The batteries in the photo are questionable.______________________________________________________________
The best 18650 cells are 3500 mAh.
If you measure their true capacity, I would be very surprised if the capacity was 2200 mAh.
There should be a battery maintenance board in the battery pack that limits the charge/discharge rate and shuts down the pack on low Voltage.
With out the BMS there is an increased possibility of fire.
73
Glenn
WB4UIV
On 4/22/2026 11:31 PM, Clare Owens via MRCA wrote:
I received this battery case with a NOS? PRC-77 from a Japanese ebay seller. It is for 4 18650 batteries and apparently was made by 3D printing. Seems to work fine and has the resistance in the 3V line. Only problem is that the '25 and '77 are analog, with no low battery alarm so it is too easy to drain the batts below their 2.5V minimum and thus ruin them. It is identical in size to the BA-5598. And I do not want to sell it.
Clare. N2RJB
On Wed, Apr 22, 2026 at 7:50 PM Tim via MRCA <mrca@mailman.qth.net> wrote:
Hi Dave ..My PRC-25 is powered by 2 “D” Cells in series (with a DIY 1 ohm resistor in series) for the 3 volt 2DF4 TX tube filament and two 6 volt, 4.5 A-H Gel Cells (Power Sonic PS640F-1) in series for the rest of the electronics. It all fits in the stock battery box and I can charge the Gel Cells by connecting pin leads to the Power connector female pins when the Z-1 plug is removed.
The 1 ohm resistor in the filament line is needed to drop some voltage (from fresh batteries) to the tube filament when it is cold-started. Mine is made from about 8 feet of 30 gauge magnet wire wound on a high value resistor as a form.With my occasional usage the D Cells last "forever".
Tim
N6CC
______________________________________________________________On Wed, Apr 22, 2026 at 3:37 PM KD2GIY via MRCA <mrca@mailman.qth.net> wrote:
______________________________________________________________On my trip to MD and DE I came across a very good deal on a working prc-25 on the Jeep dock.
I understand the radio needs 2 different voltages and it would be a pain in the ass to fabricate this.
My question is, does anyone have for sale a drop in battery insert for this radio or can let me know where I can find one on the internet?I've seen pictures of some that take d batteries.
I have looked and cannot find anything but used original dead batteries.
Thank you for your time.
Best regards
Dave
KD2GIY
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-- ----------------------------------------------------------------------- Glenn Little ARRL Technical Specialist QCWA LM 28417 Amateur Callsign: WB4UIV wb4uiv@arrl.net AMSAT LM 2178 QTH: Goose Creek, SC USA (EM92xx) USSVI, FRA, NRA-LM ARRL TAPR "It is not the class of license that the Amateur holds but the class of the Amateur that holds the license"
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