Tuesday, September 15, 2009

Charge Management

As I have gotten better and better at exceeding the EPA mileage rating for this car, I've learned more about how the
battery charging system works. And, how to maximize the charge, or as the title of this entry "Charge Management".

One thing I noticed pretty quick, you can get some incredible mileage on short hops to a store and back. But, what was
happening was that I would leave with a charged up battery, and return with the charge quite a bit lower. So the mileage
figure wasn't accurate. So, keeping that charge up is important.

Now, what happens if one just depletes the charge. As stated in an earlier entry, eventually the gas engine comes on and
runs for a few minutes to charge the battery back up. I've noticed that this happens in two different patterns.

The first pattern is this: the engine comes on and runs until the battery charge is a bit higher then midway on the gauge. This seems to be quite precise and the engine shuts off at the same point each time. Once the charge line gets to the top of the "+" and "-" signs on the gauge, you can run in electric again.

Now, as I said, there is a second pattern of charging that occurs. I'll call this a "deep cycle charge". What happens here is that the engine keeps charging until the charge is at the top of the gauge, quite a bit higher then the former charge cycle.

This charge cycle seems to come on every day at some point, when I'm doing around town suburban driving. I talk a road trip on the highway today, and it did not come on at all, probably because the battery tends to stay charged up in highway driving.

6 comments:

  1. Interesting. My FFH doesn't do this, once its warmed up I can just let off the gas and the engine will shut off. I don't tend to run my battery way down though as I think it reduces overall mileage.

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  2. This is an interesting and challenging car to figure out. Sometimes this happens when the battery is not depleted. It may be over half charge and yet the engine will come on and run and run until the charge is way up close to the "H". It's like it wants to fully charge the battery. Have you never seen your FFH do this cycle, I didn't notice it myself at first but since I have seen it do this many times.
    Fusion Hypermiler

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  3. I have never seen this behavior except when the engine is cold. Once its warmed up, my engine always shuts off when I let off the gas under 47 mph.

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  4. Question: have you been trying the hypermiling thing on some of your drives and if so what kinds of mileage figures are you getting. I find this activity addicting and reset the MPG thing just about every time I go out just to see how I can do.

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  5. Yes, I also have a blog at http://ffh.squarespace.com where I've talked about my mileage.

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  6. Sounds great. I will definitely check out your blog on Monday. Back to you later.

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