USB charger base

VK3KYY
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Location: Melbourne, Australia

USB charger base

Post by VK3KYY » Sun May 14, 2023 7:12 am

Guys

I thought some of you may be intersted some experiments I've been doing to use a USB power supply instead of the various DC PSU's which are supplied with these radios

I noticed that it was possible to buy USB charger module from AliExpress which would change 2S or 3S or 4S battery packs, with USB currents of either 1A, 2A or 4A

I have bought several different modules, and after doing some tests, the module which look like this one appear to be the best.

https://www.aliexpress.com/item/1005004503555987.html

However, as usual with such items from AliExpress etc, the module does not totally conform to its specification.

I found the 1A USB current version, consumed 950mA from USB, and the 2A USB current version consumes around 1.6A

I did not buy any "4A" versions becuase 4A USB chargers are not common, but most new USB chargers will deliver 2A.


The charge current to the radio, when the battery pack was at 8V was approximately 600mA for the "1A" module, and approximately 900mA for the "2A" module (consuming approximately 1.6A)

Doing some rough calculations, these modules over 90% efficient.

i.e.
USB: 1A * 5V = 5W
Radio 8V * 0.6A = 4.8W
4.8 / 5 = 0.96 = 96% effecient


USB 1.5A * 5V = 7.5W
Radio 8V * 0.9 = 7.2W
7.2 / 7.5 = 0.96 = 96% efficient

These figures are not 100% accurate, as the USB current sometimes reached 1.6A , so the efficiency would probably be 90%

I also tried anothe type of module, but the efficiency was terrible, only 60%, so I'm not going to post a link to that module type.

Trying the 2A module on a USB PSU which could only supply 1A resulted in only 300mA charge current to the radio, because the voltage of the USB PSU dropped to 3.5V. I don't remember how much current was taken from USB in this experiment, but I don't think it was stable.
Also some USB chargers completely shut off and then reset, if more current is taken, than they are designed to supply, and this results in a buzzing sound as the charger repeatedly resets.

So if you want to charge from 1A USB, then you should use the 1A version of the module, becuase the 2A version does not shutdown gradually



Modification of the charger base, requires that part of the plastic is filed away to allow for the USB socket to protrude enough.
I glued the module to the base plastic, becasue its then lower than the terminals that connect to the battery, and I have some short wires between the terminals and the module.

At the moment I have not filled in the large hole at the back of the charger base, in case I want to convert back to using the 10V DC charger, but I think I will fill this soon with hot glue.

One thing to be aware of when gluing the module, is that it dissipates about 0.5W and does warm up, and using hot glue to fix the module didn't guarantee that it was held firmly, so I used some contact adhesive instead. I also considered using epoxy glue, but this is probably overkill for the amount of force which is applied to the module when the USB plug is inserted.

This module type may be also available in other USB socket types, but I'm trying to standardise all my USB devices to USB C for all new devices.


usb_charger_base_1.jpg
usb_charger_base_1.jpg (94.18 KiB) Viewed 1769 times
usb_charger_base_2.jpg
usb_charger_base_2.jpg (84.83 KiB) Viewed 1769 times

kt4lh
Posts: 272
Joined: Sun Jan 12, 2020 4:27 am

Re: USB charger base

Post by kt4lh » Sun May 14, 2023 1:57 pm

The TP5100 I used to replace the guts of my charger (entirely based on Jason's webpage) accepts 5V, is dirt cheap, and has resistors you can add/remove/change to adjust the current. I've never measured its efficiency, however, but it'll run from 5 to 18v. I went with a simple 5.5x2.1mm jack as those are super common, but i have pondered making a USB dongle to go between the two. Would probably want to put some resistor across the data pins so chargers will output a reasonable current though.

I like that I can run the charger base off my bench supply that's already running 24/7 anyway.

VK3KYY
Posts: 7478
Joined: Sat Nov 16, 2019 3:25 am
Location: Melbourne, Australia

Re: USB charger base

Post by VK3KYY » Sun May 14, 2023 9:08 pm

I wasn't aware that the TP5100 would operate at 5V. But I would still rather use a module PCB which has USB connector, than to have to buy another board with a USB socket

I forgot to say the reasons I am changing to USB charging.

1. All the DC PSUs that come with these radios , require a mains adaptor plug. These are unreliable and generally dangerous.
2. I want to be able to charge the radio in the car and other places which have USB charging points.

VK3KYY
Posts: 7478
Joined: Sat Nov 16, 2019 3:25 am
Location: Melbourne, Australia

Re: USB charger base

Post by VK3KYY » Mon May 15, 2023 6:55 am

ve7mdt wrote:
Mon May 15, 2023 5:59 am
Nice idea, Roger!

Did you test if this board gives any EMI / RFI to the radio's receiver when it's on and charging / on, connected w/ the charger but battery full ?

Some of these factory chargers give out RFI and some don't, it seems to be a hit and miss.

Thanks, great mod!
Good point, but no, I've not tested for that, as I've not been using the radio while it was charging.

I will see if I notice any QRM, but at the moment I have a lot of other QRM in my shack, so I'll probably have to turn everything else off, in order for it to be a valid test.

OE1MWW
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Re: USB charger base

Post by OE1MWW » Mon May 15, 2023 8:04 am

kt4lh wrote:
Sun May 14, 2023 1:57 pm
The TP5100 I used to replace the guts of my charger (entirely based on Jason's webpage) accepts 5V...
Walter,

I checked my TP5100 - it is in the charger since the early days of OpenGD77 - as I made the charger mod.
The 5V input to the TP5100 does not step up to 8,4V. The 5V input = 5V out at the charger contact clips.
Yes, the 12V input will result in 8,4V - so the design of Roger is a universal application, USB-C is available
on many power supplies.

kt4lh
Posts: 272
Joined: Sun Jan 12, 2020 4:27 am

Re: USB charger base

Post by kt4lh » Mon May 15, 2023 11:46 am

OE1MWW wrote:
Mon May 15, 2023 8:04 am
Walter,

I checked my TP5100 - it is in the charger since the early days of OpenGD77 - as I made the charger mod.
The 5V input to the TP5100 does not step up to 8,4V. The 5V input = 5V out at the charger contact clips.
Yes, the 12V input will result in 8,4V - so the design of Roger is a universal application, USB-C is available
on many power supplies.
Oof, I guess them speccing 5v in is okay for a single 4.2v cell battery. Thanks for the heads up, I won't be making that adapter now ;)

OE1MWW
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Re: USB charger base

Post by OE1MWW » Mon May 15, 2023 1:31 pm

Roger,

just for my info (and maybe for others) - the product of your link will not be delivered to Austria
(new crazy 'packaging disposal law'), but some Aliexpress dealer do deliver, so I found & ordered:
https://www.aliexpress.com/item/1005004689821903.html and
https://www.aliexpress.com/item/1005004682732678.html
Remark: the first link - end number ...03.html seems to be like yours, just in 'green' ;-)

Low efficiency is not a big deal at that powerlevel, nevertheless, by chance, did you check one of
those in my links?


73s

SA0BUX
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Re: USB charger base

Post by SA0BUX » Mon May 15, 2023 2:50 pm

Is it the 2S 2A card that should be used?

Seems that Sweden doesn't have that restriction that you had in Austria.
If I had a 3D printer and knowed how to design objects I would make a tiny travel charger with that card that is less bulkier than the drop in charger.

OE1MWW
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Re: USB charger base

Post by OE1MWW » Mon May 15, 2023 3:28 pm

SA0BUX wrote:
Mon May 15, 2023 2:50 pm
Is it the 2S 2A card that should be used? ...
Lars,

Roger said: "So if you want to charge from 1A USB, then you should use the 1A version of the module, becuase the 2A version does not shutdown gradually"

Therefore I ordered the 1A version. Arrival will be, as usual, in 3 to 4 weeks.

SA0BUX
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Re: USB charger base

Post by SA0BUX » Mon May 15, 2023 3:46 pm

OE1MWW wrote:
Mon May 15, 2023 3:28 pm
SA0BUX wrote:
Mon May 15, 2023 2:50 pm
Is it the 2S 2A card that should be used? ...
Lars,

Roger said: "So if you want to charge from 1A USB, then you should use the 1A version of the module, becuase the 2A version does not shutdown gradually"

Therefore I ordered the 1A version. Arrival will be, as usual, in 3 to 4 weeks.

Yeah, I understood the part with the USB current , I was thinking of the voltage as the link gave me the 4S version, I guess our batteries have two cells and that the "S" in reality means how many 3.7 V cells you have.

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