Posts: 33
Joined: Mon Jan 11, 2016 4:10 pm
Delivery Date: 11 Jan 2016

Re: 2011 - Dead Battery Charger

Tue May 26, 2020 4:49 pm

I don't even really remember the bleeding process so I'm sure it was pretty straightforward. It's also an electric pump and relatively small lines, so I think the coolant speed is both constant and high, which helps.

I collected all the coolant that I drained quite carefully, which let me be pretty confident there were no huge bubbles in the system providing I could get it all back into the loop. I think I spilled about 1/2 a cup or so during the process, so I wasn't expecting perfection. I also think I went through the bleeding process relatively quickly and then just left the car in 'ready' mode for a couple of hours to clear any bubbles.

On the positive side, the worst case load into the cooling system for the on-board charger is 400-500W, which is pretty solidly nothing for cooling power electronics. Most of that is coming from a single huge module in the charger too, which helps a lot.

The 2011 service manual has the procedure listed in the 'HCO - High Voltage Cooling' section. ... -hco-43099

Page 9 has draining and refilling.
But the manual basically says:
There's a bleeder plug on the bottom side of the on-board charger, next to where the coolant inlet/outlet are. Remove that.
Completely fill the degas tank.
Remove the joint in the coolant hose at the 'traction inverter front', which is the hose closest the hood at the very front of the engine bay (motor bay? under-hood area?). Visually check for water flow and reconnect, which I'm guessing means 'does any leak out'.
Refill degas tank.
Close the bleeder plug on the charger and close the degas tank cap. I vaguely remember coolant trickling out a little at this point.
Start the car into 'ready' mode (foot on the brake, press power button, car should chime and come on with a green car icon with arrows under it on the dash, this is the 'ready to drive' mode which has the HV active) which turns on the pumps.
Watch the level in the degas tank and refill as it lowers.
Once the level has stopped falling, close the cap and turn the car off. Turning the car off with the cap open may cause coolant to surge out of the cap.

From there, it's basically make everything quiet, turn the car on and run the pumps for a minute, checking to see whether you hear gurgling from the back of the car. If so, there's still air and let it continue to bleed.

Hopefully that helps. Seems like you might have gotten a sweet deal for what is hopefully very little extra effort!

I've actually been discussing the possibility of repairing the ZE0 on-board chargers as they seem like a 'common' enough fault that, here in NZ at least, getting replacements out of wrecked vehicles is only just keeping up with demand. Still not anything to worry about, but definitely one of the more common faults. Maybe as many as 1% of cars having it happen in their lifespan, I'd hazard a guess?

Posts: 3
Joined: Wed Jun 24, 2020 9:30 am
Delivery Date: 24 Jun 2012
Leaf Number: 027104

Re: 2011 - Dead Battery Charger

Wed Jun 24, 2020 8:21 pm

@JonoNZ - fellow pixie wrangler here. When removing the OBC, did you follow the steps in the manual to the letter? Were there any steps that could be skipped? I ask because getting underneath to disconnect the HV cable seems hard to do without a lift. How did you do it?

My car has the same issues as some of the other comments (won't take a L2 charge and the pilot signal diode trick didn't work).

Is there any chance for warranty coverage or am I SOL?

My leaf is a 2012 model with 70k miles on the OD. Had battery replacement done under warranty in 2017, already down 3 bars.

Posts: 3
Joined: Wed May 20, 2020 3:07 pm
Delivery Date: 20 May 2020
Leaf Number: 023744

Re: 2011 - Dead Battery Charger

Tue Jun 30, 2020 2:10 pm

I did not have the manual to go by, but I can give you an overview of the steps I took:

1.) Backed rear wheels up on ramps
2.) disconnect 12v battery
3.) Pulled the main HV battery service plug on the floor in the back seat
4.) removed upper and lower back seats and plastic coverings from trunk
5.) Loosened bolts holding the OBC in
6.) disconnected all plugs on OBC
7.) under the car pulled the plastic belly an off.
8.) clamped both coolant hoses with long flat locking vice grips
9.) undid clamps holding hoses to OBC
10.) let remaining coolant come out of OBC
11.) Re-install everything in reverse order with new OBC
12.) Hooked coolant hoses back up still clamped, then undid vice grip clamps
13.) topped off coolant in engine bay
14.) Started the car and let it run for about 3 hours to purge any air from coolant and topped off again.

All is good. Mine is a 2012 with 51k miles. Battery replaced in 2017 - still has 12 bars showing, 54.87ah and 86.12 SOH Still have my old OBC if someone is interested in it for repair or testing?

Posts: 33
Joined: Mon Jan 11, 2016 4:10 pm
Delivery Date: 11 Jan 2016

Re: 2011 - Dead Battery Charger

Tue Jun 30, 2020 2:47 pm

Hi defenderred,

Sorry to hear you're having issues. Just to double check, your 2012 is one of the ones with the charger under the rear seats? There are a few here in NZ that are the AZE0 chassis number type registered as 2012 which causes some confusion.

You shouldn't need to get under the vehicle to disconnect the electrical connections, that's all present in the cabin, under the seats.

You do need access to the underside of the front radiator to drain the coolant loop and then to the underside of the on-board charger to disconnect the coolant lines. There's also a bleed port there that you might want to use for re-assembly. I don't recall there being a whole lot of slack in those lines, but there might be enough to let you get the charger lifted enough to get at the clamps, I'm not sure.

Stripping the rear seats out is a really easy process, so I'd recommend doing that first. It'll make planning what you do next much simpler.

Hopefully that helps. Let me know how you get on or if you have any other questions!

Posts: 33
Joined: Mon Jan 11, 2016 4:10 pm
Delivery Date: 11 Jan 2016

Re: 2011 - Dead Battery Charger

Tue Jun 30, 2020 3:43 pm

Clamping the coolant lines is a good idea. I was originally going to use it as an opportunity to replace the coolant, but it looked pretty much perfect so didn't bother in the end.

These chargers aren't particularly repairable as the power module in them is completely custom (made by Nichicon) and pretty much impossible to acquire replacements for, economically speaking. It would be possible with an un-damaged module, but that would require coming across a charger that had failed in a different way, likely the extra-low voltage section, which would probably be an easier repair directly.

Posts: 92
Joined: Thu Oct 09, 2014 5:08 pm
Delivery Date: 07 Mar 2015
Leaf Number: 200445
Location: Brisbane, Australia

Re: 2011 - Dead Battery Charger

Tue Jun 30, 2020 5:26 pm

I believe that the Leaf has a very similar but not identical charrger to the Mitsubishi iMiEV. Their charrgers fail often enough that Mitsubishi USA has extended the warranty on them, and many owners have had faulty charrgers replaced for free. I don't expect Nissan to do likewise.

In the iMiEV charrgers, there are two common failures, both involving inexpensive parts. But the gotcha is that to remove the lower printed circuit board, you need to desolder dozens of pins. A desoldering station is required for that. Some repairs have been done without removing that board, however. No one has reported failure in the potted power electronics plate (dubbed the "waffle plate") so far, that I know of.

So repairs are presumably feasible for the Leaf version. The best resource for the iMiEV charrger is this topic:

[ Edit: oops. Looks like I already posted about this last year. Sorry for the double post. ]
Last edited by coulomb on Tue Jun 30, 2020 6:08 pm, edited 3 times in total.
2012 Leaf with new battery May 2019. New to me June 2019.

Posts: 33
Joined: Mon Jan 11, 2016 4:10 pm
Delivery Date: 11 Jan 2016

Re: 2011 - Dead Battery Charger

Tue Jun 30, 2020 5:36 pm

Potentially, but I think you're several extrapolations deep there.

In many of the cases I've seen with the Leaf there's a dead output electrolytic and some evidence that it may have been caused by or have caused a significant output voltage transient, which in turn may have stressed other components within the power module.

I'm hoping to have a chance to look into some potential repair/diagnosis work in more depth, so I'll check out that thread on the iMiEV charger.

Posts: 33
Joined: Mon Jan 11, 2016 4:10 pm
Delivery Date: 11 Jan 2016

Re: 2011 - Dead Battery Charger

Thu Jul 09, 2020 6:31 pm

Well, it looks like you're probably on the right track there. The configuration and rating of the charger is a bit different so there are some associated part swaps (DC link electrolytics, input filter components etc.), but it seems to be built on the same topology, power module and shares all the same magnetics.

Looking at it, I think there's a pretty good potential that at least some of the same design faults exist in both designs.

EVs Enhanced in Christchurch, New Zealand are working on being able to repair or provide repair instructions/replacement parts for faulty on-board chargers for the Leaf, so they may be able to provide a similar service for iMiEV chargers as well.

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