# TF EV

http://www.diyelectriccar.com/

# Electricity costs

assume $0.1/kWhr = 10 cents per killowatt hour

0.3 kWh/mi

http://www.evchargernews.com/miscfiles/sce-rav4ev-100k.pdf

## Del Sol

using the performance documented at http://www.evalbum.com/1250

=> 0.5 kWhr/mile \times $0.1/kWhr = 5 cents/mile

batteries = 18 US Battery US-8VGCHC, 8.00 Volt, Lead-Acid, Flooded = @ $170 each => $3060

If batteries last 600 recharge cycles and you get 50 miles per cycle =? $3060/600/50 = $0.1 /mile

Then total cost per mile is $0.15.

## VW

using the performance documented at http://www.evalbum.com/684

=> 0.3 kWhr/mile \times $0.1/kWhr = 3 cents/mile

batteries = 18 Trojan T 890, 8.00 Volt, Lead-Acid, Flooded = @ $180 each => $3240

If batteries last 600 recharge cycles and you get 50 miles per cycle =? $3240/600/50 = $0.11 /mile

Then total cost per mile is $0.14.

# A posting about miles/charge

70 miles at highway speeds in my force (at 2100 lbs) (a very very efficient ev) is about 52 100ah Lifepos i can do a tad more than 70 (im in waterford, mi) in the winter that goes down 20% with having to use the heat and the cold.

Trackers are not as efficient. You are going to need 48 200ah lifepos to get 70 miles at 60mph no heat.

Heres my math 350wh a mile x 70 miles 24500watts (24.5khw)

24.8 /.8 (to get life from the cells) 80% dod) = 30.6 wkh

30600 / 3.2 (nominal on lifepo4;s) = 9562 / 200 = about 48 cells.

Now, this gives you really nothing in case something happens and you need to go 75 miles so perhaps 52 cells would be better.

so 48 x 200 ah cells = about $12500 shipped

Assuming you can mount them you would have a 70-80 mile ev depending on speed.

I still think you need 52 if you want to drive in the winter and use heat.

make it $13,500 ish for 52.

An example of how efficient the force is:

I have a saturn as well. Its about the same weight.

I use 48ah round trip 54 miles (45mpg max) down woodward and back to waterford in the summer no heat in the force.

With the saturn I use 66ah round trip (same speeds same route same careful hypermiling driver)

Id say the tracker would be 2x the force for watt hours a mile.

# Chevy Volt Generator operation

After a lengthy and healthy discussion about costs of driving the Volt we needed to know at what battery state of charge (SOC) the onboard generator would kick in. GM was kind enough to let us know that was intended to be 50%.

The next question to arise was that once the generator started at what SOC would it stop again as the car continued to drive.

Once again GM has been very helpful and informative and tells us the answer is 80%.

So what do these numbers mean? Mainly it tells us they wish to be very conservative with the batteries. Although A123 Li-ion cells are very robust and can handle repetitive deep discharges to below 20% and up to 100% again, up to 7000 times, GM clearly doesn’t want to take any chances with this very expensive (and possibly leased hardware). By keeping it in this limited range, the hope will be increased reliability and longevity I would have to assume.

Lets see what happens when one drives the Volt.

For the first 40 miles, as we’ve discussed, the battery will drain from full (16 kWh energy) to 50% (8 kWh), this 8 kWh will cost you roughly 85 cents in electricity. If you drive that distance or less, NO GAS.

If you keep driving, the generator will start. It will generate 53 kW of electricity. It needs to restore the pack by 30%, which is 4.8 kW, that would take ~5.4 minutes if the generator was only charging the battery. But at the same time, as the car continues to drive, the battery would continue to drain, so the generator would have to run longer.

GM estimates that in this condition, the combustion engine would provide 50 mpg efficiency.

From what engineering experts in the PHEV/EV field tell me, the battery pack, electric engine, and generator are all on the same bus (not yellow or greyhound folks), which means that one can have current flowing into the battery from the generator at the same time it is leaving to run the powertrain.

This is great stuff, and an engineering process never before witnessed by humankind. Let’s hope it works.

In the coming weeks GM will have the Volt “mules” (cobbled-together, rough and ugly engineering experimental prototypes) up and running with the first gen A123 packs (and CPI). Then these issues will be testable under driving conditions.

Right now, as per Rob Peterson of GM, “the engineers are still working out the optimum charge cycles and control systems”. As per Bart Riley of A123, “The key will be to achieve the life target for the battery across the all operational requirements (temperature, cycling, storage, SOC range)”.

## Fuel consumption

A 30 kW Diesel generator consumes 2.2 gallons per hour

## Generator Vendors

http://www.hardydiesel.com/diesel-generators-7-33-kw.html