J1772 to CHAdeMo black box

emotor werks has a DC fast charge unit - Smart charge 12000 that inputs ac or dc and outputs dc hi current.
Why not put a J1772 receptacle to input 240v ac from a hi-current Level 2 and output to the DC input port? This unit would cost about 2500, and be capable of charging a Leaf in about 1 hr, provided you can draw 70 amps from the Level 2. It would weigh about 25lb.

Why not? Because it would cost at least $2500 (probably more), and 70a J1772 charging stations are exceedingly rare. The vast majority of public charging stations only give 208V @ 30a, which is a pretty paltry improvement even for Leafs with 3.3 kW chargers.

But if you come across higher-power charging stations a lot or other higher power sources (RV parks can give you nearly 10 kW, although you wouldn't need the J1772 inlet for that), and you don't come across public Chademo stations, and you really need the fast charging for some reason, then it might make sense to invest in such a thing.

I think this would be interesting. In Canada, Sun Country Highway is putting in mostly 70a EVSEs (CS90) so this could be quite beneficial to Leaf owners.

muus said:

I think this would be interesting. In Canada, Sun Country Highway is putting in mostly 70a EVSEs (CS90) so this could be quite beneficial to Leaf owners.

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That is the singular area where this product would have any logical use.

The input would largely be 70a * 208v = 14.6kW

Then, the charger might be 90% efficient, so 13.1kW

So, it would take about 1:45 minimum to fill up the LEAF battery... not "an hour".

It's just slightly more than twice as fast as a typical 30 amp public J1772, compared to a 6.6kW charger LEAF. Obviously, it's a huge improvement for the 3.3kW charger LEAF's.

One final note. 300-400 volts of DC energy is seriously dangerous. YOU CAN BE KILLED; NOT "SHOCKED"... KILLED.

Because these units are neither CHAdeMO approved, nor are they all "isolated" per the CHAdeMO specifications, you place increased risk on yourself with their use.

TonyWilliams said:

muus said:

I think this would be interesting. In Canada, Sun Country Highway is putting in mostly 70a EVSEs (CS90) so this could be quite beneficial to Leaf owners.

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That is the singular area where this product would have any logical use.

The input would largely be 70a * 208v = 14.6kW

Then, the charger might be 90% efficient, so 13.1kW

So, it would take about 1:45 minimum to fill up the LEAF battery... not "an hour".

It's just slightly more than twice as fast as a typical 30 amp public J1772, compared to a 6.6kW charger LEAF. Obviously, it's a huge improvement for the 3.3kW charger LEAF's.

One final note. 300-400 volts of DC energy is seriously dangerous. YOU CAN BE KILLED; NOT "SHOCKED"... KILLED.

Because these units are neither CHAdeMO approved, nor are they all "isolated" per the CHAdeMO specifications, you place increased risk on yourself with their use.

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Great explanation! So is there any way to make a CHAdeMO-compliant AC-to-CHAdeMO portable converter/charger? An 80a 240v=19320w which would go 0-80% in about the same time as a 50kW. Reference for this is ... somewhere.

Thanks for the feedback. I've looked at the cost and its probably closer to $5000+ Canadian.
Meanwhile infrastructure here is still sadly lacking, so the best bet here is still a greater range Leaf battery pack. 2017?
And yes I'm fully aware of the dangers with DC voltage. I have a very solid background in electrical, electronics and industrial safety too.

dsny said:

So is there any way to make a CHAdeMO-compliant AC-to-CHAdeMO portable converter/charger? An 80a 240v=19320w which would go 0-80% in about the same time as a 50kW. Reference for this is ... somewhere.

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It exists "off the shelf" - if you're willing to spend $25k. https://andromedapower.net/ap-shop/" onclick="window.open(this.href);return false;

dsny said:

Great explanation! So is there any way to make a CHAdeMO-compliant AC-to-CHAdeMO portable converter/charger? An 80a 240v=19320w which would go 0-80% in about the same time as a 50kW. Reference for this is ... somewhere.

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Umm... wait, what? I know this is a little bit of an old post, but with the thread bumped up...
19320W = 19.32kW. Obviously 19kW and 50kW won't charge at the same rate, as Tony explained in the earlier post.

ishiyakazuo said:

Obviously 19kW and 50kW won't charge at the same rate, as Tony explained in the earlier post.

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Of course 50kW will charge faster, but the thing is that the Leaf won't sustain the full 50 kW for much of the charging cycle, if at all, so in most cases it won't be twice as fast or anywhere near that. The duration of near-50 kW charging might only be from 0-10% SOC, but I'm just guessing - Tony would have the real numbers I'm sure. After that, the rate of charge will gradually slow, so whether the charger's nameplate is 20 kW or 50 kW will make less and less of an impact and eventually won't make any difference at all after reaching a certain level of charge. For the hypothetical 0-80% charge there'd be maybe a 15 minute difference, while for a more realistic 30-80% charge the difference might not be any more than a couple minutes, and if charging above 80% there'd be no difference at all in that segment.

fooljoe said:

ishiyakazuo said:

Obviously 19kW and 50kW won't charge at the same rate, as Tony explained in the earlier post.

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Of course 50kW will charge faster, but the thing is that the Leaf won't sustain the full 50 kW for much of the charging cycle, if at all, so in most cases it won't be twice as fast or anywhere near that. The duration of near-50 kW charging might only be from 0-10% SOC, but I'm just guessing - Tony would have the real numbers I'm sure. After that, the rate of charge will gradually slow, so whether the charger's nameplate is 20 kW or 50 kW will make less and less of an impact and eventually won't make any difference at all after reaching a certain level of charge. For the hypothetical 0-80% charge there'd be maybe a 15 minute difference, while for a more realistic 30-80% charge the difference might not be any more than a couple minutes, and if charging above 80% there'd be no difference at all in that segment.

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Your numbers still don't work out... Let's crunch them, shall we?
80% of a full-capacity 24kWh battery is 19.2kWh.
Using a 19.3kW source, it will take almost exactly an hour to charge to 80%, assuming it's pulling at the maximum current draw the entire time, so 2x slower for that section if everything else is optimal (i.e. not "in about the same time as a 50kW" CHAdeMO).
Now, I know that the actual capacity used for "0%" and "80%" are probably not actually 80% of 24kWh apart, but for the sake of discussion, it's probably similar enough to the losses the charger will incur.
Still, a 1 hour charge to 80% is still better than 3~6 using the L2 EVSEs.

ishiyakazuo said:

I know that the actual capacity used for "0%" and "80%" are probably not actually 80% of 24kWh apart, but for the sake of discussion, it's probably similar enough to the losses the charger will incur.

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Not really. The usable capacity when new is about 21.5 kWh, and 80% of that is about 17 kWh. Most of the Leafs on the road probably have at least 10% degradation (especially those old 3.3 kW ones that would be interested in this), so let's call it 15 kWh. If you assume that 20 kW could be maintained throughout the 0-80% range, then that would take just about 45 minutes to complete.

My guess was that you could only fully benefit from 50 kW for the first 10% of the charge, or 1.9 kWh, which would take 2.3 minutes at 50 kW or 5.7 minutes at 20 kW, saving only 3.4 minutes on the first 10%.

I didn't put numbers on the mid range, but let's suppose that from 10-40% the 50 kW will linearly degrade to 20 kW, giving an average of 35 kW. That means over that part of the charge you'll wait 9.8 minutes at "50 kW" or 17 minutes at 20 kW; another 7.2 minute savings, or only 10.5 minutes saved over the full 0-80% range.

So yeah, I think the math works out - as it should since I get to make up numbers! But the end result of 34.5 minutes for a 0-80% charge is not that far off from the advertised "30 minutes to 80%", especially since that probably assumes you're starting somewhere above 0%, so our made-up numbers probably aren't that far off.

JonO said:

emotor werks has a DC fast charge unit - Smart charge 12000 that inputs ac or dc and outputs dc hi current.
Why not put a J1772 receptacle to input 240v ac from a hi-current Level 2 and output to the DC input port? This unit would cost about 2500, and be capable of charging a Leaf in about 1 hr, provided you can draw 70 amps from the Level 2. It would weigh about 25lb.

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I've thought about the same thing with either using 2 to 3 standard (approx. 30 amp) public J1772s on the input side, a suncountry 70amp unit or the tesla 80 amp units that I've seen pop up at a lot of hotels. My usual route has 2 hotels with Tesla units and many sports with 3+ J1772s that are usually not in use at the late hours I come on. Without even considering if such a unit could be built, with the price to do it and the question of safety and reliability you'd be better off just getting a newer BEV or putting in a second or third charger unit. If you then put in a second J1772 inlet to charge at 9-12ish kW, everything would be sealed in the car and you'd only be touching J1772s which are safe. Price would probably be on par and someone has already done it.

[/http://www.upgrademyleaf.com/exam...of public charging for this to be worthwhile.

fooljoe said:

ishiyakazuo said:

I know that the actual capacity used for "0%" and "80%" are probably not actually 80% of 24kWh apart, but for the sake of discussion, it's probably similar enough to the losses the charger will incur.

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Not really. The usable capacity when new is about 21.5 kWh, and 80% of that is about 17 kWh. Most of the Leafs on the road probably have at least 10% degradation (especially those old 3.3 kW ones that would be interested in this), so let's call it 15 kWh. If you assume that 20 kW could be maintained throughout the 0-80% range, then that would take just about 45 minutes to complete.

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But you can't assume that! That's my point. If the source is 19kW AC, and there are losses in the conversion to DC, then you're in that same 15kW ballpark, hence, an hour.
Let's start with 240V * 80A = 19.2kW. That's generous because (a) that's pretty much the absolute limit of the J1772 spec, and (b) we're assuming that it isn't 3-phase power going into it. Yes, you could juice up the 240V to be closer to 264V, but now you're playing with fire... perhaps literally.
So, you're not getting 20kW maintained EVER.
Now, you've got losses in the cable (minimal), and the conversion (not as minimal). I'd say 80% is probably reasonable (similar to the charger inside the LEAF). So you've got a (maybe) reasonable upper limit of 15.36kW DC coming out. Hence, assuming we're talking about 15kWh of capacity in the battery to 80%, that is still an hour.

fooljoe said:

My guess was that you could only fully benefit from 50 kW for the first 10% of the charge, or 1.9 kWh, which would take 2.3 minutes at 50 kW or 5.7 minutes at 20 kW, saving only 3.4 minutes on the first 10%.

I didn't put numbers on the mid range, but let's suppose that from 10-40% the 50 kW will linearly degrade to 20 kW, giving an average of 35 kW. That means over that part of the charge you'll wait 9.8 minutes at "50 kW" or 17 minutes at 20 kW; another 7.2 minute savings, or only 10.5 minutes saved over the full 0-80% range.

So yeah, I think the math works out - as it should since I get to make up numbers! But the end result of 34.5 minutes for a 0-80% charge is not that far off from the advertised "30 minutes to 80%", especially since that probably assumes you're starting somewhere above 0%, so our made-up numbers probably aren't that far off.

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As I've shown above, you're nowhere near that in real life. Assuming a 15kW charge, and you don't even take decreasing the charge as it charges up into account, you've still got 59 minutes to wait, minimum.
But as I said, 1 hour (or even a little more, being realistic) is still better than 3-6.

minispeed said:

If you think of cost of doing this charge as paying you back for time spent sitting at a charger with just the stock charger going then in terms of $/hr you'd have to be a pretty heavy user of public charging for this to be worthwhile.

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Or on a long trip, where you don't want to spend more time waiting than driving...

ishiyakazuo said:

As I've shown above, you're nowhere near that in real life. Assuming a 15kW charge, and you don't even take decreasing the charge as it charges up into account, you've still got 59 minutes to wait, minimum.
But as I said, 1 hour (or even a little more, being realistic) is still better than 3-6.

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Agreed! My point is just to illustrate how the difference in charger ratings doesn't scale directly to differences in charging times. I pitted a hypothetical 20 kW (DC) charger against a hypothetical 50 kW one, but of course it's true that if you restrict the power input of this hypothetical charger to a J1772 source you won't be able to achieve 20 kW DC, and 15 kW is a fair estimate.

OK, fair enough
I'm just trying to temper real-world expectations for such a device (the thread title is, after all, "J1772 to CHAdeMO black box").
Still, for someone like me with a 32A EVSE at home, and a '12 LEAF with CHAdeMO, this might be worth it for me just to speed up the charging at home. This week we're going to have lots of thunderstorms, so getting up to 80% or so ASAP when the weather breaks temporarily might make this worthwhile.

ishiyakazuo said:

minispeed said:

If you think of cost of doing this charge as paying you back for time spent sitting at a charger with just the stock charger going then in terms of $/hr you'd have to be a pretty heavy user of public charging for this to be worthwhile.

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Or on a long trip, where you don't want to spend more time waiting than driving...

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Yes but if you add up all your long trips and 3hrs of extra charging (assume a 4hr charge vs 1hr) and divide that by the price, $5000, if you did it once a week for a year that's $32 per hour. If someone offered you $96 to wait 3hrs once a week in an ICE car trip what would you say?

If you're needing to charge at a J1772 publicly while waiting for more than once per week I'm sorry but you bought the wrong car.

minispeed said:

ishiyakazuo said:

minispeed said:

If you think of cost of doing this charge as paying you back for time spent sitting at a charger with just the stock charger going then in terms of $/hr you'd have to be a pretty heavy user of public charging for this to be worthwhile.

Click to expand...

Or on a long trip, where you don't want to spend more time waiting than driving...

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Yes but if you add up all your long trips and 3hrs of extra charging (assume a 4hr charge vs 1hr) and divide that by the price, $5000, if you did it once a week for a year that's $32 per hour. If someone offered you $96 to wait 3hrs once a week in an ICE car trip what would you say?

If you're needing to charge at a J1772 publicly while waiting for more than once per week I'm sorry but you bought the wrong car.

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Agreed! To be honest, there's zero chance I'd have bought a BEV at this point (except for maybe a Tesla) if I didn't have an ICE in my driveway as well. But for long-range trips, I'm still likely to end up renting a car at this point, simply because I'm 6'3" and there's no way I'm going to want to do any long trips in a Honda Fit...
But yeah, I'd definitely need more data on my cell phone plan to wait that long

ishiyakazuo said:

Agreed! To be honest, there's zero chance I'd have bought a BEV at this point (except for maybe a Tesla) if I didn't have an ICE in my driveway as well. But for long-range trips, I'm still likely to end up renting a car at this point, simply because I'm 6'3" and there's no way I'm going to want to do any long trips in a Honda Fit...
But yeah, I'd definitely need more data on my cell phone plan to wait that long

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Well I'm 6'4 and have a 78 mini that I've done 3 hr+ trips in, it's not not too bad and I did 3 months with 5.5 hrs each way every weekend in a 93 Miata. As a lover of small cars I find it's not so much the size of the car but the seats that matter. The other thing is the little details like flat door panels and a dash that doesn't take up knee room. I don't like the leaf seats at all for anything over an hour and I actually can't sit in the front passenger seat for any time without being uncomfortable. My knee hits the corner of the dash at a horrible angle. I think the only reason I don't notice it driving is because I'm use to keeping my foot straight to drive with instead of letting it relax like I do the left one. The first fit was notorious for having cheap seats, my dad and I test drove one and both of us said no to the car just because of the seats.

minispeed said:

ishiyakazuo said:

Agreed! To be honest, there's zero chance I'd have bought a BEV at this point (except for maybe a Tesla) if I didn't have an ICE in my driveway as well. But for long-range trips, I'm still likely to end up renting a car at this point, simply because I'm 6'3" and there's no way I'm going to want to do any long trips in a Honda Fit...
But yeah, I'd definitely need more data on my cell phone plan to wait that long

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Well I'm 6'4 and have a 78 mini that I've done 3 hr+ trips in, it's not not too bad and I did 3 months with 5.5 hrs each way every weekend in a 93 Miata. As a lover of small cars I find it's not so much the size of the car but the seats that matter. The other thing is the little details like flat door panels and a dash that doesn't take up knee room. I don't like the leaf seats at all for anything over an hour and I actually can't sit in the front passenger seat for any time without being uncomfortable. My knee hits the corner of the dash at a horrible angle. I think the only reason I don't notice it driving is because I'm use to keeping my foot straight to drive with instead of letting it relax like I do the left one. The first fit was notorious for having cheap seats, my dad and I test drove one and both of us said no to the car just because of the seats.

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Yeah... the Fit's seats are extremely rigid. I really don't like it for long trips. The LEAF I wouldn't take on long trips just because I don't want to mess with the charging (even DCQC), but I agree that it would probably also not be ideal for long times for the knee reason (although it seems like sometimes I have the problem more than others... not sure what the deal with that is).
To be honest, the most comfortable car I've been in is a Smart fortwo, but there's no way I'll be buying one of those death traps.