putting modules in series to achieve highe...
by Solarsail
Dec 21 2020 6:20am
Forum: Battery Technology
Topic: Open source BMS for 48V to 400V lithium-ion battery pack
Replies: 236
Views: 40228

Re: Open source BMS for 48V to 400V lithium-ion battery pack

Looks like a great BMS job. I plan to build a 3p5s14s8p pack (15 modules each 14s8p) to supply 300V (5s * 14s) and 30 kWh, using 21700 cells (Samsung 50E). I am looking for a suitable BMS. I wonder if your BMS is what I need? The 5Ah cell is rated 2C cont. and a peak of 3C. That would be 8*5*2 = 80A...
by Solarsail
Dec 19 2020 6:12pm
Forum: Electric Aircraft
Topic: Flying Caravan ??
Replies: 12
Views: 320

Re: Flying Caravan ??

This is just PR for Magnix. Commercial electric flight cannot happen unless we double the gravimetric energy density to 500 Wh/kg. Elon Musk says 400 kWh/kg. Right now li-ion (e.g. Tesla 2170 and 4680) is stuck at 250 kWh/kg. Has only improved 5% in the past decade.
by Solarsail
Dec 19 2020 6:08pm
Forum: Electric Aircraft
Topic: Flying Caravan ??
Replies: 12
Views: 320

Re: Flying Caravan ??

Very different for running out of fuel at 5,000 ft. With aviation fuel, you load 50 gallons weighing 152 kg that gives you 1,700kWh of energy. With electric flight, you carry 152 kg of batteries that gives you 25kWh of energy. Which do you think will run out first?