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2G June 10th 18 03:10 AM

Electric Self Launch System
 
On Friday, June 8, 2018 at 6:30:32 PM UTC-7, Charlie M. (UH & 002 owner/pilot) wrote:
Interesting additional battery chemistry info.....

https://batterybro.com/blogs/18650-w...ally-explained


And here is a lot more detailed info:

http://batteryuniversity.com/learn/a...of_lithium_ion

While the safety of IMR and INR are good, they are not as good as LFP.

Tom

Emir Sherbi June 10th 18 04:54 AM

Electric Self Launch System
 
Yes, they are very reliable and stable. They have very long life cycle. But the energy density is lower. For the same capacity you have to think in more than 60% of weight increase.

son_of_flubber June 11th 18 01:30 AM

Electric Self Launch System
 
On Saturday, June 9, 2018 at 11:54:06 PM UTC-4, Emir Sherbi wrote:
Yes, they are very reliable and stable. They have very long life cycle. But the energy density is lower. For the same capacity you have to think in more than 60% of weight increase.


I'd be very happy to have something soon that could sustain 30 minutes of flight at best glide speed. Maybe I'd upgrade to self-launch later when higher energy density batteries become available, but maybe not.

The 'best' is the enemy of the 'good enough'.

Having learned my lesson with Betamax, I'm looking for the VHS of electric propulsion. My glider is 20 years old. There is a limit to how much I want to sink into it.

[email protected] June 11th 18 02:47 AM

Electric Self Launch System
 
"I'm looking for the VHS of electric propulsion."
And we wonder why we're decades behind the Europeans...

Emir Sherbi June 11th 18 03:49 AM

Electric Self Launch System
 
El domingo, 10 de junio de 2018, 21:30:15 (UTC-3), son_of_flubber escribió:
On Saturday, June 9, 2018 at 11:54:06 PM UTC-4, Emir Sherbi wrote:
Yes, they are very reliable and stable. They have very long life cycle. But the energy density is lower. For the same capacity you have to think in more than 60% of weight increase.


I'd be very happy to have something soon that could sustain 30 minutes of flight at best glide speed. Maybe I'd upgrade to self-launch later when higher energy density batteries become available, but maybe not.

The 'best' is the enemy of the 'good enough'.

Having learned my lesson with Betamax, I'm looking for the VHS of electric propulsion. My glider is 20 years old. There is a limit to how much I want to sink into it.


For our design, having only 30 minutes of sustained flight or selflaunch and having 1 hour of sustained flight is the same technological challenge.
The only thing that changes is the final price.

20 years old is like new, we are about to install it on a 35 years old Pegasus.

Charlie Quebec June 11th 18 05:17 AM

Electric Self Launch System
 
Yeh, waiting for an inferior quality system that is more popular is a very US approach.

son_of_flubber June 11th 18 01:37 PM

Electric Self Launch System
 
On Sunday, June 10, 2018 at 10:49:51 PM UTC-4, Emir Sherbi wrote:

For the same capacity you have to think in more than 60% of weight increase.


A lower capacity battery pack will be lighter and cheaper. Maybe that would make INR batteries feasible.


kinsell June 11th 18 03:57 PM

Electric Self Launch System
 
On 06/11/2018 06:37 AM, son_of_flubber wrote:
On Sunday, June 10, 2018 at 10:49:51 PM UTC-4, Emir Sherbi wrote:

For the same capacity you have to think in more than 60% of weight increase.


A lower capacity battery pack will be lighter and cheaper. Maybe that would make INR batteries feasible.


I think he was talking about LFP batteries not being feasible, due to
low energy density.

Emir Sherbi June 11th 18 04:04 PM

Electric Self Launch System
 
El lunes, 11 de junio de 2018, 9:37:44 (UTC-3), son_of_flubber escribió:
On Sunday, June 10, 2018 at 10:49:51 PM UTC-4, Emir Sherbi wrote:

For the same capacity you have to think in more than 60% of weight increase.


A lower capacity battery pack will be lighter and cheaper. Maybe that would make INR batteries feasible.



In your case if you want that capabilities it can be arranged.
We are trying to standardize some components but the battery size and shape can be changed without much issues.


[email protected] June 11th 18 09:55 PM

Electric Self Launch System
 
On Friday, June 8, 2018 at 7:30:29 PM UTC-4, son_of_flubber wrote:
On Friday, June 8, 2018 at 4:50:33 PM UTC-4, Emir Sherbi wrote:

INR and IMR, depending on the flight mission.



https://breazy.com/products/samsung-...50-25r-2500mah

INR 18650 2500mah Battery (2 Pack) - Samsung

20 amps of continous discharge, the Samsung 25r has been the go to battery for most vapers because of its authenticity and its transparent rating system. In terms of cell degradation the Samsung 25r has been a reliable source of power.


System provided to me by MGM Compro uses Sony US18650VTC6. Rated capacity 3000mAh. 18 stacks of 28. 57 lb with enclosure and BMS.
Projected performance at 25KW draw is 12 minutes.
FWIW
UH


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