kx3 LIPO MOD

[@W7LDT]

Did you modify the charger? The book says that that charger is only for NiMh batteries. I have a good friend that is dead today because he used the wrong charger on a LiPo. It caught fire. He tried to put it out. Killed him and burned his house down. Makes me a little jittery.

[@loctite222ms]

Interesting, but since you can't use the internal charger and have to remove it to charge. I'd rather Velcro it to the back of the rig and plug it into the external power input. That would also reduce the damage risk to the rig if something goes wrong.

[@barrykery1175]

That's also a good idea. For me, like my KX2, you have to remove the battery so I don't see it as a big deal. What ever works if fine. Barry

[@FredCDobbs151]

Defeats the purpose of having an INTERNAL battery. Barry's idea here is excellent.

[@sethlavinder]

Very cool mod! Merry Christmas Sir, 73 de Seth - W8FG

[@dawsonmatteo6318]

A tip: you can watch series on Flixzone. I've been using it for watching loads of movies lately.

[@jfyles]

Good idea. I just bought one and you are right the battery life is really bad, my question would be charging it. Will the internal charger work and who long does it take. Not 16 hours I hope. I am using mine for camping and Solar power will be the only thing i'll have. Thanks Jim WB0CZI

[@barrykery1175]

Oh My ! NO.......DO NOT use the internal charger. It is not meant to charge LiPo batteries. The only downside of this mod is you have to remove the battery to charge it. But that is no different than how it's done with the KX2. Barry

[@vertsyeux]

Jim, the internal charger definitely isn't suitable for charging lithium batteries - don't even try it!! You can buy a very small portable lipo charger off eBay - small, light, made of plastic, runs off various voltages, charges various lip combinations and costs $10-15. Search eBay for "portable lipo charger"

[@petrok1rp254]

Nice mod but what about charging? The charging of the NiMH is quiet different from the Lipol or Lion etc.

[@barrykery1175]

Charging is external, just like the KX2. I did mention NOT to use the internal battery charger.

[@barrykery1175]

You MUST remove the battery for charging with an external charger, just like you have to do with the KX2. I sent this mod to Elecraft but I guess they don't like the mod?

[@FredCDobbs151]

@@barrykery1175 I can't see why! The electronics for lipo vs nimh take the same amount of space on the board! I wish they would incorporate this, even Xiegu has elecraft beat on this!

[@vertsyeux]

Using Deans or XT60 connectors would solve both the melt-while-you-solder and exposed ground connection issues - a lot of lipo batteries and chargers even come with these connectors pre-installed. I've also been thinking about updating my KX3 to use lithium polymer batteries since the NiMH are pretty abysmal. I was wondering what option there might be to recharge the lipo in-place without having to open the case as I'm not crazy about continually moving that little ribbon-cable that connects the two pcbs. Running cables out of the enclosure is probably a non-starter since the balance connections would also be required. So, looking on eBay, there are various tiny boards specifically designed for balance-charging a 3S lipo. I'm sure a 3S lipo and one such board could be assembled into a pack covered in heat-shrink sleeving and the same size as the two original 4xAA holders combined. Since the end-cheeks are replaceable (I've replaced mine for the ones with "handles"), there's enough room to install a Lemo connector (sub-miniature, mil-spec, mucho $$$) for charging..

[@barrykery1175]

The reason I chose the connectors I used is beacuse they are common. I can use the 3000 mah battery internal to the radio or external without making an adaptor. U can use the battery external with my KX3, KX2 and my YouKits. Barry

[@Achisachis73]

Thank you for sharing but opening the radio often is a bad idea. I just use an external battery to power up the panadapter and kx3.

[@ronancullen4565]

hi, can you share what battery you use to power both? i am searching for something like that to pow er both kx3 and px3

[@Achisachis73]

@@ronancullen4565 Hi Ronan, I use a motorcycle battery that I special ordered at the motorcycle shop. It is a LiFe battery and it is very light( called Phantom power). The thing is that it costs $160 or more. You can also use a LiPo from a RC Hobby shop but those are higher fire risk. The third option is to make a battery yourself, they sell the cells online and each cell will give you 3.7 volts, you would use 4 batteries in series and make it all connections yourself. I did this because the ribbons on the radio are very delicate and I do not open the radio unless I absolutely have to, same with Px3. Cheers

[@FredCDobbs151]

Barry, when you pull the battery does the real time clock lose its setting?

[@barrykery1175]

Yes, unlike the KX2, the KX3 will loose its time once the battery is removed. I have the Elecraft utility software on my computer and it's a simple click of the mouse, within the software, to reset the clock. The problem now is, they have discontinued the battery. We are all in search of a replacement. So far I have not found one. Barry, KU3X/QRP

[@FredCDobbs151]

www.ebay.com/itm/321938359322

[@barrygkx]

@@FredCDobbs151 Careful, those are 18650 cells and they may be too thick ?

[@barrygkx]

Maximum thickness is 9/16"

[@jp_rnd7020]

Can you tell me the dimensions of the battery you used please?

[@barrykery1175]

The battery length is 3-1/4". It can be longer if needed. The width is 2". The thickness is 9/16" and that is critical. Any thicker and you are putting pressure on internal boards, not good. When I made this modification, the battery was still being sold. I had no idea they would discontinue selling them. If you find a source, please post it here. I've been looking and could not find a replacement. It really is a good mod if you want a small package and not having to carry a big bag of equipment with you. My actual, "Resonant" antenna fits in my shirt pocket and the KX3 is not 100% self contained with a much better battery. Barry, KU3X