SDU-5/E Battery Adapter   5BA

Brooke Clarke, 2000 - 2010

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5BA Top View

SDU-5 Standing on Cap
5BA Bottom
Version 2
Engraved
Version 2
Engraved

Engraved (Version 2) Engraved (Version 2)

Description
General Information
Threads Notice
O-Ring Notice
Not Certified or Approved
BT-2B Battery Tester
SDU-5/E Does NOT Float
Some Sources for Batteries
Batteries Not Included
Other Strobe
Mercury Battery Warning
Links
How to Order

Description

This battery adapter allows the use of two common CR123 photo batteries to power the SDU-5/E Distress Marker Strobe Light.  It replaces the now obsolete BA-1574/U Mercury battery.  The CR123 photo batteries have equal or better shelf life and much better life in sub freezing conditions when compared to the original Mercury battery.   There was a battery called the 4RM1B that this adapter also replaces.

This adapter will also power the TS-23 Light Output & Battery Tester for SDU-5/E Strobe Light.

General Information

What's New 9 April 2004

The latest batch of 5BA adapters (Version 2) have the top engraved:
PRC68.com
+
CR123
The main advantage of engraving is that it will last.  When it's time to replace the batteries or a few years in the future you will know that the cap is positive and to use CR123 type batteries.  The prior marking would not last as long.

This is a cap designed to fit the SDU-5/E Distress Marker Light and allows the use of readily available type 123 commercial photo batteries.  Photo installed on SDU-5/E Strobe

It turns out that the adapter allows the SDU-5E to stand on it's end without any batteries, the BA-1574/U is shorter and the SDU-5/E falls over.  When batteries are installed it will stand on just the cap.  In top right photo it's standing on my asphalt driveway.

Positive end of Lithium battery goes to the cap.  May use:

May 2007 - there are now rechargeable 123 batteries (LIR123A).  They are intended for uses where you get the classical cost savings of rechargeable batteries, like flashlights, cameras, or even the SDU-5 IF it was used as a disco light.  I do NOT recommend these for any survival use since they self discharge in a short time but the primary CR123 batteries can sit on the shelf for at least 10 years.

Threads Notice

Certificate Go Gauge in SDU-5 & Tap23 May 2007
About 1 in 1,000 SDU-5s have threads that are undersized.  This happens when the tap used to make the part gets worn out.  To check the threads in the strobe I now have a certified Go-NoGo plug gauge (shown at left laying on it's Calibration Certificate) and in case the threads need to be chased I also have the needed bottom tap.  If you buy my adapter and find that your strobe has defective threads I will clean them up for the current cost of postage.  This applies to all past customers, but I'll need a proof of purchase.  If you have tight threads contact me.

The gauge and tap are way too expensive to buy and use on just one strobe.


O-Ring Notice

 
BA-1574 Gap
5BA Gap
Less than 1% of the time an SDU-5/E is made with a defective female battery brass flange height (or the pin at the bottom of the battery compartment is too high) that will cause the battery to make contact before the O-ring.  If you install the BA-1574/U or BA-5374/U in these units the O-ring will not seat properly.   If this happens to you let me know and I will send you an O-ring that is thicker and has worked for all these cases.  The 5BA ships with the standard O-ring.  (No point in throwing away 99 out of 100 O-rings).

Not Certified or Approved

I have not tried to certify this adapter to any specifications or get any approvals for it.  I know of no problems but, if you use it for life saving applications you do so at your own risk.

BT-2B Battery Tester

Using the BT-2B batttery test set shows the SDU-5/E adapter (and two each RS 23-155) at 100% of capacity.  Note that the hours remaining table is not correct for any new battery, just obsolete ones. 

The LiMnO2 DL123A is rated at 1.4 AH with a 100 Ohm load.,  The SDU-5/E pulls about 100 mA (12V/100 mA = 120 Ohms) so might last 14 hours.  The BA-1574/U is rated for only 9 Hours at 80 deg F, so this adapter may offer over 50% more capacity.

The booklet in the bottom of the BT-2B battery tester shows the effect of cold on Mercury batteries.  At 80 deg F and a meter reading of 1.0 there are 9 hours operation in the battery, but at 32 deg F there is only 30 minutes of operation.  The LiMnO2 battery looses only about 10% capacity at 32 deg F.

SDU-5/E Does NOT Float

The SDU-5/E is designed to be attached to a Personal Flotation Device (PDF) and it does NOT float, this is why a lanyard is attached to the SDU-5/E, so that you will not loose it.  With a stock BA-1574/U Mercury battery it weighs 6 oz in air and 2 oz when completely submerged in fresh water.  When the 5BA battery adapter and two 123 type photo Lithium batteries are installed the strobe weighs 6 3/4 oz in air and 3 oz when completely submerged in fresh water.

Some Sources for Batteries

I used to have links to web pages, but most of them changed.  Just google for 123 photo battery
The military BA-5123/U is the same battery used in the ANCD (CYZ-10).  NSN 6135-01-351-1131.
18 Sep 2005 - SureFire has the 123 batteries prices at $15 for a dozen. ($21/dozen May 2007)

Batteries Not Included

 Only the cap is for sale, not the SDU-5/E and not any batteries.

Other Strobe

The ACR Firefly 4F and 4G  Strobe Distress Lights, some Life Preserver and some Minesweeping Equip may also use the BA-1574/U and this adapter should work with them also, but has not been tested.

Mercury Battery Warning

The above unit originally used BA-1574/U or 4RM1B 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.

Links

Alta Vista Translation page - http://plaza15.mbn.or.jp/~INFINITY/equipment-sdu.htm - cut this link and paste into the translator
In the book Power Up they suggested removing the dead BA-1574/U battery and then using a stack of four Mercury button cells or a PX32 Mercury battery.  The PX32 has been replaced by the A32PX Alkaline which has a capacity of about 325 mAH which would last about 3 1/4 hours.  The  USCG 161.012 specification on the distress light (including battery) requires more than 8 hours of operation.
Mike Murphy - SDU-5/E strobes
Warden's Supply - SDU-5/E strobes

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