On Thu, 6 Sep 2012 12:03:30 -0400, "tm"
wrote:


"Pat" wrote in message
.. .
On Thu, 6 Sep 2012 06:09:50 -0700 (PDT), benitos
wrote:

Le mercredi 5 septembre 2012 19:40:03 UTC-4, (inconnu) a écrit :
On Wed, 5 Sep 2012 09:24:12 -0700 (PDT), benitos
wrote: Hi , Having this power supply to provide 12V (with a back up
battery). The battery seems to be connected in // with the 12VDC
output. It doesn't seem to charge it. Do I need more than 12V to
charge it ? Yes. A 12V lead acid battery is typically charged at 14.2 to
14.4 volts. PlainBill


Max I can go is 13.8V .

Is it OK ?

Also , because it's connected in // with the output , it's Ok if there is
voltage across the battery all the time ?
I missed the beginning of this thread, but if you want to float charge
a 12 V lead acid battery, then 13.8 volts is the proper voltage to do
so. The battery will maintain its charge without overcharging. If
the battery is used and needs to be recharged, it will take longer,
but it will work. Putting a 12 volt lead acid battery in parallel
with a 13.8 power supply was a very common thing to do before all
these fancy high tech battery control ICs became available.

Pat

But you better make sure the supply does not drag the battery down when
power is removed.

or worse still, zap the output semis (that HAS happened to one PSU
here).