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> 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. .. >> >> >
