Don and Tony: Diodes will get the job done but notice the heat sinks on them. They waste a lot of energy as heat. I also read you have a single charger. I hear no mention of fusing. Fusing is a good idea but must be done very carefully. All of these issues are complicated by the placement of the diodes.
There are specifically designed 'smart' systems out there to do exactly the job of safely sharing and charging batteries similar to the systems Jim, AD6CW has suggested. If you lack experience in this area I highly recommend to you check them out. They offer smart systems that will safely shut things down using FETs to share and control. The FETs have much, much lower losses so in this case the ones with diodes and big beefy heat sinks are not your friend. The also feature both over voltage and under voltage alarms. This saved me when a power supply regulator shorted. 73, Fred, AE6QL -----Original Message----- From: Elecraft [mailto:[email protected]] On Behalf Of Don Wilhelm Sent: Thursday, January 22, 2015 4:21 PM To: N2TK, Tony; [email protected] Subject: Re: [Elecraft] Battery back-up system for multiple rigs Tony, There is no problem connecting batteries in parallel *if* (and only if) they are the same capacity, manufacturer and age. If the batteries are not identical, isolate them with diodes so one does not draw current from another battery. You will suffer the diode voltage drop in the output voltage. The diodes must be capable of carrying the full maximum current load for all the rigs that will be operating at the same time. 73, Don W3FPR On 1/22/2015 2:47 PM, N2TK, Tony wrote: > Looking for some advice. Trying to help out a friend who is setting up an > emergency communications system for the Hams in their condo group. > > They have several marine batteries they want to tie in parallel so they can > run multiple rigs, K3's plus UHF/VHF for extended periods. They have a > charger for the batteries. They use the 12V off the batteries to a > distribution box for the 12V equipment. > > > > Questions: > > - What is the best way to isolate the equipment from the batteries > if something happened to the battery (ies). > > - Is there a way to isolate the batteries from each other if > something happened to one battery so it didn't draw down the other > batteries? > > - Am I missing anything else that should be done for safety of the > equipment, batteries and the operators? > > > > Tnx > > N2TK, Tony > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [email protected] > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
