----- Original Message ----- From: "Peter VanDerWal" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Sunday, September 29, 2002 9:28 AM Subject: Comparing Range (was Re: Electric Datsun Pickup For Sale)
> > > > > >>I run a 19 mile commute (slight uphill almost the entire way to work). > >> > > > >I have a 15 mile commute, with just a couple dips/hills in it. > > > >> I've had a battery die recently so I'm only running 14 T-875s right now > >>(112V pack) and (according to the e-meter) it takes between 50 and 60% > >>DOD for the commute. Back when the batteries were newer and I had all > >>120V it typically took less than 50% usually close to 40%. > >> > > > >I am using about 50 amp/hours on a warmish day, which if my batteries are > >225 amp/hr. means that I am at approx. 80% DD - or am I figuring wrong? > >The E-Meter indicates that I am close to that, and I have a harder time > >maintaining the 55 MPH speed limit at the end. Most of my commute is at > >55 - 60 MPH, with about 4 miles at lower speeds through town. > > > Hmm that's a bit higher than me. At 112V I typically use approx 45 AH. > A bit over 1/3 of my commute is at 35 mph with the remainder at 50-55. > Your higher average speed and heavier truck account for some of the > difference, but still. > You appear to be averaging 366 watt hours per mile (from the battery > pack), that seems rather high to me ( I average around 260). You might > want to try jacking up each corner of your truck and seeing how easily > the wheels spin, something might be sticking/dragging. I have thought about this before, and will do it soon. > A 225AH battery should be good for at approx 125 AH at the 1 hour rate > (100% DOD) so your 50 Ahs should only be about 40% DOD. Whoa, here - I thought the idea was not to draw them down more than 20% of the full voltage -- that point being 80% DOD. How old are > your batteries? Brand new - they have less than 40 cycles on them. Are you keeping them equalized? I generally run an equalization charge every 10 or so charges. > >>My longest trip, back then, was 32 miles with the emeter reporting 18% > >>remaining. Though to be honest I couldn't go much over 30-40 mph uphill > >>(slight) without going below terminal voltage though it could still > >>maintain 45-50 on the flats. > >> > >>My truck weighs approx 3200lbs, it has Bridgestone Pontenza RE-92 tires > >>(LRR I think) and Royal Purple transmission fluid in both the tranny and > >>the diff. > >>Even for a small truck, my pickup is small. It's about 63" wide at the > >>widest and 64" tall at the talest with at least 7" ground clearance. By > >>my reconing that means it's less than 25.5 sq ft frontal area. > >> > >>Oh yeah, I have a GE motor and IGBT controller, which means a good motor > >>but (theoretically) a less than optimally efficient controller. > >> > > > >I'm using a ADC 9" with an Auburn Scientific Kodiak controller, which is > >water- > >cooled. > > > >> Towards the end of my commute I'm down to less than 200 amps. > >> > > > > I have a lot of stoplights and stop signs (about 8 of them!), so if I hit > >them all > >wrong (which happens occasionally!), I will have a lot of accelerations. I > >get up > >to 350 amps on accelerations from a standing stop, but typically draw less > >than > >150 when cruising, except toward the end of the run. The last several miles > >it > >takes 200 amps or a little more to maintain 55. > > > > Perhaps the difference is driving style then. I have the same number of > stops, but only three of them are on the high speed portion. I can only > get 350 amps from my pack right at the begining so most of my > acceleration is at 250 amps. This is a bit slower than average so I try > to watch the lights and time them. I frequently start braking 1/4 mile > or more from the lights so it gets a chance to turn back to green before > I get to it, that way I don't come to a stop very often (except at one > light). I do this also, but the lights are not timed - they are sensored; so you can't do it that way and get by with it all the time! > Going to work (uphill) usually takes close to 200 amps to maintain 50 > mph. Coming home (downhill) takes 120-150 amps to maintain 55. > > FWIW the hill is just steep enough that I can coast at approx 30mph most > of the way home, if it wasn't for things like lights and traffic. Last > year when my pack was in better shape and my commute was slightly > shorter (appox 18 miles...because of 9/11 portions of the post are now > closed off) I managed 36 AH for the trip once. I hit all of the lights > right going both ways and on the return trip I'd only use the motor to > accelerate from 50 to 55+ and then coast untill it dropped to 50 again. > I just wanted to see how low I could get it. I think that the toolbox protruding beyond the sides of the cab is probably part of the reason I don't get more range; I also haven't pushed it very hard, so I could maybe get some more out of it; but I don't want to abuse the batteries this time :)! Joseph H. Strubhar E-Mail: [EMAIL PROTECTED] Web: http://www.gremcoinc.com
