One possible problem I see with this simple circuit is that it has no inbuilt
hysteresis or maximum voltage charge time. A battery will charge to its preset
maximum voltage and because there is no time limit placed on the charge current
at the maximum voltage, the relay will operate and stop the charge before it has
time for the battery charge capacity to be maximised. This will lead to
"hunting" where the relay will operate and release rapidly, ad-infinitum, as the
battery voltage fluctuates above and below the preset maximum.

On Mon, 14 Jun 2010 09:00:02 -0400, default wrote:

:On Wed, 9 Jun 2010 13:13:46 +0930, "mark krawczuk"
wrote:
:
:hi, after some schematics to charge 6 volt and 12 volt sla ( sealed lead
:acid ) batteries.... basically dont need to charge them flat out , cause
:they dont get used much, something i can leave on trickle charge for a week
:or so , would be good....
:
:any body have any or know of any links ?
:
:
:
:http://electronicdesign.com/article/...gle-trans.aspx
:
:http://archive.electronicdesign.com/.../figure_01.gif