From: bobnospam@gmail.com   
      
   On 11/10/2020 12:44 PM, Jim Wilkins wrote:   
   > "Jim Wilkins"  wrote in message news:roc0gj$alc$1@dont-email.me...   
   >   
   >   
   >   
   > "Bob F"  wrote in message news:robrpv$qlk$1@dont-email.me..   
   > ...   
   > I would like to assemble these into a backup supply for a couple desktop   
   > computers and associated equipment in case of power outages...   
   > =====================================================   
   >   
   > "The cheapest way to charge a nickel cadmium battery is to charge at C/10   
   > (10% of the rated capacity per hour) for 16 hours.   
   >   
   > ==============================   
   >   
   > The equivalent slow-but-sure charging method for lead-acids is to limit   
   > the charging voltage to the "float" level, which is just below where the   
   > battery begins to gas, typically around 13.6V.  The UPSs I've checked do   
   > this, and it's a selectable option for my solar charging controllers.   
   > The disadvantage is slow charging time after the battery reaches around   
   > 80% of its Amp-hour capacity, because the battery draws less and less   
   > current at that voltage as it approaches full charge.   
   >   
   > Initially my UPS charges a heavily discharged battery at 6 Amps and the   
   > battery's state of charge determines the voltage. When the voltage   
   > reaches 13.6V it stops increasing and soon the current begins to   
   > decrease gradually, taking several/many hours to stabilize at or below   
   > 1% of the battery's Amp-hour rating, C, for instance 180mA for a 12V   
   > 18A-H AGM.   
   >   
   > That's what to expect from the battery charger built into a UPS, though   
   > you should check it yourself as the settings are different for gel, agm   
   > and flooded batteries. A UPS with swollen batteries may be available   
   > cheaply or free if you look around. Good cheap used DC-AC inverters to   
   > build your own UPS are much rarer.   
   >   
      
   I appreciate your thoughts. I definitely need to give this a lot of   
   research and thought. I may have to put together my own charge   
   controller to match up to the NiCd battery requirements.   
      
   This will be a slow project, but I will appreciate any additional   
   comments from anyone any time along the way.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)