Foam removed from batt box
3 5/16 x 9 1/2"
2 3/8" x 9 1/2"
BA-4386 - 2" hi
There are a number of PRC-25 and PRC-77 radios that don't have a reasonably priced source of power. New batteries are difficult to buy and expensive. The "Fresh" still in the plastic wrapper BA-4386/PRC-25 batteries being offered on eBay are way out of date and typically are DOA. The BA-5598/U has been banned in two issues of PS magazine for use on the PRC-25, probably because it does not have any limitation of the filament current like is in the new batteries and in the BA-4386/PRC-25. Without some current limitation a cold filament will draw an enormous amount of current thereby decreasing the tube life or even burning out the filament.
This adapter has a filament current limitation which is mandatory.
Holds 10 each "D" cells in series with a tap up two cells for the filament supply.
2577BA requires removing the foam strips in the bottom of the CY-2562/PRC-25 battery box because the adapter is 2 3/8" high whereas the BA-4386/U is 2" high. If you don't want to remove the foam strips use my 257477BA battery adapter.
"I put the prc25 on a workbench in our radio shop after the test, and found that with the battery adaptor and fresh alkaline energizer batteries, I was putting out 3.5 watts and the receive sensitivity was about .45 uV ..
Not bad performance .. I think I had checked the radio in the past with a magnesium battery and got about 1.8 watts out, so the higher voltage of 10 1.5 volt cells being 15 volts probably raised the performance of the radio a little.." Trish WA6UBE moderator of the Army Radios mailing list
The 2577BA shipps with no batteries, it's up to the user to select and install the batteries. Do not mix battery types! All 10 cells should be of the same model number and date code.
Manufacturer Chemistry Model Amp Hours Weight/each Total Adapter wt Eveready
18 5 oz 3.56 lb Ray-O-vac Renewal rechg Alkaline 713 7 4.4 oz 3.25 lb Radio Shack NiCad 23-123 2.0 oz lb Radio Shack NMH 23-519 4.5 4oz 3.0 lb King Cell NMH ? 7.5 ? ? Saft
Taboo on PRC-25
2 * 7.5 = 15 AH 23.2 oz 2.90 lb
The Alkaline offers the highest AH capacity and the lowest single use cost. The rechargeable battery offers a lower amortized cost because of the reuse but at the expense of lower AH capacity and possibly more weight and higher up front cost. The LiSO2 has very good AH capacity and is lighter than all the others, and that's why the military uses a lot of them, BUT should not be used on the PRC-25.Note: A number of companies offer "D" cells that are in fact "C" cells with an outer wrapper. For example the Radio Shack 23-124 "C" NiCad cell and the 23-123 "D" cell both have 2 AH capacity and both are priced at $ 6.99 for two. In the case of the 23-520 3AH "C" @ $14.99 for two vs. the 23-519 4.5AH "D" @ $14.99 for two, the "D" cell is the better buy. Just be alert to what AH rating you are getting for the dollar.Note: It's very difficult to test any LiSO2 battery. If you are using the BA-5598/U in a PRC-77 on an intermittent basis you will have no way to know if the battery will suddenly quit. With older batteries like the BA-4386/U you could test with the PSM-13 and have a pretty good idea of how much charge was left in the battery, but you need a TS-4403 to check LiSO2 batteries and these are very hard to get (even for the U.S. military).
While trying different battery chemistries I found that neither the TS-183 nor PSM-13 do a reasonable job. The TS-183 uses a 298 Ohm load (about 50 mA) and the PSM-13/U-410 uses 5 Ohms ( 3 Amps) as the load. One is too little and the other is way too much.
To get a fair comparison between different battery chemistries the load should be close to the actual radio load, somewhere around 1.1 Amps would be good. Since 1 Amp at 15 Volts is 15 Watts a practical and low cost way to make a load is to use a couple of 10 Ohm high power resistors like the Radio Shack 271-132 load resistors. Here is what the data looks like:
Load V V V V Open 15.8 15.7 13.9 17.0 20 Ohms 1 A 13.4 12.8 13.5 12.3 16 Ohms 13.4 13.7 14.0 12.0 2 A 11.3 10.8 13.0 10.2 3 A 9.3 8.8 12.6 7.3
The BA-4386 terminal voltage is a strong function of what the prior load has been. If first connected to a 1 Amp load the chemistry does not fully activate and the voltage is lower than when the battery has seen a heavy load, like the PSM-13/U-410 provides. But most radio users do not condition their BA-4386 batteries so this is not a fair way to test. This effect is why the BA-4386 data does not seem consistent.
These equipments may or may not accept this adapter because the 2577BA was designed to fit into the CY-2562/PRC-25 battery box of a PRC-25 and/or PRC-77 and is traller than the BA-4386.
Model Description Function GRA-114 Sound Ranging Radio Data Link ? KY-38 Voice security device, Nestor, Man portable w/PRC-25 No KY-65 Secure Voice Device w/GRC-206, PRC-104 ? PPS-15
Radar Set ?
PRC-25 VHF low band tranceiver 2577BA OK PRC-74 in the CY-6314
wing nuts & moving plate
HF tranceiver No only the
257477BA is OK
PRC-74 in the CY-6314A
HF tranceiver No PRC-77 VHF low band tranceiver 2577BA OK PRC-1077 VHF low band tranceiver ? PRC-1088 VHF low band tranceiver ? PRC-1099 HF tranceiver ? PRD-10 VHF Manpack Radio DF ? PRD-11 VHF Mini-Fix Radio DF ? PSN-6 Loran C & D receiver that mates with the PRC-25 or PRC-77 2577BA OK URR-69 ? ? USA-32 ? ? USQ-42 VHF high band outdoor intrusion receiver ? USQ-46 & TS-2963/USQ-46 VHF high band receiver & Transmitter (TS-2963) ? URC-110 Radio Set Line of Sight or SATCOM ?
note 1 - The CY-6314 battery box has a notation:
"One battery operation: plug into J2 and secure with retainer"
"Two battery operation: mount back to back, and plug into J2 and J3 and secure."
Version 6.2 has been shipping since 24 July 2002
Version 6.5 is now called the 257477BA.
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This is the time this page has been accessed since since 14 Feb 2001.