Supplemental cooling for the charger.

[Aerowhatt]

The 2014 OBC looks different than the 2012--is there a small EMI filter box bolted to the lid toward the rear of the car?

If you get a chance to open the cover and snap a picture it would be interesting to compare the interior.

I'm not sure where you are referring to exactly. I'm not up for opening the OBC cover while it's still under warranty. Can you discern the difference from a good picture of the outside of the cover?

Aerowhatt

 

[jray3]

Hey Aerowhatt, could you post a materials list and perhaps a drawing of your fan bracket? I'd like to get that cooling mod made while the weather is still so hot.

Sure I will do that as soon as I can. Some life complications at present unfortunately. What would be best perhaps a template for the bracket?
Aerowhatt

Yes, a template to trace sounds great, but I'd be good to go with a dimensioned drawing. I get your meaning about lesser fans- I had a couple die from minor mist in the Karmann Eclectric motor bay.. http://karmanneclectric.blogspot.com/2009/06/but-it-wasnt-done-was-it.html

 

[Don]

Another thought. Since the factory liquid cooling loop doesn't seem to be absorbing much of the heat generated by the charger, could it be that the cooling system needs to be flushed and new coolant installed? Chevy mandates this every 5 years for their Volts and our 2012's are probably all beyond the 5 year point by now. I'm just guessing, but I would think a good cooling system flush, a purge with clean water and a refill with the recommended anti-freeze could very well improve the heat transfer by 50% or more - Maybe this is all we really need? We went many years with no reported charger failures and now they seem to be dropping like flies . . . . and we know for sure the cooling system isn't functioning very well because the inlet and outlet coolant temperatures are nearly the same

I do know any heat exchanger with scum built up on the inside of the tubes would exhibit greatly reduced heat transfer. If we got it back working at OEM efficiency, maybe the problem is solved. What do you think??

Don

 

[JoeS]

Don, yet another possibility, although IIRC it's the non-heat-sinked components that are getting hot that are the concern.

According to the i-MiEV Owner's Manual, the car uses "Dia Queen Super Long Life Coolant Premium", or an equivalent "high quality ethylene glycol based non-silicate, non-amine, non-nitrate, and non-borate coolant with long life hybrid organic acid technology". I've used the manual maintenance schedule to point out that only at 240 months (20 years!) does the manual specify to change the motor coolant and heater fluid.

Our i-MiEV cooling system does not undergo the dramatic temperature excursions to which an ICE vehicle is subjected, and thus perhaps is not subject to the same issues. If anyone does change the fluid, it would be nice if you could do a before/after thermal measurement.

 

[pbui19]

Finally get a chance to poke around the on board charger/DCDC. Boy that thing can really get warm. It seems that one of the problem is that there is no way for the hot air to circulate, it gets all pooled into that canopy. Aerowhatt's fan is great but I would add a hose to duct cooler air lower down. First we would get better heat transfer with a wider delta-T, and there would be some convection a la ceiling fan affect.

For now, I just propped open the canopy lid when charging L2. The convection of the warmer air will be welcomed into the cabin as the weather is getting cooler here.

Another lazy person option for over night charging is to use a timer to stop/re-start charge every hour for half an hour or so.

 

[coulomb]

Another lazy person option for over night charging is to use a timer to stop/re-start charge every hour for half an hour or so.

If you go this route, I'd recommend not stopping the charging by just killing the AC input. PFC stages don't like interrupted AC, and the relay or contactor won't last long. If possible, effectively operate the J1772 switch, so the on board electronics does an electronic shut-down. That way, the cooling pump still operates while the charrger is resting, for extra cooling. Though you could kill the AC as long as it happens a half second or more after the J1772 switch is operated, to save power.

 

[tenthousandclowns]

just found this thread... I'm so glad. I live in new orleans and often charge in the daytime, where sun shines down through my back window! I'll start charging at night.

i like the blower system, i would love to buy a kit if it becomes commercial or try to make my own.

so the fan power is pulled from a 12v always on source or 12v on during charging only?

 

[tenthousandclowns]

https://www.ebay.com/itm/ONE-NEW-NIDEC-GAMMA30-A34124-58-FAN-50-AVAILABLE-J317/382554444981?hash=item59120594b5:g:RN8AAOSwgjhWbx~Q

 

[tenthousandclowns]

ok i ordered the fan. Instead of a temp activated switch, is there a 12v source nearby that is on when the charger is on? that would do for me since its pretty hot here for a lot of the year and the fan is only a few watts.

 

[footswitch]

Another lazy person option for over night charging is to use a timer to stop/re-start charge every hour for half an hour or so.

If you go this route, I'd recommend not stopping the charging by just killing the AC input. PFC stages don't like interrupted AC, and the relay or contactor won't last long. If possible, effectively operate the J1772 switch, so the on board electronics does an electronic shut-down. That way, the cooling pump still operates while the charrger is resting, for extra cooling. Though you could kill the AC as long as it happens a half second or more after the J1772 switch is operated, to save power.

coulomb, just a note, the cooling pump stops as soon as I press the J1772 button. Citroen C-Zero, 2012

Anyone can answer the previous question? A 12V source nearby that is only on while charging?

 

[kerrye]

It’s too bad the AC is not activated and diverted to the charger on Level 1&2 charging.

I’d be interested in a kit if you develop it.

 

[pbui19]

I am sure there is a 12v source back there somewhere but I don't have access to the drawing. I've been thinking of tapping into the coolant pump 12v, which runs intermittently while charging, so then the cooling fan would only run when the pump is running. My thinking is just to duct the flow to get the pooled hot air at the top out.

Haven't gotten around to it so my lazy way now is just propping up the lid and let the natural convection moves the hot air out, leaving an opening in all 4 windows.

It also has been confirmed here that level 1 charging generates less heat.

 

[Don]

It also has been confirmed here that level 1 charging generates less heat.

Especially if you use the supplied OEM 2012 Panasonic EVSE which only does 8 amps, 960 watts. That's how I've been recharging 95% of the time for the past year because of all the heat related failures we've been seeing here. I do occasionally use L1 @ 12 amps, (and even L2 @ 12 amps a couple times in the dead of winter when it was only 35 or 40 degrees outside) but my new 'rule' is . . . . "Why recharge any faster than absolutely necessary??"

Don

 

[ed5000]

It also has been confirmed here that level 1 charging generates less heat.

Especially if you use the supplied OEM 2012 Panasonic EVSE which only does 8 amps, 960 watts. That's how I've been recharging 95% of the time for the past year because of all the heat related failures we've been seeing here. I do occasionally use L1 @ 12 amps, (and even L2 @ 12 amps a couple times in the dead of winter when it was only 35 or 40 degrees outside) but my new 'rule' is . . . . "Why recharge any faster than absolutely necessary??"

Don

I've been charging at a reduced rate too. It seems to help. The car stays cooler, at least when it's parked with the windows up and the coolant pump seems to run less often.

I charge at night when its cooler outside and electric rates are lower. I use my UpgradeEVSE set at 8 amps (240VAC) so at about 1920 watts. The car accumulates nearly two bars per hour of charging. And since it's at night, there's plenty of time to get my full (or nearly full) charge I aim for.

 

[kerrye]

After about a half hour of level one charging at an ambient temperature in low 40's F and the car body reading 45f, the highest temp I could find on the charger was 58 degrees F. Coolant pump cycled once as I was checking temps, in a period of about 10 minutes.

 

[michael8554]

Does anyone have the image that Aerowhatt linked to in his post Aug 3 2018 at the bottom of page 5 ?

https://myimiev.com/forum/viewtopic.php?t=4099&start=40

I've not been able to download it.

I've PM'd him but he's not posted since 2020.

And does anyone have details of where to pick up 12V whilst charging ?

I'd like to add the cooling fan to my newly acquired 2012 I-MIEV

 

[JoeS]

michael8554, sadly Aerowhatt has passed away - we miss him!

Sorry, no pictures of his fan installation, AFAIK.

My OBC/dc-dc died on a very cool winter night while charging at 13A 240vac. The cause-effect relationship of OBC failure and case temperature I don't think has been established. kiev?

If you really want to use 12v, the output of the dc-dc is always live (or is it only when charging or in READY?), so tapping into that line (with a fused pigtail) is a possibility.

 

[MickeyS70]

My OBC/dc-dc died on a very cool winter night while charging at 13A 240vac. The cause-effect relationship of OBC failure and case temperature I don't think has been established. kiev?

While cooling the case might not totally prevent an OBC failure, it will certainly increase it’s lifetime as Aerowhatt has correctly pointed out that temperature has a negative effect on MTFB of electrical components..

Luckily where I live I don’t have to worry about excessive ambient temperatures but still I charge with low (9A) current hoping to get a few more years out of my Gen1 OBC.

Mickey

 

[michael8554]

Sorry to hear about Aerowhatt.

My search through the wiring diagrams reveals:

That plug E-03, on the rear face of the DC-DC converter, carries constant 12V from the Relay Box on pin 7.

And switched 12V from the On Board Charger Relay on pin 2.

 

[michael8554]

Ever since getting our MIEV in September we've home-charged with the metal cover over the On Board Charger (OBC) propped open, as I found the top of the OBC was getting fairly hot.

Having to unscrew the four wingbolts every time was somewhat tedious, so I've now added a 12V centrifugal cooling fan, as suggested in this thread.

https://drive.google.com/file/d/11tJkt78JNz3VVTHb8lx9bBHFMdKliIRk/view?usp=sharing

It sucks cold air from under the car and blows it over the top of the OBC.

I made one of the folds in the bracket wrongly, so it doesn't fit neatly between the top of the coolant tank and under the lip of the opening, but the lid still closes correctly.

The 12V is from Plug E-03 on the rear of the OBC:

https://drive.google.com/file/d/1TKND1mnvkGlJbk2yt21aK0ZII0sUqI6R/view?usp=sharing

I spliced a wire into Pin 2 Violet, which is only 12V during charging.

And earth from a convenient fixing screw on the OBC.