Wednesday, December 29, 2021

K2GOG EOY 2021 Loose Ends #2: Battery Upgrade


With a few less days in 2021 remaining, I was hoping to upgrade the batteries in a pair of  "vintage" Yaesu VX-1R over the holiday break, but still find myself waiting on the replacement 14650 cells to arrive. 

So for now, this project is on hold while my batteries which were ordered on December 17th should have shipped today, but have not yet status updated! 

Memory Lane: The Yaesu VX-1R

All the back in 1997, this micro-miniature amateur radio came to market with its 500mW of RF output in the 2m and 70cm spectrum bands when using the internal battery. And, plugging the radio into an external DV 6 V source provides up to 1W of RF output.

With wide analog reception from 76 to 999 MHz with few gaps, this was an interesting radio, along with some experimental AM broadcast band coverage too.

This was also my third ever amateur radio handheld, so I have always had a fond memory of it and was glad to find two at reasonable price while at the NEARFEST in Deerfield, NH this past October.

Even today when compared side by side with a modern radio like the Alinco DJ-MD5XTG, its amazing how advanced the Yaesu VX-1R was almost 25 years ago for an analog only transceiver for its size.

Spending upwards of $30 USD today for a replacement battery in 2021 is a tough sell for an older radio like this which sells for about $50 to $75 used almost 25 years after its release.

The optional FBA-20 AA battery holder accessory has become harder to find, so the cheapest way to bring new life to these great little radios is by rebuilding the original battery.

The original Yaesu FNB-52LI battery is rated at 3.6v at 700 mAh and the inside of each battery has a charge controller and lithium 14650 cell. 

Versions of the 14650 are available today in 1100 mAh capacity, although some vendors boast of some with 1600 mAh which is not very believable.

After putting four old cells in the freezer for a few hours, I was able to use a hobby knife to slice down the side of each battery and reveal the insides.

A curious thing was that all four batteries on the outside appear identical, but one of them uses a slightly different charge controller as shown below.  

Functionally, they are probably all the same and the date codes all seem around the same manufacturer period but this was interesting to see.

So when the new 14650 batteries arrive, it will be a pretty easy replacement process by swapping the old cells for the new and reattaching the charge controller before stuffing it all back inside the original casings. Will probably print some nice new labels including date codes too while I am at it.

Other battery projects

I think once I finish up the Yaesu VX-1R battery rebuilds, I will try and tackle the same idea for some other vintage radios from the late 1990's too, but those will require some more thinking as they all originally used NiCd or NiMH chemistry and I rather make everything run on lithium cells instead. 

Do you have any similar projects in mind?   Drop come comments below if you do.

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