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%23usub&data=02%7C01%7C%7C95d6bc500de44a4d03b208d61a09f33a%7C84df9e7fe9f640afb435%7C1%7C0%7C636725027361552683&sdata=Q%2Bs3sACO0XmugvJaLq6Z%2BnOZETq5XyaRU2g3q4zpNRg%3D&reserved=0 > https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.evdl.org%2Flistinfo.cgi%2Fev-evdl.org&data=02%7C01%7C%7C95d6bc500de44a4d03b208d61a09f33a%7C84df9e7fe9f640afb435%7C1%7C0%7C636725027361552683&sdata=ZyYpltnHO%2BQNs9SdcJlIF5Z08nnon4Vu9ViJcLnxmQ8%3D&reserved=0 > Please discuss EV drag racing at NEDRA > (https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fgroups.yahoo.com%2Fgroup%2FNEDRA&data=02%7C01%7C%7C95d6bc500de44a4d03b208d61a09f33a%7C84df9e7fe9f640afb435%7C1%7C0%7C636725027361552683&sdata=FxLPkagjqBQ%2B4xJz%2Fy8ZDgQPRaoJNcF8YlcaLl44cHs%3D&reserved=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] Large Format Cells vs. Small Format Cells for EVs
nd anecdotal evidence about the veracity of those tests, and their practicality. We end up falling prey to our confirmation biases and shrugging off the uncertainty of it all because the whole boneheaded tradition is confusing at best. Learn what the best people have learned, and stop thinking the old ways. On Fri, Sep 14, 2018 at 5:59 AM George Tyler via EV wrote: > From my experience, we had an in-house test company that ran independently, > we wanted to know the truth, results are not released to the public but > used > to improve reliability. The name of the company is at stake. When I see > something like a cell phone company that has battery fires I know it's > either a mickey mouse company, or someone did not do their job properly! > There is nothing to be gained by "fudging" results > component failure should follow a "bath tub" shape, on a graph of > failure rate on the vertical axis and time on the horizontal. The shape can > tell a lot about product quality, you are testing many samples, and they > should lie on the same curve. Bad production methods or bad component > quality can be indicated by a spread in different ways. We also tested > components like the SCR's used in the same manner, we ran 70A SCR's at over > 1000 amps, tested many samples for months like that, also tested spade > terminals used in the products. > > > -Original Message- > From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Lee Hart via EV > Sent: 13 September, 2018 4:46 PM > To: Electric Vehicle Discussion List > Cc: Lee Hart > Subject: Re: [EVDL] Large Format Cells vs. Small Format Cells for EVs > > Michael Ross via EV wrote: > > Yeah, I wouldn't say prove either. But testing can be far better than the > > old tried, and not very good cycling tests. > > ___ > 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) > > -- Michael E. Ross (919) 585-6737 Land (919) 901-2805 Cell and Text (919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Tablet, Google Phone and Text -- next part -- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20180914/9853c14a/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)
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%23usub&data=02%7C01%7C%7C95d6bc500de44a4d03b208d61a09f33a%7C84df9e7fe9f640afb435%7C1%7C0%7C636725027361552683&sdata=Q%2Bs3sACO0XmugvJaLq6Z%2BnOZETq5XyaRU2g3q4zpNRg%3D&reserved=0 https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.evdl.org%2Flistinfo.cgi%2Fev-evdl.org&data=02%7C01%7C%7C95d6bc500de44a4d03b208d61a09f33a%7C84df9e7fe9f640afb435%7C1%7C0%7C636725027361552683&sdata=ZyYpltnHO%2BQNs9SdcJlIF5Z08nnon4Vu9ViJcLnxmQ8%3D&reserved=0 Please discuss EV drag racing at NEDRA (https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fgroups.yahoo.com%2Fgroup%2FNEDRA&data=02%7C01%7C%7C95d6bc500de44a4d03b208d61a09f33a%7C84df9e7fe9f640afb435%7C1%7C0%7C636725027361552683&sdata=FxLPkagjqBQ%2B4xJz%2Fy8ZDgQPRaoJNcF8YlcaLl44cHs%3D&reserved=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)
Re: [EVDL] Large Format Cells vs. Small Format Cells for EVs
George Tyler via EV wrote: From my experience, we had an in-house test company that ran independently, we wanted to know the truth, results are not released to the public but used to improve reliability. The name of the company is at stake. When I see something like a cell phone company that has battery fires I know it's either a mickey mouse company, or someone did not do their job properly! There is nothing to be gained by "fudging" results Amen to that, George! That is exactly my experience. I worked designing furnace controls and large home appliance controls. These are consumer products (have to be cheap), but are also expected to last a long time (decades) and also MUST be safe! That meant the product testing cost more than the parts. Cars have to be designed the same way; otherwise they can KILL somone! -- Imagination is your preview of life's coming attractions. (Albert Einstein) -- Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com ___ 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] Large Format Cells vs. Small Format Cells for EVs
>From my experience, we had an in-house test company that ran independently, we wanted to know the truth, results are not released to the public but used to improve reliability. The name of the company is at stake. When I see something like a cell phone company that has battery fires I know it's either a mickey mouse company, or someone did not do their job properly! There is nothing to be gained by "fudging" results component failure should follow a "bath tub" shape, on a graph of failure rate on the vertical axis and time on the horizontal. The shape can tell a lot about product quality, you are testing many samples, and they should lie on the same curve. Bad production methods or bad component quality can be indicated by a spread in different ways. We also tested components like the SCR's used in the same manner, we ran 70A SCR's at over 1000 amps, tested many samples for months like that, also tested spade terminals used in the products. -Original Message- From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Lee Hart via EV Sent: 13 September, 2018 4:46 PM To: Electric Vehicle Discussion List Cc: Lee Hart Subject: Re: [EVDL] Large Format Cells vs. Small Format Cells for EVs Michael Ross via EV wrote: > Yeah, I wouldn't say prove either. But testing can be far better than the > old tried, and not very good cycling tests. ___ 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)
