With Level 2 charger, is it better/safer to charge at lower currents/power?

astronut325

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Hi All,

Just one question. I'm planning to get a level 2 charger installed in the next few days in my garage. I ordered the Grizzl-E classic charger. The question I have is... is it better/safer for the battery if I charge at a lower amp/power rating?

I'm going to get a 50 amp circuit feeding the Grizzl-E. I'm planning to use the 40 amp config to get the fastest possible charge. That said, I don't need the fastest possible charge vast majority of the time. Is it better for the battery longevity if I charger at lower amp ratings such as 32 amps, or even 24 amps? Any scientific data on this? I've been Googling and I don't see anything beyond just people on forums.

Any input is appreciated.
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TD1273

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Hi All,

Just one question. I'm planning to get a level 2 charger installed in the next few days in my garage. I ordered the Grizzl-E classic charger. The question I have is... is it better/safer for the battery if I charge at a lower amp/power rating?

I'm going to get a 50 amp circuit feeding the Grizzl-E. I'm planning to use the 40 amp config to get the fastest possible charge. That said, I don't need the fastest possible charge vast majority of the time. Is it better for the battery longevity if I charger at lower amp ratings such as 32 amps, or even 24 amps? Any scientific data on this? I've been Googling and I don't see anything beyond just people on forums.

Any input is appreciated.
I don’t know of any type batteries that prefer high amp charge but sometimes you have no choice when you have EV. I can tell that’s all I’ve charge with since I purchased this car is at home with 48 amps which works out to about 10.92 kWh and takes about 6 hours
 

Mach-Lee

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Is it better for the battery longevity if I charger at lower amp ratings such as 32 amps, or even 24 amps? Any scientific data on this? I've been Googling and I don't see anything beyond just people on forums.
No, they're all so slow it will not impact battery longevity. The max L2 rate (11.5 kW) is still considered a slow charge based on the size of the battery (98.8 kWh). You don't have to worry about battery charging impacting the life of the pack until you are charging at 50 kW or more (0.5C).

If you want to learn more, read about battery C rates. A 1C rate would be 98.8 kW, 2C=198 kW, etc.

I would set it to the max of 40A, and only reduce if you have problems with the charging equipment overheating (shouldn't if properly installed). The battery won't care.
 

alexgorod

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I used a lower current a few times when it was hot in the garage so the car doesn't turn the noisy fan on.
 

BalsaDust

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I have the same Grizzl-e EVSE in my garage and yes charging at the max 40 amps will not degrade the battery, you are using more amps for a shorter time which may impact the rest of the house if a stove is on, dryer is running and the ac is blasting.
Since I charge mainly at home once or twice a week, i adjusted the amperage down to 32 amps to hopefully reduce stress on the house current draw and less heat build up in the evse wiring.
My electric supplier doesnt have off peak rates so I charge any time its needed but try to do overnight charging whenever possible.

Tony
 


Polar

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48 amps which works out to about 10.92 kWh and takes about 6 hours
Love seeing voltage differences, they are so cool to see in practice. My 48 amp will charge my MachE at 11.25kW/hour per my HomeFlex.
 

RickMachE

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Yup.
 

yngwenli

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Only reason I see to charge at a lower rate is to never tap the grid or your ESS (home batteries if you have them).

I don't have enough solar generation to completely charge from solar even at the 32 Amp rate (7.7 kW).
 

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I chose to lower the amperage on my Chargepoint Home unit to 32 amps (it is capable of up to 48) for two reasons:

1) above 32 at 40A the cooling system was engaged to keep the inverter (AC to DC) cool and the fan was rather noisy in my garage.
2) Due to the cooling requirements it became apparent that there are energy losses at higher amperage charging.

The 32A charging easily fulfilled nearly all of my charging needs with only the rare occasion (once in six months) where I arrived home at a low SoC that it could not get back to my target of 90% by morning.
 

RickMachE

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I chose to lower the amperage on my Chargepoint Home unit to 32 amps (it is capable of up to 48) for two reasons:

1) above 32 at 40A the cooling system was engaged to keep the inverter (AC to DC) cool and the fan was rather noisy in my garage.
2) Due to the cooling requirements it became apparent that there are energy losses at higher amperage charging.

The 32A charging easily fulfilled nearly all of my charging needs with only the rare occasion (once in six months) where I arrived home at a low SoC that it could not get back to my target of 90% by morning.
This is eliminated with TSB 21-2278, which I had applied last Fall. It came out in August last year. Charging at 48amps yields no noise.

I also charge at 32amps 99.9% of the time as it's during off-peak and usually done in the first hour.
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