06/09/07 - Houston Prius EV + EBH install

[Dan]

On Saturday June 9th I will attempt a Factory EV install and Engine Block Heater install. If anyone has wanted to see one of these procedures, next weekend might be your chance.

I can't guarantee success, but we (my neighbor and I) will give it a shot. I've done some recon on this today and was able to pull the ECU plug and also found the spot for the block heater. I've got the wire taps and assuming I can fit the ECU pin in and fish it the wire across the dash, I should be in good shape.

The block heater is a Toyota of Canada model and the EV is the Japanese Factory model.

Just email, pm, or post to this thread if you want to assist in the surgery.

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[xcel]

Hi Dan:

___I have seen the OEM EV Button install pics and it looked really easy. The EBH is Wayne Mitchell’s forte’ but it is a simple well. It is getting it in there and rotated properly that looks tough

___Good Luck with the installs.

___Wayne

[Dan]

Ohh yeah... I made a blog entry with the procedures so everyone can read ahead if they want.

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[Dan]

OK... First the good news... EBH works and OEM EV works. .

Now for the bad news.

1) First stab at EV button wired it exactly, and perfectly backwards . Surprisingly, to me at least, backwards still works. Only problem is you won't get LED. Well I didn't like a ground reversal hard wired to my ECU so out with the wire clips, mosquito spray and camping lamp. Now everything works great.

2) Didn't quite get the suggestions on the EBH install right and tried to install it with the rod plugged into the cord. Well with that extra inch of coupling, the block heater won't fit. So after a quick call to FireEngineer I was informed of my error, and got it installed, then plugged in. Problem was the thermal guew went on, then off then back on since I had to re-approach the install path twice. Don't know how much effect it will have. It does work, just don't know if it could be working better.

3) To fish the cord to the grill, I took off some underplaying. In the process I stripped a nut There was a small rock that had fallen right at the thread entrance, and while I took the nut out, the rock scored the threads. So now nut 2 from the left headlight is replaced with one bright yellow tie cord.

Tests:
EV - Start the car, hit the switch and you get the popdown on the MFD "Cannot switch to EV" cuz I'm in stage one. So it works. LED now works too

EBH - It was about 90 ºF (32 ºC) outside when I plugged in the EBH and left it in for 60 minutes. The water temp (via SGII) gradually went up from 107 ºF (42 ºC) to 135 ºF (57 ºC). So about half a degree per minute.

Questions:
Is anyone running the EBH in the summer? Do you have any data to share as far as what type of measured heat exchange your seeing. If mine is low, I could consider re-installing it, but it's not something I'll do on a whim.

Special thanks to FireEngineer, mparrish, and my neighbor for providing the much needed assistance.

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[diamondlarry]

I am using mine in the summer. In fact, it's on as I type. I haven't monitored it while it was warming up but I can tell you that, after rolling down my ~.1 mile driveway, the engine will reach 150*-which FireEngineer said was the minimum temp for S4-in ~1/4 mile. On my morning commute I have a stop sign 1/2 mile after that point where I come to a complete stop and let the car do the "idle dance" to go to S4. As Wayne pointed out, and I've seen, the coolant temp will most likely drop shortly after the engine starts because the coolant in the thermos is actually cooler than the engine. This only lasts for a few seconds though. Also, the heater can be left on for as long as you want since it will self regulate but I have mine on a timer. The heating element uses 400W.

[JimboK]

In the lengthy PriusChat EBH thread, many reported the highest block temp reached with the heater was ~140F, regardless of how long it was plugged in. I'm curious as to the mechanism of self-regulation that Larry describes. I think someone suggested it might be controlled thermostatically somehow, though it could be that's as warm as it can get attached to the huge heat sink called an engine block.

Something I find interesting, however: I see a pretty wide range of temperatures after 3+ hours of EBH use. The max is ~140, but I've seen it as low as ~110. There doesn't seem to be any rhyme or reason for the varation -- comparable overnight times, ambient temperatures, etc. Maybe Wayne M. has a theory.

Anyway, as to your question: Assuming it makes it to 140F, that's a lot warmer than the 70s we see in summer mornings around here. So, yes, I plan to use it year-round.

Finally, I've discovered after getting Can-view that there are temperature sensors for both the engine block and coolant, with the CV offering data from both for display. After warmup they're nearly identical, as you might expect, but not necessarily at startup. I haven't watched them closely at startup yet -- I've been more fixated on things like current flow into and out of the battery -- but maybe they'll offer clues on the startup temp variations I'm seeing. Then again, maybe they won't.

Regardless, the Can-view is fun!

EDIT: Oh, and as Larry has observed (and you will now too), the thermos that some insist keeps coolant "hot" really doesn't, not overnight anyway.

[locutus]

Hi Dan,

Congrats on getting the "upgrades" working

I've consistently seen 130-140 as the max temperature if I switch to "gauge" immediately on the SG-II as I power on. Then it will drop to a minimum 110-115 by the time the ICE lights and go from there. In contrast to the 80 degree minimum I see without the EBH it makes a huge difference in terms of when you hit what stages. Even the mandatory S1 (which happens regardless of temps after a startup) can be 10-15 seconds shorter.

[mparrish]

Dan,

Glad to hear the installs went without a hitch. The pains of warmup for you will become slowly fading memories................

I notice a pretty consistent 112F - 120F at startup. I've never seen 140F.

[FireEngineer]

Originally Posted by JimboK

though it could be that's as warm as it can get attached to the huge heat sink called an engine block.

Something I find interesting, however: I see a pretty wide range of temperatures after 3+ hours of EBH use. The max is ~140, but I've seen it as low as ~110. There doesn't seem to be any rhyme or reason for the varation -- comparable overnight times, ambient temperatures, etc. Maybe Wayne M. has a theory.

EDIT: Oh, and as Larry has observed (and you will now too), the thermos that some insist keeps coolant "hot" really doesn't, not overnight anyway.

The mass of the engine block and transaxle connected to it are the means of regulation. And don't forget that the cylinder the heater is installed in is about 2/3 exposed to the rear of the engine compartment. Stick a piece of mineral wool on the back of the engine and see your coolant temp rise.

The temp flux at before startup is a little more mysterious. It seems to be just how the heat has transferred into the block and if the heated coolant has hit the temp sensor when you check it. It's difficult to really determine since the thermos dumps and cools the system, before the coolant has circulated.

One of my experiments, after I fix my block heater (darn body shop) will be to log coolant thermos delta using my morning block heater on and my afternoon block heater off depending on ambient temp and engine shut-off temp. One thing I have noticed is that when shuting down in the morning the thermos cools the block a little recovering the hot coolant.

Wayne