yes, that was my point...100 is most likely too much to expect, but 50 should be doable for short periods at any rate. 73 Colin, V A6BKX ----- Original Message ----- From: "John Miller" <[log in to unmask]> To: <[log in to unmask]> Sent: Friday, August 05, 2005 7:57 AM Subject: Re: battery packs > They don't make 2 hours on 100 watts though back it down to 30 or 50 and > they do alright on SSB. > ----- Original Message ----- > From: "Colin McDonald" <[log in to unmask]> > To: <[log in to unmask]> > Sent: Friday, August 05, 2005 9:44 AM > Subject: Re: battery packs > > > good points...however, i have seen those portable charging units that claim > about 7 amp hours plus about 1500 cold cranking amps to be able to jump > start a vehicle....these type of packs should provide enough current to > operate at a relatively heavy current draw for several hours given the > intermittent nature of SSB operation...if FM was going to be operated then i > think one of those packs would certainly go dead quickly but SSB only draws > that current when modulating and one is only really modulating for brief > periods of time throughout that one hour. Its not like you will be rag > chewing when you are trying to make contacts...lets say maximum 15 seconds > of modulation at 12 amps or so with 50 watts. > You take that and you times that 15 seconds over and over until you get > about 35 minutes, using the 7 amp hour pack and you are looking at an aweful > lot of contacts and several hours. > I dont know how to actually calculate that, but the math is sound and you > can figure out the number of hours you could get out of a relatively low > current supply, assuming it will provide the higher current for short > periods of time...which most of these portable packs will do. > > These portable packs are smaller then a regular sized car battery and much > lighter...easy enough to attach to a back pack or be even hand carried if > necessary. > I still want that website that gives all this info regarding battery > packs...allot of this idea of using lesser current supplies and figuring out > how long you can run a higher current draw on SSB is all on this website. > > 73 > Colin, V A6BKX > ----- Original Message ----- > From: <[log in to unmask]> > To: <[log in to unmask]> > Sent: Friday, August 05, 2005 1:26 PM > Subject: Re: battery packs > > > > Message-Id: > <20050805132709.LBGM3503.ibm70aec.bellsouth.net@[68.212.116.131]> > > > > Fred wrote, > > >Well, if you're going to use battery power, you'd better think of > > >qrp, 50 to 100 watts will drain them in a hurry, or you'd better > > >take the world's longest extension chord for the charger. > > Even then, better be two stout dudes if you're gonna pack enough > > battery power to do this. gel cell packs that would handle that kind > > of power and give you a few hours of operation are quite heavy. > > Definitely be thinking qrp in this application. > > I had a bunch of those 7 amp/hour gel clels that came from burglary > > and fire alarm systems and they can be heavy even. Up at Charity > > Hospital here in NEw oRleans we've got a couple of 100 amp/hour > > batteries and they're heavy dudes. I brought them up there on a two > > wheeled handtruck. NOt something I'd want to be packing up a mountain > > along with food tents etc. > > THough everything else in our hobby has miniaturized except antennas > > batteries haven't downsized that much. AS one fellow said, when they > > get there we'll actually see efficient electric vehicles. > > wEre I going on such an expedition I'd consider qrp cw. YEs Virginia, > > leave the laptop at home too. > > Speaking of such activities I'd probably use the National RAdio > > emergency net as a point of contact with the outside world. These > > folks use the guard frequencies 7068 10122 and 14050 khz. tHey're > > there for just this purpose. > > > > > > > > > > Richard Webb > > > > Electric Spider Productions > > "They that can give up > essential liberty to obtain a little temporary > > safety deserve neither liberty nor safety." > > --- Benjamin Franklin, NOvember 1755 from the > > Historical review of Pennsylvania > > >