the "Daily Drive" thread - December 2007

[MetroMPG]

My brother called me up to help with a job just outside of town this afternoon (self-employed natural gas technician / HVAC guy).

So I got to fire up the Blackfly and take it out to try to get the most recent layer of rust off the brake rotors.

25 miles, 74.6 mpg (US) round trip. -3C, partially snow covered/wet roads, but fairly ideal traffic conditions (mid afternoon).

This was on a cold start - he was planning to pick me up, but had a change of plans, so I had to go without having had the EBH plugged in.

The "cold car penalty" was clear: I was having a really hard time getting it over 60 mpg until about 1 third of the way into the drive.

You people with short commutes & cold weather must be hurting.

Oh, and that's with the alternator on.

[SVOboy]

Uh oh! Alternator on...

You ever going to rig something up to charge the batt? Solar schmolar?

[Lazarus]

That really outstanding when you consider the temp, cold start, road condition and driver rustyness (is that a word). You could probably figure a conservative 15% handy cap. That would put you in the mid to high 80's.

Still mid 70's in winter that's fantastic.

[MetroMPG]

It's not really the battery concern right now - it's the belt. I made up about 4 bungee belts this summer. They usually don't last very long, and I used up my last one a couple of weeks back. I just need to make a new batch.

Ideally, I need to put in an electric motor to drive the water pump - it'll be much easier on the belt.

[MetroMPG]

Laz: only possible today because of the trip length that let the car warm up & loosen up. Check my fuel economy last winter: it was 59, because the majority of the trips were short - let's say about 5 km each way.

[SVOboy]

Let's not forget you have the FS now as well,

[DifferentPointofView]

yea, I have a question. What type of battery are you running on?

[MetroMPG]

In which car? ...

The ForkenSwift runs on 8 golf cart batteries: 220 amp hour, 6v, flooded lead-acid.

When I run without the alternator in the Blackfly, I use 2 of the same type of batteries in series (for 12v), then paralleled with the stock 12v starting battery.

[DifferentPointofView]

I was just wondering if you used a high performance battery that's designed to run for many hours. I don't know if it's the same for batteries, but when you wire (DC wiring) 2 things together in series it cuts the amount of power in half. The opposite for Parallel.

[MetroMPG]

Well, a flooded lead-acid batt is designed to run for many hours, but I don't think anyone would call it high performance (relative to other battery chemistries).

---

Today's fuel consumption: 26 mpg (US). You read that right.

Ironically, that abysmal number is the result of the car's emissions test, running up and down on the dyno a bunch of times, and from idling while they were doing their thing.

The only day I had worse FE was when a vacuum line split, and the engine stuck in open loop.

OK, I'll admit I had a big part in the lousy numbers: I drove it super-inefficiently on the way to the garage, because it's only a couple of km away, and I needed to make sure it was hot for the test. So, I went in 2nd gear, at high rpm, with my left foot on the brake the whole way there. It was good and hot when I arrived, but my mileage was in the 30's.

Pulled off an even 100 mpg (US) on the way home (hot car, dry roads = easy to do), but even that couldn't salvage the day!