Speak EV - Electric Car Forums banner

1 - 6 of 6 Posts

·
Registered
Joined
·
69 Posts
Discussion Starter #1
Thought this might be of interest: it's my house power consumption as my LEAF approaches 100% charge from my 7kW Pod Point:

135264


Gradual drop-off for the last hour or so followed by a trio of "pulses", presumably some sort of balancing / top-up it's doing. This is a consistent pattern I've noticed on other charge sessions too.

That's overlaid with the house's base load, so the fridge and freezer will be switching in and out, but that's just a small amount of noise on the signal.

Measurement is via a pulse counter watching the Wh flashes on the electricity meter and feeding into my Home Assistant. It measures every minute with a resolution of 60W and "perfect" long-term accuracy assuming it doesn't miss any flashes.
 

·
Registered
Joined
·
3,322 Posts
Had some battery chargers that did this at work a few years back. The manufacturer said it was to allow the pack to "settle", to cool off a bit and make some accurate measurements without the noisy power supply in the charger interfering. These were NIMH batteries but it looks similar.
 

·
Registered
Joined
·
2,205 Posts
Similar chart from my LEAF30:

135265


Same basic shape and same three pulses.
 

·
Registered
Ioniq 38kwh 2020
Joined
·
155 Posts
it could be, it is interesting that it initially ramps down for over an hour. My ioniq, which I measure sometimes with a simple wattmeter, just literally charges at around 2kW on the granny, then about a couple of minutes before it hits 100%, it slows down. Then just stops. When I've charged on a 7kW post to full, again it charges at 6.6kW until a couple of minutes before 100%, then quickly ramps down and stops. Maybe the Leaf doesn't have much buffer at 100% charge, whereas I think the Ioniq has a considerable so it never actually charges close to full, though reports it as 100% charged.
I did have used to have a Leaf 30, and that also seemed to take a long while for the last few % of charge.
 

·
Registered
Joined
·
3,322 Posts
The usual way to charge lithium batteries is how the Leaf does it, constant current and then at the end constant voltage.

No idea what the Ioniq is doing! Must be good though as those batteries have held up really well and the buffer is supposed to be quite small.
 

·
Registered
Ioniq 38kwh 2020
Joined
·
155 Posts
The usual way to charge lithium batteries is how the Leaf does it, constant current and then at the end constant voltage.

No idea what the Ioniq is doing! Must be good though as those batteries have held up really well and the buffer is supposed to be quite small.
I've heard the buffer being about 10% I think which is quite big. mine is the 38kwh version which I think is quite different to the 28kWh version, and I understand it is at a lower voltage too, presumably to prolong battery longevity.
 
1 - 6 of 6 Posts
Top