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Discussion Starter · #1 ·
Am I right in assuming that there is an independent 12V starting system, so normally the hybrid battery pack is only chargeable from the engine? Apart from the issues of battery maintenance, does anyone see any benefit in topping up the battery overnight? What is the typical state of charge at the end of a journey for people? What's the fuel equivalence of that amount of charge? (or any pointers to places where Civic owners have been playing these games already?)
 

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Couldn't you do this with some kind of engine warmer system. Not even sure that is the correct name for the thing in English. Do ppl even use those anymore? Had it on my old Mitsu at least. Was nice for those cold winter mornings. Don't really think about it much now as I have a garage.
 

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My grandmother still has a block heater cord "engine warmer" but she lives near the UP in Mich. I don't see them in the south often but in the far northern areas with the harsh winters its almost necessary

I don't think this car is going to have any issues and since it charges on the go you should have no worries with the battery. Over charging a battery is never good for its life anyways
 

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I'm still kinda curious how the battery will hold up in the winter here though. Anyone had any experience with the Civic Hybrid maybe? I at least like to top off my starter battery with a charger when it gets really cold out. But then again the CL9 has a super small starter battery.
 

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Discussion Starter · #6 ·
I don't think this car is going to have any issues and since it charges on the go you should have no worries with the battery. Over charging a battery is never good for its life anyways
That wasn't really the concern I had. It was more in terms of saving money by burning less petrol. The gain clearly depends on the balance between charge/discharge and how much electric assist is provided.

I am assuming that at times during regular driving, the electric assist will not occur because the battery is depleted. Normal use will charge it up again at the next bend/junction so usability is not really affected.

As an example, assume my journey to work goes over a hill, drains the battery 100%, but only charges it 50% (standard engineering efficiency assumption). When I come to drive home, I only get assist half way up the hill, and get home with the battery reading 50%. If I top up the battery overnight, it will save some fuel.

Question is really how much? What does it take to drain the battery in terms of full-load driving? Is the system balanced so it never usually stops providing assist, or does charge vary between 0 and 100% quite frequently? Is battery capacity a limiting factor?
 

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I'm still kinda curious how the battery will hold up in the winter here though. Anyone had any experience with the Civic Hybrid maybe? I at least like to top off my starter battery with a charger when it gets really cold out. But then again the CL9 has a super small starter battery.
Winter is no problem.

The TSB updates I get for my Civic Hybrid are all related to preventing heat buildup. The current 2011 Civic Hybrid losses 2 mpg on the EPA highway over the new software updates :glare:
 

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Winter is no problem.

The TSB updates I get for my Civic Hybrid are all related to preventing heat buildup. The current 2011 Civic Hybrid losses 2 mpg on the EPA highway over the new software updates :glare:
Sounds good. Heat is not a concern where I live really :p Bergen is apparently one of the places on the planet where it rains the most, and if we get another winter like the last one I'll have to look into getting som tracks like Ken Block had on his winter scooby :p
 

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Am I right in assuming that there is an independent 12V starting system, so normally the hybrid battery pack is only chargeable from the engine? Apart from the issues of battery maintenance, does anyone see any benefit in topping up the battery overnight? What is the typical state of charge at the end of a journey for people? What's the fuel equivalence of that amount of charge? (or any pointers to places where Civic owners have been playing these games already?)
There would be an advantage to topping off the IMA. In normal driving the IMA charge fluctuates between 3 and 8 bars. At 8 bars the IMA is full and regenerative braking is disabled. At 3 bars the IMA stops providing assist - the 3 bars are kept for starting power, traffic jam power, etc. Once you reach 3 bars the engine controller uses some gasoline power to recharge the IMA. [It is more complicated then just charging directly up to 7 or 8 bars; the charging comes and goes depending on driving factors.] So, if you topped off each evening you would save the gasoline for recharging.

How much is the saving? It could be computed from the energy stored in the battery and the gasoline equivalent, after losses, needed to provide that much energy. Besides computing it, I don't know how to measure it given that the IMA charge fluctuates so rapidly while driving. In practice I can see the instantaneously MPG drop by about 5 MPG when one unit of regeneration is provided by the engine. Haven't timed this to get a measure of the cost for a recharge.
 

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The CR-Z IMA battery has 100.8 VDC output, and 5.75 Ah capacity. That equates to 579.6 watt-hours, or 2.086 MJ (megajoules).

Gasoline (with 10% ethanol) has 33.18 MJ/L. That means the battery stores the equivalent of 0.063L of gasoline, or 2.126 oz. Mind you, the gasoline motor is approximately 25% efficient whereas an electric motor is approximately 80% efficient (worst case).

The point I'm getting at is that even if you had a completely depleted battery, you really wouldn't gain too much energy by plugging into the grid.
 

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Discussion Starter · #17 ·
Yes, I kind of figured out that this battery is not really large enough to provide much savings. Maybe 0.5l out of a tank, £0.70 per week in my case (and this is optimistic).

I think the only value is really in battery conditioning, unless you were to more than double the IMA capacity.
 

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