Thank you Cor. I am cash strapped so this sort of DIY advice is very helpful.
Mike On Thu, Nov 6, 2014 at 5:33 PM, Cor van de Water via EV <[email protected]> wrote: > No, a programmable load will typically have built-in load, but there may > be units that only are a controller > > and expect a bank of resistors or the like externally. > > For doing it on the cheap, you can take a length of wire that can > dissipate the heat, either by spreading it out > > (I once did several cycles of testing on a 12V 110Ah battery using about > 200 ft of copper wire strung around > > my garage on two parallel strings, so I got about 80A of discharge > current). > > You can also build a dissipative load relatively easy with power MOSFETs > on a heatsink, a shunt resistor > > to measure the current, an opamp to compare the desired current to the > set value and drive the MOSFETs > > and a small 12V power supply to power the thing. > > Add a second opamp to measure voltage and stop the discharge at a set > voltage and you are pretty far > > along in having your own programmable load. Add a meter or two and some > indicators and you are in business. > > > > Cor van de Water > Chief Scientist > Proxim Wireless Corporation http://www.proxim.com > <http://www.proxim.com> > Email: [email protected] Private: http://www.cvandewater.info > <http://www.cvandewater.infom> > Skype: cor_van_de_water Tel: +1 408 383 7626 > > ________________________________ > > From: Michael Ross [mailto:[email protected]] > Sent: Thursday, November 06, 2014 2:25 PM > To: Cor van de Water; Electric Vehicle Discussion List > Subject: Re: [EVDL] Q about using an electronic load. > > > > I have heard of putting a roll of fencing in a tank to steam off heat. > Is this useful with a programmable load? Or is this just a crude way to > discharge. > > > > Someone mentioned needing a heat dispensing means would be needed with a > programmable load. > > > > Any recommendation of actual units to look at? > > > > On Thu, Nov 6, 2014 at 4:55 PM, Cor van de Water via EV > <[email protected]> wrote: > > Correct - a *supply* can use switching to minimize losses, > a *load* simply burns the power away in linear mode (current control). > > 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 Tel: +1 408 383 7626 > <tel:%2B1%20408%20383%207626> > > > > -----Original Message----- > From: EV [mailto:[email protected]] On Behalf Of Roger Stockton > via EV > Sent: Thursday, November 06, 2014 1:12 PM > To: Electric Vehicle Discussion List > Subject: Re: [EVDL] Q about using an electronic load. > > Michael Ross wrote: > > > If I have a programmable electronic load, rather than purely resistive > > loads, is this an unrealistic way to discharge batteries? > > > > I gather they use power MOSFETS and switch them to product the desired > > output current from the batteries. I think this implies some > transients > > at some frequency. > > A programmable load is fine for discharging batteries. > > I believe the power devices are operated in linear mode, not PWMed, and > have not observed any transients on the load current on any of the > electronic loads I've used. > > Cheers, > > Roger. > > _______________________________________________ > 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) > > > > > > > > -- > > Put this question to yourself: should I use everyone else to attain > happiness, or should I help others gain happiness? > > Dalai Lama > > > > Tell me what it is you plan to do > > With your one wild and precious life? > > Mary Oliver, "The summer day." > > > > To invent, you need a good imagination and a pile of junk. > > Thomas A. Edison > <http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html> > > > > A public-opinion poll is no substitute for thought. > > Warren Buffet > > > > Michael E. Ross > > (919) 550-2430 Land > > (919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Google > Phone > > (919) 631-1451 Cell > (919) 513-0418 Desk > > [email protected] > > <mailto:[email protected]> > > > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20141106/3aca5f24/attachment.htm > > > _______________________________________________ > 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) > > -- Put this question to yourself: should I use everyone else to attain happiness, or should I help others gain happiness? *Dalai Lama * Tell me what it is you plan to do With your one wild and precious life? Mary Oliver, "The summer day." To invent, you need a good imagination and a pile of junk. Thomas A. Edison <http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html> A public-opinion poll is no substitute for thought. *Warren Buffet* Michael E. Ross (919) 550-2430 Land (919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Google Phone (919) 631-1451 Cell (919) 513-0418 Desk [email protected] <[email protected]> -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20141106/a7c7ae26/attachment.htm> _______________________________________________ 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)
