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Or You can buy a Landis controller, plug it in, and have good batteries and capacity for 6-7 years, without the worry. > From: hazen indiana edu > To: elec-trak cosmos phy tufts edu > Date: Thu, 21 May 2009 14:56:56 -0400 > Subject: Re: (ET) charger problem > > > You can fret and worry all the time about how to change your batteries. The simplest way to be sure is with a hydrometer. You can get one that has a thermometer to correct for temperature if you want. The best way for me is a simple four ball unit. They are cheap, easy to use and will put you in the ball park. I use an Emeter on the tractor that keeps a running total or amps in and out. It tells me when I have used 50% of my amps and then I drive back to the house to recharge. When the Emeter says I have filled them back up I check with the four balls again. If all balls are floating and quick to go to the top I know they are fully charged. I verify the electronic metering with the four ball unit a few times a year and they are always a close match. Be sure and flush/pump the acid in the glass tube a few times to get a correct reading in each cell. Unbalanced cells are easy to identify this way. Measure twice and worry less. > > Dwight > > Dwight L. Hazen > > Ham Radio wb9tlh arrl net http://wb9tlh.ampr.us > > Light speed computers, starships and ray guns, oh my! > > > > -----Original Message----- > From: elec-trak-bounces cosmos phy tufts edu [mailto:elec-trak-bounces cosmos phy tufts edu] On Behalf Of David Roden > Sent: Thursday, May 21, 2009 1:58 PM > To: elec-trak cosmos phy tufts edu > Subject: Re: (ET) charger problem > > On 21 May 2009 at 9:51, tbamc wrote: > > > I think U. S. Battery recommends about 46.5v for equalization, and as > > far as I know the E-T charger won't get there. > > I usually say "ask the manufacturer," but I think USBMC's charging > directions are aimed more at users who need to get the highest possible > capacity from their batteries on every single cycle, and are willing to > sacrifice some cycle life for it. > > They recommend constant current to 2.583 volts per cell, then constant > voltage at this point for an additional 2-4 hours. They suggest to reduce > the voltage by 0.028 Volts per Cell for every 10 deg F above 80 deg F, and > increase voltage by the same amount for temperatures below 80 deg F. > (Following this algorithm to the letter requires a much smarter charger than > the GE, by the way.) > > I think this is needlessly aggressive for most users. I wouldn't much > exceed 2.5 volts per cell (45 volts for an ET), and stop the charge when the > current falls to 0.05C regardless of time. I'd probably add an equalization > phase of perhaps 2 hours at 0.2C or so for the ET, since it taps the battery > pack. I would still use USBMC's temperature adjustment. > > > David Roden - Akron, Ohio, USA > > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = > Note: mail sent to the "etpost" address will not reach me. To send > me a private message, please use the address shown at the bottom > of this page : http://www.evdl.org/help/ > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = > > > > > _______________________________________________ > Elec-trak mailing list > Elec-trak cosmos phy tufts edu > https://cosmos.phy.tufts.edu/mailman/listinfo/elec-trak > > _______________________________________________ > Elec-trak mailing list > Elec-trak cosmos phy tufts edu > https://cosmos.phy.tufts.edu/mailman/listinfo/elec-trak |