Re: [EVDL] decreasing pack voltage
In addition a 70Ah battery should do 145 amps continuous with no problem. You might want to check the peak currents when accelerating Sent from my iPhone > On Sep 14, 2018, at 12:36 PM, Damon Henry via EV wrote: > > Ummm, actually you failed to ask a question... > > The principle behind what you are talking about is that in an EV Volts X Amps > is equal to Power (Watts) and it requires a certain amount of power to > maintain a certain speed. If you drop the voltage of your pack it will then > require more amps to maintain the same speed. In this case, it takes 85 x > 120 = 10.2 kw to drive 55 mph. If you lower your pack voltage to 70 then > 10200 / 70 = 145.71 amps to maintain 55 mph. > > This is the straight math. There are other factors involved as well. Can > your overall system maintain 70 volts at 145 amps. My guess is that it can > because most of the components that people build EVs with work fine in this > range, but it is generally harder on all of your components. > > Without more specifics that is the best I can answer your implied question. > > Damon > > Damon > > From: EV on behalf of ken via EV > > Sent: Thursday, September 13, 2018 11:18 PM > To: Electric Vehicle Discussion List > Cc: ken > Subject: [EVDL] decreasing pack voltage > > I have a 85 volt system that draws 120 amps at 55 mph, but want to lower > my pack count (I found brand new cells ) but to do only top speed of 40 > mph . > > at 40 mph my voltage is 70 volts and 40 amps, Am i asking a oboius ? the > cells are 70 ah . > > ___ > UNSUBSCRIBE: > https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.evdl.org%2Fhelp%2Findex.html%23usubdata=02%7C01%7C%7C95d6bc500de44a4d03b208d61a09f33a%7C84df9e7fe9f640afb435%7C1%7C0%7C636725027361552683sdata=Q%2Bs3sACO0XmugvJaLq6Z%2BnOZETq5XyaRU2g3q4zpNRg%3Dreserved=0 > https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.evdl.org%2Flistinfo.cgi%2Fev-evdl.orgdata=02%7C01%7C%7C95d6bc500de44a4d03b208d61a09f33a%7C84df9e7fe9f640afb435%7C1%7C0%7C636725027361552683sdata=ZyYpltnHO%2BQNs9SdcJlIF5Z08nnon4Vu9ViJcLnxmQ8%3Dreserved=0 > Please discuss EV drag racing at NEDRA > (https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fgroups.yahoo.com%2Fgroup%2FNEDRAdata=02%7C01%7C%7C95d6bc500de44a4d03b208d61a09f33a%7C84df9e7fe9f640afb435%7C1%7C0%7C636725027361552683sdata=FxLPkagjqBQ%2B4xJz%2Fy8ZDgQPRaoJNcF8YlcaLl44cHs%3Dreserved=0) > > -- next part -- > An HTML attachment was scrubbed... > URL: > <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20180914/a75625d2/attachment.html> > ___ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > 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 Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] decreasing pack voltage
Ummm, actually you failed to ask a question... The principle behind what you are talking about is that in an EV Volts X Amps is equal to Power (Watts) and it requires a certain amount of power to maintain a certain speed. If you drop the voltage of your pack it will then require more amps to maintain the same speed. In this case, it takes 85 x 120 = 10.2 kw to drive 55 mph. If you lower your pack voltage to 70 then 10200 / 70 = 145.71 amps to maintain 55 mph. This is the straight math. There are other factors involved as well. Can your overall system maintain 70 volts at 145 amps. My guess is that it can because most of the components that people build EVs with work fine in this range, but it is generally harder on all of your components. Without more specifics that is the best I can answer your implied question. Damon Damon From: EV on behalf of ken via EV Sent: Thursday, September 13, 2018 11:18 PM To: Electric Vehicle Discussion List Cc: ken Subject: [EVDL] decreasing pack voltage I have a 85 volt system that draws 120 amps at 55 mph, but want to lower my pack count (I found brand new cells ) but to do only top speed of 40 mph . at 40 mph my voltage is 70 volts and 40 amps, Am i asking a oboius ? the cells are 70 ah . ___ UNSUBSCRIBE: https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.evdl.org%2Fhelp%2Findex.html%23usubdata=02%7C01%7C%7C95d6bc500de44a4d03b208d61a09f33a%7C84df9e7fe9f640afb435%7C1%7C0%7C636725027361552683sdata=Q%2Bs3sACO0XmugvJaLq6Z%2BnOZETq5XyaRU2g3q4zpNRg%3Dreserved=0 https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.evdl.org%2Flistinfo.cgi%2Fev-evdl.orgdata=02%7C01%7C%7C95d6bc500de44a4d03b208d61a09f33a%7C84df9e7fe9f640afb435%7C1%7C0%7C636725027361552683sdata=ZyYpltnHO%2BQNs9SdcJlIF5Z08nnon4Vu9ViJcLnxmQ8%3Dreserved=0 Please discuss EV drag racing at NEDRA (https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fgroups.yahoo.com%2Fgroup%2FNEDRAdata=02%7C01%7C%7C95d6bc500de44a4d03b208d61a09f33a%7C84df9e7fe9f640afb435%7C1%7C0%7C636725027361552683sdata=FxLPkagjqBQ%2B4xJz%2Fy8ZDgQPRaoJNcF8YlcaLl44cHs%3Dreserved=0) -- next part -- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20180914/a75625d2/attachment.html> ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
[EVDL] decreasing pack voltage
I have a 85 volt system that draws 120 amps at 55 mph, but want to lower my pack count (I found brand new cells ) but to do only top speed of 40 mph . at 40 mph my voltage is 70 volts and 40 amps, Am i asking a oboius ? the cells are 70 ah . ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
