What power (or current into your battery) are you looking for? If you want to charge from a 120V outlet then ~1500W is all that you can hope for in 99% of circumstances while at 240V you typically have at least a 30A circuit (dryer outlet) and public charging often supplies 208V (two phases of a 120V 3-phase supply) and then the power is at least 80% of that for more than 2h loads, so 24A at 208V or 5kW.
Personally I am in favor of switching power supplies because they are small, light and isolated. To avoid high cost, I tend to take what I have and modify it to add the controls I need for current and voltage limit. My current EV has a 2.5kW (max, it runs quite warm at 1500W) Bycon resonant transformer charger that is very heavy and I think the previous owner of my EV overpaid for that charger, but it works well and has enough control to stop charging by itself (timer circuit). The power factor is surprising good considering that it simply is a transformer and two diodes on the output, but the fact that it is a resonant transformer causes this - and a higher loss, unfortunately. Once I add a lithium pack in parallel to the existing lead-acid batteries, I will also add a "bulk" charger to increase the speed when I plug into a J1772 charger, but I will maintain the current Bycon to keep the ability for 120V charging (which is 99% of my charging now, even though the Bycan can be switched to 240V and I have a conversion cable from J1772 inlet, so I *can* use public charging. 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 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 Jay Summet via EV Sent: Wednesday, February 04, 2015 12:38 PM To: Lee Hart; Electric Vehicle Discussion List Subject: Re: [EVDL] 120&240v (kit/assembled) battery charger? (Open source?) On 02/04/2015 10:15 AM, Lee Hart via EV wrote: > Jay Summet via EV wrote: >> I'm looking to buy a kit (or an assembled) battery charger for a 120v >> lead acid system, with an eye to upgrading to a LiIon system in the >> future (also near 120-130 volts, limited by my controller/motor combo). > > Hi Jay, > > If you want to build it yourself, have you considered an "old school" > charger as an alternative? A 120vdc pack is the "sweet spot" for > making very simple chargers. > > In the extreme, a "bad boy" charger is just a bridge rectifier off the > 120vac line. Or a half-bridge from the 240vac line. Add a series > inductor to handle the current peaks (a "Bonn" charger), and you have > a decent charger. Add a plain old 60 Hz transformer, and you have > isolation (a "third world" charger). > > The easiest way to regulate it is with phase control. Use two SCRs in > place of the diodes in the bridge. This makes it equivalent to the > Russco or K&W chargers. > Keeping things simple has some advantages, but I can't think of a way to do it safely without a quite large transformer. (I'm not comfortable with just a phase controlled SCR directly to mains....then you lose the isolation protection from ground...) My 110V charger is transformer based, and I certainly wouldn't want a LARGER transformer in my truck. I suspect that simply by adding a solid state input cutoff relay and a voltage sensing circuit to one of my existing chargers I could get the same general price/performance as a "bad boy" charger. Jay _______________________________________________ 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) _______________________________________________ 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)
