KX2 small/light charger

I’ll be flying this summer with my KX2 without checked-in luggage so space and weight is limited.

Do you know of a smaller alternative to the KX2 charger? Have you build something based out of a lighter charge brick?

(I plan to use the battery inside the TRX as I will be activating in pedestrian portable style; I can’t use any other batter types).


Alternative small and lightweight external battery solution for KX2, KX3, FT-817/818 and other Sota radios

from company EREMIT.

External small LiFePO4 batteries 2x 12V 2 Ah, or 1x 12V 4 Ah to order with appropriate plug alternatives.

In addition, a small charger for LIFEPO batteries with the appropriate plug.

Suitable for batteries and KX2.

The Eremit company also builds a separate charging socket suitable for the battery charger in the batteries for little money.

The whole thing either 2 batteries each 2Ah, or 1 battery 3 Ah with charger and separate charging cable for less than 100 euros.

With up to 4000 charging cycles, the batteries are very durable, safe, BMS-controlled, very light and suitable for airplanes.

Alternatively, the new board from Elecraft

KXIBC2 – internal battery charger for the KX2

which means that the battery can be left in the device for charging - a small power supply unit is simply connected to the DC IN.

Take a look at Rene and Carin’s website


Maybe this hint is something for you.

DG1NPM, Nobbi

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I recently received and installed the KXIBC2 internal battery charger. I got it predominantly so I didn’t have to keep opening up the transceiver to charge the internal battery. I suspect that it is only a matter of time before I damaged the internal PCBs. The KXIBC2 does exactly what you would expect (although a little tricky to solder the red wire/pin into the hole on the main PCB), and it will recharge the internal battery from the 2.1x5.5 barrel port for external power.

The main thing to note is that the KXIBC2 charges at a relatively slow rate (250mA). The fast charger can fully charge this battery within 2 hours, but the KXIBC is likely to take much longer. Simple maths is a 2.6aH battery at 250mA rate is approximately 10 hours for a full charge from empty. If the unit is off then you’ll need a 14 or 15v 300mA supply to recharge the battery, which you could do overnight. I think there is also alot of demand and a long lead time for the KXIBC2 unit to arrive. I’ve waited 10 weeks to get mine (arrived 2 weeks ago).

The KXIBC2 will charge from voltages up to 15v, although a minimum of 13.7v is needed to ensure the internal battery is fully charged.

I recommend the KXIBC2 (you can still remove the battery and use the fast charger), but it may not suit you if you need to quickly charge the battery (and carry the fast charger anyway). A smaller 14 or 15V 300mA PSU/wall-wart is probably going to be smaller than the fast charger. I have a 75Wh battery pack with USB and DC outputs from it. I can set the DC out to 15V and it will happily recharge the internal KX2 battery using the KCIBC2 module.

Recharging one Li-ion battery from another battery is possible, but needs some form of charging circuit. Li-ion batterys like to be charged with a CC/CV process (at a Constant Current and then a Constant Voltage). Many Li-ion batteries have a BMS (battery management system) internally to the battery pack and can help peform this function. However, I don’t think the original battery packs have any BMS on them, so I wouldn’t charge the electraft battery from another battery without contacting Elecraft first. Worst case is that you could get a Lithium fire on your hands (which can be very difficult to put out).

I hope this gives you some more information to help you make a good choice!?

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I’ve looked at these before. Seem ideal and a good price. But sadly they don’t appear to ship outside Germany as I couldn’t enter an address with any other country specified.

Can’t blame Brexit for this one. :slight_smile:

I got someone in DL who was visiting the FN rally to order me an Eremit battery and I picked it up in person and paid cash. Zero problems.

Or you need a DL contact to buy and then ship it for you and deal with Brexit issues.

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When I travel I use a cheap USB 3s LiPo charger that I got on Amazon ($10 USD for a 2 pack). It does require you to have a balance lead on your battery, which I have added to all my 3S 18650 packs (still fits inside the KX2 easily). It has worked well for me. Search Amazon for “Blomiky 2 Pack 11.1V 1.5A USB Charger”.


Comme ça?

High current Tyton T connector for the radio on left, 3S balance connector on right.


Yes, but I do it so the pack fits inside the KX2.


Didn’t have a KX2 when that battery holder was made. :wink:

I bought a compact charger of this type in AliExpress: Charger AliExpress, Link2

73, Peter - HB9PJT

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Some great feedback on this thread. Thanks for all the suggestions.

Those won’t help as I want to keep using an internal battery on this trip AND need a light/small charger to charge it.

Also the KXIBC2 is horrendously expensive to import into the EU zone…

This is a very elegant solution; requires some work but the charger could hardly be any smaller since I will of course bring a USB charger anyway… Downside is that it needs a bit of DIY.

I think we have a winner :slight_smile:

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Is my entry too late?

I use a USB C 18650 charger board. Bought 2 from eBay last year for £10. The link for the one I bought no longer works, but it was described as ‘Type C BMS 2S 3S 4S 1A 2A 4A 18650 Lithium Battery Charger Board USB C Module’. I bought the 3S 2A variant. And these all look mighty similar at first glance: Type C BMS 2S 3S 4S 1A 2A 4A 18650 Lithium Battery Charger Board USB C Module | eBay

Small and easy to pack, as I usually have some sort of USB adapter and type C cable anyway. Seems to charge my batteries (Elecraft and ‘Cameron Sino’ I think it is) fine so far. No fires and an apparently full battery when the light changes colour. It does get a bit warm, so I make sure it is not covered over when in use. YMMV.


Nice one. FYI I also have some of those ‘Cameron Sino’ 3S 18650 batteries ($12 USD from eBay). The cells are good but the BMS is crap. I had one fail so that one of the cells wasn’t getting charged at all. I manually balanced the cells and then ran a couple of charge/discharge cycles on my fancy battery workstation, and all 3 cells tracked ok. I put a balance lead on that pack and only use a balance charger on it now. After ~4 years of use (and a LOT of cycles) the capacity is still good (about 2100mAh).

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Or a DL contact who visits the UK regularly… Hmmm, thinks…

Reminds me of when I went to the USA about 10 years ago. I got a mate over there to buy some very expensive Technical Rope Rescue gear which I then brought home in my luggage… saved my volunteer/charity team a tidy sum. That’s the sort of import tax evasion I have no bad concience about! :grin:

Think the statute of limitations has gone on that one…

I corrected that for you Gerald :wink:

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Thank you all for the repies.

I went the very easy route and bought a 3s LiPo charger on Aliexpress and a small adapter so I don’t even have to solder the plug myself :sweat_smile: Works fine :slight_smile:

62g vs 250g for the original charger.