Cheapest/fastest EVSE for existing 240v garage socket?

[ThreeEyes]

Hi all, we're buying an i3 and hoping for some advice for our specific garage setup.

We already have a 240v socket in our garage for our clothes dryer.

We would like to use the existing single socket. Is it OK to use a splitter there as long as we don't charge the car and dry clothes simultaneously?

What is the best EVSE that can:

- Plug into a socket rather than hardwire into house
- Work with our solar roof panels ideally
- Offer fastest charging

Thanks!

 

[jadnashuanh]

Need to know how big the circuit breaker is that feeds that receptacle, and, the type of the receptacle. The EVSE only needs the two hots and ground, but if it has a neutral, it won't matter.

If it is a 30A circuit, the biggest EVSE you can use is a 24A one because the rules in the USA require using no more than 80% for things that may run for longer periods of time. This one is 20A, and probably has the plug you need, but they make others as well. I like the fact that they are made in the USA... http://www.clippercreek.com/store/product/lcs-25p-20a-240v-charging-25-cord-nema-14-50-plug/

I'm not sure about the electrical code about daisy chaining to a second outlet, but it should work, and if you can use the same plug, no problem at all just swapping as needed. You'd quickly trip the breaker if both things were turned on at the same time.

To get the maximum charging on an i3, you need a 30-32A EVSE, and the smallest circuit you can use is a 40A if you hardwire it, or a 50A if you want to plug it in (there are no 40A rated plugs, so you must make things match by bumping things up).

 

[alohart]

What is the best EVSE that can:

- Plug into a socket rather than hardwire into house
- Work with our solar roof panels ideally
- Offer fastest charging

A JuiceBox might be worth considering. The JuiceBox 30 would charge your i3 at the maximum speed but would have to be set to output a lower current if your dryer circuit isn't capable of providing 30 amps continuous. You would need to replace its standard plug or buy an adaptor to match your outlet. A disadvantage of this model is that it has no status lights like most of its competitors. It isn't UL-listed which bothers some people, but is generally less expensive than its competitors.

The JuiceBox Pro 40 includes a WiFi transceiver and smartphone app that allows one to monitor and control the JuiceBox, so no status lights are needed. Not only would it charge your i3 at maximum speed if your dryer circuit has the necessary capacity, but it has the capacity to charge at 40 amps continuous which supports future EV's. It, too, would need its plug replaced or an adaptor purchased. This model is undergoing UL certification although it hasn't yet received a UL listing. Its cost is a bit higher than lower capacity EVSE's without WiFi.

JuiceBoxes are also made in the U.S.

 

[ThreeEyes]

Thanks guys. I'm trying to find out from my electrician what the amperage is.

How long would each of the above 2 EVSE take to fully charge the i3 approximately?

Are there any considerations or disadvantages to cheaper systems if we have solar panels on the house? I've heard some EVSE can communicate with the solar box but I'm not clear what advantage that brings.

 

[jadnashuanh]

My take on EV panels is that IF you can charge while they are outputting their max, you need to determine what your baseline load is, and how much excess you could be sending back to the grid. That's the ideal size of your EVSE. If you only recharge at night, it really doesn't matter since you're using borrowed energy from the grid, or from your storage bank (which would need to be bigger by the nominal load).

The i3 can handle 7400W at any one time. It tapers off the demand as the battery approaches max, and may start out slower if the battery is too hot at the beginning, using some energy to cool them first.

7400/240=30.83A at that rate, it would take about 3.5h to recharge a nearly depleted i3 battery. FWIW, my normal line voltage is averaging 245VAC, so 245*30=7350, or essentially at full rate. European specs are peak, the US specs are average, so a 30A USA spec is essentially equivalent to a 32A European unit.

The i3's battery lets you use nearly 19Kw of power, and the recharging circuit is not 100% efficient and it may need to cool things in the process, so you need to put in more power than the battery actually stores...for rough numbers, figure maybe 20Kw.

So, your answer really depends on how many watts you can use at any one time, and how many you need to refill the battery. Taking our 20,000W/7400W max gives you 2.7 hours. But, it does not use the EVSE's maximum output the whole time, so that's why they say around 3.5 hours.

A 20A unit with 240vac input produces 4800W. If your voltage was 230V, 20*230=4600W, 220v, 20*220=4400W. Many EVSE websites have charts for typical vehicles, but you can figure it out for yourself.

Power=volts*amps, and the max the i3 can use is 7400. Anything less, slower recharging rates. Note, a smaller output may not take quite as long as may first be inferred because charging at a lower rate means less heat and therefore cooling, but given that it must occur longer, not much. Depends somewhat on ambient. THe difference may not be as great as it first appears because of that fact.

 

[ThreeEyes]

Great answer. So roughly speaking:
30A EVSE = 3.5 hrs
20A EVSE = 4.5 hrs
?

 

[jadnashuanh]

Great answer. So roughly speaking:
30A EVSE = 3.5 hrs
20A EVSE = 4.5 hrs
?

Approximately...maybe a little closer to 5 hours. It depends on the temperature, your voltage, and how big your battery actually is (yes, I know they all start out the same size, but functionally, they can vary sample to sample, and day to day a little bit). IOW, stating an exact time is tough. BMW says 3.5 to (4) hours and they don't always say the 4hours part because it just depends...then, most people don't run their battery dry...the times stated are for max. If you only have used 50% of the charge, it will take half as long to recharge it verses if you parked and the SOC just reached zero!

Note, the supply voltage to the EVSE can easily change 10vac or more on a day to day or hour to hour basis, and since power=volts*amps (and the amps is a constant), changing the voltage up or down will mean more or less power available to put into the batteries. Hot, muggy summer day, and the voltage may drop quite a bit as everyone starts cooking dinner and turning up their a/c units!

 

[ThreeEyes]

My electrician has confirmed we have 40A socket. The JuiceBox seems cool but doesn't look cool. Would you guys agree the next best for value, performance and looks is the EV Power Pros 7.2 kW?

Edit: That said, does the Android app make the JB worthwhile? Could it help us with solar charging configs, or switching between using our electric dryer on the same circuit?

 

[alohart]

My electrician has confirmed we have 40A socket.

I'm guessing that you meant to write "40A circuit" because no 40A sockets (outlets) exist in the U.S. What does your electrician say about installing a 50A outlet on your 40A circuit? Some people contend that this isn't allowed so that an EVSE connected to a 40A circuit must be hardwired. Others say that a 30 or 40A electric range circuit is allowed to have a 50A outlet, so why wouldn't the same apply to an EVSE?

The JuiceBox seems cool but doesn't look cool.

It is rather plain, but you could decorate its cast aluminum case to your liking

Would you guys agree the next best for value, performance and looks is the EV Power Pros 7.2 kW?

I had never heard of this EVSE until you mentioned it. I couldn't find it on EV Power Pro's Website, so maybe they don't sell it retail to individuals. I wanted to find some more detailed information about it, but was unable to learn much about it. There were a couple of complaints on Amazon about some of the units buzzing while charging. That's almost certainly the coil of the large relay that's in all EVSE's. I wonder about the quality of that relay if some of them buzz.

A serious limitation pointed out by some users was its incompatibility with timed charging as set in one's car. This EVSE apparently won't start charging except when the car is set to charge immediately; i.e., if one sets his car to start charging at a later time, the EVSE won't start charging. Many i3 owners use delayed charging to take advantage of off-peak electricity rates or to condition their battery packs and cabin in cold or hot weather. Because this EVSE doesn't seem to work with delayed charging, I wouldn't buy it.

Edit: That said, does the Android app make the JB worthwhile? Could it help us with solar charging configs, or switching between using our electric dryer on the same circuit?

Being able to monitor and control one's EVSE using a smartphone app is appealing to me, but it requires the JuiceBox being able to join one's WiFi network. Our apartment parking space is way out of our apartment's WiFi range, so I couldn't use that functionality. I also don't like my EVSE using electricity at all times even when not charging.

The JuiceBox smartphone app would allow you to reduce the EVSE's charging current (even while charging) so that it doesn't exceed what your solar panels are producing. If you are charging your car and need to use your dryer, you could use the smartphone app to stop charging so you could use your dryer, and then you could use the smartphone app to resume charging after the dryer has finished.

The only JuiceBox model with WiFi and a smartphone app is the $599 Pro 40, so the less expensive JuiceBoxes don't have this capability.

 

[I33t]

That Juicebox Pro40 looks to have a good set of specs for a very reasonable price. They suggest an IOS iphone app is in the works, and the unit can be controlled via the web anyway. It also enables remote control of charging which is something not common in EVSE's.

alohart, do you know what the standby power draw is?

Anyone here have one?

 

[ThreeEyes]

My electrician has confirmed we have 40A socket.

I'm guessing that you meant to write "40A circuit" because no 40A sockets (outlets) exist in the U.S. What does your electrician say about installing a 50A outlet on your 40A circuit? Some people contend that this isn't allowed so that an EVSE connected to a 40A circuit must be hardwired. Others say that a 30 or 40A electric range circuit is allowed to have a 50A outlet, so why wouldn't the same apply to an EVSE?

Thanks for the informative reply alohart. And yes, 40A circuit not socket

If I have a 40A circuit, which I do, can I install the JuiceBox Pro 40 and just plug it into my existing 4-prong wall socket – the same one the dryer uses?

 

[Schnort]

it probably is not the same plug as your dryer.

My Siemens EVSE has a 3 prong plug. I think this is pretty standard for plugged EVSE.

I considered the juicebox, but it wasn't eligible for my rebate because it isn't UL certified (or wasn't at the time, if it is now)

 

[alohart]

If I have a 40A circuit, which I do, can I install the JuiceBox Pro 40 and just plug it into my existing 4-prong wall socket – the same one the dryer uses?

All JuiceBoxes are delivered with 14-50 plugs. EMotorWerks sells adaptors from 14-50 to other common receptacles. Which do you have?

If your clothes dryer receptacle is rated at 30 amps, then I would defer to an electrician to advise whether passing a continuous 30 amps through this receptacle would be safe. You might be limited to 80%, or 24 amps. But if your circuit is 40 amps, an electrician might install a 14-50 receptacle so that you could plug in a JuiceBox without any adapter. I've read that an outlet that's rated higher than the circuit can't be installed (e.g., a 14-50 receptacle on a 40 amp circuit), but I've also read that it's OK to do so.

Regardless, you would need to set the JuiceBox's maximum charging current to be no more than the maximum that the circuit and receptacle allow to avoid tripping a circuit breaker or damaging an outlet.

 

[ThreeEyes]

Thanks! I have a 14-50. So I can just plug in the JB and go?

 

[alohart]

Thanks! I have a 14-50. So I can just plug in the JB and go?

To be safe, you should set the JuiceBox's maximum charging current to be 32 amps, the maximum continuous current that's safe on a 40 amp circuit. But even if you don't do this, your i3 won't request more than 30 amps. However, when your buddy with a Tesla Model S, Toyota RAV4EV, or Mercedes B Class ED visits and asks for a charge, the JuiceBox would happily allow 40 amps continuous which would heat up your circuit wiring a bit and eventually trip the circuit breakers.

 

[TonyWilliams]

Thanks! I have a 14-50. So I can just plug in the JB and go?

To be safe, you should set the JuiceBox's maximum charging current to be 32 amps, the maximum continuous current that's safe on a 40 amp circuit. But even if you don't do this, your i3 won't request more than 30 amps. However, when your buddy with a Tesla Model S, Toyota RAV4EV, or Mercedes B Class ED visits and asks for a charge, the JuiceBox would happily allow 40 amps continuous which would heat up your circuit wiring a bit and eventually trip the circuit breakers.

Yes, a 40 amp charge station plugged into a 40 amp circuit is not proper (many electricians will hang their hat on the fact that NEC allows it because there are no 40 amp outlets). Our JESLA plugs into a NEMA 14-50 plug and is coded to properly pull 40 amps, but can also be plugged into lower amperage outlets with the proper plug without exceeding the 80% capacity of that outlet.

Not cheap, but quality rarely is:

http://shop.quickchargepower.com/JESLA-is-THE-40-amp-J1772-portable-charging-solution-JESLA.htm

 

[ThreeEyes]

The Jesla is literally not quite a Tesla but it looks very nice!

 

[jadnashuanh]

As long as you can adjust the EVSE internally for something legal based on the circuit involved.

 

[Jaypi]

You could also get nrg for a monthly payment & no one time fees.

http://www.nrgevgo.com/los-angeles-basin/

 

[ThreeEyes]

You could also get nrg for a monthly payment & no one time fees.

http://www.nrgevgo.com/los-angeles-basin/

Is this generally considered good value? What about if I have solar panels on the roof and generate part of my own electricity power?