Hi Kevin, > I have a need for switching AC and Battery power at our > repeater site. Current setup is mains 230v AC and 12v > Battery charging via solar cells. Due to the increasing > chargers for mains (and still going up) we want to utilise > battery power more and use the mains for back-up and when > the batteries drop below 11v. > The mains is connected to a power supply at 13.8v, this > is in parallel with the batteries.
It would be prudent at this point to say you really need to have enough battery capacity in place to run the equipment for x-minutes of time. You might want to consider the position where your system is primarily a battery operated package or a mains operated system with battery backup. > I had built a small switching curcuit with 2x relays. One > relay has the AC inline so the mains power supply can be > turned off by the controller remotely or by the scheduler. In the real world... most often a recipe for trouble. > The second relay was triggered by the AC line so that if > the mains went off it would tell the controller which would > then switch the repeater to low power mode, timers etc. You don't have to use a relay but what ever works and is easy. > The problem with the way I had set it up was that when the > mains was switched off, even with a solid 12+v on the battery > the relay would click continually because the controller for > some reason would see a low voltage and switch the mains > relay back on. > When the volts was back up to the 13.8v the mains relay would > switch off again, back to battery power. I may be pulling > straws here in what is actually happening. The relay control circuit needs sample input conditioning, RF immunity and hysteresis for proper operation. > I have tried to remedy the problem, and had it working for > awhile, but it then started doing it again. I would like > some suggestions on what way to go? If the system battery capacity is enough... you would need to replace the relay control circuit with one containing the above mentioned considerations. Then replace or retrofit the power supplies from regulated sources to actual battery charging circuits of the proper type. As a general rule regular regulated power supplied don't make the best battery chargers. > Should mention I am using a RLC-3 controlling the repeater > and ower requirements. > Thanks Kevin. I make commercial circuits for this type of situation. If no one comes up with an easy answer you like... Email me direct and I'll give you some additional information (free) if you want to "roll (make) your own". cheers, skipp skipp025 at yahoo.com www.radiowrench.com
