Yep, should work just fine.
Mark
On 4/24/15 11:46 AM, TJ Trout wrote:
Sorry this was completely wisp unrelated, I only plan on connecting
the batteries once and awhile and don't need them to be floated, etc.
So I'm guessing it's safe to parallel a power supply and a battery
when the power supply is turned off?
On Fri, Apr 24, 2015 at 6:20 AM, Mark Radabaugh <m...@amplex.net
<mailto:m...@amplex.net>> wrote:
On the subject Lewis brings up...
There are a variety of battery charging schemes:
Single Stage, Two Stage, and Three Stage.
The very short version of this:
Single Stage - usually a float charger, low amperage, fixed
voltage. Not intended to supply current to a load. Very slow to
recharge batteries. When used to power a load as well as charge
batteries will usually leave batteries undercharged. May also
cause poor equipment operation when AC is restored after an
extended outage as the DC voltage will rise slowly - this can
cause unpredictable operation of attached network equipment.
Two Stage - High(er) voltage and current to charge battery, float
voltage after fully charging battery. Usually dangerous to your
batteries when also powering a load - the charger can't tell the
difference between the current going into the batteries versus
into the load. The charger always thinks the batteries are still
bulk charging and leaves the voltage too high and will cook the
batteries.
Three Stage - Similar to two stage but also includes a boost
voltage above the bulk charge to equalize the voltage in all of
the batteries. Can also cook batteries when trying to supply
load current.
Best version - a 3 stage charger with separate current sensing for
the load and battery current, along with temperature monitoring of
the batteries. This allows the charger to know how much current
the batteries are consuming so that it can determine charge state
accurately. Temperature compensation is to adjust the float
voltage for temperature.
Mark
On 4/24/15 9:06 AM, Lewis Bergman wrote:
And as a side note, you should be worried about the opposite
issue. Every supply is built to handle a load all the time. You
need a supply that is designed to both handle a load and float
batteries. A standard PS has a good chance of cooking your
batteries if you constant load is much lower than your PS rating.
On Fri, Apr 24, 2015 at 7:46 AM, Mark Radabaugh <m...@amplex.net
<mailto:m...@amplex.net>> wrote:
DC power supplies rarely care if there is another source of
voltage that the power supply sees on it's input. It is
not unusual for a AC/DC supply to have to power up into an
existing potential. Many DC loads, on a brief power
interruption, still have significant voltage that the power
supply is going to see when AC returns.
* This comment is general and may not apply to every power
supply *
From experience the only supply I know that won't deal with
power on the output is one of the larger MeanWell AC/DC 48V
supplies. The internal voltage regulator is too slow to
respond and ramps the voltage up over the high voltage limit
and shuts the power supply down if it's powered up when there
is already a battery voltage on the output. If you power up
the supply and then add the battery it's fine - but not very
practical.
Every other AC/DC supply I have tried has worked fine doing
what you are asking to do.
Mark
On 4/24/15 1:34 AM, TJ Trout wrote:
I have a dc load that I need to power using a switching
ac to dc power supply but I also occasionally need to
power the load from batteries, I was planning to put the
load, power supply and battery clamps in parallel, is
that a acceptable solution ? Can I power the load from
battery and back feed DC into the supply without damaging
it? Would there be a significant drain back into the supply?
If this isn't ok, what's better solution? Diode ? SPDT
switch ?
The load is 50V 100A so that makes diodes and switches a
challenge to find. ..
