Is it easy to create exactly 10 amps? (not rhetorical) Don't many chargers vary a good bit depending on the load the work into? In which case, you need to have a second instrument for the current measurement, and it needs to be sufficiently accurate and steady.
I measure four wire resistance all the time for temperature measurements using platinum RTDs and thermistors. It is the only way to go for accuracy. My main point is to know and understand if your instrument is up to the task. On Tue, Aug 19, 2014 at 2:53 PM, Cor van de Water via EV <ev@lists.evdl.org> wrote: > It is not a problem to create a known current in the order of 10 Amps > either by using the existing charger on the vehicle or an external power > supply. That produces a 1mV drop for a 0.1 Ohms resistance. > Since the measurement does not need to be extremely accurate, > you just want to verify that all connections are in the 0.1 mOhm range > and none are more than double that, you can suffice with pretty simple > instrumentation that allows you to distinguish between 1 and 2 mV, while > you send that approx 10 Amps through the connection, either by actually > charging > or with external means. You just need to take care to always probe on the > same spot on the battery terminal (preferably as close as possible to the > cell themselves, so the Alu or copper contact would be good if you can > reach it, the alu nut around that contact would be the next best thing. > Read up on 4-point resistance measurement (Kelvin sensing) if you are > not familiar with how the sensing points will influence the measurement: > http://www.allaboutcircuits.com/vol_1/chpt_8/9.html > > Cor van de Water > Chief Scientist > Proxim Wireless Corporation http://www.proxim.com > Email: cwa...@proxim.com Private: http://www.cvandewater.info > Skype: cor_van_de_water Tel: +1 408 383 7626 > > ​SNIP > -- 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 michael.e.r...@gmail.com <michael.e.r...@gmail.com> -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140819/52ac5067/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)
