John : Here is a few battery suggestions for your portable K1 station.
If you want 5W you will need a 12V+ pack. If you are willing to settle for about 3w out the K1 will hum along nicely at 9 to 10V. It is quite a miserly rig so you can easily manage a day outing with battery capacity in the range of 2 to 3 Ah. I use a couple of different packs depending on the circumstances. My suggestions : 1) a small sealed lead acid (aka GEL-Cell) battery in the range of 2 to 3 Ah - Walmart also sells a good little charger for SLAs for about $25 called the EverStart Battery Companion (1.5Amp trickle charger). It is actually a 3-stage smart charger perfect for SLAs that are >= 2Ah. 2) 9v (actually closer to about 10.5V when fully charged) R/C NiMH battery packs The Radio Control packs you should be able to get at Radio Shack along with the proper charger. Radio Shack usually sells a combo pack with a charger (part 23-432) for about $20. These packs are in the 1500 to 1700 mAh range. If you go this route I suggest you buy a 2nd pack so you have a backup. Another good idea is to cut the leads on the pack and solder appropriately rated pico-fuses on both leads (these look like resistors) then put heat-shrink tubing over them and tape the leads against the body of the pack with electrical tape (the pic-fuses are a bit fragile so you don't want break them). (Hint, these packs also fit inside a FT-817 and make a good cheap internal battery for that rig.) 3) Go with rechargeable AA cells. You can buy 8 and 10 cell holders depending on what voltage you want (note that NiMHs are nominally about 1.2V when fully charged). You can find lots of these at WalMart, Radio Shack etc, along with 4 cell quick chargers. I would go with a reputable name (ie Duracell etc) rather than the no-name ones and try to buy cells that are in the 2000 mAh range. Note that the K1 will tolerate up to about 15V in so you can use a 10 cell holder if you are using NiMH rechargables. In practice I have found that a 10 cell holder with NiMHs will give 13+ V when fully charged which is perfect. For safety reasons, (both yours and the rig) I strongly recommend that you fuse whatever battery solution you decide on and don't forget that you need to be careful with NiMH packs as these batteries can generate a very very high current for a short period of time if shorted out. Needless to say this can result in burns or even an explosion. Best of luck Michael VE3WMB / VA2NB P.S. Another related idea. I standardized my QRP power connections on a 2 pin Molex connector (polarized). Most of my battery packs have a short pigtail with the female version of this Molex and I have a slightly longer length of wire that is fused and has the male Molex on one end and the appropriate coaxial power connector that fits into the K1. This allows me some flexibility in how I power my K1. For instance I have a cigarette lighter plug that has the female Molex so I can use this "adaptor" to plug my K1 into the cigarette lighter jack in my car if I want to operate from the car. For some of my otherQRP rigs like the ATS3 that have a different power connector I just made up a fused power cord that has the male Molex on it so I can use any of the battery options that I already have for the K1. I found that this modular approach works very well. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
