Question about ChargePoint Homeflex Amps

[Ngkgb]

I just had the Homeflex charger hardwired and when I was setting it up it asked for the Brraker Amperage, which is 50. Does this mean it will charge at 50 Amps? I don’t see any way to chose the actual amps when charging. Am I missing something?

thanks

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[jayazusa]

It will charge at 40a they plan for 20% overage.

 

[jollyroger]

you need a 70 amp breaker to charge at 50 amps.

 

[Ngkgb]

It will charge at 40a they plan for 20% overage.

Thanks. That makes sense.

 

[Ngkgb]

It will charge at 40a they plan for 20% overage.

Quick question. In the energy screen in the truck it says it’s charging at 42A. Is it safe to assume that only 40A are going through since it’s charging at 9.37 kw according to the ChargePoint app?

 

[MtnRiv]

So you have 2 things going on:

1) The truck can receive a maximum of 48A. The the truck is selected to only receive a MAX of 42A based on your description.

2) The ChargePoint Flex in its Hardwired configuration can safely charge at 48A if it is paired with a minimum 60A breaker. On install, the tech should have set the dip switches in the charger to do a max rate based on the breaker size. If you are seeing 9.37kwh, your flex charger might only be set to deliver a MAX of 40kw.

If the truck is set to receive a MAX of 42A and the charger will only give 40A, then the truck will only get 40A.

if the truck is set to 48A and the charge point is set to a max of 40A, you will still only get 40A.

if the truck is set to 32A and the charge point is set to 40A, you will only get 32A.

basically, the truck cannot pull more amps than the charger can give. The truck can limit the amps it takes in through the software. You have a 50A breaker, so it should be set charge at a max of 40A. If it is a 60A, is should be set to deliver a max of 48A. If it is a 70A, it could be set to a max of 50A, but the Rivian can’t receive 50A anyway. The breaker is upsized to allow for the constant amperage, not just peak amperage. It’s a safety measure as it would likely cause a fire if it was improperly sized.

hope that helps

 

[Polar]

Yes - the truck is making assumptions.

Your best source will be your charge point app - use that.

 

[Ngkgb]

So you have 2 things going on:

1) The truck can receive a maximum of 48A. The the truck is selected to only receive a MAX of 42A based on your description.

2) The ChargePoint Flex in its Hardwired configuration can safely charge at 48A if it is paired with a minimum 60A breaker. On install, the tech should have set the dip switches in the charger to do a max rate based on the breaker size. If you are seeing 9.37kwh, your flex charger might only be set to deliver a MAX of 40kw.

If the truck is set to receive a MAX of 42A and the charger will only give 40A, then the truck will only get 40A.

if the truck is set to 48A and the charge point is set to a max of 40A, you will still only get 40A.

if the truck is set to 32A and the charge point is set to 40A, you will only get 32A.

basically, the truck cannot pull more amps than the charger can give. The truck can limit the amps it takes in through the software. You have a 50A breaker, so it should be set charge at a max of 40A. If it is a 60A, is should be set to deliver a max of 48A. If it is a 70A, it could be set to a max of 50A, but the Rivian can’t receive 50A anyway. The breaker is upsized to allow for the constant amperage, not just peak amperage. It’s a safety measure as it would likely cause a fire if it was improperly sized.

hope that helps

Thanks! That does help! I turned the Amp setting in the truck down to 40 and it didn’t change the rate so I think it was always just pulling 40.

 

[Riviot]

I'm technically only an amateur electrician in this state, but I also had one hardwired to 50amps. It's pretty easy to turn off your main breaker, change dip switches, replace the 50amp breaker with a 60amp breaker (don't go cheap! And torque appropriately) and turn main back on.

 

[Trinculo73]

I'm technically only an amateur electrician in this state, but I also had one hardwired to 50amps. It's pretty easy to turn off your main breaker, change dip switches, replace the 50amp breaker with a 60amp breaker (don't go cheap! And torque appropriately) and turn main back on.

Please DO NOT do this unless you can also confirm that the wire between the breaker panel and your home charger is #4 wire or better. #6 wire is not rated for 48a continuous, and if the installer used a 50a breaker it's pretty likely they used #6 wire because it's 30% cheaper

 

[Ngkgb]

I'm technically only an amateur electrician in this state, but I also had one hardwired to 50amps. It's pretty easy to turn off your main breaker, change dip switches, replace the 50amp breaker with a 60amp breaker (don't go cheap! And torque appropriately) and turn main back on.

I asked about upgrading to a 60Amp breaker but electrician said it’s not a good idea since my panel is only 100 A. I didn’t really question him. 50A breakers serves our need fine.

 

[Ngkgb]

Please DO NOT do this unless you can also confirm that the wire between the breaker panel and your home charger is #4 wire or better. #6 wire is not rated for 48a continuous, and if the installer used a 50a breaker it's pretty likely they used #6 wire because it's 30% cheaper

This is correct. They used a #6 wire. Previous electrician had used only a #8, which may have been the reason for the outlet burning necessitating the new install.

 

[ndmiller]

I get 25 miles per hour at home on my Chargepoint Flex with 50 amp breaker (@40 amps 9.2KW). That's 200 miles overnight, plenty as I only charge to 70% ~250 miles.

 

[Ngkgb]

I get 25 miles per hour at home on my Chargepoint Flex with 50 amp breaker (@40 amps 9.2KW). That's 200 miles overnight, plenty as I only charge to 70% ~250 miles.

I’m also getting about 9.4 according to ChargePoint app

 

[Riviot]

Please DO NOT do this unless you can also confirm that the wire between the breaker panel and your home charger is #4 wire or better. #6 wire is not rated for 48a continuous, and if the installer used a 50a breaker it's pretty likely they used #6 wire because it's 30% cheaper

Indeed, I forgot to mention this, hence the amateur hour. Our electrician used leftover #4 wire after connecting our home generator with an 80amp subpanel.

I asked about upgrading to a 60Amp breaker but electrician said it’s not a good idea since my panel is only 100 A. I seedidn’t really question him. 50A breakers serves our need fine.

Ah that makes more sense. Subpanel or main? If main, you should look into utility subsidized upgrades and getting part of the cost back on taxes. We had an old Stab-Lok panel at the cabin and replaced it to 1. put the Rivian charger on it there (#4 wire) and 2. those things are scary AF fire hazards. We got 30% back on the tax return since it was a required upgrade for EVSE, and $1k from the utility for upgrading from 100 to 200.

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