Re: Payload Power Sources



The graph that you have shared has the horizontal axis in units of Ah (Ampere*hours) not in hours.  It is fine.

This means that all current draws are about 7.5 Amp hours with the smaller draws performing better than the large draw.

Howard, KC9QBN

On Fri, Mar 27, 2020 at 9:02 AM Joe WB9SBD <nss@...> wrote:
I am very confused on a battery pack.

Say you have a pack that can run 1 amp of current draw for 10 hours.
One would think that if you only drew 0.5 amps that it should run for 20 hours or close to it true?

Now many of you old timers here will remember these awesome surplus packs that looked like this.

These things were OLD like 20 years old when we used them yet the power they could provide was incredible!
They were rated at 7500mah, incredible! Sadly this supply of "NOS" dried up and new packs were very prohibitive in prices. Easily ending up being like $100 bucks a flight!

But I found a source for Brand new ones, that would make it like $15 to $30 bucks a flight! YES!

But it's performance curve makes absolutely no sense to me!

This makes zero sense at all. I can draw 2 amps  or 0.25 amps and it changes the lasting run time by only like 15 minutes?

That doesn't make any sense!


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Howard L. Brooks
Professor of Physics and Astronomy
241 Julian Science and Mathematics Center
DePauw University
2 E. Hanna Street
Greencastle, IN 46135
Office: (765) 658-4653
FAX: (765) 658-4732

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