The dump pack and the EV battery can be connected through a DC/DC converter that only needs to handle the *difference* in voltage, so bucking down a little initially when the dump pack is a few volts higher than the EV and boosting up a little towards the end when the dump pack is down and the EV battery is climbing in voltage. This means that only a *fraction* of the power needs to be handled by that DC/DC converter and it can concentrate on supplying the desired current into the EV pack, while also being super-efficient, since the normal ~90% efficiency of a good DC/DC will only affect the fraction of the power, the majority of the transfer will be direct connect so 100% efficient minus the discharge/charge efficiency of the batteries themselves. This also means that if the dump pack only needs to do this once an hour, the power requirement drops to ~20kW which means a standard 200A service can handle 2 of these setups.
Cor van de Water Chief Scientist Proxim Wireless Corporation http://www.proxim.com Email: [email protected] Private: http://www.cvandewater.info Skype: cor_van_de_water XoIP: +31877841130 Tel: +1 408 383 7626 Tel: +91 (040)23117400 x203 -----Original Message----- From: EV on behalf of Lee Hart via EV Sent: Sat 5/9/2015 10:45 AM To: Electric Vehicle Discussion List Subject: Re: [EVDL] StoreDot promises electric car that charges in 5 minutes Bill Dube via EV wrote: > The cells can charge in 5 minutes to 90% or better. These have been > available for years. > However, no one will pay for a charger large enough to charge a car in 5 > minutes. It would cost ten or twenty times more than the car. > Such a charger would be as big as a sea container. Well, not THAT bad. But still, pretty big and expensive! If I had to do this (especially for a demonstration project), I'd use a second set of the same batteries as a "dump pack". Have the dump pack all charged and waiting. Parallel the two, perhaps with enough resistance to limit the current. -- Don't worry about people stealing your ideas. If your ideas are any good, you'll have to ram them down people's throats. -- Howard Aiken -- 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 For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/ms-tnef Size: 4192 bytes Desc: not available URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150509/66d4ca2a/attachment.bin> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
