Battery Fan Upgrade Project

[thunter]

Googling for the part numbers Eli posted in the first message I ran across these at onlinecomponents.com

All are 120 x 120 x 38mm, ball bearing, 12V

Delta FFB1212VHE-F00 1A 12W 3200RPM 151.85CFM 53dB $16.07 125cfm@.24" pressure.
Delta FFB1212SHE-F00 1.5A 18W 3600RPM 170.92CFM 56.5dB $26.40 145cfm@.24"
Delta QFR1212EHE 12V 1A 12W 5000RPM 173.83CFM 59dB $18.86 130CFM@.24"

The Delta datasheet also lists a QFR1212GHE at 1.8A and 210 cfm, showing 180cfm@.24" pressure, $ 18.86 but they are out of stock.

The last one(QFR1212EHE) appears to be a higher pressure fan as they can reach .8"+ whereas the others top out lower. That along with the fact its only 1A so I can run it off my grid charger makes me lean towards it. The only thing I am not sure about is the 5000rpm which seams rather high.

Any thoughts?

Todd

[Willie Williford]

If you are replacing the fan with a higher cfm,:

Computer Fans and Computer Fan Accessories - FrozenCPU.com *

I ordered from them. Good prices and fast delivery.

Willie

[Rush]

At one point I installed 2 fans since the bat pack I had didn't have the plastic shroud. I had no way to measure what the actual cfm was and had no way to compare it to a shrouded pack, so no conclusions possible. Sorry about that.

You would think that it cooled better since there was more air being pulled thru the pack.

One of the problems I see, when everything is back in place, IPU, carpet etc, is that there is no clear way for the air that is exhausted by the fan to exit. It is sort of blown all over the place, there are exit holes in the IPU, it can exit thru the bottom of the alum tray the pack and dc/dc sits in, but there is no dedicated exhaust tube like for the DC/DC fan.

Maybe we could hook into that tube? (as long as it has a filter in it to keep the rodents from coming and getting charged up on the battery...)

[Rush]

Originally Posted by Willie Williford

If you are replacing the fan with a higher cfm,:
Computer Fans and Computer Fan Accessories - FrozenCPU.com *
I ordered from them. Good prices and fast delivery.
Willie

Next fans I'm going to get will have LED's, that way at night, since I have my IPU off, the back will be lit up.

[Willie Williford]

Need some discussion on the temps. of the battery.

What is the difference between the radiant heat temperature of the batterys and the air temperature as it exits the suction cooling fan?

Thanks
Willie

[Eli]

Unfortunately I didn't end up completing this project in the fashion I wanted. I do have all the fans. Some of them are VERY big and beefy.

The one universal with this is that you're going to have to hack up the fan for it to fit. All of the lower flange material needs to be ground down so it will fit into the stock manifold.

Short of modifying the fan, I think running the fan whenever the car is on is the easiest step towards keeping the battery cool we can take.

I'm curious on the details of your fan failure though; they have a MTBF of 30,000 hours, so really should be good for the life of the car - even if run whenever the car is on.

[Eli]

Originally Posted by Willie Williford

Need some discussion on the temps. of the battery.

What is the difference between the radiant heat temperature of the batterys and the air temperature as it exits the suction cooling fan?

Thanks
Willie

It depends on how hot the batteries are and how hot ambient is, but I've noticed an 8-12 degree temp difference across the pack.

IE: if the intake air is 75 and the pack is 90, the outlet air will be ~85.

[Rush]

Originally Posted by Willie Williford

Need some discussion on the temps. of the battery.
What is the difference between the radiant heat temperature of the batterys and the air temperature as it exits the suction cooling fan?
Thanks
Willie

There are a number of variables to consider 1) Actual temp of bat pack, 2) temp of air coming into bat pack, 3) cfm of air being moved thru bat pack, ie Fan HI/LOW, 4) heat being generated by bat pack charging, 5) heat being generated by bat pack discharging, 6) amount of external heat being applied to bat pack by Sun, other adjacent components. Those are just 6 that I can think of off the top of my head.

It's sort of like trying to figure how how many btu's a house needs to stay at 70 deg, there are many variables (how many cubic ft, wall R values, window U values, ceiling R values, Floor R values, is the floor a poured slab, is there a basement, how many square ft of west north east and south facing windows, how many people in the house, etc.) to be considered.

And while there may be an average temp differance in one area, that difference maybe totally different than another area. Here in Tucson, the beginning temp of the battery pack is very dependant on how long the car has been parked, is it in the sun/shade? are the windows open/closed?.

As an example, here in Tucson, if it was a 40 deg night, and in the morning the car has been sitting in the sun for a couple hours with the windows closed, the battery pack temp might be 80 or so degrees. If the car has been sitting in the shade for a couple hrs, the battery pack temp might be only 50. If I don't care about the pack temp, when I start the car I might turn on the heat, further heating the battery pack.

Just my 2 deg (C) worth...

[Rush]

Originally Posted by Eli

IE: if the intake air is 75 and the pack is 90, the outlet air will be ~85.

Eli - I have a temp sensor that I've mounted to my fan outlet and it reads within a degree or 2 of the temp that the OBDII reports for the pack temp.

[Eli]

Originally Posted by Rush

Eli - I have a temp sensor that I've mounted to my fan outlet and it reads within a degree or 2 of the temp that the OBDII reports for the pack temp.

I think we're talking about different things here? I thought he was asking what the temp rise of the air is as it passes through the pack. Like you said, there are a lot of variables.. The 8-12 degree figure was just a few observations over the course of a few weeks last summer, so it's by no means comprehensive.

Re-reading his question, I understand now. I haven't had the outlet air temp sensor mounted in a while, so I'm not sure.