Yesterday whlie searchig also for a 48v solar controller for the same projet, i found this Meter that supercceds for much the xantrex products and think will the ideal solution Im looking for.
http://www.victronenergy.com/battery-monitors/BMV-700 It works from 6.5 to 95vdc one version and up to 385v the 700S version and less than 4ma. Eliminating any need for external power supplies etc. There is also a version that can monitor a second battery and the best thing is that has minimal connections; just one UTP wire from the meter to the shunt and a short wire to positive from shunt. The product is supported by an extensive documentation plattform (white papers) and also a software and connectivity network that provides others solutions to mobile, offgrid or many energy storage solutions Marco Gaxiola Enviado desde mi iPhone > El 26/07/2015, a las 6:14 a.m., Robert Bruninga via EV <[email protected]> > escribió: > > You are right. I was not paying attention. If the zener is only droping > from pack voltage down to the 35v maximum input voltage fo the device and > it only draws 150 mA, then you'd probably use two 12v zeners to drop from > the fully charged pack voltage of 56 down to around 32v and so th zeners > would need to be rated at 0.15A * 24v or 3.6W and since there are two of > them, then a pair of 2W zeners would do it. Bob > > -----Original Message----- > From: EV [mailto:[email protected]] On Behalf Of EVDL > Administrator via EV > Sent: Saturday, July 25, 2015 11:59 PM > To: Electric Vehicle Discussion List > Subject: Re: [EVDL] 48V Energy Meter (Lead-Acid)... > >> On 25 Jul 2015 at 17:38, Robert Bruninga via EV wrote: >> >> But remember it is still dropping all that voltage as HEAT. So say >> your meter device needs 500 mA at 12v, and your pack is 48v. Then the >> zener is droping 36v at 500 mA and will be disipating over 18W of heat. > > I'm no expert, but I just can't see it being this bad. The manual I have > as previously referenced > > http://www.evdl.org/docs/ce-emeter.pdf > > -- admittedly an old one, but I would hope they don't use MORE current now > -- says 50ma to 150ma depending on backlight intensity, and sleep at > 28ma. > > You also don't need to drop 36v. The meter will be happy at anything > between 12 and 30 volts. So with a 48v pack you're dropping perhaps > 20-24v at 150ma, or 3.6 Watts maximum. That still requires a fairly beefy > zener, but not 18 Watts' worth. Sure, it's waste, but it's negligible in > a golf car that's typically using between 1 and 3.5 kW just moseying > along. > > Cor's suggestion of an extra zener clamp across the meter is an EXCELLENT > idea. > > But perhaps it's all moot since off the shelf low-power DC:DC isolators > have gotten quite cheap, thanks to Chinese sweatshop manufacturing. > > Disclaimer: I have not tried any of this with an E-meter, though a long > time ago I did something similar (IIRC using a power transistor and a > zener) with an even older Cruising Equipment amp-hour counter. > > David Roden - Akron, Ohio, USA > EVDL Administrator > > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = EVDL > Information: http://www.evdl.org/help/ = = = = = = = = = = = = = = = = = = > = = = = = = = = = = = > Note: mail sent to "evpost" and "etpost" addresses will not reach me. To > send a private message, please obtain my email address from the webpage > http://www.evdl.org/help/ . > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = > > > _______________________________________________ > 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) > _______________________________________________ > 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) > _______________________________________________ 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)
