Daox's 2004 Toyota Prius Build Thread

[Daox]

Ben Nelson was very kind and let me borrow his scangauge until I get a replacement. Thus I was able to monitor my coolant temps this morning. I can definitely tell a difference. I was up to 150F a lot sooner than I normally am. It normally takes ~2.9 miles to get up to 150F. This morning (which is just as cold as it has been any other morning) it took roughly 1.5 miles to get up to 150F. This is a vast improvement. I only hesitate to say its amazing since it was the first trip with the grill block that I could actually measure.

I also figured it would be a good idea to monitor my 12V battery since they are known to go bad after ~4 years and its now winter, so capacity will be decreased. I turned on the scangauge before turning the car on to see that the 12V was at 12.1V! Looks like that is going to need to be replaced. Thankfully, owners of the Prius usually notice a mileage increase after replacing the 12V. So, at least there is something to look forward to.

[bwilson4web]

One thing I like about your approach is the space behind the shield for:

• plug-in socket - an all weather socket with cover
• sensors - a set of distance measurement devices. I don't know if ultrasonic sensors can 'reach out' to vehicles at highway speeds. IR lasers would be another approach. Think 'homegrown' adaptive cruise control and accident mitigation.

Bob Wilson

[bennelson]

Today was also the first real snow of the season. Just enough that I actually have to go shovel the driveway. Not exactly sure how that will effect Prius fuel economy.

I also love to steal car design concepts from the Prius. On my bio-fuel pickup truck project, I am going to try to integrate a "coolant thermos" in it.

Doax's mods always look really good. His grill block looks almost stock.

[orange4boy]

Daox,

It seems to me that the Prius battery suffers from one or both of underuse and undercharging. I'm starting to think it's underuse. It's too bad that you can't get in to it to do an SG reading.

Compared to a regular car battery which gets a big drain every time it's started, The Prius battery gets a small draw for just a few seconds. Not enough exercise. The batteries that I discharge and recharge almost every day are healthy as lead horses.

Before you give up on it, a good bit of exercise might revive it like your Paseo's deep cycle. At least a good equalization charge would be in order.

If you do replace it are you going to go yellow top, stock or other aftermarket?

[bennelson]

Does the Prius us a "standard size" battery, or something smaller?

Maybe you could rotate batteries from one vehicle to another every once in a while?

Otherwise, maybe throwing a load on the battery and then a full charge from a good charger may help.

[bwilson4web]

Originally Posted by Daox

. . .

I also figured it would be a good idea to monitor my 12V battery since they are known to go bad after ~4 years and its now winter, so capacity will be decreased. I turned on the scangauge before turning the car on to see that the 12V was at 12.1V! Looks like that is going to need to be replaced. Thankfully, owners of the Prius usually notice a mileage increase after replacing the 12V. So, at least there is something to look forward to.

The OEM battery has a "DO NOT REMOVE" sticker and under that is a plastic cover for the six, filler holes. I got another year from my OEM 12 V battery by adding a little distilled water to cover the tops of the plates and then reassembled. But you are about due.

I replaced my OEM battery last January with an Odyssey PC925. A little expensive but I wanted a battery with 10 years of life. The tricky part is the 'metric' posts on the OEM battery.

In my case, I made two short jumpers, heavy gauge wire, and bolted them to the bolts on the ground and battery B+ assembly. I'll post photos if you're interested.


FYI, I didn't see any change in MPG after replacing the 12 VDC battery. However, there is a lot of information showing replacement of the traction battery gives a solid mileage boost for 3-4 months.

Bob Wilson

[orange4boy]

Mine is an aftermarket maintenance free floodie with a standard warranty. They probably do make one for the 2004+ models and would be cheaper than the other two options.

Those yellow tops do seem to be the cat's meow though. I have on in my van as the short run / backup battery. Got it free at the recycling depot.$ I have a friend who swears by them and has a 10 year old one in his truck. My electrak also has the X-large yellow tops which are probably 8 years old and still very juicy.

Does anyone have a long term report on the yellow top in a Prius?

[orange4boy]

Does the Prius us a "standard size" battery, or something smaller?

It's a wee one all right. I think the posts are reversed from gen1 to gen2

[Daox]

Thats an interesting theory about the battery being underused orange4boy. I'd love to test it to see if could revive it. Perhaps I'll rig up another battery for the time being and see what can be done with it. I'd also like to try adding water like Bob suggested. I'm all for prolonging the life of the battery. 4 years does seem short for a battery that doesn't see much action. I just have to rig up something reliable since its really our main car.

If all that fails, I was planning on going to the yellow top. The design is superior, capacity is a bit higher, and it should last longer.

[bwilson4web]

Just check your dimensions. I went with the largest Odyssey battery that would fit in the space:


The jumpers solved the problem very nicely.

You'll notice the "DO NOT REMOVE" cover didn't quite go back as nicely as before but the battery recycler didn't care. <GRINS>

Bob Wilson