Enginer PHEV DC/DC Overheating issues

It's cloudy to rainy this afternoon with 31~33 degC. I drove to and back to my old home. In total 1 hr blended mode driving, my all added cooling fans(3 12cm fans+ 2 6cm fans) were on and I put a larger cooling box 235x175x120mm on the lid above the converter. The performance of converter had much improved! As I watched the BMS display the Io was continous on. The heat protection mode of the converter has not happened as usual. The mileage was improved from 1.9 to 1.6 L/100km.
But I found the temperature of my Lithium battery and toyota HV battery was up to 42 deg C. I had never noticed so high temp in the same road. I don't know whether the RFE battery has heat protection mode?
Thanks!

 

Hi EPA,

Have you done the Prius HV battery cooling fan modification? This mod switches the HV battery fan to highest speed to keep it cool. If the Prius HV battery gets too hot the CCL (charge current limit) is decreased which the ECU will prevent the Prius battery from further charge.

I believe the BMS16D uses the RFE battery temperature sensors to switch off the DC Converter if the RFE battery gets too hot. If this happens the PHEV switch red LED will come on. I do not know at what temperature this happens.

 

Hi John,
Not yet, After installation of six fans for converter the passenger compartment noise has bothered my wife. If I do the HV battery fan mod, she probably will be unhappy. I will try to turn the AC temperature to 25 degC and amount to larger in summer mid-day drive. I will also observe the HV battery temp & CCL change in next few days.
ps, where can I buy the fan modification kits ?
Thanks
Regards

 

There is no kit. You just buy the parts from an electronics store or EBay. It is just a relay, two resistors and a capacitor. All described at this link:

Prius OEM fan control - EAA-PHEV

The fan running at full speed is very loud but you can switch it on and off with a toggle switch.

 

Last night driving I turned off AC with windows open and the MFD showed 27degC outside. I observed the relationship between the temperature of HV battery and CCL change from SGII. As the BUC/BLC reached 40/39 degC, the CCL from defaults 12.5 decreased to 12.1 and then 10.7. As the BUC/BLC reached 41/40 degC, the CCL showed 10.5. I think Jack is right that phev users should turn on AC and have HV fan modification in hot weather area.

 

Below is a photo to my latest cooling mods to my MDTECH DC Converter which will be mounted on top of my Enginer box lid. Thus using the open architecture being pilot tested by Jack.

 

Hi John,
Nice mods, it will totally prevent the overheat issue of conveter in summer. But if it is mounted on the Enginer box lid, the noise from the fans will be more obvious. And cutting or drilling the box is not an easy work to me.
Below is the photo to my latest tentative cooling mods. You can see more cooling plates. I removed the 12cm inlet fan but preserved two 6cm inlet fans to decrease the noise. Putting two 12V 6cm 2700RPM fans to combine the two 48V fans in serial. To decrease the risk of overload to these fans, there is near 1cm space between the fans in serial. In the last 2 weeks I found better cooling effect than my previous mods.

 

Hi John,
Nice mods, it will totally prevent the overheat issue of conveter in summer. But if it is mounted on the Enginer box lid, the noise from the fans will be more obvious. And cutting or drilling the box is not an easy work to me.
Below is the photo to my latest tentative cooling mods. You can see more cooling plates. I removed the 12cm inlet fan but preserved two 6cm inlet fans to decrease the noise. Putting two 12V 6cm 2700RPM fans to combine the two 48V fans in serial. To decrease the risk of overload to these fans, there is near 1cm space between the fans in serial. In the last 2 weeks I found it had better cooling effect than my previous mods.

 

I used 8 fans from eBay

http://www.ebay.com.au:80/itm/ws/eBayISAPI.dll?ViewItem&item=180717278446

The CPU cooler I salvaged from a computer that was thrown out into the rubbish bin at work. I also salvaged ferrite cores from the computer power supply.

 

Hi EPA,

You do not need to drill holes into the Enginer box lid. You could either use silicon sealant or adhesive Velcro.

The noise made by my Prius HV Fan mod drowns out the noise made by the Enginer fans so noise is not much of an issue.

 

I have built in some exaust fans into the left vent panel at the rear adjacent to my DC Converter fan outputs. The 8 x 12v exaust fans are powered by two solar panels mounted on the inside of the rear window. Probably will use a 12v solar regulator to connect the solar panels directly to these fans. These fans should exaust hot cabin air to the outside whilst parked in the sun and whilst driving. I have removed the rubber air seals.
This should help to bring down the overall cabin air temperature in summer. Not such a big deal in winter.
I can also connect my 12v solar regulator to my 12v auxiliary battery. Use a power diode to block current going from battery to exhaust fans.

 

a that's nice . just like with the prius solar roof panel buth then on the gen 2