Fast charging not as fast as I expect

steelboots

Hi,
I had to cover a 160k journey this morning, and was starting with 75% charge. I got to my planned fast charger (Topaz near Galway airport) with 33%. Plugged in and it seem to go up 6% in 2 mins, so I headed in for the tea. Came back after 27 min and it was at 75%, so took 27 mins to go from 33% to 75% (42%).. would not like to be waiting on a 10% to 90% charge  . Have very little Fast Charging experience but this was slower than I would have expected, and its a pretty new charging point, useful location though. Are you experiencing the same speeds of charging ?

KCross

It will be down to two main factors

Charger power
Battery temp

I presume it's a 24kWh leaf? The 30kWh is faster.

I've charged my 24kWh from 30-80% in 20mins and 20-80% in 23mins but the battery was at 6-7 temp bars. You were probably at 4-5 temp bars?

Once the charge goes above 50% ish the rate of charge drops off quite quickly and anything beyond 80% isn't a whole lot faster than a 6kW charge at home.

steelboots

Thanks KCross, 

Yes its a 24kWh, and the battery temp was 4 bars and finished on 5. Would not like to be relying on charging on a regular basis. 
Thanks,

Water John

As K says, on the 30kWh Leaf, normally 2% per min, all the ways up.

Villain

This is one example of why plans by ESB to charge per minute are crazy.

BoatMad

Water John wrote: »

As K says, on the 30kWh Leaf, normally 2% per min, all the ways up.

Nope , on my 30 kWh, it's quite fcp dependant , was at templeville road, recently , on a dbt , at 86% , the dbt showed 30 A , ie around 12Kw. 5 bars of bat heat , with one being added during the whole fcp session ,

I think the earlier software in some chargers , charged harder ( or ignored the car etc )

BoatMad

Water John wrote: »

As K says, on the 30kWh Leaf, normally 2% per min, all the ways up.

Nope , it's quite fcp dependant , was at templeville road , on a dbt , at 86% , the dbt showed 30 A , ie around 12Kw. 5 bars of bat heat , with one being added during the whole fcp session , initial charge showed usual 100A , ambient 8 degrees

I think the earlier software in some chargers , charged harder ( or ignored the car etc )

Ps the tech guys in ecars Informed me that they had requested a throttle back from 85 % , so it could be a function of the charger and not the car commanding it

cros13

Sometimes ESB dial back the power output of the charger.

Until it's replacement one of the castlebellingham rapids was only putting out 25kW (of 50kW) peak.

KCross

BoatMad wrote: »

I think the earlier software in some chargers , charged harder ( or ignored the car etc )

Are you saying the charger can overrule your car and blast in whatever rate it likes?

That would seem like a silly thing for the car manufacturers to allow? Surely they have a way to limit the power injected by a rapid? Isnt that what the BMS is supposed to do?

cros13

KCross wrote: »

Are you saying the charger can overrule your car and blast in whatever rate it likes?

That would seem like a silly thing for the car manufacturers to allow? Surely they have a way to limit the power injected by a rapid? Isnt that what the BMS is supposed to do?

The rapid has a direct connection to the battery... it's up to it's programming to heed the BMS. The standards lay out the data to be reported by the BMS and after that it's up to the rapid.

76544567

My wife picked up her 30Kw leaf last week.
I was driving it yesterday.
Started at 100% charge and did 101Km and had used 58% of the battery according to the Leaf (42% remaining when I got to the FCP).
I plugged it into a fast charger and charged from 42% up to 92%.
Both car and charger indicated the exact same % at those times.
Yet the indicator on the FCP then said that I had put in 9.7 KWh into the car after I ended the charging at 92%.
I thought that even if the car is 27Kwh that 50% of a charge would be at least 13.5KWh.
Something doesnt add up.
Either the charger is telling fibs or the car is. Which is it?

KCross

76544567 wrote: »

My wife picked up her 30Kw leaf last week.
I was driving it yesterday.
Started at 100% charge and did 101Km and had used 58% of the battery according to the Leaf (42% remaining when I got to the FCP).
I plugged it into a fast charger and charged from 42% up to 92%.
Both car and charger indicated the exact same % at those times.
Yet the indicator on the FCP then said that I had put in 9.7 KWh into the car after I ended the charging at 92%.
I thought that even if the car is 27Kwh that 50% of a charge would be at least 13.5KWh.
Something doesnt add up.
Either the charger is telling fibs or the car is. Which is it?

The % readout on the car is "lying". It "hides" some of the capacity to make it less likely that you will run out.

There is also the charger efficiency. It said 9.7kWh but the car didn't take all that onboard. You probably got 90% of it.

The % readout on the charger is whatever the car told it, that's why they match.

You have 28 Kwh usable energy in the 30 Kwh, possibly a bit less with a cold battery (4 battery temp bars and less), with a 100% charge and a fully balanced pack ( don't set end timers) end timers won't allow the pack to fully balance.

I only set an end timer if I need less than 80% , when I charge to 50-70% I use an end timer.

The Leaf hides about 8% of battery at the low end (that's in my 24 Kwh) , around 30% and below, not sure what happens in the 30 Kwh.

You need Leaf spy and a bluetooth to OBD II V 1.5 dongle. Use on Android, it will tell you exactly what is going on.

Leaf spy will also show you the power going to the battery from the charger and measure the Kwh sent to the car. And it will also show you the Kwh consumed per trip so it makes calculating what you use a lot easier and with much more precision.

Some chargers show the Kwh consumed but I don't know if this includes the total power including that consumed by the charger itself, Leaf spy will show you this.

KCross

[Deleted User] wrote: »

Some chargers show the Kwh consumed but I don't know if this includes the total power including that consumed by the charger itself, Leaf spy will show you this.

It's total delivered. I've checked against leafspy and it's usually about 110% of what the battery takes in.

Total delivered would be to the battery only, but I know what you're saying, total including the consumption of the charger.