That's not luck the inverter should limit the current. All the ones I have seen do. We're you batteries ruined? Did they explode? I have an imiev and it charges the batteries fully but it limits regen current to 100 amps I believe. Been a while since I looked. I'm sure the inverter limits voltage as well. I was merely addressing short current bursts into a full cell.
Sent from my Verizon Wireless 4G LTE smartphone-------- Original message --------From: Cor van de Water via EV <[email protected]> Date: 1/6/2016 1:48 PM (GMT-06:00) To: Electric Vehicle Discussion List <[email protected]> Subject: Re: [EVDL] Melted fuse leg (not blown fuse!) Paul, I am afraid that it will not be a good idea to do a one-time test at a certain (low) current level and judge the effects for a practice of repeatedly doing this at much higher current levels, especially if this has potential to quickly destroy an expensive pack or even set the vehicle on fire. I have reported on the following event before and this was on lead acid, but just to get an idea what regen braking can do: My previous EV truck was an S10 where the US Electricar conversion was re-converted by Wavedriver with their own controller for a V2G project they did with PG&E in 1994-1995 The Wavedriver controller allowed its characteristics to be configured via serial port, so I played around with the level above which regen would be disabled and a couple other things. This controller could accelerate and regen at its max current level, 250A (this was a 312V setup with an AC Induction motor (Hughes) direct coupled to a manual transmission box that was always in 2nd gear, effectively serving as reduction gear to allow the motor to hit redline of 9000 RPM at 72MPH. So the next day after increasing the regen threshold to always regen instead of only after 10% discharge, I drove onto the freeway, was merging onto the next and had someone not giving me space so I braked. The pack voltage went from the well-charged 320V to 420V as the batteries could not absorb the 100kW of power that was thrown at them in their charged state and the controller detected a max-allowed DC bus level critical error and shut down to protect itself. I coasted to the side of the freeway, restarted the car to reset the controller and drove on and re-configured the re-gen parameter to only start after 10% charge had been taken out. This power and voltage level would have been sufficient to kill my EV if it had not been stopped by a safety built-into the controller, not only the sheer DC bus voltage but also the voltage per cell could have caused damage when sustained, the BMS (if I would have had one) could have failed and the pressure quickly building up in the cells at such an over-voltage could have caused cells to burst or at least vent violently. I was lucky the controller had this safety protection, I do not know what a Li-Ion equipped vehicle with a different controller would have done, but I think there is a good reason that regen is disabled or severely limited, hopefully the BMS simply says: overvoltage, no more charge current allowed. And that is a good thing. 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: Paul Dove [mailto:[email protected]] Sent: Wednesday, January 06, 2016 4:44 AM To: Cor van de Water; Electric Vehicle Discussion List Subject: Re: [EVDL] Melted fuse leg (not blown fuse!) 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) -------------- next part -------------- An HTML attachment was scrubbed... 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