Onboard charger : less efficience at low power ?

[SoulEV2016]

Hello,

I have reading somes points about the fact that i charge at 1100w (EVSE charger) because of my solars panels strategy.
Torque Pro and Custom PIDs indicate an 33-43% of efficiency at the Onboard Charger.

During the august month, i will rise the EVSE Charger at 2500w to view if the comsumption at the plug is really less than others months.

:mrgreen: stay tune ... measure take on the plug only (not with torque pro) from a kWh-meter.

 

[mtndrew1]

There is a fixed overhead during charging of several hundred watts, regardless of throughput.

In general, the lower the AC charging amperage, the higher the percentage of incoming power is wasted.

 

[SoulEV2016]

By chance, you don't know the max efficiency of this Onboard Charger ?
Attached to the power chosen ... ?

If i do a simple math equation, it's 15,4A so, at 230v = 3540w ... ?
I will make somes test ... in september.

 

[mtndrew1]

I typically see about 85% efficient at 7.2 kW, but it's warm where I live and there are cooling systems running during charging.

Efficiency might approach 90% in a cool climate.

 

[SoulEV2016]

Ok, the max is 85% of efficiency, thanks :idea:

 

[JejuSoul]

I typically see about 85% efficient at 7.2 kW, but it's warm where I live and there are cooling systems running during charging. Efficiency might approach 90% in a cool climate.

In the last few weeks I am seeing about 83% efficiency at 7.2 kW with the battery fans running at level 2. I saw 85% when the weather was cooler. If I turn on the AC efficiency falls to 73%.

I have not found an official rating for the Soul EV OBC efficiency but I do have one for the 2016 Sonata PHEV - 91.7%. It probably uses the same Mando 6.6kW OBC. But I need to check that.

 

[SoulEV2016]

I have made a shortcut :lol: ...
CAR is OFF during the charge (OBD2 Bluetooth).
SMARTKEY is far away (CAR locked).

complet LOG here (Libreoffice ODS Format) : http://up.sur-la-toile.com/i1hYe (mirror = http://www.4shared.com/file/fT-AM88Fce/trackLog-2016-aot-04_13-51-34.html )


1,1 kW setting (absolute low EVSE setting).

1,4 kW setting.

1,7 kW setting.

2,05 kW setting.

2,4 kW setting.

2,6 kW setting.

3,0 kW setting.

3,4 kW setting.

3,56 kW setting.

 

[SoulEV2016]

And a little GIF to finish the search.

 

[tractioninc]

Thank you, that's very interesting information. I'm surprised by the big efficiency dip at 2.4 kW. I wonder if you'd measure that same value if you repeated your experiment?

 

[SoulEV2016]

You have the complet LOG here (Libreoffice ODS Format) : http://up.sur-la-toile.com/i1hYe (mirror = http://www.4shared.com/file/fT-AM88Fce/trackLog-2016-aot-04_13-51-34.html )

:mrgreen: You can draw graphics ... :twisted:

 

[notfred]

I'm a bit concerned by the voltage sag under load. At light load your EVSE is supplying 220V, but by the time you have wound it up to max then the voltage is down to 204V. That's almost a 10% voltage drop. You have nearly 300W being lost somewhere as heat and if it's all in one bad contact then it could be heading for an electrical fire.

EVSEs are one of the nastiest things in the house in terms of fire risk - they draw a lot of power for many hours. Make sure everything remains only lukewarm at most when charging!

 

[SoulEV2016]

no, it's normal.

i have made my wiring for the minimal power supply.
1,5mm² = 10A constant current at 230v, max 16A for 3h only.
usually, i charge at 4,8A (all days) or 8A (1 time per month).

it's only for the test (efficiency is not impacted, like i see in the spec. of the OBC = 110-240v AC).

 

[SoulEV2016]

effect of ramping voltage when the pack is full = decrease of efficiency.

Free LOGS in CSV : http://up.sur-la-toile.com/i1ins

 

[SoulEV2016]

And when you travel from 80 to 100% with SOC displayed on dashboard, the efficiency is low, too ... (67 to 64%).
Blue line is the restriction of regenerative brake (or Chademo Fast Charge).

:mrgreen: too bad that the Chademo is not allowed to reach the max voltage like the internal charger.
the internal charger can output full power at 100% of SOC displayed on dashboard (95% of SOC from the BMS).

so ... if it can, the BMS only restrict to 48kW at 100% SOC displayed on dashboard.

this point is interesting because normal regenerative braking (without touch the brake pedal) is 43kW in agressive driving.

Free LOGS in ODS format (libreoffice) : http://up.sur-la-toile.com/i1inA

 

[SoulEV2016]

With 15min of charge at 1,1kW and then at 2,2kW.

 

[SoulEV2016]

Graphic from a 2,2kW charge at -5°C
To validate the 3 temperatures probes on OBC canbus.
Climate 1 & 2 work together (brown line).

 

[SoulEV2016]

Displayed by TORQUE PRO : in charge (after 2h at -5°C).

After 1 night at -9°C.

 

[SoulEV2016]

End of a charge from 95% to 100% at 2,2kW at 0°C.

Free LOGS (ODS format - Libreoffice) : http://www.4shared.com/file/yJ9XHcZTce/trackLog-2017-janv-18_13-59-33.html (mirror = https://www.sendspace.com/file/zgbt88 )

 

[SoulEV2016]

strangely, i don't have a real gap between the 1,1kW and the 2,2kW EVSE setting ... like Torque Pro indicate.

1,1 kW.

temperature deviation = 3,2°C.

2,2 kW.