A folder of notes that I once received with an old RCA base unit had a hand-drawn design for a battery backup which instead used the battery voltage for the relay coil, and a little switching circuit to pull it in when the charger output dropped out due to mains fail. The author had also designed a battery voltage monitor that would shut everything down when the batteries dropped to a certain level. All discrete components... would probably all be done with a single chip today.
Wish I'd kept a copy... I let the folder go with the radio when I traded it away. George, KA3HSW / WQGJ413 ----- Original Message ----- From: Mike Morris To: [email protected] Sent: Friday, May 11, 2007 9:57 PM Subject: Re: [Repeater-Builder] Mastr II Power supply battery revert option questions At 06:22 PM 05/11/07, you wrote: Hi All, Does anyone know what charging current the Mastr II battery charger / battery revert option supplies to the batteries? Is using this a good idea or a bad one? I highly doubt its a smart charger or has a trickle function to float batteries. Im looking at using the charger thats built into my power supply but im open to other options as well. Thanks --Don KD7WKF Charger technology has advanced tremendously since the Mastr II and equivalent Moto power supplies were designed. I've seen a few sites where a modern automatic charger was put on a good deep cycle battery bank, and a multipole relay switches the repeater system from the Mastr II (or Micor) supply over to the battery bank. The relay coil is simply hooked to the power line so the system switches over to the battery when power fails.
