Michael, Your ego is boasting,"I can design my own" but, your statements show IMHO the fact is that you don't know "Real World Design." Perhaps you should build your own and invest a dollar in your own design. Then test it on your vehicle and brag about it. But, quit the argument, because Lee's bridge will work and your design is only in your imagination and dreams. Put up or shut-up!
*Dennis Lee Miles * *Director **E.V.T.I. Inc.* *E-Mail:* *[email protected]* <[email protected]> On Fri, Apr 18, 2014 at 1:48 PM, Michael Ross <[email protected]>wrote: > My packs are 16 (or possibly 17) cells of LFP. My highest charge voltage > is 60VDC, so a half pack would be OK - always below 30V. CMOS logic and > handle that which is convenient. > > Should be interesting. > > > On Fri, Apr 18, 2014 at 1:31 PM, Lee Hart <[email protected]> wrote: > > > Michael Ross wrote: > > > >> I will probably be implementing a DC battery system for lighting and so > on > >> so I can get op amp power from there. > >> > > > > I don't know about your lighting system, but in an EV, the pack is > > isolated from ground. The voltages you want to measure are "floating" and > > not ground referenced. You can't power the comparators from a grounded > 12v > > system. You either needed a 12v DC/DC converter with isolated output, or > a > > HVDC-to-low voltage power supply to power the comparators. > > > > > > Or there is already a converter to > >> 12V on it. I would not use TTL if I can get around it - because it is > >> noise vulnerable. I would likely resort to some optos if noise gets > >> difficult. > >> > > > > From a "do this task" POV, an op amp comparator is exactly the right > >> function. > >> > > > > Technically, the function needed is a window comparator. This uses two > > comparators. One detects a voltage above the reference, and the other > > detects a voltage below the reference. But you can get two (or more) > > comparators inside a single chip (LM393 for example). > > > > However, IC comparators are intended for voltages under 30 volts. It > takes > > a lot of parts to use them to compare higher voltages. > > > > If the difference between the two halves is too great then it warns. > >> if the difference is intermittent then the indication stops. I think > >> I may like this better than a slowly increasing brightness > >> > > > > If you want a hard "digital" on/off indication, use the LED in an > > optocoupler in place of the red LED in the Batt-Bridge. Use the output of > > the optocoupler to switch some "digital" device, like logic gate or > relay. > > Or, there are optocoupler with built-in hard-switching digital outputs > that > > could directly switch something on/off. > > > > But in any case... start by precisely defining the problem you wish to > > solve *without* assuming a solution. Exactly what must the output do? > Work > > backwards from there. > > > > -- > > If you're not stubborn, you'll give up on experiments too soon. > > And if you're not flexible, you'll pound your head against the wall > > and you won't see a different solution to a problem you're trying > > to solve. -- Jeff Bezos > > -- > > Lee Hart's EV projects are at http://www.sunrise-ev.com/LeesEVs.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) > > > > > > > -- > Put this question to yourself: should I use everyone else to attain > happiness, or should I help others gain happiness? > *Dalai Lama * > > Tell me what it is you plan to do > With your one wild and precious life? > Mary Oliver, "The summer day." > > To invent, you need a good imagination and a pile of junk. > Thomas A. Edison< > http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html> > > A public-opinion poll is no substitute for thought. > *Warren Buffet* > > Michael E. Ross > (919) 550-2430 Land > (919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Google > Phone > (919) 631-1451 Cell > (919) 513-0418 Desk > > [email protected] > <[email protected]> > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140418/306305a4/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/20140418/ca5109de/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)
