Survivalism & Self Sufficiency Topics > Amateur Radio How-To's

DIY Handheld Radio External Battery Pack

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Greekman:
Here is a battery bank I did for my HT.



It uses this battery case.
https://www.fasttech.com/products/1286603

I had to rewire it for 2series-2parallel since my radios battery is a 7.4V.
Then I added the RCA plug and the fuse holder.



I had to work new holes in the place of the existing ones, so I added a new wall to host the plugs. It is made from a DVD case, epoxied on and soon I will be adding supporting structures in the area the original PCB screw points are

For batteries I will be using 4 Samsung 2600 (pink) in the 18650 size. Cheap and of good capacity are a best buy for this application. Alternatively one can use the Sanyo 2600 (red) or the Panasonics NCR18650B 3400 (green). With the latter it will be more than 4 times the OEM battery.

One more pic showing the wiring in more detail.



(the black wire snakes under the fuse holder and is connected to the RCA plug case.)
All other wires carry the positive current.
Fuse is a 3A one, since my TH-F7 maxs at 2A.



Then the wires end in two fake batteries that are placed in a Kenwood battery case.
It is of a good coincidence that my HT does not have a automatic battery detection feature. So I choose the lithium option from the menu and make it think it is powered by the original lithium battery (7.4V, 1550mAh).
Also it does not use 3 contacts for the OEM lithium battery, just two. This is most critical cos I do not know how this would work with the radio was using a 3rd contact to monitor nattery state. Being dump proved to be helpful in this case

Issues to be resolved…
- I have observed some voltage drop from the 18650 batteries to the battery case. (to be expected with some many connections). I have yet to measure it and see how to limit it.
- I have not yet monitored how the battery measuring feature of my HT corelates to the power available of the battery bank.

That is all for now….Greekman

viking:
Nice job!

backwoods_engineer:
Nice work, but I suggest next time you use Anderson PowerPole connectors.

Greekman:
yep I know about them.....
But it is an expensive proposition to order them. Especially since the USPS international postage prices have skyrocketed
No one else uses them. Even if the RCA are a stange option i will not be them first oen that uses them in my area.
It has become very hard to procure parts. what you see are left-overs in my local market. I.E I will have to special order mic sockets for cases. No one wants to stock these items anymore.
A.P.s are very big for this application...

FreeLancer:
That's cool!  I want to try making some 18650 battery packs.

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