Travel charger for radio batteries

[SA0BUX]

I have searched for some travel charger for handheld radio batteries that is smaller than the desktop chargers included with the radios.
Sometimes I have several different models in my luggage which takes both space and weight.

I hade ideas building something with a USB charging module and some connectors, maybe I could 3D-print something but I don't have a printer.

Then I found something on Aliexpress that could work, it has the USB charging circuit in the connector and have two two clips that you connect
to the battery, the clips are a bit flimsy but it works when you need to charge some battery packs on your hotel room.

There was several shops that sold them.

https://www.aliexpress.com/item/1005005519348352.html

S59a990a6790748ce8fa4c2a56dc1e14az.jpg (119.46 KiB) Viewed 2999 times

[VK3KYY]

My friend told me a little trick about charging batteries that have flat terminals. There are small magnets available at stores like Daiso or Oomomo Japan Living (Japanese chain stores), and they are metal on the outside and thus conductive (probably nickel plated), and you can use it to attach it w/ an alligator clip to the battery's terminal (typically flat and hard to attach to). I tried it w/ my MAHA 777 Plus charger and it worked well, when the pogo pins universal dock can't reach some of my batteries b/c of shape or size.

This does not work. On the GD77, RT3S, DM-1701, RD-5R, DM-1801, or any of my other radios, including the UV-K5(8) and UV-82

The terminals on these radios are not made of a metal to which magnets will stick, and I've tried with really strong magnets, not just the tiny ones.

Try it yourself.

[SA0BUX]

I have seen these on Aliexpress. Not very cheap (in terms of Cheap China Radio category). No specs on current, it might be lower than what can be achieved? I guess one could DIY and save 80% of the cost, but it depends on how someone likes to build stuff or save time.

I noticed that there are 3 versions to choose from also. The good thing is that it will work on many radios as it's universal.

My friend told me a little trick about charging batteries that have flat terminals. There are small magnets available at stores like Daiso or Oomomo Japan Living (Japanese chain stores), and they are metal on the outside and thus conductive (probably nickel plated), and you can use it to attach it w/ an alligator clip to the battery's terminal (typically flat and hard to attach to). I tried it w/ my MAHA 777 Plus charger and it worked well, when the pogo pins universal dock can't reach some of my batteries b/c of shape or size.

I will try some measurements towards the battery when I have time, and I need to find my USB V/A meter too or buy a new one.

[SA0BUX]

I have now measured with my DMM.

Charge current was just above 1 A and voltage across the charging contacts 7.4 V

I used the USB port on an Intel NUC so I need to test some other USB power sources later and also measure on the USB side
with my new USB power meter UM34C.

The chargers I bought from Aliexpress supports both 1 and 2 cells, and was USD 9,65 with free shipping to Sweden.

[VK3KYY]

I have now measured with my DMM.

Charge current was just above 1 A and voltage across the charging contacts 7.4 V

I used the USB port on an Intel NUC so I need to test some other USB power sources later and also measure on the USB side
with my new USB power meter UM34C.

The chargers I bought from Aliexpress supports both 1 and 2 cells, and was USD 9,65 with free shipping to Sweden.

I noticed with the USB "2S" charger module, which I fitted into one of my charger base unit, that it does not charge the battery to 100%.
I think their max charging voltage is set to lower than the voltage of the TP5100 modules

[SA0BUX]

I have now measured with my DMM.

Charge current was just above 1 A and voltage across the charging contacts 7.4 V

I used the USB port on an Intel NUC so I need to test some other USB power sources later and also measure on the USB side
with my new USB power meter UM34C.

The chargers I bought from Aliexpress supports both 1 and 2 cells, and was USD 9,65 with free shipping to Sweden.

I noticed with the USB "2S" charger module, which I fitted into one of my charger base unit, that it does not charge the battery to 100%.
I think their max charging voltage is set to lower than the voltage of the TP5100 modules

Have to investigate more, but I need to make a better lab area at home current desk is totally crammed ,have a new desk but need to mount it first

At end of charging the voltage was 8V something.

But this charger will work fine when I travel.
Not charging to 100% will also increase lifetime on the batteries, similar to laptops where you can set it to charge only 80-90% in the bios.