What if you don't have enough juice for 100 amp panel

[swngdncr]

As I gain more information, options for charging the Lightning are falling off the list. I'm not an electrician so there is a big learning curve here. Looks like a separate dedicated meter is not an option, we'd have to upgrade to 400A service and it would cost 20K and take a year or more. So, this is what we are working with:

• 200A Main Panel
• 100 amp sub panel in garage w/240V circuit on 60A breaker, plus 20/20/15 110v breakers for lights/plugs
• The 240V circuit no longer needed for other uses, could be repurposed to eV charging

Question: Can we put an 80 Amp breaker in place of the existing 60 amp breaker and reassign that circuit to the FCSP, and charge at a lower rate if needed when running other things in the garage? Or do we buy a 48Amp EVSE from Amazon which would work with the existing 240V circuit. Appreciate advice from those more knowledgeable out there. I did find an electrician to come out, but the education here helps me have a more productive/educated discussion with the electrician and ask the right questions. Thanks.

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[Stlww18]

You can only replace the 60A with an 100A if the wire gauge is appropriate for the 100A circuit (it's unlikely it is). Even though the FCSP only pulls 80A you have to have a circuit rated for 100A. You can, however, derate the FCSP to an appropriate amperage to match the existing circuit.

 

[webspoke]

Easiest option, no re-wiring, re-use the 60A/240 circuit for the FCSP - and reconfigure the FCSP for 48A instead of 80A - no need to buy a different charger. That gets you up and running, with still reasonable recharge times.

If you need a way to charge while waiting for the FCSP, have your electrician add a 14-50 outlet on the same circuit - you can use the included with truck mobile charger on that one, it will charge at 32A.

 

[jefro]

You manage load center by it's load calculation. You can't just put in a new higher breaker any more than you can put a 10A fuse in a 8A location to keep it from blowing. Well you can but you get smoke as a result usually if lucky.

You need to calculate how much energy you need to replace on a typical day. Then you manage evse current setting from there.

Remember that an evse is one of the "continuous load" device that have to be on a higher amp circuit. So a 60A circuit is needed for a 48A charge setting. That would have to be hard wired I think.

Your use may allow you to use a lower current adjustable evse. Many are adjustable and either a smart of dumb charger. You may not need or want a smart charger unless you want to pay more for a few options.

 

[greenne]

Easiest option, no re-wiring, re-use the 60A/240 circuit for the FCSP - and reconfigure the FCSP for 48A instead of 80A - no need to buy a different charger. That gets you up and running, with still reasonable recharge times.

If you need a way to charge while waiting for the FCSP, have your electrician add a 14-50 outlet on the same circuit - you can use the included with truck mobile charger on that one, it will charge at 32A.

Unless you are using the backup power system ..48A is still enough juice to charge overnight for most applications. Unless you drive 100mi a day 48A should be enough for a good overnight charge...

I'd just reconfigure the charger for 48A and call it a day...

 

[swngdncr]

Thanks for the feedback/education. I started reading the unboxing installation thread, and this confirms what I was thinking would be the case. We just set it to 48A and be done with it. We don't need to charge overnight, I'm retired and can charge anytime during off peak, midnight to 3PM... But, it doesn't look like there will be any economically reasonable way to do the HIS if we need to spend 20K to upgrade our service. I'm still hoping for an off grid solar charging solution.

 

[greenne]

Thanks for the feedback/education. I started reading the unboxing installation thread, and this confirms what I was thinking would be the case. We just set it to 48A and be done with it. We don't need to charge overnight, I'm retired and can charge anytime during off peak, midnight to 3PM... But, it doesn't look like there will be any economically reasonable way to do the HIS if we need to spend 20K to upgrade our service. I'm still hoping for an off grid solar charging solution.

My opinion, the HIS is expensive for what it is. It requires a very specific electrical situation to work. If backup power is needed, you could probably find a whole home generator for less money and hassle.

 

[hturnerfamily]

Many of these 'charging' threads revolve around those 'new to EVs' who have no experience with charging an electric vehicle, and how the 'lectricity needs work. Most of it is OVERKILL.

Stick with the easy stuff - you can always 'upgrade' later, but if you've spent $5,000 to upgrade a panel, and install equipment you ultimately find you didn't really 'need', it's too late.

By the way, even if all you have is a 120v outlet, it will still charge your truck. Don't overthink it.

Most owners will use the included Mobile Charger on a NEMA 14-50 outlet, with 30amps of charging to handle most ALL situations - it's VERY RARE to ever 'need' any more.

 

[LagSwag1]

Fwiw I got my quote from my electrician today to upgrade from 150A to 400A service and it's only 3500 and will be done as soon as they get a 400A main in. So might be worth looking into if you haven't gotten a quote already. If your 20k number is from a quote, then that's rough and I am sorry.

 

[swngdncr]

Yeah, it's California. I talked to an electrician who is in the process of getting his upgraded, similar situation as ours. He has been working with PG&E for 9 months already, and told me it was going to be 15-20K. PG&E rep called and told me basically the same thing 15-20K and a year or more. They would have to run a new service line from the street, which is about 150'' of trenching and cable. Then, the service goes under the house, so I don't know if they'd have a way of pulling the wires under the house, but it's a major undertaking. Oh well... at least we have one option we know will work.

Fwiw I got my quote from my electrician today to upgrade from 150A to 400A service and it's only 3500 and will be done as soon as they get a 400A main in. So might be worth looking into if you haven't gotten a quote already. If your 20k number is from a quote, then that's rough and I am sorry.

 

[Amps]

If you don’t do anything but re-purpose what you have, you’re looking at a charging rate that replaces ~18-23 miles range per hour of charging using 2 mi/kWh as truck consumption. I think you’ll be fine.

 

[VTbuckeye]

My typical daily driving is less than 30 miles, often less than 20 miles. This should be replaceable with 120Vx12 amps. However, when it is hot and the battery cooling is active the actual charge rate going into the battery will be less than 1.4KW. When it is cold (single digits to teens) 1.4KW may not actually put any net charge into the battery after the heating system tries to warm the battery while charging. In those temps our other EV spends the first 10 to 30 minutes (temperature dependant) just warming things before adding range to the battery. Sometimes a garden hose is a great choice, sometimes a fire hose is the best choice. 30amp charging will likely be enough for most people, but often it is better to have the capacity and not need it than to need it and not have it. We have natural gas for heat and hot water, so our big electric uses are car charging, one 1800btu window AC unit (likely to become mini split heat pump in the next years), electric dryer and electric range. When our solar gets installed we will upgrade from 100amp service to 200amp. This will accommodate our two 30 amp EVSEs and our fcsp. We will not be using all three at once. The fcsp will be for fast charging at home as be the 30 amp EVSEs will be for our routine charging overnight.

 

[swngdncr]

Yup, that will be plenty for us 95% of the time. Plus, we still have the gas vehicle, if we need to make a long trip and another one before the truck can recharge sufficiently, then we either go to a charge station or take the ICE vehicle... We don't need a 100% solution that costs 10x as much as a 90-95% solution.

If you don’t do anything but re-purpose what you have, you’re looking at a charging rate that replaces ~18-23 miles range per hour of charging using 2 mi/kWh as truck consumption. I think you’ll be fine.

 

[jefro]

You shouldn't set it to 48A charge on a 50A outlet. You are supposed to derate a continuous load 25% so you set a 50A to 40A evse charge rate.

One can replace 30 miles on a 16A 240VAC evse easily. Close to loss or loss on heating winter.

 

[Maquis]

Unless you are using the backup power system ..48A is still enough juice to charge overnight for most applications. Unless you drive 100mi a day 48A should be enough for a good overnight charge...

I'd just reconfigure the charger for 48A and call it a day...

Whether or not the backup power is used is irrelevant to the charge current setting of EVSE.

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