Hi Roland, The best estimator for range on conversions that I have seen is a simple rule of thumb based on the original vehicle.
Figure that a lithium pack of 9 kWh is about the equivalent of 1 gallon of gas for the original vehicle. If you could get 30 mpg in the original vehicle, you will get about 30 mile range from a 9 kWh pack. Scale up according to actual pack size. This has the advantage that it automatically takes into account vehicle characteristics, driving style, etc. A 10 mpg Suburban will get 10 miles from a pack that a Honda Civic driven carefully might get 30 miles or more. Mike On July 31, 2014 8:10:19 PM MDT, Roland via EV <[email protected]> wrote: >I did this type of battery shunt test a little bit different over 50 >years ago when I working in a military battery shop. I apply this >method to every battery pack I had in my EV,s. We use a amp meter >instead of a volt meter. We connect a amp meter shunting a mechanical >fasten battery link to the two posts that the link was connecting to. > >Making up a new battery pack, we first torque all the link connections >to the same torque reading. Turn on the battery charger and set it for >a known ampere. We check the amp reading of each link and find the >highest ampere reading of one link. > >Then we re-torque all the other battery connections until the amp meter >reads the same as the highest reading. Run a load on the batteries >with a load bank, or in a EV, just run the EV for about 5 miles. Do >the shunt test again which in my EV only takes less than 15 minutes. >It is normal to find one battery connection at about 5 inch lbs less >than the initial torque of 75 in.lbs in my batteries. > >I than apply a thick coating of petroleum jelly to the link connection >all the way down to the battery surface. The batteries are enclosed in >a epoxy seal battery box that has incoming filter air drawn in with a >acid proof exhaust fan. > >In about a month I will be getting three Nissen Leaf batteries which I >will reconnect for 180 ah at 210V nominal. It is recommend to use the >battery in the 3.65V - 4.15V per cell range. Do not charge over 4.2V >per cell. > >The pictures that they sent me looks like the battery links are copper >which I assume the battery load terminals are copper too. I am going >to have to remove them so I can parallel three modules in parallel and >series 81 of these parallel modules in series. > >I was planning to buff the copper bars with my metal bench mount buffer >with a new buffer wheel, because the other ones had compound infuse >into for other metals. > >After you polish or clean any links, it is best to wear throw away >latex gloves, to keep the finger print oil off polish metal. > >I will then apply the petroleum jelly over these bars and connections. > >The weight of my EV which is now at 7020 lbs will weigh 5500 lbs which >was about the original weight of the vehicle. My 1st gear overall >ratio is 25.7:1, 2nd gear is 17.6:1, 3rd gear is 10.0:1 and 4th gear is >5.57:1. At 7020 lbs, I normally use the third gear to accelerated up >to either 25, 35, or 45 mph which is max speed in this town and 4th >gear at speed drawing 75 to 125 battery amp and 200 to 300 motor while >accelerating and 75 battery ampere or 200 motor ampere at 45 mph. > >I try the Uve Rick's EV Calculator and its way off on the Lithium >battery with a EV weight of 5500 lbs. The 1st gear range is listed as >616 miles, the 2nd gear range is at 582 miles, the 3rd gear range is >537 miles, and the 4th gear range is 495 miles. I think if you delete >the last digit in each number, it will be closed. > >At one time we had a formula to give a estimate range or is there >another range calculator that can be use? > >Roland > ----- Original Message ----- > From: Lee Hart via EV<mailto:[email protected]> > To: Electric Vehicle Discussion List<mailto:[email protected]> > Sent: Thursday, July 31, 2014 12:48 PM > Subject: Re: [EVDL] Lithium battery setpoints... > > > Michael Ross wrote: > > In air, aluminum oxide forms nearly instantly. Therefore, sanding > > is a useless activity, if the goal is to remove aluminum oxide... > >You're right; aluminum oxide forms very quickly. However, the longer it > > is exposed to air, the thicker the insulating layer gets. So cleaning >the terminal to remove the oxide immediately before assembly minimizes > the thickness, and thus *does* reduce the resistance. > >Very thin insulating layers behave strangely. First, the very thin >oxide > layer is porous; it has lots of holes. Like spray painting something; >before you have enough paint to completely cover, you can still see the > >underlying surface through the holes. With enough contact pressure, the > > metal can deform in to fill these holes to make contact anyway. > >Electrons can also "tunnel" across very small gaps even when there is >an > insulator in the way. The contact resistance doesn't go from 0 to > infinite as soon as there is a tiny layer of some insulator; it > gradually rises as the layer gets thicker. > >> I don't like the idea of sanding terminals. You want then to have >the >> flat machined surface they have leaving the factory o get a good >bolted > > joint with as much contact area as possible... > >What you think is a flat machined surface is actually a mountain range >under a microscope. Machining, sanding, polishing etc. just reduces the > > scale of the mountains. > > When the two surfaces touch, only the peaks actually make contact. >Increasing the contact pressure makes the metal deform, flattening the >peaks, and improving the contact area. The deformations also break any >oxide layer that may have formed, if it's thin enough and weak enough. > (Aluminum oxide is a tough one, because it grows strong and thick). > >If you're bolting together steel, the contact pressures needed to >deform >it are tremendous. But lead, copper, silver, gold, and aluminum are all > > very soft metals -- it takes a lot less contact pressure to make them > deform to improve the contact. > > > I suppose one might prove whether the resistance is changed for the > > better if you have a really good instrument to check it. But this > > will not be your garden variety multi-meter. > >It's pretty easy to measure what's happening yourself. The test is not > difficult. I would urge people to try it themselves. It's especially > enlightening with hard-to-connect metals like aluminum. > >You need a digital multimeter with a millivolt scale (usually 200mv or > 400mv full-scale). And, you need a source of a known DC current of an > amp or more. A 10-amp battery charger with a ammeter will do. > >Let's say you want to measure the resistance of the connections to a >12v > battery: Run the battery down, so it will actually charge at 10 amps. > Connect the charger at a point somewhat away from the battery, so the >will be current is flowing in the wires and terminals you want to >check. >Set your meter to its millivolt scale. Connect one lead to the post of >the battery itself. Connect the other lead to the terminal that >connects > to this post. > >Read the millivolt drop of the terminal, and the charging current from > the charger. Use Ohm's law to calculate the resistance. For example: > > R = V / I = 10 millivolts / 10 amps = 1 milliohm (0.001 ohms) > > Under normal circumstances, 0.001 ohm would be a good connection. But > it's a *bad* connection in an EV traction pack! At 100 amps, it would > have a 1 volt drop, and so produce 100 watts of heat! > >Chinese lithiums I've tested straight from the factory are this bad, >and > sometimes worse! > >If you don't believe that cleaning, bolting, and contact "greases" >help, > try an experiment. > > 1. Get two pieces of aluminum that's been sitting around a long time. > Bolt them together. Measure the torque if you can; if not, use a > socket wrench and apply a "know" force. > > Measure the resistance between them (as described above). Notice > that the tighter the bolt, the lower the resistance (to a point; > then it doesn't matter any more). > > 2. Take them apart. Clean the two surfaces with sandpaper, file, > wire wheel, etc. Clean off any resulting dust. > > Bolt them together again, and measure the resistance again at > several different bolt torques. You will find that the resistance > is lower, at every bolt torque (though it still reaches a point > where more torque doesn't reduce resistance). > > 3. Add any kind of contact "grease". Noalox, axle grease, vaseline, > etc. Repeat the test. You will find no difference in resistance, > with or without the grease, no matter which one you use. > > But... leave the bolted pieces of aluminum outdoors for a while, > where they will get hot/cold/wet/dirty etc. Without the grease, > the contact resistance will go up. With the grease, it will stay > about the same. > >This is a complex subject. I hope I have not oversimplified it too >much. > The experts already know it, and can ignore my analogies. But I hope >those with only a little knowledge may gain some understanding. And, I > hope people will *measure it for themselves*. That's far better than >listening to experts debating how many electrons can dance on the head > of a pin. :-) > -- >The definition of research: Shoot the arrow first, and paint the target > around where it lands. -- David Van Baak > -- >Lee Hart's EV projects are at >http://www.sunrise-ev.com/LeesEVs.htm<http://www.sunrise-ev.com/LeesEVs.htm> > _______________________________________________ >UNSUBSCRIBE: >http://www.evdl.org/help/index.html#usub<http://www.evdl.org/help/index.html#usub> >http://lists.evdl.org/listinfo.cgi/ev-evdl.org<http://lists.evdl.org/listinfo.cgi/ev-evdl.org> >For EV drag racing discussion, please use NEDRA >(http://groups.yahoo.com/group/NEDRA<http://groups.yahoo.com/group/NEDRA>) > >-------------- next part -------------- >An HTML attachment was scrubbed... >URL: ><http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140731/05a8f629/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) _______________________________________________ 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)
