Submitted by Michael Clark for Matt Krump
Got a question for the electrical engineers out there. I'm replacing the battery pack in the Cherokee with some new Deka Dominator Gel batteries. 12V each, #26 for a total of 312 nominal volts. They were shown to work well for years on the Geo Force with 13 - 15 batteries each without equalization. I don't trust a series string of 26 to stay equalized. My plan is to make a simple shunt with a 600W 15 volt zener diode in series with a light bulb or two as an indicator and load. Lee Hart has used a similar design using two 5W 6.8V zeners in series with a bulb or two. I think he uses two diodes to split up heat production and sink it to two battery terminals. His shunt is designed for AGM batteries. I looked up Hawker odesey charging voltage and the recomended max is 14.7V. My reasoning for a slight difference in design is that the gel batteries that I will be using have a recommended maximum charge voltage of 15.5V roughly at 90 degrees F. For a charger I am using a Manzanita Micro charger that operates at a fixed user-adjustible amperage with variable voltage until a user adjustible voltage limit is reached. Then an adjustible timer begins running while the amperage is decreased and voltage is maintained. I've thought about using commercially available regulators, but they are all $45 per battery or more and with 26 batteries, that is just too much for now. Any thoughts anyone? Matt Kramp _______________________________________________ Florida EAA mailing list listserv@floridaeaa.org http://www.floridaeaa.org
