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Discussion Starter · #1 ·
I am on Long Island and we have lost power and will be without power through Thursday/Friday. This is not unusual where I live. We lose on average power 4 to 5 times per year.

We have a whole house Generac 20KW standby automatic generator powered by natural gas. We are fine. The 20KW can handle two central AC, dryer, range, etc. - all our house needs.

If I use the Ford charging station, 32 amps, 240 volts, how do I determine whether or not my 20KW generator can handle charging my MachE?

I am mechanical, but the calculations are beyond my ability and when I went to the Internet I could not figure out how to use the calculators.

I am sure there is a simple conversion.

Thanks in advance!

(PS: Of course with an ICE this was not a concern - just another thing to think about with a BEV)


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If everything is running off of 240v then your max output is roughly 83amps. I don't know your driving habits but it might be wiser in your power outage situations to use the charger at 120v to ensure you have enough amperage for your household vitals.
 

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Discussion Starter · #3 ·
Thanks:

My generator has "shedding": the AC are not priority: the AC will only come on when there is enough power - if not they are "shed". So if everything is running, and I plug in at 240 volts, and there is not enough power, the transfer switch will "shed" turn off the AC.

Can you show the formula to arrive at 83 amps?

Thanks.
 

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Thanks:

My generator has "shedding": the AC are not priority: the AC will only come on when there is enough power - if not they are "shed". So if everything is running, and I plug in at 240 volts, and there is not enough power, the transfer switch will "shed" turn off the AC.

Can you show the formula to arrive at 83 amps?

Thanks.
Watts=Volts X Amps
Amps=Watts/Volts
 

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Discussion Starter · #5 ·
The Ford charger that comes with the MachE is 32 amps, 240 volts. Is that then 7,680 watts or .7680 KW?

I would think it would be more.
 

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Discussion Starter · #7 ·
Got it and thanks!

My 20 KW generator will be more than sufficient to carry the Ford charger and at least one AC or maybe even two!

Good news!
 

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Yep, unless you have really big AC's --- both ON will be less load then the Ford Charger.
Remember also, the Ford Charger can be controlled via the wifi app to a much lower load
if you have all night to make your desired charge level.

If you have an electric hot water heater --- that will be a high load when on, close to 6 KW.
 
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Discussion Starter · #9 ·
Yep, unless you have really big AC's --- both ON will be less load then the Ford Charger.
Remember also, the Ford Charger can be controlled via the wifi app to a much lower load
if you have all night to make your desired charge level.

If you have an electric hot water heater --- that will be a high load when on, close to 6 KW.
Thanks!

Appreciate the quick reply!

I do not have an electric hot water heater.
 

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Thanks:

My generator has "shedding": the AC are not priority: the AC will only come on when there is enough power - if not they are "shed". So if everything is running, and I plug in at 240 volts, and there is not enough power, the transfer switch will "shed" turn off the AC.

Can you show the formula to arrive at 83 amps?

Thanks.

Depending on the transfer switch on your Generac system, you can add extra smart management modules (up to 8) to even out the load. The real reason for these modules is to smooth out the power transfer when the generator starts up. Many items have a high start up current but a much smaller run time current. You A/C units are a good example. The 20 kw Generac generator would never be able to handle everything in the home starting up all at once. So they added these modules to start up the large draw appliances in a timed sequence. And as you said, if the load on the generator exceeds the rating of the unit, it begins to shed loads temporarily. You get to pick in what order your system will shed the connected loads. It is a good system.

In Florida with a mostly electric home, we have 8 of the SMM units connected to our 22kw generator. The 40A Juicebox EVSE is one of them.

Hope this helps.

Jim
 

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Discussion Starter · #11 ·
Depending on the transfer switch on your Generac system, you can add extra smart management modules (up to 8) to even out the load. The real reason for these modules is to smooth out the power transfer when the generator starts up. Many items have a high start up current but a much smaller run time current. You A/C units are a good example. The 20 kw Generac generator would never be able to handle everything in the home starting up all at once. So they added these modules to start up the large draw appliances in a timed sequence. And as you said, if the load on the generator exceeds the rating of the unit, it begins to shed loads temporarily. You get to pick in what order your system will shed the connected loads. It is a good system.

In Florida with a mostly electric home, we have 8 of the SMM units connected to our 22kw generator. The 40A Juicebox EVSE is one of them.

Hope this helps.

Jim
Thanks:

Yes it does.

I fully understand what you are saying in theory: that start up current is much higher than running current and that is the reason for the delay in adding first one zone of AC, then a second zone of AC after the generator has been running for 5 minutes.

When I get my charger, I will have my Generac dealer put the circuit for the charger on shedding, to come on after the AC units. Doing this beyond "my pay grade". Again in theory I know what I want done, but I cannot go into the transfer switch and actually do that.
 

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If you do not feel comfortable working inside of the breaker panel, then don't!

You know what needs done. You Generac installer will be able to do it very quickly. And the SMM units are not that expensive.

It is waiting the next 75 days until my MME Premium is here that is the hard part! But it is not like I am counting days or anything..... 😉

Jim
 

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It might appear to be insignificant currently to repurchase an up generator on the grounds that at the present time you have power. You are not stressed as of now. You simply need to tap the switch and there it is. Bill toward the month's end comes to your direction and you pay.
 
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