18650 Batteries and Charger

And can be used to jump start the Universe :wink:


I took a chance and ordered these

So far so good, and a holder for the batteries here

I replaced the wiring with thicker wire and added a PP connector.

A good match for my QCX mini, MTR or KX1.
Roger MW0IDX


I don’t know if the universe, but the car yes, verified :rofl:



yes I have an iMAX B6 charger. If you want some LiPos I have a few from a Dyson battery pack you can have.



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I have been using 18650 cells from a Dyson battery pack now for years. Jump on this one!



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In the time I was looking for a charger I found reports about fake iMAX B6 in bad quality and with inaccurate measured voltage. But it’s long time ago.

73, Ludwig

You’re right, I forgot about the limit. But the other protections are useful.

What I like personally is to see how many people are recycling older 18650s out of battery packs.

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I do Andy ! (as you probably know)

I have not made the switch to LiFePo yet … since I can get lots of old laptop batteries for free, and most of those still contain Li-Ion technology.
My battery packs are home made, with balancing leads for the charger, and a polyfuse and PowerPoles for the output.

I do have an iMax B6 charger, but it’s a bit too heavy for travel, so I have this little charger:


It works from a 9-16V input, so I can use it with a wallwart, in the car, from a solar panel …
and most important, I can’t forget how to use it, there are no buttons :wink:
It can only slowly charge via the balanceing lead, but I like it better … there is probably less fire hazard.
(search your favourite shop for “BC-4S15D” charger)

For testing, selecting and matching the good cells, I have a Liitokala Lii500 charger (search your favourite shop for that name). It can charge and discharge 4 cells at a time, and measure their capacity. For a similar device for LiFePo, see post above from MX0IDX.

Backup solution is the powerbank trick, with a seperate cell holder, as discussed several times before on the reflector.
See an example in this SOTA News (scroll down to " Airport security and batteries"):



This is the right way with the Battery Management Board. This is the only way to protect the battery from deep discharge and it does not cost much. Lithium cells are very robust, but they do not forgive deep discharge.

73, Peter - HB9PJT


Excuse me, now working


Fraser what did you use for a mic on the tr USDX?

Yep… re-cycling old laptop batteries goes for me too! I bought the Accucell6 with a Zippy 8400mAh from a hobby shop so adding balancing wires to the batt holders means I can charge packs without removing the batts. Btw, the one with the blue tape is the ‘worst’ of the current crop so I keep an eye on that one!!



Sorry, not Fraser, but as a user of truSDX I can tell what I use.

I find that SSB tx audio is poor in this rig, but we all are aware of its minimal design, so it’s good we can still do CW & SSB with this tiny toy!

As I said, the audio quality is not very good, so in order to improve it I did two things:
a) adjust the audio settings via these menus:

  • Noise gate = 1
  • TX Drive = 2

That reduces the distortion in the digitalisation of the voice.

b) Use an external mic (PC headset) instead of the built in mic.
That also adds clarity in the voice.
To be able to use the mic and add an external PTT switch I added an easy to build adapter.

The RCA connector is for the PTT cable.

The pinout conforms to:

See all details here:

Good luck with your truSDX, not a jewel but a fun rig.
73 Ignacio

Ps: I’m using 18650 with it and due to very low current draw it works fine and last very long. Don’t get mad looking for the perfect charger, almost any LiIon charger will do the deal.


I bought a £5 baofeng type clip on mic. with earpiece (the Secret Service type). I had to cut off the kenwood style plugs and do a bit of rewiring to suit the 3.5 mm TRS types that the (tr)USDX uses. I think the mic. was off ebay.

I chose the earpiece type as the radios speaker is so poor, especially for outdoor use.


Lots of good info in this thread. I didn’t see this mentioned so I will add it - these tiny USB 3S LiPo chargers work great:

I put balance leads on my 3S 18650 packs. These cheap chargers are great for travel - I used one to keep my battery topped up between activations on my trip to Iceland. Saved a lot of space and uses the same USB charging gear that I brought for my phone. Came in a pack of two, and both still work after a couple of years.

At home I use a much better charger, but for travel these little USB chargers are hard to beat.



Iam using B6, but also this cheap tester

73, Ivica

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On my last Winter Tour, I used this solution, it’s something I made for my first steps in SOTA , back in 2014, for powering an FT857D. No need to fiddle with cells, BMS boards or anything, it’s all built in, each battery even has a 5 LED charge indicator.

I have a whole bunch of laptop batteries which can be charged two at a time in a Dell Latitude Cpi (the second battery slot can also house a floppy, CD/DVD or a ZIP drive, and I still have those in my “museum”, hi. The laptop is still operational as well, running Windows XP).

I scavenged two such laptops for their battery connectors, and used those in a frame which takes two such 4-cell batteries in parallel, via some 30A Schottky diodes.

With a whole box of spare batteries (see picture) I can do lots of activations :wink:
And I can exchange batteries one at the time, without even switching off the rig.
(of course I don’t carry that box to a summit, but change batteries back at the car, when needed)

The battery pack stays in my backpack, all I have to do is connect the PowerPole adapter lead and plug it into my KX3.



Lots of good responses. I have used a pair of 3 cell battery packs from 12 volt electric drill sets sold by Black and Decker and others. The nice feature is the cost. For about $35.00 you can find the drill kits , usually on sale. The batteries are well marked as to the connection and a set of spade lugs, very common, can be used to make a connection cable. So for this price you get the 3S batteries, a charger, and a drill - which can be used for your next project. These have lasted since about 2012 thru the use of a K2, KX1, MTR2, and KX3 in the field.


Another DIY battery pack, 6x18650+BMS.