Without backlight and without use of the alarm relay (coil current) you may be able to run it at 20mA.
Best thing is to hook it up to a lab power supply that you can configure the output current (or build the circuit that you want to use) and test it! Cor van de Water Chief Scientist Proxim Wireless office +1 408 383 7626 Skype: cor_van_de_water XoIP +31 87 784 1130 private: cvandewater.info <http://www.cvandewater.info> www.proxim.com <http://www.proxim.com/> This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. From: Chris Meier [mailto:m...@comcast.net] Sent: Monday, July 27, 2015 4:53 PM To: Cor van de Water; Electric Vehicle Discussion List Subject: Re: [EVDL] 48V Energy Meter (Lead-Acid)... No backlight. On July 27, 2015 6:48:21 PM CDT, Cor van de Water via EV <ev@lists.evdl.org> wrote: You mean to limit it to 20mA even while you turn on the backlight? Then the meter's switching converter will try to draw more, so the input voltage drops, while the converter tries to draw even more, so the input voltage drops more - until it reaches a point where the converter no longer works and stops drawing power, then the input voltage will recover to a point above where the converter starts again and the cycle will repeat. Result will be a pulsed 12V output on the power converter, more than likely the meter will simply not work at all as if it is powered off. Cor van de Water Chief Scientist Proxim Wireless office +1 408 383 7626 Skype: cor_van_de_water XoIP +31 87 784 1130 private: cvandewater.info www.proxim.com This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. -----Original Message----- From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Chris Meier via EV Sent: Monday, July 27, 2015 4:44 PM To: Lee Hart; Electric Vehicle Discussion List Subject: Re: [EVDL] 48V Energy Meter (Lead-Acid)... What happens with the E-meter/etc if you limit the available current, say to 10-20ma? Will it retain accumulated amphours? Counting function? No display until xx ma? -Chris On July 27, 2015 5:56:16 PM CDT, Lee Hart via EV <ev@lists.evdl.org> wrote: Cor van de Water via EV wrote: Lee, Thanks for setting me straight that the backlight draws so much power that it is better not to use a zener. The older E-meter/Link-10 had LED displays. They drew more current. The later LinkPro/LinkPro-Lite has an LCD display with LED backlight. These draw less, but the backlight is still a power hog and takes about 30ma at full brightness. The measurement electronics adds an additional 10-20ma depending on what it is doing at the moment. An ordinary buck converter can be OK if both the meter power and measurements are connected only to the pack, since then no chassis connection exists. Sure; that's fine if you don't mind the continuous supply current. It's not a problem in an EV that's driven (and charged) regularly. The problem comes if you park the EV for months, and forget to disconnect the meter and don't have some kind of charger connected. Do you know if the meter can be powered off when the car is not used without losing its memory? Yes, they have an EEPROM that retains setup information. But it will reset the accumulated amphours to zero. -- Pollution is nothing but the resources we are not harvesting. We allow them to disperse because we've been ignorant of their value. -- R. Buckminster Fuller -- Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com ________________________________ 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) -- Sent from my Android device with K-9 Mail. Please excuse my brevity. -------------- next part -------------- An HTML attachment was scrubbed... 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