So, for Field Day running CW only any ideas about what the required amp hours will be?
Sent from my iPad On Jun 15, 2013, at 8:06 AM, Michael Babineau <[email protected]> wrote: > Robert : > > If you are planning to use Lead-Acid technology (SLA or wet-cell ) > then, as others have suggested, you should double your calculated capacity, > as you never want > to drain a Lead-Acid battery by more than 50% .. > > so > > 10 hr requires 7 Ah > 20 hr requires 15 Ah > etc. > > The reality is that you will probably spend somewhat more than 50% of the > time listening and tuning around > for stations when you are S&P so the real split may be more like 30% TX and > 70% RX, but 50/50 is probably > a good guess. > > One further point .. don't discharge a Lead acid battery below 10.5 v. > Repeatedly doing this will shorten > its lifespan. Don's suggestion of setting the low voltage indication on the > K2 to 11v is a good idea. > > For picnic-table-portable operations, battery booster packs (intended to > jump-start cars) work very well > and it is easy to find one with an SLA in the 10Ah to 20Ah range, often on > sale. You can take the plastic > case apart to install some fusing and even powerpole connectors to customize > it for your application > (I also removed the jumper cables from mine). Some of these packs now even > come with USB ports to allow for impromptu > powering/charging of i-Devices. It is often cheaper to buy one of these than > to purchase just the equivalent capacity SLA > battery .. so you get a nice carrying case with a handle and other goodies > for free. > > Best of luck ... > > Michael VE3WMB > > > >> From: Robert G Strickland <[email protected]> >> Date: June 14, 2013 6:28:10 PM EDT >> To: Elecraft <[email protected]> >> Subject: [Elecraft] K2 qrp battery drain estimation > > >> If I'm operating a K2 at 5w cw, in S&P contest mode, I compute the current >> drain under the stated conditions as follows: > >> conditions: >> 50% listening, 50% transmitting >> CW 50% duty cycle > >> current: >> 200ma receive, more or less >> 1.0a transmit, more or less > >> current draw per hour: >> 100ma [30min rcv] + 250ma [30min xmit @ 50% duty cycle] = 350ma per hour > >> 10Hr requires a 3.5Ahr battery >> 20Hr requires a 7.5Ahr battery >> etc... > >> Is this more or less accurate, or have I missed something? Thanks. > >> ...robert > -- >> Robert G Strickland, PhD ABPH - KE2WY >> [email protected] >> Syracuse, New York, USA > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
