My HT Radio Powerbank, Generation 2

This I got to brand, maybe as the "GR-P Powerbank"

So... this has been an evolvement of my former design.

This was a battery case with 4 18650 Lithium-Ion batteries wired 2s2p and feeding 7.2 (8.4)V to the radio through dummy batteries in a AA battery case.

This one goes one step further.

It uses four 18650s of a working voltage of 14.4-16.8V and a step down DC-DC converter set to output 13.2V.

The converter is thermally glued on an aluminum heatsink with its fins outside the powerbank.

A LED indication light will be added as soon as I calculate the forward voltage of those at hand, and find the proper resistor for them.

My Kenwood TH-F6/7 radio (and the some Yaesus too) can take car battery DC voltage AND operate with it. 

Most significantly when the TH-F6/7 operates with such a voltage the medium power setting changes from the original 0.5 to 2watts!

A side benefit is that the radio is also charged when not in use, and fast charged too.

Working current is 2A according to the original Kenwood PG-3J accessory specs, so we are good on the important parameters, like cabling, battery load, DC converter specs,  etc.

Concerning other radios, some Yaesus can be charged and operated with a 12V input straight on the radio (see the FT-60R) and the Baofengs and the Wouxons accept a 12V input to their craddle charger. So it becomes a matter of making the proper cables for them.

Powerbank capacity depends on the batteries of course. The ones used are Panasonic NCR18650A 3100mAh ones, but you can get as high as 3500mAhs these days. Speaking in watts that is 44W, exactly four times the radio's battery power.

Batteries are charged independently outside the case of course, and are matched because 4 lithiums in series is not that good idea.

That is all, if you like it wait untill I receive the parts for my next project.. ;)