PRC-90 Battery Adapters 90BAv2 & 90BAv3

©Brooke Clarke, 2001 2007
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Open view
Fig 1
Fig 2
Positive end showing
Cap is Negative
Fig 3
O-Ring is installed on radio
Fig 4
90BAv3 Battery Adapter for PRC-90 family radios
Fig 5 90BAv3
90BAv3 on PRC-90-2
90BAv3 installed on PRC-90-2
90BAv2 Description
90BAv3 Description
Survival Vest Radio Pocket NSN 8415-00-442-3616 
Tester for Mercury BA-1568/U
Mercury Battery Warning

90BAv2 Description

This is a functional replacement for the BA-1568/U Mercury battery (NSN 6135-00-838-0706) used in the PRC-90, PRC-90-1, PRC-90-2, PRC-103, PRC-106, and  (but not the PRC-63, PRC-125) survival radios and the training version of these, maybe the PRC-604 radio.  It uses 4 each CR123 type LiMnO2 photo batteries in a cap that extends about 3" below radio.  Has groove to allow attaching to radio earphone strap with 8" tie wrap (included).  The 123 cells are rarted at 1.3 AH compared to the BA-1568/U rating of 1.0 AH. 

When 4 each 123 batteries are tested with the BT-2B the meter reads 0.8 where 0.5 is full scale for the BA-1568/U.  I don't know the capacity of the BA-5368/U LiMnO2 battery (NSN 6135-01-435-7947), but have been told a number of times it is very expensive.

I cut off the old cap, see Fig 1 and 2 above, and used an 8" tie warp to attach the adapter through an eyelet hole in the earphone strap.  This allows room to remove the adapter from the radio to change batteries. 

90BAv3 Description

The version 3 adapter is the same as the version 2 adapter except it has threads on the bottom for the radio cap and it ships without a tie wrap.  The groove for the tie wrap is still there in case you want to tie a lanyard between the adapter and the radio, which might be good if you were also using regular batteries.

90BA Description

This used a couple of much smaller 6 volt batteries and fit inside the radio housing, but had very little talk time.  Discontinued.


  • Lightly coat O-ring with Radio Shack Lube Gel  64-2326 or equivalent Silicon grease.
  • Install O-Ring onto radio past threads as shown in Figure 4 above
  • Place Plastic tube into battery adapter with label showing
  • Slide 4 each 123 photo batteries into adapter Negative end first (cap is negative) will look like Fig 3 above
  • Screw on 90BAv2 adapter until it seats on radio
  • 90BAv3 screw radio cap on bottom of adapter
  • Apply sticker to radio with install date and a replace date (maybe 5 years until replacement)
  • Optionally attach tie wrap to groove in adapter and tie to radio earphone pouch strap eyelets. (n.a. for 90BAv3)

  • Leave a little slack so that adapter can turn for removing and installing.
  • Optionally cut off old battery cap after confirming good operation. (n.a. for 90BAv3)
  • Survival Vest Radio Pocket NSN 8415-00-442-3616

    Fits PocketThe pocket that can be sewn onto survival vest SRU-21 will hold the PRC-90 with the 90BAv2 battery adapter attached.  My pocket has contract number DLA-100-82C-C-0394 and manufacturer Camlet Corporation,Roch. NY.  If the radio is installed into the vest antenna first then the battery adapter makes a nice handle to remove the radio.

    Tester for Mercury BA-1568/U

    The BT-2B survival radio battery tester shows them to be at the normal 50% indication for a full BA-1568/U.  Note that the modern batteries may have different capacity than the original battery so the test set no longer is calibrated.  I have a couple of old stock (9/88) Mercury batteries, one shows a little below 50% and the other starts at 40% and drifts down to 30% in a matter of seconds.
    The RS 23-266 (2CR-1/3N) is rated 0.16 mAH and the PRC-90 draws 35 mA in receive mode so these might last about 4.5 hours in receive more, much less in transmit mode.  A fresh BA-1568/U might last 14 hours according to the booklet that is attached to the BT-2B test shown in the photo above.

    The LiMn02 photo 123 type batteries have a very flat discharge curve and can NOT be tested in the BT-2B tester.
    When fresh batteries are installed a sticker should be placed on the radio with an installation date and a replace date.  The LiMn02 battery has a 10 year shelf life and I've seen 5 years used as a replacement cycle time.


    This adapter was designed for SAR ground work to allow CAP personal to communicate with military aircraft involved in the search.  It has not been tested or certified for any official use.  If used for survival purposes it's at the users own risk.

    Included & Not Included

    Included: Cap, O-ring, Insulating Tube with polarity diagram, tie wrap
    Not included: radio, batteries

    Mercury Battery Warning

    The above units originally used Mercury based batteries.  Mercury is one of the heavy metals that has been found to be bad for humans. (Lead wine containers may have caused the end of the Roman empire?)  Any military battery whose model number is BA-1001 to BA-1999 is a Mercury battery.  These should be kept in Zip-Lock bags and disposed of in accordance with hazardous materials regulations.  If any crystals form on the battery they should be considered as poison.
    Back to Brooke's  Products for Sale, Survival Equipment, Military Information, Personal Home page created 17 Sep 2001.

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