Great topic So can the ammeter/battery gauge that evwest sell be used to turn off a charger? What do you set it to turn off, when a voltage is attained? Anyone use this meter in their setup for charge control?
FYI- If the owner is looking for a state of charge with more than 4 bars I used a cheap one off ebay on my boat, it has 10 bars and doesn't require a stepped down voltage, runs directly off the pack. On Sat, Jul 25, 2015 at 3:35 PM, Cor van de Water via EV <[email protected]> wrote: > Marco, the link was missing in the post I received. > > Damon, > As others have said - this is a non-isolated solution to power the meter. > However, if you power the meter from the traction pack, the meter does > *NOT* > connect the traction pack to ground, so a non-isolated solution is not a > problem > as long as you take care wiring the meter correctly: don't wire it to > ground = chassis > but only to the traction pack + and - so the meter will float with the > pack. > This is different than using a 12V input to power the meter, since the 12V > negative is > always connected to ground (chassis) so in that way, you connect the > traction pack > through the meter. > At 48V it is possible that the traction pack negative is anyhow connected > to chassis, > but this is not guaranteed and it is better to connect the meter to the > pack anyway. > > Note that the zener drops a fixed voltage in *reverse* direction (in > forward direction > it is just another diode) so you need to calculate the highest and lowest > voltage that > your pack is reaching and see if that stays in spec for the meter. For > example a > lead-acid pack may go from 36V on acceleration while empty (1.5V per cell) > to 60V on > equalization charge (2.5V per cell) This means that a 25V to 27V drop will > give you > power for the meter, but any larger swings and the meter will not work and > a DC/DC is > better: with a 27V zener, the meter supply voltage goes from 9V to 33V on > that swing. > > Yes, a series fuse or resistor is highly recommended. In fact, to protect > your meter > it is a good idea to have a 33V zener across the meter as well, so that if > the power > supply goes too high, it starts drawing more current and drop it across > the series > resistor in the supply line. Normally the voltage on the meter will be > below that > zener's voltage and no extra current will flow, that is why I recommend a > zener as > dropping element, not a resistor. > A slightly fancier setup is to use a transistor that can withstand a > higher voltage > than the pack can reach and which drops the voltage to a level that the > meter can work with > so you extend the meter's linear regulator's voltage input range > externally. > > My reason to use a dropping zener or linear regulator (while I am fanatic > about efficiency) > is that the meter draws a very small current, so even a DC/DC converter > will have low efficiency > and I doubt that it will draw less current than when simply dropping > voltage with a zener, > but that will depend on the quality of your DC/DC. The other reason is > that a zener is > cheaper than a DC/DC converter. > > Hope this clarifies, > > Cor van de Water > Chief Scientist > Proxim Wireless Corporation http://www.proxim.com > Email: [email protected] Private: http://www.cvandewater.info > Skype: cor_van_de_water XoIP: +31877841130 > Tel: +1 408 383 7626 Tel: +91 (040)23117400 x203 > > > > -----Original Message----- > From: EV on behalf of Ing. Marco Gaxiola via EV > Sent: Sat 7/25/2015 9:43 AM > To: 'Robert Bruninga'; 'Electric Vehicle Discussion List'; 'damon henry' > Subject: Re: [EVDL] 48V Energy Meter (Lead-Acid)... > > > Thanks to all for your recommendations. > > Rush, yes.. I have 2 of them thanks to you :), but the owner of > the vehicle I'm going to use the meter wants something that tells him in > 'percentage' an E-meter only has 4 LED lamps. > > Cor, yes you are right; Xantrex is the new name of the E-Meter > product, and yes the new one works only up to 35V, but tech manual does not > says at any place where to move the decimal point or another different > voltage value reading. Maybe they just took out that feature on this new > models. > > Damon, an isolated power supply Cannot be done by just using a > Zener diode, that would be non-isolated and could work fine for your > motorcycle as long as you share grounds for 48V and 12V for your e-meter. > But just as Robert says; you would waste more energy on the (48-12V = 36) > 36Volts side in heat all time, than the power the meter consumes itself. > You'd better use a mini 'switched power supply'. Some products like this > ones would work perfectly (especially the first result): > > Saludos... > > > Ing. Marco Gaxiola > CEO/Director > Juarez #18, Col. Bachoco > Tel: +52(662)301.1070 > Skype: info.energyev > www.energyev.com > > > > -----Mensaje original----- > De: EV [mailto:[email protected]] En nombre de Robert Bruninga > via EV > Enviado el: sábado, 25 de julio de 2015 07:50 a.m. > Para: damon henry; Electric Vehicle Discussion List > Asunto: Re: [EVDL] 48V Energy Meter (Lead-Acid)... > > You must have a series current limiting resistor. The disadvantage of any > zener power supply/regulator is that you are wasting all the drop-down > voltage as heat. So for a 12v zener from 48v, only 1/4th of the power > drawn actually goes into the device. The rest is wasted. > > bob > > On Sat, Jul 25, 2015 at 9:20 AM, damon henry via EV <[email protected]> > wrote: > > > Hi Cor, > > I have been around and using E-meters for many years now and this is > > the first time I have ever heard of using a zener diode as a method to > > create an isolated power supply for one. Is it really that simple? > > If so I might switch to this on my motorcycle (48v). I currently have > > a small 12 volt battery that I use just for running my meter, which is > > a pretty simple setup, but does require me to charge the battery once > > a week, and/or disconnect the battery if I leave the motorcycle unused > for a long stretch. > > If I understand this method I would simply connect the emeter power > > through a zener diode off my traction pack and that would provide both > > the required isolation and enough of a voltage drop to keep from > > burning the meter out. That sounds easy :) Do you just wire the zener > > into one of the power leads from the traction pack to the emeter? > > Does it matter whether it is on the positive or negative lead? Are > > there other components that could/should be added like a fuse or current > limiting resistor? > > thanksDamon > > > > > Date: Fri, 24 Jul 2015 23:15:24 -0700 > > > To: [email protected] > > > Subject: Re: [EVDL] 48V Energy Meter (Lead-Acid)... > > > From: [email protected] > > > > > > The older (pre-decessor or just re-packaged?) Link 10 meter from > > > Xantrex was also limited to 35V (it is the 7800-series linear > > > voltage regulator > > max input) > > > so a 1:10 pre-scaler could be used to measure higher voltage, while > > powering the > > > unit from an isolated power supply between 12-35V although if it is > > > just > > 48V as in your case, > > > the prescaler is needed but the power supply can simply be a zener > > diode, dropping the > > > 48V (max charge voltage for example 60V so you would need a 25V or > > > next > > higher zener) > > > > > > If I am not mistaken, the Link 10 had a software feature to shift > > > the > > decimal dot a place > > > so you could take the 10:1 pre-scaler into account in Voltage and > > > energy > > measurements. > > > Not sure if this unit has that same feature - Lee might know as he > > > has > > made a > > > companion board for the Link 10. > > > > > > Regards, > > > > > > Cor van de Water > > > Chief Scientist > > > Proxim Wireless Corporation http://www.proxim.com > > > Email: [email protected] Private: http://www.cvandewater.info > > > Skype: cor_van_de_water XoIP: +31877841130 > > > Tel: +1 408 383 7626 Tel: +91 (040)23117400 x203 > > > > > > > > > > > > -----Original Message----- > > > From: EV on behalf of Ing. Marco Gaxiola via EV > > > Sent: Fri 7/24/2015 11:08 AM > > > To: 'Electric Vehicle Discussion List' > > > Subject: [EVDL] 48V Energy Meter (Lead-Acid)... > > > > > > > > > I'm looking for an energy meter for a lead-acid 48V (Nominal) > > bank. A friend recommended me this one from Xantrex: > > > > > > > > http://www.xantrex.com/power-products/power-accessories/linkpro-batter > > y-monitor.aspx > > > > > > that looks great and ideal for my Project. But unfortunately maximum > > reading voltage is up to 35Vdc. (although using a pre-scaler in the > > input voltage and a 48V to 12V DC-DC power supply; the firmware > > parameters in the programming options of the device, according to the > > datasheet; are only up to 35Volts range) > > > > > > if someone does know of a similar product solution that could > > > be > > recommended, please advice. > > > > > > > > > (Application: It's intended to be used on an Electric Polaris > > Vehicle. I'm upgrading the battery pack, extra charger and adding some > > solar panels in order to improve range, charge time and ability to > > slowly self-recharge while in the sun. To be used on a Ranch.) > > > > > > > > > Ing. Marco Gaxiola > > > CEO/Director > > > Juarez #18, Col. Bachoco > > > Tel: +52(662)301.1070 > > > Skype: info.energyev > > > www.energyev.com > > > > > > > > > > > > > > > --- > > > El software de antivirus Avast ha analizado este correo electrónico > > > en > > busca de virus. > > > https://www.avast.com/antivirus > > > > > > _______________________________________________ > > > 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) > > > > > > > > > -------------- next part -------------- A non-text attachment was > > > scrubbed... > > > Name: not available > > > Type: application/ms-tnef > > > Size: 4207 bytes > > > Desc: not available > > > URL: < > > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150724/750 > > 52e4f/attachment.bin > > > > > > _______________________________________________ > > > 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) > > > > > > > -------------- next part -------------- An HTML attachment was > > scrubbed... > > URL: < > > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150725/4e0 > > cef71/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) > > > > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150725/b060c3ae/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) > > > > --- > El software de antivirus Avast ha analizado este correo electrónico en > busca de virus. > https://www.avast.com/antivirus > > _______________________________________________ > 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) > > > > > > > -------------- next part -------------- > A non-text attachment was scrubbed... > Name: not available > Type: application/ms-tnef > Size: 8147 bytes > Desc: not available > URL: < > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150725/226cd3cd/attachment.bin > > > _______________________________________________ > 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) > > -------------- next part -------------- An HTML attachment was scrubbed... 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