Cor, It wasn't the losses I was aghast at it was the thought of having a mini-stove going in my battery box!
I was also wondering if the easiest way of measuring the cell terminal connection resistance would be to disconnect the pack and just put a large resistor across it sufficient to draw half an amp or so but what ever it was, very carefully measure the current flow (and keep monitoring it in case it changes as the resistor value changes with heat) and then measure your voltage drops across each connection. Much the same as other have suggested, just a bit more 'regulated', maybe. MW On 19 Aug 2014, at 17:15, Cor van de Water via EV wrote: > Martin, > Delivering 300A at 120V is 36,000 Watts, so losing 350W in the wiring > and terminal connections means only 1% loss in the grand scheme of > things. > A single traffic light turning red in front of you so you have to stop > and again accelerate up to speed is likely a bigger difference in the > efficiency of a trip... > > 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 > > > -----Original Message----- > From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Lee Hart via EV > Sent: Tuesday, August 19, 2014 9:08 AM > To: Martin WINLOW; Electric Vehicle Discussion List > Subject: Re: [EVDL] CALB bolt terminals getting hot - > > Cor van de Water via EV wrote: >>> Depends on your current. Typically I would say in the order of >>> magnitude of 0.1 mOhm (milliOhm) because a 300A current will then >>> give 30mV drop, which produces 300A x 0.03V = 9 Watt of power loss >>> as heat. > > Martin WINLOW via EV wrote: >> At EVERY connection? In a 120V lithium pack that 's 38 x 9 = >> nearly 350W of heat! > > No; Cor has it right. And, 0.1 milliohms is a *good* connection. You > will discover that it is damnably difficult to make a connection that > good with aluminum terminals! > > -- > You never change things by fighting the existing reality. To change > something, build a new model that makes the existing model obsolete. > -- R. Buckminster Fuller > -- > Lee Hart's EV projects are at http://www.sunrise-ev.com/LeesEVs.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) > > _______________________________________________ > 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)
