You can grab old files from Victor's old website via the Wayback Machine ( archive.org).
https://web.archive.org/web/20051031031417/http://www.metricmind.com/misc/ultracap.gif https://web.archive.org/web/20051031031314/http://www.metricmind.com/misc/test1.gif https://web.archive.org/web/20051031031004/http://www.metricmind.com/misc/compare.gif Phil H. On Wed, Feb 27, 2019 at 10:14 AM Roger Stockton via EV <[email protected]> wrote: > Jay Summet wrote: > > > I'm wondering how much capacity the capacitors are adding to the system, > > as the voltage of the capacitors can never go below the sag voltage of > > the LiIon cells under load, and can never go above the LiIon cells > > voltage during regen. > > > > I'd love to see a comparison graph of the voltage of the system battery > > bank during a hard acceleration and a hard regen event both with and > > without the capacitors installed to see the voltage regulation effect. > > Victor Tikhonov (of MetricMind) used a string of 2.7kF Maxwell supercaps > (17F total) in parallel with the lithium pack in his CRX conversion, back > in 2004. > > Something Victor mentioned on the site for his conversion is the need to > disconnect the string of caps from the battery during charge. > > Unfortunately, the links in Victor's original message (quoted below) > appear dead, however, his comments describing the results of his > measurements are still informative. > > > -----Original Message----- > > From: Victor Tikhonov [mailto:[email protected]] > > Sent: October-07-04 4:53 PM > > To: [email protected] > > Subject: Does the passive balancing of uptracaps stack really works? > > > > I've made a few measurements on the most easily accessible > > caps (last 10 caps in the series string) after couple of > > driving/charging cycles. Objective was to see if they are > > drifting apart far enough that the passive resistor based > > balancing cannot keep up with bringing them all back to order. > > > > Looks like whatever initial voltages are settling at, they all > > go up and down at the same rate, so at the end of the day > > while overall average SOC is different, deltas between the same > > caps are still identical. Which tells me that for my circumstances > > making active balancing would be waste of effort. > > > > Will see how well this keeps repeating in the long run. > > > > http://www.metricmind.com/misc/ultracap.gif > > > > In case you missed the link showing about 10x stiffness > > improvement using ultracaps, captured data screens are here: > > > > http://www.metricmind.com/misc/test1.gif > > Left half - with caps, right half - without. > > (did few hard regens in the middle - to separate data points) > > > > Zoomed in version: > > http://www.metricmind.com/misc/compare.gif > > > > I'm noticing a side benefit I didn't think of before: > > no matter what the SOC of the battery is, combined > > with ultracaps it feels just as stiff at the end of > > discharge as full. This is because ultracaps have fixed > > internal resistance no matter how discharged they are. > > > > When the pack getting tired, recharging caps from LiIons > > after accelerations getting slower, but by the time it is > > completed, the pack is as stiff for the next acceleration > > as the fresh one. > > > > From here (bottom plot) you can see how efficient > > my system happen to be (motor power out / batt power in): > > > > http://www.metricmind.com/misc/eff.gif > > This is actually unrelated to the presence of the capacitors. > > > > So far I'm very pleased with outcome of my setup. LiIons > > don't get much chance to see more than 30A out of them > > during quick accelerations, the same absorbing regen. > > The caps do all the work :-) > > > > -- > > Victor > > '91 ACRX - something different > > > _______________________________________________ > 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) > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20190228/8a4c8c61/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)
