Re: [Elecraft] KX2 battery options.
DIY 2x 3x 4x 18650 Battery Holder Storage Box Case With DC Power Plug 5.5x2.1mm eBay $1.76 free shipping Charge your own 18650 and drop into holder. Ken ke4rg -Original Message- From: elecraft-boun...@mailman.qth.net On Behalf Of John Harper Sent: Monday, November 19, 2018 9:23 AM To: Elecraft list Subject: [Elecraft] KX2 battery options. Mike, if you do build a KX2 battery, make sure to include a protection circuit. Some links and other info here: http://ae5x.blogspot.com/2018/02/shrink-wrapping-my-kx2-batteries.html 73, John AE5X https://ae5x.blogspot.com __ 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 Message delivered to ktalb...@gamewood.net __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] KX2 battery options.
On 11/19/2018 08:54, Detrick Merz wrote: 4 cells: at full charge, pack voltage is too high for the KX3. On the flip side, nominal pack voltage will remain high enough for the radio to operate at higher power until the pack is nearly dead. I've dealt with this two ways: Depending on the chemistry, Li-Ion cells can be something like 3.2 to 4.2 V fully charged. I used 4 of the 4.2 V cells to power the KX1, with a low dropout linear regulator to limit the voltage to 14 V. With a little better heat sink, that regulator should work with the KX2 or KX3. The schematic is here: sdellington.us/hr/KX-1_regulator4.pdf 73, Scott K9MA -- Scott K9MA k...@sdellington.us __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] KX2 battery options.
I've done both, for my KX3, using cells salvaged from old laptop batteries. 4 cells: at full charge, pack voltage is too high for the KX3. On the flip side, nominal pack voltage will remain high enough for the radio to operate at higher power until the pack is nearly dead. I've dealt with this two ways: 1) only charge the pack up to ~15.5v. This keeps the peak voltage within the acceptable range, but sacrifices some capacity. It may also increase the longevity of your cells (i.e. allow more charge cycles). It may also prevent any cell balancing from ever happening. 2) Charge the pack fully and use a buck converter until pack voltage falls off a bit. This will allow you to maximize the pack capacity but keep the input voltage where the radio wants it. The downside is the possibility of birdies (buck converters are switchers) and having to carry yet-another thing. Some power is "wasted" by the buck converter, but it can be removed from the equation pretty quickly (it doesn't take terribly long for the pack voltage to drop to where the radio is happy). 3 cells: peak pack voltage is perfectly acceptable for the radio, but may not allow operating at full power. Nominal pack voltage (11.1v) also won't allow full power out. When the pack is near dead, output power may need to be significantly reduced. I've dealt with the 3 cell pack by using a boost converter. This allows for higher output power but sacrifices efficiency (some power "wasted" by the boost converter), and may result in birdies from the converter. Since I already have both 3- and 4-cell packs, I use both of them. I ended up picking up a boost-buck converter. It's pretty small (deck of cards), and hasn't created any RFI that I've noticed yet -- even operating out in the field where the noise floor is very low. It lets me use either pack on the input side, and set the output voltage where I like. I can run the KX3 at 15W until the packs go dead. I've also used it with my Bioenno LiFePO4 pack if I needed a little more power to complete a contract. -detrick K4IZ On Mon, Nov 19, 2018, 08:07 Mike Short I have a bunch of 18650 batteries. Should I build a 3 or 4 cell case for > it? > > Mike > AI4NS > __ > 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 > Message delivered to detr...@merzhaus.org > __ 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 Message delivered to arch...@mail-archive.com
[Elecraft] KX2 battery options.
Mike, if you do build a KX2 battery, make sure to include a protection circuit. Some links and other info here: http://ae5x.blogspot.com/2018/02/shrink-wrapping-my-kx2-batteries.html 73, John AE5X https://ae5x.blogspot.com __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] KX2 battery options.
IMHO, use 3S1P pack, 12.6/11.1 fully charged/nominal. The 4S1P pack 16.8/14.4 - voltage is too high. -Original Message- From: elecraft-boun...@mailman.qth.net On Behalf Of Mike Short Sent: Monday, November 19, 2018 8:05 AM To: elecraft@mailman.qth.net Subject: [Elecraft] KX2 battery options. I have a bunch of 18650 batteries. Should I build a 3 or 4 cell case for it? Mike AI4NS __ 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 Message delivered to ktalb...@gamewood.net __ 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 Message delivered to arch...@mail-archive.com
[Elecraft] KX2 battery options.
I have a bunch of 18650 batteries. Should I build a 3 or 4 cell case for it? Mike AI4NS __ 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 Message delivered to arch...@mail-archive.com
