> > >>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.
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. How old are your batteries? Are you keeping them equalized? An unballanced pack (or an old one) will go empty sooner. Also it's natural for your batteries to be able to produce less current, even at 50% DOD, than they do at 100%. > > >>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). 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.
