Heater Failed 2011 Gen 1

[EmmaK1]

Hi Guys,

I guess I had a good one but the heater in my 2011 Leaf has finally failed.

The error codes indicate that the control boards in the Eberspacher water heater have failed and probably taken out the 30A fuse.

I have been half expecting this so am not majorly disappointed and pleased it happened in the summer. There is no point in replacing it as only 2nd hand ones are available now. I could put a diesel heater in somewhere but there is insufficient space under the bonnet (hood), the boot (trunk) is already cramped with the 11kW range extender, and anyway I don't want diesel/kerosene in the car... So I have a plan.

As I live in a warm wet part of the UK 1000 to 1500 Watts will be adequate most of the time. What I intend to do is remove the (water) heater matrix and insert a holder for a bank of 12v PTC heaters powered from the 12v battery. I believe that the DC/DC inverter will cope with this no bother and all the heater functions will operate normally. It should also be possible to use this with timer heating. Selecting the number of units to use would give crude temperature contol and be no more onerous than the manual control in any older car. By switching the PTC heaters individually they will all get roughly equal use and if one fails the rest will continue to operate until the dud can be replaced.

To my mind this is probably the simplest and cheapest way to restore some heater function. At current prices online it should be possible to achieve this for under $200. The limits may be the output and physical size of the PTC's I can obtain. I understand that the working life of some cheap PTCs can also be limited. Obviously I would install suitable safeguards e.g. a fuse and relay at the battery connection so there will only be poweer to the PTCs only when either the ignition or timer heater are on. Also possibly for the individual PTCs depending on the wattage of each unit.

What do you guys think? Has anyone else done this? Any suggestions or advice would be welcomed.

Thanks Guys,

Em

 

[LeftieBiker]

I tested a standalone system using 120 volt PTC heaters mounted on the fronts of the seat rails, with an inverter and 12 volt battery. My conclusion was that it could be scaled up with more heaters, and you could eliminate the separate battery by using a larger OEM type battery. Total cost would be in the $300-400 range (using an inexpensive square wave inverter) and you could adjust it either with a master switch or just by turning heaters on and off.

 

[GerryAZ]

Are you planning to use PTC heater elements to heat water to circulate through the heat exchanger in the dash? If not, how will you duct the heated air into the dash? I agree that 12V PTC heaters should work and the DC-DC converter should handle the load. I set up a 2kW sine wave inverter to run power tools and connect it to the battery with jumper cable clamps. The DC-DC converter easily puts out 100 amperes to run the inverter and keep the 12V battery charged.

 

[EmmaK1]

Thank you for the replies.

I intend to remove the (water) heater matrix and insert a holder for a bank of 12v PTC heaters conected to the 12v battery terminal through a fuse and relay. The air will blow through the PTC heaters in exactly the same way it currently blows through the heater matrix.

I located the heater matrix and pipework yesterday evening. It should be fairly easy to blank off by fitting a U return bend under the hood at the left side of the bulkead where the rubber hoses connect to the metal pipes from the matrix. The end of the heater matrix can be seen by removing the lower center console panel in the left footwell. I may modify the mouldings to make a quick release panel for future access.

The PTCs I intend to use are the type used in small fan heaters. They would only be powered when the heater is on. I still have to work out where to take the relay operating signal from. I am experienced in domestic and motor vehicle wiring but am not an electronics expert.

The attached photo is a 12v 400W ceramic PTC advertised on a well known internet site. It is approximately 5.9" x 2.6" x 1.3" and I think I should be able to fit three, possibly four, into the heater box water matrix space. It may be possible to fit a larger number of smaller units but I wont know until I have removed the heater matrix and measured it.

 

[EmmaK1]

There is a very interesting article here on how and why the water PTC heater fails (with links to two more articles and an informative video).

https://tonyfowkesautomobiles.com/nissan-leaf-ptc-heater-repair/

 

[EmmaK1]

Hi Guys,

An update...

The heater is air mixing and the flaps continue to operate automatically even though there is no heat from the heater matrix.

I will try a solid state relay which uses a big mosfet. The current draw is tiny but can switch 40A at 220/240 volts. It should operate from the feed to the blower motor without tripping any error codes. This means the PTC elements will only receive current when the blower motor is running.

Am going to bypass (water) heater matrix with a return loop at the bulkead. I am reluctant to just block it off as this may put back pressure on the coolant circulating pump.

Will also locate blower motor supply then check the relay works ok. I suspect the motor supply is pulse wave modulated for speed control in which case the mosfet may either not trigger or switch on/off with it.

Can any of the my followers suggest another location to take a heater on off signal?

More to think about, Em

 

[BillAinCT]

You can add a pressure sensor and turn on a predrive transistor to turn on the MOSFET. You have to empirically find the turn on value at the low fan setting. A more complex circuit could give you more power for higher pressures. Uncharted territory is fun. :lol: