I have a 2018 Leaf and winter temperature has dropped to minus overnight recently in Canada, I couldn't start the vehicle last weekend and there was "Service EV System No Power" error on the screen. I just want to post this to help other people to fix the problem.
Symptom: Cannot start the vehicle, with error "Service EV System No Power" on the screen. Now, if you pay closer attention to the beep (say pressing the lock/unlock on the key fob), you can hear it has very weak beeping sound. I couldn't even open the charging port remotely.
What I tried (DID NOT WORK): I have been using jumper cables and Li-Ion battery booster over the years, I have saved many people on the parking lot by boosting their gasoline engine before I had the Leaf. I know what I am doing. Okay, I have tried using the NOCO Li-ion battery boost GB40 and IT DID NOT work, it did not start the vehicle. Then, I tried hooking up with the jumper cable with a gasoline car, nope it did NOT work either.
What I tried (DID WORK): I hooked up a 120V battery charger (it was for my boat deep cycle battery) and charged the Leaf battery for 10 min and I was able to START the vehicle, FINALLY!!!!
What I have learned: Looking up Tesla's boosting instructions, when using booster cables you cannot treat it like gasoline engine, they told you to charge the dead battery for 5-10 minutes before you try to start the vehicle. Unlike boosting a gasoline engine, I believe the "cranking amp" is not really relevant. Keep in mind, if you are in the -30C in Canada and someone tried to help you in the parking lot, you need to tell him to WAIT 10 minutes at least, that's gonna be a bit interesting.
What I did: It was a Saturday afternoon, I called the dealership and they told me there was no appointment available until the following Monday. Yes, it may be under warranty but I would need to take a half day off, drive to the dealership, wait there.. it's not worth my time. So I went to Canadian Tire and grabbed a battery for $140 CAD. Installed it, very easy. Notice it in the picture, the original Nissan battery has +/- terminals CLOSER to the right (they call it "negative on left and positive on right corner"), however the new battery I got has the terminals closer to the LEFT (they call it "positive on left and negative on right corner"). There is no problem for the RED positive terminal because there is a lot of slack, but for the BLACK negative one, it was a very tight and I barely made it. Okay after installing the new battery, vehicle started no problem! To make sure this fixes the problem, I posted this after 15 days. so you have confidence to follow what I did if you encounter the same issue. Hope this helps!!!! But honestly, I am not very happy with Nissan because the battery just died so quickly.
Battery I used:
MOTOMASTER OEPLUS Group Size 51 Battery, 500 CCA
SPECS - Group #: 51; CCA: 500; CA: 615; RC: 75
ORIGINAL EQUIPMENT - GROUP #: 51; CCA: 410