On Mon, 10 Feb 2020 08:43:04 -0700, Dan Marotta wrote:

A couple of very good perspectives HERE
https://www.avweb.com/features/reade...-and-comments-
february-7-2020/?
MailingID=280&utm_source=ActiveCampaign&utm_medium =email&utm_content=Bryant+Crash+Prelim%2C+Drone+Ce rtification+NPRM&utm_campaign=Bryant+Crash+Prelim% 2C+Drone+Certification+NPRM-
Monday+February+10%2C+2020.

Let the flames begin...

That was an interesting read.

For fun, I dug up the numbers on a 7.2 AH SLA, Gasoline, and a SAFT Li-
ion cell and lobbed the lot into a spreadsheet. I picked on SAFT cells
because they made the cylindrical Li-ion cells used in the Antares, and
used the numbers for their highest capacity cell.

Here's what it showed:

Parameter Yuasa NP7-12 Petrol (1 litre) SAFT LS133600

Chemistry SLA Hydrocarbon Li-ion
Voltage (V) 12 3.67
Capacity (AH) 7 17
(w.hr) 84 9600 62.39

Weight (Kg) 2.200 0.755 0.090
Volume (litres) 0.739 1.000 0.323
Density 0.976 0.755 0.278

To hold equal amounts of energy, we need
Units installed 114.286 1.000 153.871
Weight (kg) 251.429 0.755 13.848
Volume (litres) 84.497 1.000 49.728

I hope the formatting doesn't get too mangled by the wonders of NNTP.

Its interesting that petrol (gasolene) is lighter than SAFT cells by a
factor of over 10 and takes up around 50 times the space - and this is an
underestimate because its the total volume of the cells and doesn't count
either the extra space needed because cylindrical cells can't be packed
without leaving air gaps or the space needed to cooling air to circulate
round the batteries, which are quite widely spaced inside the Antares
wing.



--
Martin | martin at
Gregorie | gregorie dot org