Thanks Cor, I wasn't confused but I did think about that after I hit send and I agree it wasn't quite correct, it's been a while since I did this but when I measured my vehicle I was using 350 amps to accelerate the vehicle and regen would generate a max of 100 amps if I remember correctly. So my point is still valid. It's not likely you will damage the battery even if fully charged.
I did a test on the bench where I took a fully charged cell and put 15amps into it for 5 minutes. The cells heated up 40 degrees C in 5 minutes. It's the heat that accelerates damage so yes the effect would not be nothing but a few seconds of braking will not be enough to cause significant heat rise on a cell IMO. Sent from my iPad > On Jan 5, 2016, at 8:01 PM, Cor van de Water via EV <[email protected]> wrote: > > Paul, > While the data you quote is correct in a certain context, your explanation is > not, since it uses a different context. > Regen braking will put back in your pack around 5% of an average trip > since a trip typically consists of long periods of driving and a handful > times of braking. > > However, the way you explained it (how much energy do you get back from regen > braking) is well over 50% since it is a simple calculation to take the energy > that the vehicle is traveling with (kinetic energy) and calculate how much of > that energy is transformed from kinetic energy via the drivertrain, the motor > working as generator and finally the controller, back to the pack. > This can easily be over 2/3 of the kinetic energy, so that a cycle of braking > and then pulling the energy from the pack again to accelerate can show a > restoration of around 50% of the previous level after the conversion: > kinetic - electric - chemical(battery) - electric - kinetic > Since Kinetic energy goes by the speed squared, you can typically regain > about 70% of the previously traveled speed by accelerating just from the last > regen battery charge, before you start dipping deeper into your pack. > > Hope this clarifies the confusion, > > Cor van de Water > Chief Scientist > Proxim Wireless > > office +1 408 383 7626 Skype: cor_van_de_water > XoIP +31 87 784 1130 private: cvandewater.info > > http://www.proxim.com > > This email message (including any attachments) contains confidential and > proprietary information of Proxim Wireless Corporation. If you received this > message in error, please delete it and notify the sender. Any unauthorized > use, disclosure, distribution, or copying of any part of this message is > prohibited. > > > -----Original Message----- > From: EV [mailto:[email protected]] On Behalf Of paul dove via EV > Sent: Tuesday, January 05, 2016 5:53 AM > To: Electric Vehicle Discussion List > Subject: Re: [EVDL] Melted fuse leg (not blown fuse!) > > Hello Roland, > Not sure where you get your information > However, Dr. Dahn says that most damaging parasitic reactions that cause > early cell failure happen above 4.0 volts he does not say all of the effects > cease. He also states that it is the length off time held at the highest > charge voltage that causes the most damage. Longer is worse. > > You may not be doing what you think are. If anything the taper CV stage > should be eliminated. > > In addition, regenerative braking only puts about 5% of energy used to move > forward back. so if you drive 100 feet you would need to brake 2000 feet of > braking to get back to start before you would start to go over 100% state of > charge ...... so unless you park on a hill and start you drive rolling down > the hill it's not going to effect the battery. It still won't do much even if > you do this for a short time frame. > In addition, Dr. Dahn sated that Nissan uses two different chemistries.... > > > - Lithium Cobalt Manganese Oxide (Li[NiMnCo]02) > - Moderate parasitic reactions at 30°C > - ~50% of Nissan Leaf and Chevy Volt packs > > - Lithium Manganese Oxide (LiMn02) > - Highest parasitic reactions of all examples at 30°C and even worse at > 60°C > - ~50% Part of the Nissan Leaf and Chevy Volt battery pack > - Ill-suited to use in battery packs without thermal management, like > the Nissan Leaf. > > > > > From: Roland via EV <[email protected]> > To: Jay Summet <[email protected]>; Electric Vehicle Discussion List > <[email protected]> > Sent: Monday, January 4, 2016 11:41 PM > Subject: Re: [EVDL] Melted fuse leg (not blown fuse!) > > > Hello Jay, > > I adjust my voltage to 4.0 volt per cell which is about 95% of the rated 4.2 > volt maximum cell voltage. The PFC charger has eight control switches which > are set according to your charger manual depending what type of battery and > BMS you are using. > > I chose to turn all the switches off, which allows the charger to start to > taper the current as some as it reaches the max voltage set point you want. > The charger will then taper to 0 ampere and will not charge any more. > > According to my BMS Orion Manual, the maximum charge voltage should not go > above 95%, so as to leave room for regenerative current. > > > > Roland > > > > > > > > > > > ----- Original Message ----- > > From: Jay Summet via EV<mailto:[email protected]> > > To: Electric Vehicle Discussion List<mailto:[email protected]> > > Sent: Monday, January 04, 2016 7:42 PM > > Subject: [EVDL] Melted fuse leg (not blown fuse!) > > > > Has anybody ever melted the plastic and holder of an Automotive ATC > fuse, without blowing the fuse itself? > > I had a cheap AutoZone in-line fuse holder with a 30 Amp fuse on the 12 > volt line between the DC-2-DC and accessory battery, and today one side > of the holder and one side of the fuse melted and made a nasty burning > smell while I was driving down the road. > > This was especially concerning with my new Leaf Modules just recently > installed ;> > > I was actually quite relieved to find it was "just" a melted fuse. The > funny thing is that the fuse itself didn't blow, it still has > connectivity when I touch inside where the leg used to be. > > The only thing I can think of is that while I was moving wires around > for the install of the new charger the fuse got slightly jolted and one > leg had a loose contact with the holder, causing a high resistance > connection and lots of heat without going over 30 amps. > > Impressively melted photos here: > http://www.summet.com/blog/2016/01/04/melted-fuse-leg/ > > Jay > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Read EVAngel's EV News at http://evdl.org/evln/ > Please discuss EV drag racing at 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/20160104/74b0105c/attachment.htm> > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Read EVAngel's EV News at http://evdl.org/evln/ > Please discuss EV drag racing at 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/20160105/b924a725/attachment.htm> > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Read EVAngel's EV News at http://evdl.org/evln/ > 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 > Read EVAngel's EV News at http://evdl.org/evln/ > 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 Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
