Batteries for QRP - Keynote # 7, 1999
Some time ago I was asked about batteries for QRP operation. My long-time friend and new FISTS member VA3RJ supplied me with the following information. It seems to be very thorough and should answer any questions you might have.
You wanted some info, or sources, for gel-cell batteries (actually they are sealed rechargeable lead acid batteries). They are used quite extensively in the security field as battery back-up when a.c. power goes down. I (VA3RJ) am quite familiar with them, as my line of work was mainly in the security field (closed circuit TV, etc.).
I use a Radio Shack HTX-202, 2 mtr FM, handheld, which can run 5 watts in it's high power position. With a 12 volt, 4.5AH gel-pack, I can run the handheld all day before recharging.
The gel-cell batteries run in the $25 to $30 (US) range (from Mouser Electronics). The batteries have male quick connect tabs mounted on them (+ and - terminals). They can be quickly hooked up to the rig with a female quick connect terminal and the run of the positive and negative wires.
Ni-Cad AA batteries are 1.2 volts each, but they are rated at 1100mAh - which is quite good. The normal AA rechargeables are usually rated at 200 or 300mAh. So these will power the rig for a longer period of time.
I have some sources for the gel-cell batteries - Yuasa-Exide Battery Company, PO Box 14145, Reading, PA 19612-4145. E-mail: Friedmana@yuasainc.com WebSite: http://www.yuasainc.com They are a good, well-known, and reliable supplier of the sealed lead acid (gel-cell) batteries. Check their site for specs. Check the NP series batteries.
Newark Electronics carries the Yuasa-Exide batteries (NP series), and also carries Keystone battery holders. WebSite: http://www.newark.com Toll Free 1-800-463-9275. Allied Electronics carries Keystone battery holders, Panasonic Ni-Cads and sealed lead acid (gel-cell) packs (LC series), and Power Sonic (PS series) 6 and 12volt gel-cells. WebSite: http://www.allied.avnet.com. Toll Free 1-800-433-5700.
Digi-Key carries Panasonic Ni-Cads, and Keystone battery holders. WebSite: http://www.digikey.com Toll Free: 1-800-344-4539.
Mouser Electronics carries EaglePicher sealed lead acid batteries, CF and CFM series, 6 and 12 volt units, and chargers. Also Power Source P series gel-cells and chargers, Keystone battery holders. WebSite: http://www.mouser.com. Toll Free: 1-800-346-6873.
Power Sonic Company has the gel-cells (sealed lead acid batteries). The URL is - http://www.power-sonic.com.
Example - Here are some transmit specs on my HTX-202 2 mtr handheld FM unit: @ 7.2volts (6 x 1.25V AA Ni-Cads) 2.5 watts, current 0.8A @ 9 volts - 4 watts output, current drain 0.95A @ 12 volts - 5 watts output, current drain 1 Amp @ 13.8 volts - 6 watts output, current drain 1.1 Amp.
One thing to keep in mind with the batteries - always keep them charged up once a month, even if the batteries are not used. That goes for the gel-cells and the Ni-Cads. Shelf storage without periodic recharging will ruin the batteries (i.e. they will discharge to a point where you will not be able to get the charge back into them). So regular, once-a-month- charging of the batteries is essential. Also, always carry a second battery pack, or gel-cell, when operating out in the field (in case the first one gets low). Don't want to be caught losing power in the middle of a QSO - HI.
For the data sheets on the Yuasa sealed lead acid batteries (NP - series) go directly to: http://www.yuasainc.com/np-prod.html. Batteries for stand-by power, go directly to: http://www.yuasainc.com/standby.html.
Other sources of these batteries are surplus jobbers, and ham flea markets. Only problem with these sources is the fact that you do not know the shelf life nor how much use the battery has had. I would stay away from these batteries, and purchase a new battery through a reputable dealer. I made the mistake of purchasing a small 12 volt 2Ahr gel-cell from a local surplus store only to find that it would charge up to the 13 volts ok, but would not hold the current. So be cautious of the surplus store and flea market batteries!!!
If you find this info helpful, you might consider dropping VA3RJ a note of thanks. Dave has his own web site with much useful ham info. You can find his site via my Ham Personal Pages Links on my web site at home.windstream.net/johnshan/. And as usual you can Email me or send me regular mail at John Shannon, 478 E. High St., Kittanning, PA 16201-1304.
Next month correspondence from my readers. Some interesting info on what others are doing with their QRP setups. My space is used up again, so 73 till next month. -30-