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 ?

benitos wrote in news:db0655c6-cdee-4e28-93fa-
:

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 ?



It will charge to maybe 30 percent, higher if the 12v supply gives
a bit more then 12 volt.

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

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 ?

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

"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.

"tm" wrote in message
...

"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.




I think I would at least have a resistor between them. There's guys around
here that know a lot more than I about the care and feeding of batteries,
but it is my belief that some resistance in series will help prevent
overcharging. Perhaps as little as 10 ohms or so.

Mark Z.

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).

"Mark Zacharias" wrote in message
...
"tm" wrote in message
...

"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.




I think I would at least have a resistor between them. There's guys around
here that know a lot more than I about the care and feeding of batteries,
but it is my belief that some resistance in series will help prevent
overcharging. Perhaps as little as 10 ohms or so.

Mark Z.

No, you do not want any current to feed back into the unpowered supply. Use
a good quality schottky diode of to appropriate current rating. Also,
consider a fuse to avoid a fire. Lead acid batteries like to be charged from
a constant voltage, current limited power supply.