800km day in 30kWh Leaf

From NZ EV Wiki
Jump to: navigation, search

Background

The following is based on a comment by Steve Withers in the NZ EV Owners Facebook group, in response to a question about the feasibility of driving a 30kWh Nissan Leaf from Wellington to Whangarei in one day. There is specific detail about battery heat management here, which isn't on the main Trip Planning page.

Charge level

You can do it in one very long day, but your enemy is going to be battery heat. You can help reduce that and still have a very enjoyable road trip.

Start on 100% having charged over night. Get a good sleep. Start early. 5-6am.

After you start, you basically want to just to up to 80%. But there are exceptions. It saves time and your battery won't get as hot. Your going to have to fast charge 7-8 times in one day. You can't do 100km/h very often as it will keep your battery too warm for an 850km drive.

You're going to have to top up to 90%-95% in Palmerston North to get to Mangaweka. It's only 81km but it's mostly uphill.

Speed

Keep your speed down to around 80km/h. This really helps shed battery heat. Find a slow camper van or truck and stay behind it. But give others a chance to pass. I will follow the slow thing until a queue forms behind, then I'll pull over and let the 3, 8 15 whatever cars pass me.... And then they can pass the slow thing...and I never have to go faster than the slow thing because it is always in front of me.

Cooling

Heat loss is best when rolling at about 75-80km/h. For each charge of about 50% you'll heat up by about 8C. You don't really want to be over 50C for long periods. If you're starting on 25C, and drive at 100km/h, then you'll get to 50C after your 3rd fast charge.

At around 55C the car will simply refuse to charge any more. So it's a balancing act speed vs charging vs need to cool it down. The good news is the car can generally it shed heat quickly above 48C. It shows down after that. Ideally, you manage it so your charging window for temperature is between 42C and 52C. I use Leaf Spy to see this, but if you don't have it, then you're fine up to 10 white temperature bars, but your want to avoid (or cool down from) the two red bars at the top. Ideally, you'll get to 9 white bars (about 40C) and charge to just before the first red bar. You'll be in this zone for most of the day. It's ok. But you to be able to keep going you'll have to cool down enough the next fast charge doesn't heat your battery up beyond it.

At 100km/h your battery just gets warmer. You can do it if you need to for safety, but it just means you'll have to go slower later.

The car cools down ok if you stop in a shady, breezy place, but cools down faster at 75km/h. Don't park in the sun on pavement on a hot day if you're trying to cool down. Otherwise, no problem.