[Milsurplus] question about charging a PRC-68A battery

[WA5CAB at cs.com]

Eugene,

If you use a standard bench supply (which should work just fine) there's 
one thing you need to look out for.  Back in the olden days early on in my 
last Day Job (30+ years ago) we used HP bench supplies to re-charge the 
silver-zinc packs that we used in our pipeline inspection pigs.  We learned the 
hard way that if a supply was charging a pack and you absent mindedly turned of 
the supply without disconnecting it first (or if the lights just blinked or 
if you tripped over the line cord and unplugged it), it would eat the pass 
elements faster than you could say Oh S...!.  The HP supplies in those days 
had no back current protection on the outputs.  So if you use this method, 
either make sure that yours does have protection or add a diode between one 
output and the battery pack.  And if you are using the constant voltage chart 
or charging to a specified end-point voltage, make your voltage 
measurements across the battery or add about 0.6 volts to the supply's output voltmeter 
reading.

In a message dated 4/28/2010 8:02:52 PM Central Daylight Time, al at ar88.net 
writes: 
> Eugene,
> 
> The safe way would be to use a 20-30 volt power supply with a series 
> resistor to limit the current to 80 mA into the battery.  This is the 
> standard "trickle charge" of C/10 where C is the battery ampere-hour 
> capacity, in this case 800 mA.  16 hours will insure full charge, and if 
> it sits on charge for a couple of days no harm will be done.
> 
> If you have a bench supply with variable current limit, you can use that 
> directly without the resistor.
> 
> Al
> 
> On 4/28/2010 8:33 PM, W2HX wrote:
> >Hi there.  I have a PRC-68A which works FB with Brooke's AA battery 
> adapter.
> >I also acquired one of those NiCd rechargeable batteries for this radio.  
> It
> >says the following on it:
> >
> >
> >
> >15 VOLTS 0.80AH AT 0.16A
> >
> >
> >
> >I do not have a proper charger, per se, but can anyone tell me how I 
> might
> >charge this battery with a DC power supply and an ammeter? What would the
> >correct set up lok like? Would I set the volts to whatever necessary to 
> get
> >0.16A or something? Or set the voltage at something set?  The battery
> >currently has 5Vdc worth of charge and the battery is NOS, never used.
> >
> 

Robert & Susan Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480