[Elecraft] K2: ext battery suggestions?
What are folks using in terms of an external battery for the K2? I'm sure there are lots of options, so please include advantages/disadvantages of each. I've look at the archive and unless I'm doing something wrong, I don't get a lot of hits with respect to the k2. Thanks, de Doug KR2Q ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
[Elecraft] K2: ext battery suggestions?
I use sealed GelCells Doug... These are the found in UPS units, usually in pairs. The price is right I can get them for free when the cells "fail". It seems that one battery will go well before another. I use them in tandem with the internal battery for QRP. Picked up a Solar panel to keep a charge on them, but haven't deployed it yet. You could use motorcycle or mower batteries as well. My preference is to stay away from anything that can spill. Cheers, Julius n2wn ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] K2: ext battery suggestions?
I assume you are talking about the QRP 15W K2, Doug. I've had excellent results with a 7 AH sealed 12V AGM battery. Mine is made by Interstate, but there are many vendors with similar size and ratings. Size is 6" x 3.75" x 2.5" and it weighs in at a little under 6 lbs. Will run K2 on receive for over 24 hours and I can easily get a day (8 hours) of operating from it on CW. Can also be easily charged with a 10W solar panel. Think I paid about $22 for it a couple years ago. Of course both smaller and larger batteries may be used depending upon if you're carrying it and the length of your operating period. I also have a 2.9 AH PowerSonic that weighs 2.5 lbs that I sometimes use if I won't be out long. Batteries Plus carries a good selection and they may have a store near you. 73 ... Craig AC0DS ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] K2: ext battery suggestions?
Doug: In order to run the K2 at full power for an extended period of time I use a 73 Amp-hour gelled electrolyte battery and a PG40S SuperPWRgate both from West Mountain Radio. The regular station power supply furnishes charging power. I cannot tell you how long it will last because I've never run it down, but I did some duty cycle calculations that showed that it should last for most of a day of round the clock operation at 100 watts CW, and at least a week at 5 watts. I have found as several other list members have reported, that the voltage drop through the diodes in the PG40S does not lead to any problems for operating the K2. Drawbacks: 1) This is not a cheap configuration, plan to spend close to $300 by the time you include fuses, powerpoles, battery connectors et cetera. 2) It is not conveniently portable; the battery weighs 58 pounds. 73, Steve Kercel AA4AK At 06:07 PM 6/2/2007, DOUGLAS ZWIEBEL wrote: What are folks using in terms of an external battery for the K2? I'm sure there are lots of options, so please include advantages/disadvantages of each. I've look at the archive and unless I'm doing something wrong, I don't get a lot of hits with respect to the k2. Thanks, de Doug KR2Q ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] K2: ext battery suggestions?
In a message dated 6/2/07 6:07:47 PM Eastern Daylight Time, [EMAIL PROTECTED] writes: > What are folks using in terms of an external battery for the K2? I have generic 7 AH and 12 AH gel cells for when I take the K2 away from AC. I also have a zero-cost charger for them. It's an old, small UPS in a plastic case that was tossed because its batteries were dead. I opened it up and extended the battery wires out through a slot filed where the case halves meet. On the far end of the wires I put Anderson Power Poles, same as on the K2 power cable and the short cables I put on the batteries. To charge a battery, I just hook it to the UPS and turn on the UPS. It brings the battery up to full charge in a few hours, and then trickle charges it. 73 de Jim, N2EY ** See what's free at http://www.aol.com. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] K2: ext battery suggestions?
Hi The following taken from the instructions for my Solar Controller Kit may be helpful. I have also used a 35 amp hour electric wheelchair gel cell battery and 2 35 watt solar panels with my controller on field day to run a K2/100 at about 75 watts out. This allowed operation for the full duration of the field day (day and night) without using any external power. Don Brown KD5NDB Sizing Your Solar Charging System The solar panel and battery needs to be matched to your system requirements. Although there is a wide range of specifications that will work, there are certain limits that must not be exceeded or damage to your battery may occur or at least may shorten its life. The first requirement is the amount of power in amp/hours you will need to operate your equipment. This is simply the average ampere draw times the number of hours you want to operate the equipment. This number will be the size of battery you will need. You should add 15 to 25% to this number to have some reserve capacity. Next you need to determine the size of your solar panel. Solar panels are rated in watts or sometimes current. If it is rated in current multiply by 14 volts (the fully charged battery terminal voltage) to get watts. Unless your panel can track the sun as the earth rotates you will need to figure on only about 4 hours of charging time near the rated output of the panel with several hours at reduced output. To make the math easy let's use four hours of sun per day. Divide the battery capacity by four to get the charging current. To convert to watts multiply by 14 volts. This is the size panel you will need. You can use a larger panel but you must not exceed the maximum charging current of the battery. This is about 1/3 of the batteries amp hour capacity. Just make sure the charge current is not higher than this number. OK let's design a system for the Elecraft K2. Suppose you want to operate for 4 hours per day. The K2 draws 250 ma on receive and about 2.5 amps on transmit. Let's assume 75% of the time is receiving and 25% is transmitting. So .25 amps times 4 hours times .75 is 0.75 amp/hours for receive. When transmitting assume about a 50% duty cycle so 2.5 amps times 4 hours times 25 times .50 is 1.25 amp/hours. Add the receive requirement to the transmit requirement and we get 2.0 amp/hours. Add 25% for a reserve and we get 2.5 amp/hours. The internal battery option for the K2 has a 2.9 amp/hour battery so lets design for it, as it is a little larger than we need in the above example. 2.9 amp/hours divided by four hours is 0.73 amps for our charging current. Multiply by 14 to get watts and we get 10.2 watts. The maximum charge current for this battery is 2.9 amps divided by 3 or 0.97 amps times 14 volts is 13.5 watts. A 10 watt panel would be perfect for this application. You could probably use a 15 watt panel safely because most of the panels will not reach their rated output unless they are exactly perpendicular to the sun at high noon at a mid latitude. The panels should be mounted facing south at an angle equal to your latitude so they get direct exposure to the sun for the most hours. Solar Panels are constant current devices. Constant current devices seem a little strange because most of us are familiar with constant voltage devices like batteries and power supplies. A constant current device like a solar panel will supply the same current into any load up to its open circuit voltage as long as the load current is equal to or greater than the current supplied by the device. For instance if a solar panel is capable of supplying 1 amp of current it will supply that same one amp into a short circuit, a 6 volt battery or a 12 volt battery. The current supplied is determined by the size of the cells in the panel and the amount of light falling on the panel. Panels will supply 18 to 30 volts open circuit determined by the number of cells in series. This is the reason for a controller. Without one the panel would keep supplying the charging current as long as the panel is in the light possibly overcharging the battery shorting its life. - Original Message - From: "J F" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]>; "Elecraft Discussion List" Sent: Sunday, June 03, 2007 6:20 AM Subject: [Elecraft] K2: ext battery suggestions? > I use sealed GelCells Doug... > > These are the found in UPS units, usually in pairs. > The price is right I can get them for free when the > cells "fail". It seems that one battery will go well > before another. > > I use them in tandem with the internal battery for > QRP. Picked up a Solar panel to keep a charge on them, > but haven't deployed it yet. > > You could use motorcycle or mower batteries as well. > My preference is to stay away from anything that can > spill. > > Cheers, > Julius >
Re: [Elecraft] K2: ext battery suggestions?
I run the entire hamshack on 4 EV-1 pullouts and 3-55W Solar panels. I estimate the batteries will run two rigs and the computers for about 2-3 weeks if I include the TiVo. Al WA6VNN ** See what's free at http://www.aol.com. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
