I've made one of this and works (but some components value need change) http://www.talkingelectronics.com/projects/BatteryCharger-12vSLA/BatteryCharger-12vSLA.html -------------------------------------------------- From: "Clint Sharp" Sent: Tuesday, November 04, 2008 5:15 PM To: "Microcontroller discussion list - Public." Subject: Re: [EE] Lead Acid battery charging > In message > g>, Luis Moreira writes >>Hi Guys, >>I need to charge some 12V 1.2Ah batteries and unfortunately someone as >>"relieved" me of my battery charger over night, so I was wandering if I >>could just use a current limited bench power supply. >>The charger was charging the battery at a 135mA rate but I can not >>remember the voltage level, I think it was around 16V. Is this correct >>and what is the maximum rate of current I can safely use? >>Any draw backs or things I should look out for? >>Thanks >> Luis >> >> > I used to use a current limited bench PSU for charging salvaged UPS > batteries many years ago, it worked very well but was rather expensive > for a 'simple' battery charger. > > SLA batteries usually have charge recommendations printed on the side. > > The current drawn is a function of battery charge state, battery > temperature and charge voltage, but for temperatures under 25C I'd > consider 135mA somewhere about right for your 1.2AH battery, charge > voltage should be 14.4v so you'll probably find the measured current a > little lower. > -- > Clint Sharp > -- > 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