---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Tue 10/06/20: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 10:35 AM - Re: Re: voltage monitor (Robert L. Nuckolls, III) 2. 11:27 AM - Re: Re: voltage monitor (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 10:35:51 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: voltage monitor New post Posted: Sun Oct 04, 2020 4:51 pm Post subject: voltage monitor Reply with quote ---------- From: Technical Manual for Model No. LR3D-14 and LR3D-28 Linear RegulatorWith Over-Voltage Protection, Low-Voltage Sensing, And Field-Adjustable Charging Voltage "The LV warning light will begin to flash when the voltage sensed at terminal 3 drops to approximately 12.7V and below" Disregard if this is not relevant to this discussion. It is very relevant. Thank you. This is news to me but I've not been directly involved or plugged in to B&C design decisions for some years With that in mind, and given the number and variety of programs I've worked it seemed prudent to verify the hip-pocket archives. Dug out my AEC9005 drawings and the setpoint was 13.0 volts. All the data I have on early LR3 series regulators suggest that 12.7 has been the setpoint from day one. Just for grins, I plotted Time-to-12.7v for four batteries. An AeroVolts, an exemplar EarthX, a Miady 16AH device and just for the heck of it, a fresh Enersy 16AH battery. Plots attached. I've also included a test for a A123, 26650 cell where I deduce that a 4x4 array of these cells in a 14v system battery would fall below 13.5 volts in about 30 seconds. I suggest these plots show that a 13.5 volt lo volts warning threshold would be suited to all chemistries. Note that the SVLA falls like a rock to well under 12.7 when it looses alternator support . . . well, it IS a 12v battery while LiFePO4 devices are generally considered to be 13.2 volt batteries (although AeroVolts labels theirs as a 12V while the plots show that it has the highest alternator- out voltage of the lot). Hence, I stand better informed and agree that the legacy LR3 configuration is unsuitable for lithium battery management without (easy to do) modification as is our AEC9005 LV Warning Module. Sorry for ignoring you the past day or so. Been wrestling with some issues in a car I've got sold . . . along with a recalcitrant wifi router. Ever see the look on the fact of a couple teenagers when you tell them, "the wifi is down"? Bob . . . ________________________________ Message 2 _____________________________________ Time: 11:27:54 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: voltage monitor At 05:52 AM 10/5/2020, you wrote: > >the link charlie posted shows a graph i am used to seeing with the >earthx. i take this graph to mean i will give up 3ah of battery by >using 13.0 as a setpoint vs. 13.5 volts. i have no second >alternator so it is important to me to know asap when i have only >battery power to keep the engine running. 13.5 is cool . . . Bob . . . ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.