Charging strategy and tools

[plannersteve]

I'm trying to figure out a charging strategy. We typically might drive 15 to 20 miles per day. I've been reading that PHEV battery will probably last longer if charging is done between 20% and 80% State of Charge.

It looks to me like the car already stops using battery somewhere above 0%, so I'm thinking I can run it as long as allowed on EV and still be at least 10% SOC.

For charging it back up, I had planned on just plugging it in at night and unplugging when we use the car in the morning. But now I'm not sure that this is not charging too much. Do I need to use the timer to keep from overcharging?

On my first night of charging, I just left it plugged in and in the morning the charging indicator was no longer on. But I can't find out if the car has logic to turn off charging somewhere before 100% SOC or if I need to use the timer to accomplish this.

Sorry if this is covered elsewhere, I wasn't able to find it in a search.

 

[jaapv]

The charging strategy is built into the car software. It does not charge to maximum capacity by default. The thing to avoid is the use of CHAdeMO chargers, and to disconnect-reconnect after the car has stopped charging when full.
I have a suspicion that charging at 6A might be beneficial for battery life.

My dealer tells me - and they have several hundred of these cars running since 2013- that the battery of the car is surprisingly robust in their experience. In their customer base they had just one with a battery replacement and the owner had been charging by CHAdeMO exclusively and often. Actually they only had to replace a few cells. All others are running at or above the expected specification.
Most battery capacity complaints can be solved easily by battery software maintenance,

 

[minical]

I've noticed that whenever I plug into the chargers that show you battery %, mine always shows around 30% when in the car is showing the battery is completely drained and can no longer operate in EV mode. Also whenever I charge from close to empty I only consume ~8kW of electricity which is about 70% of the 12kW battery pack rating.

I'm assuming the software adjusts this as battery degradation occurs and maintains your average range.

 

[karl]

You just have to drive the car, and plug it in when you can.

The car will do the rest.

(Ok, don't regularly unplug and reconnect after just a short drive, as stated by the manual.)

You don't need to touch the 'charge' or 'save' buttons unless you want to show off the car when arriving at your destination or keep a small reserve for driving in cities along the way - admittedly something i mostly do for showing off too... As if some random pedestrians would care...

If you are worried about fuel consumption, keeping the speed low - perhaps at least less than 110 km/h, but I suspect 100km/h is even better - will matter more than anything else you can do.

Don't be afraid of driving long stretches on ”1 bar", it's designed for that.

The most convincing analysis I've seen on this site suggested that running on save or charge when the charge was more than 50% was slightly less efficient due to a reduced charge rate, and I think the charge mode will eventually settle for 50% when driving really long in that mode. But I think this is now religious territory so I'll stop.

 

[plannersteve]

Thanks for the responses. I'm glad to hear I don't need to think about getting up in the middle of the night to unplug to prevent overcharging. Our use pattern will probably seldom result in anything other than charging overnight.

Is there any logic to use 8A vs 12A charging mode? If the high charge rate of CHAdeMO is reducing battery life at a faster rate, would using the slower 8A be best? I usually have the time to use that so that's my plan.

Karl, I do understand the religious nature of some topics.

 

[karl]

Is there any logic to use 8A vs 12A charging mode?

It doesn't hurt but I doubt it matters at all actually, 12 A is a small fraction of what the battery can handle. Regen braking must produce more than 100A for instance, if I got my numbers right.

A Chademo charger is also pumping in much more power and perhaps more importantly is directly connected to the battery rather than via the on board charger. As it's focused on speed, and let's face it, much larger batteries,
I doubt there is much subtetly involved in the process, ie no cell balancing etc.

 

[Craigy]

Is there any logic to use 8A vs 12A charging mode?

It doesn't hurt but I doubt it matters at all actually, 12 A is a small fraction of what the battery can handle. Regen braking must produce more than 100A for instance, if I got my numbers right.

A Chademo charger is also pumping in much more power and perhaps more importantly is directly connected to the battery rather than via the on board charger. As it's focused on speed, and let's face it, much larger batteries,
I doubt there is much subtetly involved in the process, ie no cell balancing etc.

I’m not sure what difference being “directly connected to the battery” makes, in both chademo and normal charging the cars onboard battery monitoring software ultimately controls the current being delivered to the batteries. When we tested our chademo charger at work with an oscilloscope the request was for 90 amps continuous for the charge to 80%, it then quickly tapered between 80 and 100% under control of the car.
I’m not convinced it actually gets to 100% using the chademo charger but pretty close so less cell balancing is certainly achieved. But it certainly doesn’t just put as much current in as possible, it is controlled and I would assume if temperatures went too high charging would be suspended or throttled. Also the batteries are air cooled during this process. So more subtlety thank you might think.
As you pointed out the charging from regen can be higher than this, though obviously for less time, though if you were coming down a mountain it’s more than feasible you could do this for longer still. This would also be way less controlled than a charging station.

 

[Tai626]

6A charging rate is for 220V countries.

8A/12A is for 110V North America.

Maybe charging at 12A is more efficient just because the AC-DC converter (rectifier) is used for shorter time (8hrs, if low SoC). Perfect for weekdays.

I do have a 240V (16A) EVSE installed and use it on weekends.

Tai