http://tech.groups.yahoo.com/group/power-assist/ The discussion of power assistance for p Tue, 10 Nov 2009 01:52:38 GMT robbiehatfield http://tech.groups.yahoo.com/group/power-assist/message/84789 http://tech.groups.yahoo.com/group/power-assist/message/84789 You really don't want to get into a *John Schuyler* kind of thing here by quoting old posts from someone who sounds like they're singing a *new* tune now do Tue, 10 Nov 2009 01:31:18 GMT andrsnj1 http://tech.groups.yahoo.com/group/power-assist/message/84788 http://tech.groups.yahoo.com/group/power-assist/message/84788 ... Ok. Then what is the maximum amp hours that I can get out of your "10 ah" cell/pack with your low voltage cut-off and your cat herder while discharging to Tue, 10 Nov 2009 00:08:54 GMT G Daigle http://tech.groups.yahoo.com/group/power-assist/message/84787 http://tech.groups.yahoo.com/group/power-assist/message/84787 All rechargable battery chemistries have an operating voltage range.. and all are damaged if over-discharged. LiFePo4 cells are fully charged when up to 3.6v Mon, 09 Nov 2009 23:50:51 GMT Don Harmon http://tech.groups.yahoo.com/group/power-assist/message/84786 http://tech.groups.yahoo.com/group/power-assist/message/84786 Thanks Chalo - we finally meet on a common ground ! J Don From: power-assist@yahoogroups.com [mailto:power-assist@yahoogroups.com] On Behalf Of chalocolina Mon, 09 Nov 2009 23:45:02 GMT chalocolina http://tech.groups.yahoo.com/group/power-assist/message/84785 http://tech.groups.yahoo.com/group/power-assist/message/84785 ... It was not you but Joshua who said that 100% discharge could be done with LiFePO4 packs, and andrsnj1 who said that it should be standard operating Mon, 09 Nov 2009 22:31:23 GMT Don Harmon http://tech.groups.yahoo.com/group/power-assist/message/84784 http://tech.groups.yahoo.com/group/power-assist/message/84784 That's true. Single Pack doesn't need a BPM. LVC can be built-in to single pack. Multiple packs need a cat herder (BPM). Also a BPM is not a substitute for Mon, 09 Nov 2009 22:25:48 GMT EVsolutions http://tech.groups.yahoo.com/group/power-assist/message/84783 http://tech.groups.yahoo.com/group/power-assist/message/84783 Harmon keeps referring to multiple packs whereas everyone else here refers to multiple cells that when combined form a single pack. Gets confusing sometimes. Mon, 09 Nov 2009 22:23:49 GMT Don Harmon http://tech.groups.yahoo.com/group/power-assist/message/84782 http://tech.groups.yahoo.com/group/power-assist/message/84782 Sorry, I should have used the word "capacity" (100% of capacity) ! Sorry if I confused you? Don From: power-assist@yahoogroups.com Mon, 09 Nov 2009 22:05:00 GMT andrsnj1 http://tech.groups.yahoo.com/group/power-assist/message/84781 http://tech.groups.yahoo.com/group/power-assist/message/84781 Realistically it is a fool's errand to try and achieve 100% DOD. But ... Here is a quote from your post on November 8 A LiFeBATT battery pack or packs can go Mon, 09 Nov 2009 21:46:41 GMT Don Harmon http://tech.groups.yahoo.com/group/power-assist/message/84780 http://tech.groups.yahoo.com/group/power-assist/message/84780 The BPM doesn't limit DOD, it responds to the VMS TTL signal, which is programmed in the VMS firmware. A well balanced LiFeBATT pack should give 100% capacity, Mon, 09 Nov 2009 21:26:08 GMT Don Harmon http://tech.groups.yahoo.com/group/power-assist/message/84779 http://tech.groups.yahoo.com/group/power-assist/message/84779 Exactly - Only people like AndersonJ want to argue this point. Theoretically it's possible on a Cell level, like Joshua has already pointed out. Realistically Mon, 09 Nov 2009 21:11:52 GMT chalocolina http://tech.groups.yahoo.com/group/power-assist/message/84778 http://tech.groups.yahoo.com/group/power-assist/message/84778 ... I don't know, and I'm not sure whether it matters. I have no problem with BMS per se, as long as it's cost-effective and doesn't spend too much of the Mon, 09 Nov 2009 20:53:27 GMT Don Harmon http://tech.groups.yahoo.com/group/power-assist/message/84777 http://tech.groups.yahoo.com/group/power-assist/message/84777 You are all talking about "a battery pack" meaning a single pack of X amount of cells. When you build large scale battery systems consisting of 20 -50 battery Mon, 09 Nov 2009 20:50:47 GMT EVsolutions http://tech.groups.yahoo.com/group/power-assist/message/84776 http://tech.groups.yahoo.com/group/power-assist/message/84776 Motor controllers have a Low Voltage Cutoff built in to protect older battery chemistries from being damaged. IF you didn't have that LV cutoff in your Mon, 09 Nov 2009 20:33:48 GMT EVsolutions http://tech.groups.yahoo.com/group/power-assist/message/84775 http://tech.groups.yahoo.com/group/power-assist/message/84775 All I remember was David Lalonde going on and on and on about how a BMS is only needed for the charging/cell balancing stage and you don't need no steenkin BMS