Good info. I've been contemplating batteries here lately as well. I run a Mastr II 30 AMP PS for the repeater. But if I were running a smaller, lower powered repeater than the MASTR II, and using an Astron 35 or 50 amp PS for power supply and floating the batteries, what would keep the PS from melting down if the AC power was off for an extended period of time and the batteries were discharged then AC power restored? I was charging a small motorcycle type battery with my 35 Amp Astron and melted the insulation off of the 12 ga wire from the PS to the battery as well as killed the supply.
Jamey Wright -----Original Message----- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] Behalf Of Eric Lemmon Sent: Tuesday, June 07, 2005 9:33 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] RS Astron up to 15 volts, will it be ok Mathew, The answer to your first question is yes, the Astron can be adjusted up even higher without ill effects. But, I strongly suggest that you get rid of that West Mountain device and connect your radio directly to the battery bank through a fused lead. That will cure your low power issue. Now, connect the anode of a heavy-duty Schottky power diode at the positive output terminal of the Astron power supply and connect the cathode of that diode to the battery bank. I prefer to use an International Rectifier diode #122NQ030R which is rated at 30 volts and 120 amperes. I use a short piece of copper bar stock, 1/8" thick, 1" wide, and 2" long to mount the diode to the positive terminal of the power supply. Note that this is a "reverse polarity" diode; the case is the anode and the 1/4" terminal screw is the cathode to which the battery lead is connected. This diode is available from Digi-Key as stock number 122NQ030R-ND for $16.04 in single quantities. The great value of a Schottky power diode is that the forward voltage drop under load is about half that of an ordinary silicon power diode, and is stable over a wide range of current. The 122NQ030R has only 0.5 volt drop at 120 amperes. You should adjust the output voltage of your Astron power supply to provide the correct float voltage for your battery bank when the radio is in standby mode. You'll find that the voltage going to the radio will vary only a small amount between standby and transmit modes. The best part of this arrangement is that nothing happens if the commercial power fails or the power supply goes belly-up; the diode prevents the power supply crowbar circuit from shorting out or dragging down the battery bank. 73, Eric Lemmon WB6FLY Mathew Quaife wrote: Can an Astron RS-70 power supply be taken up to 15 volts and survive ok? Here is the situation. I have a bank of batteries for the repeater and a West Mountain PWRgate 40 amp switch that goes between the power supply, the batteries and the repeater. When I put it in line, and hook it all up, I lose a considerable amount of repeater power. Nearly 1/4 of the power. Measuring the voltage out of the power supply is 13.6 and the voltage out of the PWRgate is about 12.6 volts. Any ideas or suggestions? Yahoo! Groups Links Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
