FAN Noise during Charging

[georg Kohler]

I was wondering if anybody understands the relationship between the fan coming on when charging and when not ?

Mine has starting doing this a while back - It's "obviously" related to the amount of charging that's going on (Heat generated inside the battery pack) 

- I expect this to happen once in while during the summer times

I assume during charging the fan comes on if the battery pack reaches a certain temperature 

As I mentioned ours started doing this a while back if we start charging at a low level < 50% or below

Now last night it did this at 60-70%  on a charger that can provide 50A  ---- That seemed a bit strange

Question:

How does the battery cooling System (I assume that's what drive this :-) actually work ?

Is it a heat exchange  that's running coolant trough some of the battery compartment(s) or is it just a simple fan system?

It could be just a  faulty temperature sensor

Georg

[Jacob Field]

The Think's battery pack is not cooled except passively, similar to the original Nissan Leaf. The cooling loop runs only through the motor and the PCU (which houses the inverter, charger, DCDC, etc.)

If you want to see photos of the inside of the pack let me know - I've opened two of them before.

I'd guess the temperature sensor that determines whether or not the coolant fans should run is faulty, either that or something inside the PCU is heating up a bunch when it charges. The second option seems pretty unlikely as it would probably break before heating the coolant up that much.

If it were my Think I probably wouldn't worry about it, though I might look into where the coolant sensor is to see if it's an easy replacement.

- Jacob

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[Phil Hochstetler]

The heat being generated is probably in the charger itself (that converts the A/C wall power to the DC power that charges the pack).

It may be why the fans are coming on.  The charger only draws up to 16 amps on 240 so the power is limited to less than 4KW, thus the slow charging.

Phil H.

[georg Kohler]

Thanks for the replies  - that helps a bunch

Quick Question

Does on you're Think(s) the cooling fan ever come on ? mine is really going -:)  very loud ...

I've had mine for +10 years now and I hardly ever remember it coming on

Georg

[Jacob Field]

I've only heard it when I've plugged in after driving freeway on the summer. 

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[Frank Smith]

The temperature sensor is inside the PCU. When driving or charging the pump cools the PCU and motor by circulating coolant through the radiator, motor, and PCU. If the PCU temperature is too warm it activates the fans at low speed. If the temperature gets even warmer the PCU activates the fans at high speed. Normally the fans only run in the summer and typically at low speeds. 

John Mayer suggested removing the low speed resistor as he felt that the PCU should not be allowed to get too warm and the need for a low speed fan means the PCU is already getting too warm. The low speed resistor are also prone to failure which would really cause the PCU to overheat before the high speed fan mode would activate.

Here are my suggestions.

1) verify the coolant reservoir is full.

2) When charging verify the pump is moving coolant. You can typically see the coolant moving in the reservoir with the cap off. With a dental mirror you can see the fluid coming out the small vent hose that runs from the top of the PCU to the reservoir. If the vent is clogged you can get air trapped in the PCU which will cause overheating.

3) place a box fan in front of your car when charging. This will prevent the need for the fans in the car to run and also cool the battery a very little. Replacing a failed box fan is easier and cheaper than replacing a failed car fan or PCU.

Good luck,

Frank

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بــــــــلوم اعداد القيادات الإدارية Preparing administrative leaderships Diploma يعقد اونلاين خلال شهر أغسطس برسوم مخفضة للتواصل واتس / 00201556660922 - 00201009306111

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FAN Noise during Charging

georg Kohler <kohler...@gmail.com>: Aug 07 03:55PM -0700

I was wondering if anybody understands the relationship between the fan coming on when charging and when not ?

Mine has starting doing this a while back - It's "obviously" related to the ...more

Jacob Field <jacobtim...@gmail.com>: Aug 07 04:00PM -0700

The Think's battery pack is not cooled except passively, similar to the original Nissan Leaf. The cooling loop runs only through the motor and the

PCU (which houses the inverter, charger, DCDC, ...more

Phil Hochstetler <phil.hoc...@gmail.com>: Aug 07 04:15PM -0700

The heat being generated is probably in the charger itself (that converts the A/C wall power to the DC power that charges the pack).

It may be why the fans are coming on. The charger only draws up ...more

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coolant replacement interval

Jason Timm <pdx.jas...@gmail.com>: Aug 07 01:59PM -0700 I finally flushed the brake fluid, no signs of water in it. So now I'm thinking about coolant life, our blue 424 FYP is at 70k now. What's the recommended coolant replacement interval? ...more

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Abridged summary of 2011-think-ev...@googlegroups.com - 1 update in 1 topic

"windhon...@gmail.com" <windhon...@gmail.com>: Aug 07 01:12PM -0700 front Brake pads are from Peugot 104 I believe Part # ADB2258   ...more

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[georg Kohler]

Frank

I was wondering about some of the points you've made

-Is the cooling actually Running  = it's hard to see with the car on the ground where the hoses run - but there is one hose that you can touch form underneath -  its doesn't seem like there is any flow   ---

- But then if  that's true (no flow) the motor would most likely overheat while driving -

same goes for low water level ???

Also again just to be clear - this only happens if the Charge level is < 60%  or so  = once the charger reduces the charge current the fans turn off  - meaning the system somehow still works as designed  - it's just that the fans come on much earlier then ever before = every time now when start charging beloved 60% or so whereas before we might hear them once or twice a year (at most)  if my girlfriend came home on a totally  empty battery that is..... :-)

Question:

There seem to be two cooling circuits

A) AC                     Upper (big) fan / radiator)

B) PCU /Motor     Lower 2x smaller fans / radiator)

Are both filled by the same coolant reservoir (Upper right under the hood )  -if so there is plenty of coolant inside the reservoir 

 I'll check tonight if i see any fluid moving within the reservoir

But then again - if the vent would be clogged and we have no fluid moving wouldn't that prevent the system from cooling the motor as well ?

Last question (and I kind of already know the answer :-( )  is there an easy way  of checking the temperature inside the PCU 

where is the pump located that's moving the Fluid  ?

Again I really appropriate all you're inputs

Georg

PS: Also I hate to admit - I never changed the coolant  - we have not done anything to that car except

- Rotating / changed tires

- Replaced the 12V battery a couple of times - including the Positive terminal as it was falling apart... (most (if not all) of our issues owning the car where related to the weak (faulty?)  12V battery charging system)

- Changed the front brake pads

- Added a Multi media radio with Apple play

- Just recently replaced the outer tie rod ends

Odometer shows 65 K

[Jacob Field]

The coolant should be running, there are two little 12v pumps underneath the radiator on the right side of the car, right behind the bumper there. If they're not working, maybe this is causing your problem?

I'm pretty sure there's only one coolant loop, the little line coming form the top of the PCU is for air or something to my understanding. There's a big coolant hose that's hard to see that goes from underneath the PCU to the motor. However I'm away from my car for the summer and can't check for sure.

- Jacob

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[georg Kohler]

I'll check on that tonight 

- Two 12V pumps ?  - that might explain it if they are for two different circuits

Georg

[Frank Smith]

The two pumps are in series. one coolant loop. 

Temperature can be read in the CAN bus messages.

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[georg Kohler]

So I think I "Know' whats failing

A) Either the slow speed on the fans is not working

B) there is valve (Pump ? ) of some sort that prevents the coolant to flow trough the radiator unless the fans are running at high speed

How did I come to this conclusion?

As suggested I checked the return flow of the coolant into the reservoir after I cam back last night

- Car was charging  - no fan noise  %  60% charged

The return coolant was way to hot in my opinion and would not change temperature even after running for a couple of minutes

 So I tried it with the car running - not charging - just power enabled -  Same thing - with the return coolant being even a bit hotter

-At this point I'm convinced that there is Thermostat that's not opening  -meaning the coolant is not running trough the radiator

Put everything back together  - started charging again

Came back after 10 min - fans are running on high speed ..

I did check the return coolant - and sure enough the coolant is not hot anymore  ..

At this point I believe my fans never operate at low speed  (As I don't think there is thermostat at the entrance of the radiator ..

This could explain why the operates  just fine when driving  - there is enough air flow during driving to keep things cool ..

Here is the thing I don't like ..

I would think just running trough the radiator (without any driving wind or fan wind ) should have cooled down the heat generated by the charging a bit - I could  be wrong about that

While driving I am running everything on the hot side  - meaning it will only start cooling (turn the fans on)  if the motor is about to over heat  ..

Question:

Does the radiator have a thermostat ?

What turns on the low speed fans ? (I assume there has to be a temperature sensor  - saving energy is important they would not run those fans  unless they are needed-even at low speed

Georg

[Frank Smith]

There are no valves or "thermostats" like a gas car since having the car be too cold is not a problem. Gas cars do not run efficiently when cold hence the thermostat. If I were you I would get a box fan for when charging. Allowing the car to overheat to the point of activating the high speed fans will surely reduce the life of sensitive electronics in the PCU. I would also jumper the low speed resistor, since it is not working anyway. This will cause the fan to run at high speed as soon as the car begins to get to hot. When used with the box fan when charging, the car fans should seldom come on. If you do not like my suggestion to jumper the bad low speed resistor get a new one from www.thinkparts4u.com 

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[georg Kohler]

Ok -sounds like this might be a common Issue ?

Sounds like there is two power lines going to the Fans - one with a resistor and one without - therefore you're assessment that the Low speed resistor has gone bad

I can replace it unless it's in a difficult spot  -  ("nothing"  is ever is easily accessible on a Think..)

I'll give it a try  - Thanks

Georg

[Frank Smith]

The resistor is not hard to replace, it is located in the center of the car in the front bumper. Between the two fans. You will need to jack the car up enough to slide under. I believe it is held in place by 2  10 mm bolts. It is made of white plastic and has a grey plug with two brown wires.

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[georg Kohler]

I saw that - its kind of hidden inside the radiator frame - I'm pretty sure it needs to be in the air stream of the radiator/ fan  to stay cool

Based on a Norwegian Blog I figured  out that it is a 3Ohm 100Watt resistor ---- US9$ for 6  units at amazon

Most likely I will mount it to aluminum cooling fins  - that should do the trick

I'll let you know how it goes - it will take a few days until I get to it