What conditions need to met for the Fastchargers to give me max KW Charging?

jerkwagon

jerkwagon

New Member
I know battery temps are important and battery level as well, but what are the conditions?

I have a 2021 Kona and according to sites it says "Fastcharge Power (max) 77 kW DC"

I have a hard time getting over 50 kw let alone 77kw. A few days ago i plugged into a 50kw charger and was at 8% battery and was only getting 24kw from the charger. It was around 25c.

anyone know what are the optimal conditions for high KW chargings?
 
jerkwagon said:
I know battery temps are important and battery level as well, but what are the conditions?

I have a 2021 Kona and according to sites it says "Fastcharge Power (max) 77 kW DC"

I have a hard time getting over 50 kw let alone 77kw. A few days ago i plugged into a 50kw charger and was at 8% battery and was only getting 24kw from the charger. It was around 25c.

anyone know what are the optimal conditions for high KW chargings?
Click to expand...
I googled the charging rate for a 2021 Kona and was surprised that Hyundai says charging 10% to 80% at 100 kW DC is only 1 minute quicker than at 50 kW! Sounds like the charging curve doesn't allow full 100 kW charging to proceed for very long.

KONA Electric's lithium-ion polymer battery only takes about 47 min to charge from 10% to 80 % state of charge (SOC) when using a 100 kW direct current (DC) fast-charger station. If connected to a 50 kW station, this charging time is 48 min.
 
insightman said:
I googled the charging rate for a 2021 Kona and was surprised that Hyundai says charging 10% to 80% at 100 kW DC is only 1 minute quicker than at 50 kW! Sounds like the charging curve doesn't allow full 100 kW charging to proceed for very long.

KONA Electric's lithium-ion polymer battery only takes about 47 min to charge from 10% to 80 % state of charge (SOC) when using a 100 kW direct current (DC) fast-charger station. If connected to a 50 kW station, this charging time is 48 min.
Click to expand...

thanks but did you read my question? you failed to acknowledge any part of it..
 
As you stated, battery temp is a big factor; For the NMC battery chemistries like what the Kona uses, optimal battery temp should be between 70F (21C) and 80F (27C).

SOC is another major factor and most vehicles will peak between 40% and 50% SOC, except Tesla (maybe just older Teslas?) that peak at like 5% and decline steadily from there. Vehicles that have a low max charging speed like the Bolt of Kona can potentially sustain that peak for longer, to 70-80%.

But honestly the single biggest factor in practice is the CCS charger you're plugged into not being broken somehow. It is entirely possible your lower-than-expected charging speeds is because the charger(s) you are using have been power restricted or have some kind of fault. It's disgustingly common...
 
jerkwagon said:
thanks but did you read my question? you failed to acknowledge any part of it..
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Sorry I didn't elaborate. I forged ahead with my answer without asking what your state-of-charge was at the beginning of your charging session. The "optimal conditions for high KW chargings" occur when your traction battery is at a low SOC.

I found that the info I copied is different in different places. On this Hyundai page, it says for the 64 kWh battery:
When using a 100 kW direct current (DC) fast-charger station, KONA Electric’s lithium-ion polymer battery only takes about 47 min to charge from 10% to 80 % state of charge (SOC). If connected to a 50 kW station, this charging time is 64 min [48 minutes for the 39.2 kW battery]. This page doesn't say what the max charging rate is.

I searched this forum for "temperature" and "charging" and found this post, which says: "I have found a strong dependence of range on the temperature of the car during charging."
 
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insightman said:
Sorry I didn't elaborate. I forged ahead with my answer without asking what your state-of-charge was at the beginning of your charging session. The "optimal conditions for high KW chargings" occur when your traction battery is at a low SOC.

You quoted "sites" claiming a 77-kW limit, but the Hyundai information I found says your Kona can charge at 100 kW. Furthermore, the information I copied for you indicates your Kona can charge at higher than 50 kW only for a minute or two before it limits itself to a 50-kW charging rate. That's why charging on a 100-kW DC charging station is only a single minute quicker than charging on a 50-kW DC charging station.

I searched this forum for "temperature" and "charging" and found this post, which says: "I have found a strong dependence of range on the temperature of the car during charging."
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Can only get 100 kW charge with a Kona during a hard braking regen. When DC plugged in, 77kW is max and most I ever saw was 76kW, very briefly.
 
My observed max was 78, maybe 79 kW briefly, at SoC less than 60% and my OBD2 widget said the
battery max temp was 98.6 degF (funny that). Summer roadtrips to FL and back, at 150 kW EAs.
Started ramping down around 68 - 70%.

_H*
 
insightman said:
Sorry I didn't elaborate. I forged ahead with my answer without asking what your state-of-charge was at the beginning of your charging session. The "optimal conditions for high KW chargings" occur when your traction battery is at a low SOC.

I found that the info I copied is different in different places. On this Hyundai page, it says for the 64 kWh battery:
When using a 100 kW direct current (DC) fast-charger station, KONA Electric’s lithium-ion polymer battery only takes about 47 min to charge from 10% to 80 % state of charge (SOC). If connected to a 50 kW station, this charging time is 64 min [48 minutes for the 39.2 kW battery]. This page doesn't say what the max charging rate is.

I searched this forum for "temperature" and "charging" and found this post, which says: "I have found a strong dependence of range on the temperature of the car during charging."
Click to expand...


thanks, i yeah i stated i was at 8% (SOC) i was shocked to only get 26kw it was listed as a 50kw charger..
 
I have read on here were some chargers are not reliable ie. EVgo. Were you on Petro Can or Electrify Canada?

Have you checked the reviews of the station on plug share? The station you were at may be notorious for poor charging and the station being the problem and not the SOC or temperature.
 
aamyotte said:
I have read on here were some chargers are not reliable ie. EVgo. Were you on Petro Can or Electrify Canada?

Have you checked the reviews of the station on plug share? The station you were at may be notorious for poor charging and the station being the problem and not the SOC or temperature.
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Likely a BC Hydro Chargepoint 50 kW unit which are notorious for intermittent charge rates, even the ABB machines don't fare much better at times.
Bad communication...which is another reason to switch to per/Kw rather than time based;)
 
aamyotte said:
I have read on here were some chargers are not reliable ie. EVgo. Were you on Petro Can or Electrify Canada?

Have you checked the reviews of the station on plug share? The station you were at may be notorious for poor charging and the station being the problem and not the SOC or temperature.
Click to expand...
this was a chargepoint DC in port coquitlam. ill check the reviews, i honestly think its my car.. i dont think i have ever had over 30kw, and i normally only use DC to top up so i can make it home, so adding 20-40 kms tops..
 
jerkwagon said:
this was a chargepoint DC in port coquitlam. ill check the reviews, i honestly think its my car.. i dont think i have ever had over 30kw, and i normally only use DC to top up so i can make it home, so adding 20-40 kms tops..
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Can you try a charging station that claims to deliver 350 kW? That would eliminate the charging station from the chain of suspicion.
 
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jerkwagon said:
yeah thats what i dont get, i was at 8% SOC and only getting 26kw from a 50 kw charger. temp was aroun 24-27c
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The temperature on the graph is the battery temperature and not outside temperature. With a OBD2 reader, you can get these readings. There are 4 temperatures readings of the battery. When the lowest reading reaches the value in the table, you get the maximum power.

On 50kW charger, the maximum power is obtain when battery temperature reached 15C. In this case, you can maintain it up to 72%.
 
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herode10 said:
The temperature on the graph is the battery temperature and not outside temperature. With a OBD2 reader, you can get these readings. There are 4 temperatures readings of the battery. When the lowest reading reaches the value in the table, you get the maximum power.

On 50kW charger, the maximum power is obtain when battery temperature reached 15C. In this case, you can maintain it up to 72%.
Click to expand...


this could be the problem.. i did drive it for a bit so maybe the batteries were warmer , definitely was not 15c..
 
jerkwagon said:
I know battery temps are important and battery level as well, but what are the conditions?

I have a 2021 Kona and according to sites it says "Fastcharge Power (max) 77 kW DC"

I have a hard time getting over 50 kw let alone 77kw. A few days ago i plugged into a 50kw charger and was at 8% battery and was only getting 24kw from the charger. It was around 25c.

anyone know what are the optimal conditions for high KW chargings?
Click to expand...

With the conditions you described, the battery temperature was definitely optimal. The 50kW station had probably a problem. It should have maintained it's max amperage of 125A. At 8%, the battery charging voltage is around 330V, Power should have given you about 41kW. I don't think the car was limiting the power.
 
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