Alan, The rated capacity of the battery will be down to a specific voltage - not 0 volts. Typically between 1.65 and 1.8v/cell. Rather than using the generic 14AHr capacity rating you'd be better off getting hold of the data sheets for that type and looking at how it will perform in your application - and inyour temperature range. The data sheets will also advise on charging requirements and temperature compensation factors. If you can't find the data sheet for that specific type, look at a number of data shhets for similar batteries - this should give ypu an idea of what to expect. Richard P On 31/08/06, alan smith wrote: > k...looking at using 14 A/hr 12VDC battery. In theory if I have a 480mA = current source at 18V from a solar array, it would take 2 hours to charge b= ack 1 A/hr of > capacity....? I need to keep a constant 12VDC, so plan on using a boost= convertor > and monitor the battery itself to keep it from discharging below around = 9 or 10V. > > If the load itself is 1.2A, I'm actually thinking that 14A/hr battery ac= tually wont suffice > since that would again in theory, allow a total 1.4A draw for 10 hours, = but means it will drop the battery voltage to zero? Not a good thing to do= to a battery. And I have to have the total draw of about 8 to 10 hours. > > So maybe a pair of batteries, or split the load to a set of batteries ma= ybe? > > > --------------------------------- > Yahoo! Messenger with Voice. Make PC-to-Phone Calls to the US (and 30+ co= untries) for 2=A2/min or less. > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- = http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist