Sorry, guess that term wasn't real clear. A power supply doesn't control the charge rate, it controls the output voltage. Most bulk storage batteries don't want to charge at high rates, say over 0.5C, although you can probably get away with it for a time. Controlling the charge rate generally improves battery life, although other things like equalization can help with this too (FLA's only!).
For the SLA I have here, the recommended maximum continuous CV charge rate is 0.3C. In a way they're fairly picky when it comes to charging rates. Charging in a CV regime is fine as long as the rate is limited to whatever is best for the battery. But most power supplies that can handle a 100W rig like the K3 can may output more than this recommended charge rate, and unless you manually set the current limit to the max rate, they're uncontrolled in this respect. As with all things, YMMV applies. If you have a mega-battery like some 1200AH deep cycle home power type, then the max rate will be different. It's a guess, but I think most hams wouldn't be using that type of Rolls or Surette battery for their stations. I'd sure like to have a set for the main PV system here though. The home power batteries we use for the main PV system are 210 AH 6V golf cart batteries, a series string of 8 of them. The charger/inverter is set up to charge them at a rate only as high as 0.2C in normal circumstances (this is Exide's recommendation for max life). However, if we're off grid for awhile, I set it up to run 0.35C for about 2 hours to bulk them up. In this system , it is normal to pulse charge them. Some people call this a float or trickle charge. Xantrex just calls it "normal" for some reason. 73, matt W6NIA On Mon, 08 Jun 2009 00:36:13 -0500, you wrote: > >I'm not quite sure what is meant by the term 'uncontrolled source'. A >regulated power supply makes a fine battery charger. Review the >charging recommendations at the various battery manufacturer sites >such as here: > ><http://www.power-sonic.com/index.php?doc_id=116> > >or here: > ><http://www.powerstream.com/SLA.htm> > >and you will see that constant voltage charging is one of several >recommended charging methods. > >The charge voltage needs to be carefully regulated, which Aston and >other power supplies should do, and it is certainly a very good idea >to put a fuse in line with each battery to protect against the unknown. > >But there is absolutely nothing wrong with constant voltage float >charging. At the phone co. we kept batteries on float charge for 20 to >25 years and they were instantly ready, indeed constantly on line, and >fully charged. > >Keep the charge voltage set correctly, use proper safety precautions, >follow the battery manufacturer's recommendations, and you should be fine. > >The recommended charge voltage varies by the type of battery. Flooded >batteries require a somewhat lower voltage than do SLA or AGM types. >For flooded cells the usual recommendation is about 13.5 to 13.6, but >some manufacturers are lower than this, and for AGM it is usually a >bit higher at 13.6 to 13.8. Check with the battery manufacturer to be >sure. > >What you are trying to do is keep the battery fully charged but yet >not burn off the water nor damage the plates. > > >73 de dave >ab9ca/4 > > > > > >Matt Zilmer wrote: >> I just have to chime in on this one. >> >> I run my K3/100-based station on solar photovoltaic power, with a 100 >> AH SLA battery for storage. Quick description of this installation is >> that I use a charge controller to regulate battery charging. It's a >> Micro M+ c/c and can put out 4A for a 12VDC system. >> http://edge.rit.edu/content/P07308/public/Custom%20Charge%20controller >> The article is from October, 2001 QST. >> >> As others have stated, you should not charge *any* battery directly >> from an uncontrolled source like a power supply. If you want to use >> the battery as the main power source and recharge it periodically (or >> whenever the sun shines), you have to regulate the charge rate and >> voltage level presented to the battery. The Micro M+ does a fine job >> for smaller installations, and its max charge rate of 4A is adequate >> for topping a battery in the 100AH class. The Micro M+ uses pulse >> width to control the charge rate, and this is suggested for FLA and >> SLA battery types - others work with this method too (AGM, etc.). >> >> You can use the Micro M+ or its equivalent for any type of source - >> power supply, solar PV, bicycle generator, etc. When the weather is >> cloudy, I use a little Tektronics 3A AC/DC power supply and just run >> it full bore into the c/c. This works fine too. >> >> <Details are below for those that are insomniacs> >> >> Near the _big_ PV panels on the roof are the two Siemens SR50's, which >> are rated 50W each, and they are in parallel for the 12VDC system. The >> feed to the shack travels through a weatherproof enclosure that has a >> 10A fuse and GFP circuit breaker. This might be overkill. Together >> the two Siemens 50W panels are nameplate rated at around 6A. In >> practice, maximum output is a little over 5A on a really good sun day. >> >> The feed down to the shack is 8AWG THHN wire, about 30 feet of it, in >> flexible NMT. The 8AWG is to minimize the voltage drop to the charge >> circuitry. >> >> Both the battery and charge controller are here in the shack. >> >> 73, >> matt zilmer W6NIA >> K3 #24, K2 #2810 >> >> >> On Sun, 07 Jun 2009 21:17:17 -0700 (PDT), you wrote: >> >>> <I am using an Alinco DM-330M power supply. Across the output of the <power >>> supply I have a 26 AH battery. If the AC power quits I have <many hours to >>> shut down the K3. >>> >>> Charging a battery with a DC supply not meant for that purpose is a very >>> BAD idea. >>> >>> In the case of Astron supplies it can damage parts of the DC regulator. If >>> there is a "Crow Bar" circuit that operates with a battery connected to the >>> power supply output it will ruin your day or even burn your house down! >>> >>> Bill - K6WLM >>> >>> >>> >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:Elecraft@mailman.qth.net >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Elecraft@mailman.qth.net >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> >> ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
