Kx3 lithium batteries life
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I have had lithium batteries in my KX3 since I received it last Nov. I
use the batteries only to keep the clock alive and have never used them to transmit or receive.. I use an external power supply to transmit etc, I now find that if I try to turn on the rig using just the batteries the rig comes on then immidiately turns itself off. I assume the batteries are to the point where there is not enough voltage to power up the rig but the B T voltage reads 10.5 to 11 volts which I thought should be enough to turn the rig on Does the clock in the KX3 take that much power that even lithium batteries have a very short life .?? Has anyone else experienced this situation?? Is there something I am missing ?? Ken K1DWZ ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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It depends on the quality of the batteries, some will hold a charge for a
long time for up to a year shelf life and still have 75-80% charge. I checked mine the other day (bought in Oct) and was still in good shape. I do use an outboard charger/conditioner for the first time on the batteries takes about a full day to complete the condition. Fred/N0AZZ -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of [hidden email] Sent: Friday, March 15, 2013 10:34 AM To: [hidden email] Subject: [Elecraft] Kx3 lithium batteries life I have had lithium batteries in my KX3 since I received it last Nov. I use the batteries only to keep the clock alive and have never used them to transmit or receive.. I use an external power supply to transmit etc, I now find that if I try to turn on the rig using just the batteries the rig comes on then immidiately turns itself off. I assume the batteries are to the point where there is not enough voltage to power up the rig but the B T voltage reads 10.5 to 11 volts which I thought should be enough to turn the rig on Does the clock in the KX3 take that much power that even lithium batteries have a very short life .?? Has anyone else experienced this situation?? Is there something I am missing ?? Ken K1DWZ ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ----- No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2240 / Virus Database: 2641/5677 - Release Date: 03/15/13 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by K1DWZ
Ken,
The lithium batteries should be able to keep the clock going for quite a few years. When the KX3 is off, the KXBC3 current should be around 50 to 75 microamps, depending on battery voltage, which comes out to roughly 1.5 mAH per day. 73, Rich AC7MA On 03/15/2013 08:33 AM, [hidden email] wrote: > I have had lithium batteries in my KX3 since I received it last Nov. I > use the batteries only to keep the clock alive and have never used them to > transmit or receive.. I use an external power supply to transmit etc, I now > find that if I try to turn on the rig using just the batteries the rig comes > on then immidiately turns itself off. I assume the batteries are to the > point where there is not enough voltage to power up the rig but the B T voltage > reads 10.5 to 11 volts which I thought should be enough to turn the rig on > Does the clock in the KX3 take that much power that even lithium batteries > have a very short life .?? Has anyone else experienced this situation?? > Is there something I am missing ?? > > Ken K1DWZ > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Some earlier posts have referred to a LED on the charger/clock board
that seems to blink 24/7. So there may be more load than just the clock on the internal battery. I haven't noticed anything glowing or blinking on mine. Still your message made me curious, so I measured the drain from the internal batteries (8 NiMH cells). With the radio turned off, it was about 50 microamps. This was surprising to me as clock chips usually pull much less than that (a factor of 30 less give or take). So I pulled out the schematics and found the KX3 uses a Microchip PIC24F16K101 as the time keeper and charge controller. The chip spec puts the real time clock drain at 350 nano amps, and says that the run mode currents should be 8 uA or so. Sure enough, there is a Yellow LED shown on the schematic (D2). But like I said, I don’t see it blinking on mine. Given the 50uA current draw I experienced, that is still only 18 mAH over an entire year. If you are talking 2800 mAH for a Energizer Ultimate Lithium, that is less than 1% of its capacity. So that can't explain the early demise of your batteries. You would expect those cells to say above 11 volts for almost their entire life, which would be about 12 hours of KX3 receive, and about 6 hours at with occasional transmit at 5 watts. Now you mentioned that you keep the radio powered by a external supply and really only use the Lithium batteries for time keeping. If that were the case then you would need to have an external supply that was always above about 12.4 volts to keep the Lithium batteries from partially discharging. 73, Bob, WB4SON ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
73, Bob, WB4SON
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Bob,
I think you forgot to multiply by 24hrs/day for your annual energy consumption, but your conclusion is still valid. Even at a ~440 mAH for one year, the battery drain can be ignored for practical purposes. Most of the current is consumed by the shunt regulator and the resistor dividers on the +12V line. The LED does blink faintly as an 'alive' check when KX3 power is off, at a 1/2 second period. This is how often the microcontroller wakes up to check power status. Maybe an adventurous individual will put a scope across the resistor in series with the LED to measure average current, and the result may be surprising on how little it takes to produce a visible blink. 73, Rich AC7MA On 03/16/2013 11:07 AM, Bob wrote: > Some earlier posts have referred to a LED on the charger/clock board > that seems to blink 24/7. So there may be more load than just the > clock on the internal battery. I haven't noticed anything glowing or > blinking on mine. > > Still your message made me curious, so I measured the drain from the > internal batteries (8 NiMH cells). With the radio turned off, it was > about 50 microamps. This was surprising to me as clock chips usually > pull much less than that (a factor of 30 less give or take). > > So I pulled out the schematics and found the KX3 uses a Microchip > PIC24F16K101 as the time keeper and charge controller. The chip spec > puts the real time clock drain at 350 nano amps, and says that the run > mode currents should be 8 uA or so. Sure enough, there is a Yellow > LED shown on the schematic (D2). But like I said, I don’t see it > blinking on mine. > > Given the 50uA current draw I experienced, that is still only 18 mAH > over an entire year. If you are talking 2800 mAH for a Energizer > Ultimate Lithium, that is less than 1% of its capacity. So that can't > explain the early demise of your batteries. You would expect those > cells to say above 11 volts for almost their entire life, which would > be about 12 hours of KX3 receive, and about 6 hours at with occasional > transmit at 5 watts. > > Now you mentioned that you keep the radio powered by a external supply > and really only use the Lithium batteries for time keeping. If that > were the case then you would need to have an external supply that was > always above about 12.4 volts to keep the Lithium batteries from > partially discharging. > > 73, Bob, WB4SON > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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