Help w sticker shock over adding amp to detatched garage

[ebennett22]

We are having sticker shock in advance of our MR model 3 delivery--quoted $5,500 in GA to install 100 amp. We have a detached garage that is 75 yards from the house panel. We have 20 amp today in the detached garage. All but $650 is for trenching/labor/etc. What have other people done to solve? Has anyone trenched themselves? I am worried about handling that amperage myself.

What do people do for remote garages? Run in the air? Buried cable? The world's longest extension cord? Looking for ideas to reduce this terrible price tag. Thanks in advance.

 

[skitown]

We have a Model S that charges on a 50 amp circuit with a HPWC and a Model 3 that charges at 20 amps with its UMC.

With some experience under our belt I can say that 20 amps for a Model 3 could work for us for as our only option. Granted we have the option to charge it with the HPWC but never do. You may want to try just using 20 amp for a while if that’s a “free” option. Just a thought.

 

[Raechris]

Wow - I was told the wire is the expensive part and a voltage drop was likely over that distance. You certainly don’t need 100amp, car can’t handle more than 60amp line (48 to car). Do you have any power in garage now? I was shocked () to find my 15amp/240 clipper creek does just fine for the last year.

 

[lencap]

I feel your pain, but I think there is a solution. The MR M3 can't use all the energy from a 100 AMP circuit. In fact Tesla recommends a 40AMP circuit for that model. A 40 AMP circuit on the M3 is very efficient - provides 30 miles/hour of range. The maximum that any M3 can process is 44 miles/hour on a 60 AMP circuit, and that is determined by the internal charging capacity. My understanding is that the MR model tops out at 40 AMP service. The link is here: Wall Connector

Check the owners manual (online PDF version) for more info.

If 40 AMP is all the car will handle it will be a LOT less expensive to run the 75 yards of cable to the garage. It should cut your installation price significantly. I don't know if there are any EV rebates for charging stations in your area, but if they exist they can further cut your costs.

I have a 40AMP Clipper Creek J1722 connector that was installed for my Nissan Leaf and both BMW i3s. Works fine on the Tesla, and the charge rate is very close to 30 miles/hour. Tesla includes the J1722 adaptor with their standard charging cable, another saving. (I have the LR M3 RWD - no longer offered and I'm very glad I ordered it before they shifted to AWD only for the LR battery).

Good luck - you'll love the car.

 

[Evbwcaer]

Have you considered just living with the 20amp, that will get you around 7 miles per hour I would guess?

There are people on this forum who have converted a 5-20, which is a 120v/20a and what I think you have now, to a 6-20, which is a 240v/20a. Apparently it is very cheap, using the existing wire and is all legit if your wiring is fairly modern. For this to work there can only be the single outlet on the circuit. (get a 12v garage door opener, small solar panel and battery if your opener is on the same circuit) I'm guessing a that would be around 16 miles per hour for a Model 3.

Tesla sells both a 5-20 adapter and a 6-20 adapter, $35 each.

Convert NEMA 5-20 to 6-20?

 

[ewoodrick]

We are having sticker shock in advance of our MR model 3 delivery--quoted $5,500 in GA to install 100 amp. We have a detached garage that is 75 yards from the house panel. We have 20 amp today in the detached garage. All but $650 is for trenching/labor/etc. What have other people done to solve? Has anyone trenched themselves? I am worried about handling that amperage myself.

What do people do for remote garages? Run in the air? Buried cable? The world's longest extension cord? Looking for ideas to reduce this terrible price tag. Thanks in advance.

Find another contractor and get a different price. If you can find someone to just do the trenching, you may could also work deal with an electrician. Running 100A at 100 ft and trenching 75 isn't going to be cheap, unless you want to do the trenching.

 

[skitown]

Have you considered just living with the 20amp, that will get you around 7 miles per hour I would guess?

There are people on this forum who have converted a 5-20, which is a 120v/20a and what I think you have now, to a 6-20, which is a 240v/20a. Apparently it is very cheap, using the existing wire and is all legit if your wiring is fairly modern. For this to work there can only be the single outlet on the circuit. (get a 12v garage door opener, small solar panel and battery if your opener is on the same circuit) I'm guessing a that would be around 16 miles per hour for a Model 3.

Tesla sells both a 5-20 adapter and a 6-20 adapter, $35 each.

Convert NEMA 5-20 to 6-20?

I’m under the impression I see more like 15 miles per hour at 20 amps on the Model 3.

Wall Connector

 

[Evbwcaer]

I’m under the impression I see more like 15 miles per hour at 20 amps on the Model 3.

Wall Connector

That is at 240 volts. You probably have a 20 amp at 120 volts now. Does it look like this:

 

[spaghetti]

I can confirm getting 15 miles/hr using a NEMA 6-20 adapter from Tesla and using the UMC.

 

[SM18]

Mid Range Model 3 maxes out at 32 amp charging capacity from a 40 amp circuit; which yields 30 miles of range per hour of charging. You'd be getting 15miles/hr using your existing 20 max amps. I recommend just digging it yourself and saving $5k. Invite some friends and family to help and treat them to pizza or a BBQ after.

 

[Evbwcaer]

I can confirm getting 15 miles/hr using a NEMA 6-20 adapter from Tesla and using the UMC.

Is that on Model 3?

 

[brkaus]

Not sure about your layout. Consider 20a charging in the garage, and a 14-50 somewhere on the house you can use if needed?

 

[Evbwcaer]

Mid Range Model 3 maxes out at 32 amp charging capacity from a 40 amp circuit; which yields 30 miles of range per hour of charging. You'd be getting 15miles/hr using your existing 20 max amps. I recommend just digging it yourself and saving $5k. Invite some friends and family to help and treat them to pizza or a BBQ after.

I believe this is not correct. The original poster's 20 amp outlet, I suspect, is 120 volts. 40 amp circuits are, to my knowledge, always 240 volts. So the OP would have half the power because half the volts, so about 7mi/hr.

 

[lencap]

According to the Tesla charging chart, linked in my earlier post, a 20AMP circuit will provide 16AMP throughput to the M3-MR, giving 15 miles/hour range. If you charge overnight on your 20AMP circuit you should have at least another 150 miles of range for your morning drive. That's quite a bit - far more than my Leaf or either of my BMW i3s had. You may also want to limit your charge to 80% of battery capacity (seems to be based on an Elon tweet suggesting keeping the battery charged from 30-80%). If you charge to 80% that implies a range of 208 miles or so, which would take less than 14 hours if your battery pack was fully depleted when you began charging, which is highly unlikely. I'd say start with your 20AMP circuit, use the provided Tesla adaptors and you may find that you're fine with what you have!

 

[spaghetti]

Is that on Model 3?

Yes

 

[ebennett22]

Thanks for this idea! We will investigate. I'm worried our wiring is ancient (guessing 30+ years old but I can investigate further). We have a ring camera, 2 lights, and a wall socket all on this circuit today. But darkness beats paying $5.5k.

We considered 100 amp since the electrician said the cost increase was nominal and we thought we'd prepare for a 2nd EV someday.

 

[skitown]

That is at 240 volts. You probably have a 20 amp at 120 volts now. Does it look like this:

Ahh I stand corrected. It’s actually on a 240v 30 amp circuit that was existing when we bought the house. I do have the car dialed down to 20amps just to baby the outlet as I guess I don’t trust whoever installed it. Regardless my estimate is irrelevant.

 

[Evbwcaer]

Does running the 100 amp require upgrades to your home's electrical service? I guess what I am asking is does your panel have room for an additional 100 amps now? There could be a ton of money in upgrading the whole system to accommodate an additional 100a, whereas if you ran 40 amps to the garage you might not need the upgrade at your main panel and could save that way.

 

[IslandHydro]

It may be that a good portion of the bid is in the ditch work (since that's not in their wheelhouse). If you do your own ditching, leave the electrical to the electrician, you might save a chunk and still not end up doing things you're not qualified for.

 

[ebennett22]

Hi, I may be a little confused. Today we have a NEMA 5-15 120 volt (common household outlet). Not sure if it's 15 or 20 amp yet--it's really cold out today.

According to Tesla's website, the most we could expect for 1 hour of charging is 3 miles of range. My commute is short but not that short.

Thanks!