Darryl Umale wrote: > I am interested in building a 24V battery charger for > a set of Costco deep cycle marine batteries(700CCA @ 95AH) > > does this sound right: > Transformer = 24V @ 2.4A > B. Rect. = 200PRV, 30A > C. Reg. = 5A regulator > V. Reg = ? ~ not sure > (all via Jameco.com)
The transformer you list is far too small for a reasonable charging time. It would deliver less than 2 amps DC, which would take over 95ah / 2a = 42.5 hours to recharge from dead. The simplest thing you can do is buy a complete power supply that has voltage regulation and current limiting. The finish voltage for a 24v flooded battery is about 2.5 volts per cell x 12 cells = 30 volts. If you like shopping at Jameco, they don't have any 30v supplies, but they have lots of 15v supplies; you could use two (one per battery). For example, Jameco part no. 203537, Cosel switcher, 15v 7amp, $24.95. A dead battery can easily draw 100 amps or more from its charger. Linear supplies will all limit their output current, and so protect themselves while still charging the dead battery. But switching power supplies often do not have current limits; they simply shut down if the load tries to draw too much current. This protects the supply, but won't charge a dead battery. So, if you want to use a switcher, add a low value resistor in series with the output to limit the maximum current to a level where the supply won't shut down. A cheap source of such a resistor for the above mentioned 15v 7amp switcher would be a 6v car headlight (they limit current to about 6 amps). -- Lee A. Hart Ring the bells that still can ring 814 8th Ave. N. Forget your perfect offering Sartell, MN 56377 USA There is a crack in everything leeahart_at_earthlink.net That's how the light gets in - Leonard Cohen
