Mike Nickerson, The 24 volts being used for the overall system voltage was a technically painful choice but needed for a salt environment. I have been shocked at 48 VDC in salt bilge water and can say that it is weird and unpleasant. There are an increasing number of marine electronics that utilize 24 to 28 volts DC as well as consumer/commercial DC/DC step downs to 12 VDC and 110v AC mod and full sine inverters. Some of that stuff was not even around 5 years ago, Moore’s Law, huh?
The use of 24VDC from a PV standpoint is that the down coming voltage from the roof can be kept above the system voltage (for MPPT) whilst not being a painful shock/burn. Roof down voltage is about 30 plus VDC on one panel (5 PV modules) and 72 VDC on the other panel (6 PV modules). A Schnieder and Outback controller is used for the control of the 2 down coming voltages. The Outback is a refined MPPT (tracking the mix of current to voltage for maximum charging efficiency, Maximum Power Point Tracking). The Schnieder (was called a Trace C40) is meat and potatoes. I look forward to the total replacement of the 11 x 235 watt PVs with thin film flexibles and dropping the 72 VDC down coming voltage to about 36 VDC…… more time…. more money. The boat was designed around the roof. The gross size is about 10X26 feet but with the correct PV system I can drop from 11 huge rectangles to full coverage. Also the weight is 11 X 44 pounds which will be dropped, with the thin PVs, to a total of 140 pounds. From 484 pound to 140 pounds is a stellar achievement and reduces the inertia of rocking and the sustained lean angle. PV heat dissipation is still a trick thing and is part of the hot water heating system. History button of http://www.mogcanalboat.com/ gives a bit more design insight. I sold the Onan 4Kw,1800 rpm genset a long time ago, never used it. A superb gen, it was not needed. The Lestronic 48 VDC charger was used about 5 times in 10 years and is currently used to hold down the floor tiles in the garage. I have a woefully small 24 VDC charger and have no immediate plans for a Lestronic or marine unit, but, someday though. Best to all, George Hi George, Thanks for the specifications. The 24V operation is interesting. Most cars use higher voltage and lower current. That allows smaller sized wires to carry current. However, I suspect the 24V has some benefits too. First, lower voltage is safer than higher voltage. Does the 24V integrate better with the solar cells? Seems like it might. When people ask about solar cells on a car, the typical answer is to skip them on the car and put the cells on the carport instead. The boat is big enough that it's top is probably the size of a carport. How many square feet of solar cells are on the boat? Is there charging for the batteries besides the solar panels? Mike -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150429/7e0cbd19/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
