I had a similar experience: I had a couple of deep cycle batteries in an outdoor steel enclosure that I would charge periodically by connecting a standard automotive charger. At times I would forget it was connected, so eventually the batteries were cooked. After some research on the web, I settled on an IOTA DLS-15 power supply with an IQ4 smart charge controller. It is connected full time to the (new) batteries, and I only have to add water every couple of months. I have not noted any kind of noise generated by the charger. This setup works very well for me.
Richard, N7TGB -----Original Message----- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] Behalf Of Dave Schmidt Sent: Tuesday, January 09, 2007 9:26 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Battery backup I have to agree with Dave. Using the proper charger or power supply for keeping the batts up. I have my batteries housed in a stainless steel enclosure that is anchored into concrete outside my ham shack. I learned the hard way about using the proper charger... I just tapped into my repeaters 25amp power supply to keep the batteries charged till I could make a charging circuit ... ahhhh, big mistake. That charging circuit - oops, I forgot... about a month of operation, I was working around the tower and smelled what smelled like battery acid. Sure enough, I cooked both flooded lead acid batteries and they were fuming acid vapor. Lucky the box is a comercial built ss box. Now, after that incident, I have been using a marine (boat) "smart charger" which automatically determines wether to charge or float. Since battery chargers are, ummm, quite noisy and not all that nice on batteries due to most of them only using a half wave recifier ( AC is not nice on batteries ). I added a 25A bridge rectifier and added extra filtering which is just a big Motorola mobile power filter block from the Micor dayz. It is also isolated using some BIG diodes - like Dave's, the threaded case type diodes which is bolted to a heatsink. The system is running well in this configuration. If using flooded type batteries, do a monthly check on acid levels ! I recomend AGM batteries ( Absorbed Glass Mat ) or if that is a little pricy, get marine deep cycle batteries - do not use automotive batteries unless you just absolutely half to. Dave / N9NLU www.kmcg.org On 1/9/07, ve7ltd <[EMAIL PROTECTED]> wrote: I have had good luck using a pair of diodes to isolate a power supply from a charging circuit. I essentially have a Statpower 10amp battery charger (specifically designed for the flooded cells I am using). The batteries float on the charger voltage when the AC power is available. The battery positive lead then feeds through a diode and joins the "positive power bus" of my repeaters. Using a proper charger is the most important part so you dont boil off the electrolyte in your batteries. The positive power bus is fed from a large GE power supply. The positive lead from the power supply feeds through a diode to feed the power bus. The idea of using a diodes is to keep the higher voltage of the power supply from passing current into the batteries when AC is available, and vice versa when AC is off. However, if you are using a high power PA or your repeater draws more than about 20 AMPs on TX, you have to be careful of your choices of diode. I use large feedthrough diodes, mounted on large heatsinks, but on lower current draw you could get away with using a smaller bridge rectifier mounted to an unpainted metal piece in your repeater cabinet with some heatsink compound. Dave Cameron VE7LTD --- In Repeater-Builder@yahoogroups.com, "wm5c" <[EMAIL PROTECTED]> wrote: > > Hi, > > New member here. Thanks for allowing me to join. > Our club has acquired some large lead-acid 12v batteries we would like > to use to back up our repeater in emergency situations. Does anyone > know of a good (but simple and inexpensive [we are a very small group > in a very small town]) circuit to accomplish this? Any input would be > appreciated. > > Danny WM5C > Heart Of Texas Ham Operators Group (HOTHOG) > Brady, TX > www.hothog.org >
