working on a 120v fast charger. Good idea or waste of time?

[Rocky_H]

PIT AREA UPGRADE KEEPS US 131 ON THE CUTTING EDGE

Oh, that's cool. It says they're going to be replacing most of the regular 120V outlets with 14-50 outlets, because they're planning it for more of the campers and motor homes that they expect. Nice of Tesla to realize that mobile home outlets are like the common U.S. go-to standard for remote electricity and therefore made that their standard charging plug. It kind of obviates the need for this battery charging device at this particular track, though.

@Zooomer Where someone mentioned using DC directly to charge, there are mobile CHAdeMO charging units that some places sell in 10kW and 20kW power levels that are about the size of a large roller suitcase. They're kinda expensive, though, at approximately $4,000 or $8,000 respectively. If you search for "mobile CHAdeMO" or "portable CHAdeMO", you can find some listings.
EVTV Motor Verks Store: 20 kW CHAdeMO Portable Fast Charger, Battery Chargers, 20kwchademo
Portable CHAdeMO or CCS Combo DC Quick Charger

 

[Sophias_dad]

View attachment 373284 View attachment 373284 DC solar does this. seems like they are just off the shelf components. tow it with the 3.. lol
Products | DC Solar Solutions

They had offered my City 10 of them around town as remote charging stations. We are still chatting about it..

The battery in that thing is enormous! Its 48kwh right there, I found a slightly larger one for ~$7100, or a 24v x 408Ah(9.8kwh) for only ~$1500... but its 472 lbs.

 

[Tozz]

My suggestion does not bypass the circuit breakers. 12A is 12A, if there's too much current flowing either or both breakers will trip. The only possible fault condition would be one leg tripping and one remaining live... which will make the car stop charging.

If one outlet has the line and neutral reversed it would result in the adapter outlet only having 120v on it. The 120v neutral wires are not hooked up in the adapter.
-J

Hmm, my bad. You are indeed correct, my mistake. My thinking was wrong.

 

[Zooomer]

It stores 44 amp-hours at 12 volts, or about 528 watt-hours. So, in order to feed your hungry Tesla 10kwh, one time, you'll need an array of 20 such batteries. Have you done the math on the cost of such batteries?

No, there's no 120V involved in the capacity of a battery, unless I suppose its a 120V battery! It doesn't matter how fast or slow they charge, they can store only so much power, in this case volts times amp hours equals watt hours.

You don't need a battery that stores 10KW to feed the car 10KW when you are plugged into multiple 120 sources. That's my point. There would never be a situation trying to top the Tesla off on battery alone. The point of my thread is "fast 120 charger" not 'how to fill your tesla off car batteries'

@Zooomer Where someone mentioned using DC directly to charge, there are mobile CHAdeMO charging units that some places sell in 10kW and 20kW power levels that are about the size of a large roller suitcase. They're kinda expensive, though, at approximately $4,000 or $8,000 respectively. If you search for "mobile CHAdeMO" or "portable CHAdeMO", you can find some listings.
EVTV Motor Verks Store: 20 kW CHAdeMO Portable Fast Charger, Battery Chargers, 20kwchademo
Portable CHAdeMO or CCS Combo DC Quick Charger

thanks much. I'll dig in.

*Checked into it. Those do not have batteries. They are simply AC to DC converters that allow the user to bypass the vehicle's inverter. It takes high amp 240 and converts to DC allowing you to charge the car. Tons of money for what it does.

I'm getting convinced that what I'm building doesn't exist in the market, however exporting into CHAdeMO is a better solution as it would bypass my inverter to 240 and the vehicle's inverter. You could just charge batteries and feed the vehicle with them. You wouldn't be able to use the Tesla packs tho. You'd have to use 12v batteries. 33 of them, each charged by a 120 to 12v converter. So 32 batteries, 32 chargers (12.5v*32=400v). Batteries in series to feed the CHAdeMO output. Problem then is you have a fixed solution. You couldn't charge off 1 or 2 or 3 120v sources. You'd have to know what you were charging from initially as the chargers would be discreet to the batteries they were charging. Wiring would be fixed. I don't like that....

**thought about it some more. You'd use 24 volt chargers and charge batteries 2 in series but overlap the chargers. So 1st charger would charge batteries 1/2 in series. 2nd charger would charge batteries 2/3 in series and so on. That way you could do it on one or two 120 sources.

 

[cbutters]

Two of those batteries + a quick220 adapter might work.

Although I will say.... what are your timeframe requirements? Its going to take a powerwall sized battery to give any meaningful charge quickly; even then it will take hours and hours.

the battery in the video is a 4kwh battery, two of them would get you 8kwh
each battery could maintain about 800 watts for hours at a time. so you are only getting 1.6kw of power being delivered at any given time; that only gets you ~6.5 miles charge per hour on a model 3, and could only charge for 4-5 hours; account for inefficiencies and you might get 24 miles in 5 hours on this setup.

 

[davewill]

Seems pretty unpractical. It'll be too heavy to carry around, and if it's to be permanently installed, the money would be much better spent on running a 240v outlet. Not to mention that people might get a little frosted if you hog 2 or 3 circuits just to charge one car a little faster.

 

[Leeclanual]

Easier to get the track to install a/multiple 14-50 outlet(s)... sell them that more performance EVs will race.

 

[Big Earl]

You don't need a battery that stores 10KW to feed the car 10KW when you are plugged into multiple 120 sources. That's my point. There would never be a situation trying to top the Tesla off on battery alone. The point of my thread is "fast 120 charger" not 'how to fill your tesla off car batteries'


thanks much. I'll dig in.

*Checked into it. Those do not have batteries. They are simply AC to DC converters that allow the user to bypass the vehicle's inverter. It takes high amp 240 and converts to DC allowing you to charge the car. Tons of money for what it does.

I'm getting convinced that what I'm building doesn't exist in the market, however exporting into CHAdeMO is a better solution as it would bypass my inverter to 240 and the vehicle's inverter. You could just charge batteries and feed the vehicle with them. You wouldn't be able to use the Tesla packs tho. You'd have to use 12v batteries. 33 of them, each charged by a 120 to 12v converter. So 32 batteries, 32 chargers (12.5v*32=400v). Batteries in series to feed the CHAdeMO output. Problem then is you have a fixed solution. You couldn't charge off 1 or 2 or 3 120v sources. You'd have to know what you were charging from initially as the chargers would be discreet to the batteries they were charging. Wiring would be fixed. I don't like that....

**thought about it some more. You'd use 24 volt chargers and charge batteries 2 in series but overlap the chargers. So 1st charger would charge batteries 1/2 in series. 2nd charger would charge batteries 2/3 in series and so on. That way you could do it on one or two 120 sources.

Please fix your units. kW is power (like horsepower) and kWh is energy (like gallons of liquid fuel). Batteries store energy in kWh.

To add 10 kWh of energy to your car in one hour, you would need to charge at 10 kW for one hour (~40 amps @ 240 volts).

If your hypothetical battery bank is plugged into two 120 volt outlets and pulling 12 amps on each, it's receiving 2.8 kW of power from the wall. To add 10 kWh of energy to your car in one hour, the battery pack would need to supply the remaining 7.2 kWh of energy. Once you account for losses, you'd probably want two Tesla modules for a total of 10.6 kWh of energy storage. Going rate on Tesla modules right now is about $1,500 each.

 

[Zooomer]

If you remove the batteries altogether, you could build a device that allowed charging off of 2 120 sources at the same time. That alone would be highly useful for most. I think that's the point people miss here saying it's impractical or there's no market. There are a bunch of threads and people wanting to go electric who don't have or can't charge on 240. Asking if 120 would be enough for their commute. Normally it's not. With my device, it would be (regardless of whether it used batteries.

Looking for some wisdom for choosing 75D vs 100D
Posts all the time of people wanting to charge on 120. ASking if it's possible.

 

[ecobra]

From normal 110 outlets you are limited to a little over 1 kw (110 x 12 amps if you are plugged to an extension cord, 15 if you are plugged directly in). So you need to chain 6-8 of them together to get the power to get the 8-10 kw for a base Tesla single charger and twice that many for the dual / upgraded chargers that you may have in your garage. This is not practical and will end up being dangerous and probably the subject of a 'Hold my beer' photo.
To get fast charging at a track, they either need a super charger, or you need some battery system with a CHAdeMO interface / cable.
That said, I only ever had 1 chance to drive my car faster than I could recharge it on a 6 kw generator at the track and that was because everyone early and 5 of us had the track to ourselves.
My background - About 6 years ago I designed and tested a DC fast charger, I was one of many, it worked, but our company didn't get the funding needed to continue.

 

[Big Earl]

Once the track installs 50 amp outlets for RVs, you'll be able to charge at 7 kW (32 amps max provided by the gen 2 mobile connector), which will add about 10% to the Model 3's battery in one hour.

 

[David99]

There could be a situation where such a device might be useful, not very cost effective, though. Depending on how much energy you want to be able to store in that battery determines the majority of the cost.

With 2 120 Volt outlets combined, you can charge aprox 90 miles over night (12 hours). That's a good amount of driving you can do daily and costs you nothing but a few good cables.

The maximum you can harvest in addition would be the remaining 12 hours of the day where you are not home. To capture all that energy, your battery would have to be able to store aprox 30 kWh. That'll cost you around $7500. Add the cost for a good 240 Volt inverter, chargers, rack and wiring. A total of $10k at least. That's a lot of money to be able to charge 90 miles extra. For less money you can get a dedicated 240 Volt outlet installed even when the panel is far from the parking spot.

 

[SammichLover]

Also, many tracks are going to have 240V receptacles for welders.

Ding! Although I found out yesterday I'm going to need to either spend $85 on a NEMA 6-50 adaptor for my UMC or get/do some electrical work to install a NEMA 14-50 plug.

Alternately, start work on pushing through a Tesla DC install which would be sweeter yet, or try find a beat-up old Gen 1 HPWC in a bargain bin somewhere and install that. 11kW > 7kW.

Found I'm currently draining about 20-22kWh/20 min session (likely to raise with rise in skill, I think?). With a pre-driver's meeting charge up to 90% and 11kW charging, that's bringing it down to (22kWh - 7.2kWh)/75kWh that's only 17% to 20% charge net loss per session on an hour rotation. If you've got a down session during that time you're near zero net SOC drop for that.

 

[cbutters]

There is no such thing as a 120V fast charger for EVs with 70+kWh packs. /thread

 

[mspohr]

There is no such thing as a 120V fast charger for EVs with 70+kWh packs. /thread

You could have RTFT to see that he is thinking of using a battery to provide fast charging. This battery would be recharged by 120v. So, yes, it is possible to do 120v fast charging.

 

[cbutters]

You could have RTFT to see that he is thinking of using a battery to provide fast charging. This battery would be recharged by 120v. So, yes, it is possible to do 120v fast charging.

I did read it; (notice that I already replied earlier in the thread with a potential off the shelf solution).
The point is; he wants a solution that runs off 120v to charge his car at the race track. The point is; If you have a battery large enough to cart to the track with you; it already has more power than you could possible pull over 120V over the course of a day at the track; thus the 120V is irrelevant.

For example: Let's pretend he gets there at 6am and race time is at 10AM, thats 4 hours that he has to charge. Using a standard 120V outlet he cant pull more than 1.44kw out of that outlet. 1.44kw * 4 hours = 5kWh

5 measly kWh... Thats only enough to charge a model 3 5% and if you include charging losses its probably only 3% by the time it goes out of the wall-> portable battery -> car charger and then ->the model3's battery.

So yeah its fine if you want to get a giant 100 kwh battery and take it to the track with you; that could be useful; but don't pretend that he could build anything that is going to charge with any reasonable utility out of a 120V outlet at an event that only lasts a few hours; it is not possible given the constraints of that type of outlet.

 

[mspohr]

I did read it; (notice that I already replied earlier in the thread with a potential off the shelf solution).
The point is; he wants a solution that runs off 120v to charge his car at the race track. The point is; If you have a battery large enough to cart to the track with you; it already has more power than you could possible pull over 120V over the course of a day at the track; thus the 120V is irrelevant.

For example: Let's pretend he gets there at 6am and race time is at 10AM, thats 4 hours that he has to charge. Using a standard 120V outlet he cant pull more than 1.44kw out of that outlet. 1.44kw * 4 hours = 5kWh

5 measly kWh... Thats only enough to charge a model 3 5% and if you include charging losses its probably only 3% by the time it goes out of the wall-> portable battery -> car charger and then ->the model3's battery.

So yeah its fine if you want to get a giant 100 kwh battery and take it to the track with you; that could be useful; but don't pretend that he could build anything that is going to charge with any reasonable utility out of a 120V outlet at an event that only lasts a few hours; it is not possible given the constraints of that type of outlet.

Here's more math.
Tesla battery module 24v 5 kWh hooked up to a 240 volt 10kW inverter to provide fast (L2) charging. Charge the Tesla 5kWh in 30 minutes. Could add more battery modules for more charging.
OK, now we need to recharge the battery for the next run. 120v 20 amp circuit provides 2.4 kW or 1.9 kW continuous. This can recharge the battery module in 2 hours. Add a second 120v 20 amp circuit and can recharge in 1 hour (1C rate).

 

[Rocky_H]

I did read it;

Apparently not very well.

Using a standard 120V outlet he cant pull more than 1.44kw out of that outlet. 1.44kw * 4 hours = 5kWh

Right there you demonstrate how you either didn't read or didn't understand what he was proposing. He's talking about being able to plug into several 120V outlets--not just one--to collect and pool energy to then dump into the car. So the power level he's looking to use would be more like 6 to 10 kW if he could plug into 4 or 5 outlets.

But again, this is all kind of moot since the article was posted earlier about how this particular race track is upgrading to add a lot of 14-50 outlets.

 

[Runt8]

If you remove the batteries altogether, you could build a device that allowed charging off of 2 120 sources at the same time. That alone would be highly useful for most. I think that's the point people miss here saying it's impractical or there's no market. There are a bunch of threads and people wanting to go electric who don't have or can't charge on 240. Asking if 120 would be enough for their commute. Normally it's not. With my device, it would be (regardless of whether it used batteries.

Looking for some wisdom for choosing 75D vs 100D
Posts all the time of people wanting to charge on 120. ASking if it's possible.

Quick220?

110-120 and 220-240 Voltage Converters & Accessories

 

[diamond.g]

Has the Model 3 started working with the chademo adapter?