I want to charge the battery that comes with the Prius.

I want to charge the regular battery that comes with the Prius so I can start off in the morning with a full battery. This shouldn't be too hard to do. I was thinking maybe a switch to disconnect the battery from the car and than into the charger. A trickle charger could be very small and automatic so it wouldn't over charge the battery.

Or the charger could be connected to the battery without disconnecting it from the car. This would allow it to keep the water warm and to keep the 12 volt battery charged.

I can see that the main problem would be driving off with the car still plugged in.

Does any company make such a thing?

I don't think it is worth the effort or the risk. Just drive it.
The battery of your Prius holds about the equivalent energy of 2 tablespoons of petrol.
If you drive properly your battery will be almost fully charged when you put it away at night anyway.

Just curious: What are you trying to accomplish?

Those batteries hold more than 2 tablespoons of gas worth of energy. It should increase fuel mileage if you could top up the charge every night. This is a great idea.

But the software in the car would run the engine anyway to warm up the catalytic converter. Plus the car doesn't like a fully charged battery and will spin the engine trying to get it down. Most plans to plug in a Prius is to add batteries to make it worth while.

Pris battery capacity 1310.4 Watt/Hours
1 watt hour = 860.42065 calories
1310.4 x 860.4 =1,137,468.16 calories
a gallon of gasoline contains about 31,000,000 calories
1 US gallon = 256 US tablespoons

31,000,000/256 = 121,093 calories in 1 table spoons of petrol

121093 x 9 =1,089,837
[SIZE=+1]Sorry, your right, it is about 9 tablespoons of gas or 133ml.[/SIZE]


now the battery in your Prius only uses 60% of its total capacity so reduce that to about 60% and you have 6 tablespoons or 80ml.

Now I doubt you will pull up your driveway every night with a flat battery or more correctly a battery at 40% charge so lets assume that on average your battery is at 50% of the usable range of charge, you can fit in an additional 3 table spoons worth of energy.

Yep, sorry I was wrong, on average you can put 3 table spoons gas equivalent energy into the battery each night without causing harm to the battery.

Now when a Toyota dealer needs to charge a Prius traction battery they need to get a special charger from head office sent to them, they don't have one in their store because it is so expensive I believe there are only 2 or 3 in the mainland USA. What will your battery charger cost?

No, it's not a good idea. The mileage gain would be unmeasurable, and the cost and complexity very high. You aren't talking about a 12V lead acid battery. This is a couple of hundred volts of sophisticated battery. You will end up killing yourself, the battery, or setting your car on fire, all to save a quarter cup of fuel. It's just not worth it.

Tom

The OP was talking about the 12V battery. He won't kill himself, but it's still not worth the trouble. Given the conversion losses of a 12V charger and amortizing the cost of the charger it's not obvious that it would save any money or reduce his carbon footprint.

How did I miss that detail? I'm going to blame it on my daughter's wedding. The ceremony was on Saturday, so I'm still in a post wedding haze induced by too many house guests, significant amounts of alcohol, and large expenditures of cash.

Tom

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And you still think oil is dear at $4 a gallon when 1 galllon of gasoline contains about 31,000,000 calories
How many Big Macs is that?

82.

One number for the Big Mac is 576 Calories, (aka kcal). Don't forget that food energy value is generally given in thousand-calorie units, inconveniently also called Calories, though if you are lucky they might get capitalized.

Well, if it's the 12 volt, I suppose you could put solar panels on the roof of the Prius and set it up that way. I believe other owners have done that.

patsparks,
That is Watt*Hours, not Watt/Hours.
And remember the usable energy in gasoline in an Otto cycle gasoline engine is about 20%, so multiply times 5. Otherwise, your conversion constants were good.

archae86,

Like IC engines, your body muscles are only about 25% efficient in converting the calories into useful motion, the rest going to heat.

I'm beginning to think the Chevy Volt series hybrid method is the better way, since you don't need the weight of a transmission, and the complexity goes down for customization (more modular separation of engine and battery charging there). The Prius parallel hybrid arrangement is a complicated torque engine/electric blending circus along with battery charging strategies that don't make it easy to tinker with as much. I've heard the auxiliary battery installation jobs run around ten thousand or so. Ridiculously overpriced, but probably necessary.

He is definitely operating under a few misconceptions.

First off, keeping the 12v aux battery will NOT keep the water warm. Period.

Secondly, he's confused about which battery he's viewing in the bar graphs, thinking he's seeing the 12v battery charge.

Thirdly, a trickle charger at 12v, either 2 amps or 6 amps or 15 amps will not charge the Main battery at all, the applied voltage is way too low, not to mention there is no facility at which to apply the charge.

AND FINALLY....

For argument's sake, if he could do such a thing, the battery would be back to it's fluctuating normality within a mile.

This is definitely a zero-sum game.

ZC1

Again, the auxilliary battery removal and installation is free. You can do it yourself in less than 30 minutes. Honestly.

You must mean the Main Hyrid battery.

But even that installation doesn't cost near 10 thousand dollars.

ZC1

OK - there are two batteries, the 12 V and the HV. one is to the right of the trunk, the other is bellow the passenger seat. Locate both of them and remove all protective covers. Start touching the exposed contacts - if you die - you have identified the HV battery.

ah the quest for ever better mpg. The quest to sop using the ICE and just plug in.

If they can build a tesla sports car they can build a plug in Prius. The question is how expensive is it? The costs have to come down as we cannot afford the initial costs whatever the long term savings right now.

Im in my mid 50's and have a new 08 Prius. I would be willing to wager that before I trade the Prius, maybe 6 years or so, that batteries will have undergone tremendous advances and drops in cost making a plug in not only possible but affordable for most.

What a rush that will be!