Hi David, Thanks for reminding me, I wanted to respond to this but got sidetracked and forgot. In several discussions with Lee Hart, the gist of the zener battery balancer is that there is no one perfect solution and it is just a matter of matching the parts that you can get to the batteries you are using. So, if the batteries exhibit a full charged resting voltage of 13V then it is best to match that with the voltage where the zener regs conduct (almost) no current. There is no sharp cut-off with zeners (unlike electronic circuits) but they are simple and rugged and luckily available in different voltages, so you can mix and match, for example getting a 6.2V and a 6.8V zener and putting those in series will give you a pretty good shot at a regulator that should stop bypassing below 13V while giving a decent bypass capability. When you use 5 Watt zeners then it should be no problem to size the circuit for a max 1/2 Amp bypass. For example if the max voltage on the battery is 15V then 2V is dropped by the bypass resistor, so a 3.9 Ohm 2 Watt resistor should do the job, together with a red LED and 100 Ohms 1/4 Watt resistor to indicate when the reg is bypassing.
Note that zeners are not always exactly the nominal voltage, so do measure when they start conducting and if it is much lower than you expect, you can string two of the "6.8" zeners in series instead. Hope this clarifies, 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.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:[email protected]] On Behalf Of EVDL Administrator via EV Sent: Sunday, November 08, 2015 2:53 AM To: [email protected] Subject: [EVDL] inquiry about Lee's battery regulators The list received in inquiry about battery regulators recently. The poster dropped it in the middle of a thread so folks might not have noticed it. The gist of it is this, edited a bit to remove some excessive battery information: Could you help me with the zener battery regulators that are described in "Minimalist Battery Regulators" by Lee Hart, with modifications by Cor Van de Water? http://www.evdl.org/pages/hartregs.html I own a hybrid sailboat with 12 x 12 volt 155AH (C20) AGM batteries. I would like to install zener regulators to make sure that each battery gets the right voltage. Minimum voltage needs to be 12.18v, and maximum voltage needs to be no more than 14.6v. I like the Cor Van de Water design better because the life of a LED is much longer than a regular bulb. Can you tell me what Zener diode I need for Cor's version? Two of 6.8 V? By the way, I was trying to buy the kits, but the link doesn't work, and it's for flooded batteries. (Not sure what he means here. -- David) Thanks, Pascal Lardy 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 Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag racing at 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 Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
