Yahoo Groups archive
Thread
2005-10-25 by rgmccaig
If I took 2 9v batteries in series to create 18V, plus a resistor in series to lower the voltage, could I plug that in to run my Evo? I am thinking the load of the Evolver is 15V / 0.5 A = 30 ohms? So a 10 ohm resistor in series with the evolver would take 1/4 of the 18V, ie 4.5 V, leaving 13.5V for the Evo. Anybody know if I'm thinking about it the right way?
2005-10-25 by Jonathan Villegas
Hello, The thinking is not right. Putting a resistor in series with your batteries just throttles the current flow. The Evo (desktop) needs about 750 mA of current at 13.6 VDC (output rating of wall-wart). Nine-volt batteries aren't capable of supplying 3/4 of an Amp of current. If it works at all, it will be for a very short time. You might want to research battery packs (of the appropriate voltage) used by camcorders or photographers. This may be a better solution for battery operation. ~ Jonathan www.lbop.net --- DSI_Evolver@yahoogroups.com wrote: Message: 3 Date: Tue, 25 Oct 2005 00:14:21 -0000
From: "rgmccaig" <rgmccaig@...> Subject: making a simple battery pack? If I took 2 9v batteries in series to create 18V, plus a resistor in series to lower the voltage, could I plug that in to run my Evo? I am thinking the load of the Evolver is 15V / 0.5 A = 30 ohms? So a 10 ohm resistor in series with the evolver would take 1/4 of the 18V, ie 4.5 V, leaving 13.5V for the Evo. Anybody know if I'm thinking about it the right way? __________________________________ Yahoo! FareChase: Search multiple travel sites in one click. http://farechase.yahoo.com
2005-10-25 by matsag21
Hello, there is a thread on the subject in the evolver board. here is the link: http://www.ex5tech.com/ex5ubb_cgi/ultimatebb.cgi?ubb=get_topic&f=23&t=000148 let us know how it goes! cheers Mathieu --- In DSI_Evolver@yahoogroups.com, Jonathan Villegas <jville.geo@y...> wrote:
> > Hello, > > The thinking is not right. > > Putting a resistor in series with your batteries just > throttles the current flow. > > The Evo (desktop) needs about 750 mA of current at > 13.6 VDC (output rating of wall-wart). Nine-volt > batteries aren't capable of supplying 3/4 of an Amp of > current. If it works at all, it will be for a very > short time. > > You might want to research battery packs (of the > appropriate voltage) used by camcorders or > photographers. This may be a better solution for > battery operation. > > ~ Jonathan > www.lbop.net > > > --- DSI_Evolver@yahoogroups.com wrote: > > Message: 3 > Date: Tue, 25 Oct 2005 00:14:21 -0000 > From: "rgmccaig" <rgmccaig@i...> > Subject: making a simple battery pack? > > If I took 2 9v batteries in series to create 18V, plus > a resistor in > series to lower the voltage, could I plug that in to > run my Evo? > > I am thinking the load of the Evolver is 15V / 0.5 A = > 30 ohms? > > So a 10 ohm resistor in series with the evolver would > take 1/4 of the > 18V, ie 4.5 V, leaving 13.5V for the Evo. > > Anybody know if I'm thinking about it the right way? > > > > __________________________________ > Yahoo! FareChase: Search multiple travel sites in one click. > http://farechase.yahoo.com >
2005-10-25 by rgmccaig
Thanks to you both.. Guess I'm off to find an RC battery as mentioned in the other thread. I understand my mistake about the current limit; I forgot to wonder how much current a 9v could supply. I'm still curious, if you have a given battery you must work with, and you want to reduce the voltage you are delivering, what is the best way to do that (rather than a resistor in series)? cheers --- In DSI_Evolver@yahoogroups.com, "matsig21" <mathieu@t...> wrote: > > Hello, > > there is a thread on the subject in the evolver board. > here is the link: > http://www.ex5tech.com/ex5ubb_cgi/ultimatebb.cgi?ubb=get_topic&f=23&t=000148
> > let us know how it goes! > > cheers > > Mathieu > > > --- In DSI_Evolver@yahoogroups.com, Jonathan Villegas > <jville.geo@y...> wrote: > > > > Hello, > > > > The thinking is not right. > > > > Putting a resistor in series with your batteries just > > throttles the current flow. > > > > The Evo (desktop) needs about 750 mA of current at > > 13.6 VDC (output rating of wall-wart). Nine-volt > > batteries aren't capable of supplying 3/4 of an Amp of > > current. If it works at all, it will be for a very > > short time. > > > > You might want to research battery packs (of the > > appropriate voltage) used by camcorders or > > photographers. This may be a better solution for > > battery operation. > > > > ~ Jonathan > > www.lbop.net > > > > > > --- DSI_Evolver@yahoogroups.com wrote: > > > > Message: 3 > > Date: Tue, 25 Oct 2005 00:14:21 -0000 > > From: "rgmccaig" <rgmccaig@i...> > > Subject: making a simple battery pack? > > > > If I took 2 9v batteries in series to create 18V, plus > > a resistor in > > series to lower the voltage, could I plug that in to > > run my Evo? > > > > I am thinking the load of the Evolver is 15V / 0.5 A = > > 30 ohms? > > > > So a 10 ohm resistor in series with the evolver would > > take 1/4 of the > > 18V, ie 4.5 V, leaving 13.5V for the Evo. > > > > Anybody know if I'm thinking about it the right way? > > > > > > > > __________________________________ > > Yahoo! FareChase: Search multiple travel sites in one click. > > http://farechase.yahoo.com > > >