CHAdeMO Questions

Just out of curiosity, has anyone experienced any issues when charging our i-MiEV using commercial Level 3 EVSEs here in the US? I haven't, and mine has worked flawlessly with both Blink and NRG eVgo.

This UK article brought this to mind: https://speakev.com/threads/unreliable-ecotricity-chademo-charging-with-i-miev-ion.1072/

Completely unrelated to this, does anyone know if there is a minimum dc current that needs to be provided via the CHAdeMO port for the i-MiEV to accept a charge, and is anyone aware of any differences in implementation of CHAdeMO between our i-MiEV and the Leaf?

Theoretically, CHAdeMO simply needs the proper handshake between car and charger to engage the contactor.

The i-MiEV (at least in Japan) is able to discharge through the CHAdeMO port, running equipment such as V2G or the MiEV Power Box. Mitsubishi has a V2G system in place at their headquarters. It combines solar, grid, a few dedicated i-MiEV batteries, and 6 CHAdeMO plugs for the fleet to plug into. The cars serve as extra battery capacity for the building, but can also charge from the system. I'm not sure if the LEAF has the same capabilities software-wise, but I don't see why not. Nissan is doing the same experiments.

To answer your original question, I've only used QC once and had no issues. The main issue is whether or not the quick charger even works, and if it does, the cars seem to charge.

JoeS said:

Just out of curiosity, has anyone experienced any issues when charging our i-MiEV using commercial Level 3 EVSEs here in the US? I haven't, and mine has worked flawlessly with both Blink and NRG eVgo.

This UK article brought this to mind: https://speakev.com/threads/unreliable-ecotricity-chademo-charging-with-i-miev-ion.1072/

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Only used QC a few times, once as a test to see if it works, but didn't need charge. The 2nd time, I noticed that the rate was low but I think because the battery was "cold". It was a short 2 miles drive in the morning.

Yesterday, in warm SoCal, the QC started at ~30+kw at about 50% SOC, then tapered to ~10kw approaching 80%. The Miev stopped the charge at 81%, but restarted upon pressing the charger "Start" button, again at around 10kw. But I stopped at 83% SOC, didn't want to push it. The whole time duration was ~20 minutes, enough time to dust the car and shake out the carpet etc...

This was at a LAWater Utility building, it was free access.

I use CHAdeMO frequently, but have never been able to go much past 80% SOC in a single session, unlike the LEAFs that regularly camp out for a 100% charge on Blink DCFC stations. Given Joe's discovery, I'll take the time sometime soon to wait around and watch to see if the disconnect happens when amps fall to 5 or less.

Among the litany of Blink shortcomings, I have noticed that the second head is no longer reliable. They designed the stations to allow a second car to plug in and order up a charge that would commence as soon as the first car finishes. That has failed the last few times I've tried, meaning that I have to swipe my card and go through the touchscreen menu again.

pbui19 said:

Yesterday, in warm SoCal, the QC started at ~30+kw at about 50% SOC, then tapered to ~10kw approaching 80%. The Miev stopped the charge at 81%, but restarted upon pressing the charger "Start" button, again at around 10kw. But I stopped at 83% SOC, didn't want to push it. The whole time duration was ~20 minutes...

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Using 360v*5A = 1800W is the end charge power level at which the car tells CHAdeMO to stop and won't allow charging below this. Guess we then have to switch over to J1772 to fully top up the car. Using my EVSEUpgraded Mitsu unit I've charged mine at 120v*6A = 720W all the way to 100%, and it continued charging/balancing as it tapered down after that until it shut off.

The CHAdeMO chargers I had used all stopped at exactly 80%SoC (told to me by both the CHAdeMO display and CaniOn). I thought that the charger itself was programmed to do that, and not the car.

In addition to the stopping at 83% that pbui19 saw, has anyone else seen a power level lower than 1800W or any higher SoC when using CHAdeMO?

I replugged the charger after a stop at 82% and was able to reach 98.5% before it shut down. The lowest current reading I have a picture or video of is 10 amps, around 93%.

I heard Fuji quick chargers will go straight to full charge and not make the stop at 80%.

PV1 said:

I replugged the charger after a stop at 82% and was able to reach 98.5% before it shut down. The lowest current reading I have a picture or video of is 10 amps, around 93%.
.

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Was that a free charger ?
Or did you have to pay again when you re-connected ?

Just curious as the QC chargers here mostly are pay (that I would use to go to Cape Cod) at the Nissan dealers.

It was a free charger. You probably would have to pay for another session to get the last 20% since (at least on Eaton units) it was a complete unplug, replug, and start a new charge session. If you are paying for time instead of per kWh or per session, that last 20% is more expensive than the first 80%.

JoeS said:

In addition to the stopping at 83% that pbui19 saw, has anyone else seen a power level lower than 1800W or any higher SoC when using CHAdeMO?

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I didn't unplug, just push the start button again, because i recall reading on this forum about restarting so I thought to try it. It looks like it would have continue to charge beyond 83%, it was still drawing ~30A @3xx vdc, don't recall exact number.

I pushed "stop" to end the charging. I didn't hesitate to experiment especially with a free access.

My car stops charging at 82% every time. Both of the ones I use are operated by Greenlots.

Pete

You don't have to actually reach 80% to make it charge to full. If you interrupt the charge some time before you reach 80% and then restart it can keep going past 80%. I've experienced this a couple of times. Also on stations where the charge has always stopped at around 80%, if uninterrupted. The CHAdeMO charge is primarily controlled by the vehicle. I don't doubt that some stations can impose their own limits, though.

I was incorrect in an earlier post. During my quick charge, the car stopped at 80.5%, not 82%. When it did, CaniOn was showing roughly 30 amps at 361 VDC. It showed 361 VDC the entire time it was charging.

After re-plugging to continue charging, current started at 45 amps, but quickly dropped to 30 amps, then continued its slow decline.

I believe the chargers are programmed to stop around 80% to keep charge times down and reduce stress on the batteries. 25 minutes to 80% sounds a lot better than 1 hour for full charge.

(Also, I saw on Plugshare that new Quick Chargers are located in Morgantown, WV and Boardman, Ohio, but the Sheetz locations in central PA are gone :? )

The way Lithium charging always works is that a maximum constant current is maintained until maximum voltage is reached.

On the i-MiEV and friends, the maximum voltage is 361 volts (according to CaniOn). In my experience, charging in somewhat cold weather at 118A on CHAdeMO, the 361 volt limit can be reached as low as 40% SOC. From there the vehicle will instruct the station to reduce the current. Just as it asked for a specific voltage of 361 to begin with.

If you restart the charge, the vehicle guesses you'll want to reach full, not just 80%, and doesn't instruct the station to stop charging at 80%, but keeps going. On restart, the current will hunt until the maximum 361 volts is reached again and then reduced gradually.

Personally I think the 361 volts at 118A is rather conservative and they could keep charging at a higher voltage to make the batteries charge a little faster, but it's not like one could do anything about this.

i have tried at least a dozen times at the local Eaton dcqc with no luck, the main breaker kicks inside the charger box and requires a maintenance call to reset.

My local miev racing buddy went down there this past week to give it a go-- and it worked fine for him with no problems.

Hmm...looking like the problem is on my side of the connector?

Sounds like it.

Does it charge at all or does it trip immediately after the safety checks? I'm wondering if the port's polarity is backwards on the car side.

PV1 said:

Sounds like it.

Does it charge at all or does it trip immediately after the safety checks? I'm wondering if the port's polarity is backwards on the car side.

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From within 10 seconds or less after the safety check. The battery symbol comes up on the display and fills it in green up to the level that corresponds to my pack, then the voltage can be seen to ramp up to ~450 and then drop back down in the 300's range, then it says starting to charge 0.0 kwh. The display then turns the battery red and pops the breaker, error messages ensue, etc.

That may be an important observation if there have been cars delivered with reverse polarity in the chademo port...?

I just watched the video I recorded when first using an Eaton unit.

Mine will do safety checks, ramp the voltage up to 450 volts, drop to near zero, then come up to the car's voltage as the display changes to the red battery charge gauge. Current then ramps up as the car starts charging. I believe this is when the contactor in the car is engaged, and sounds like this is when the breaker trips. If the polarity is backwards, that is a total of over 650 volts (charger's +330 combined with the car's alleged -330 volts) between the car and charger. If both car and charger have +330 volts as would be normal, there would be no current flow between them. Current flows to the car when the charger starts to lift its output voltage. As instructed by the car, the charger will try to bring the battery to 361 volts, allowing up to 125 amps to do that. Once the battery reaches 361 volts, fewer and fewer amps are then required to maintain that voltage.

Think of this like accelerating. We push the throttle to send 100 amps to the motor (amps of charging power equivalent) to bring the car up to 50 mph (desired voltage is equal to desired speed). As we reach that speed, fewer amps are required, so we cut back on the throttle input to avoid overshooting our speed (amperage cuts back as the battery reaches its target voltage so to not overshoot the target).

If the polarity of the car side of the CHAdeMO port is backwards, the charger would discharge the pack completely and reverse charge it to -360 volts. That is hypothetical of course. The safety features (circuit breaker, mainly) prevent that from happening, plus the battery would most likely explode if it were reverse charged like that.

A reversed connection may not be the only cause, but it's the only thing that I can think of. Unless the CHAdeMO port is shorted somewhere. Either way, I don't think it is wired correctly on the car, since other vehicles charge without issue. I think a visit to your favorite (local) dealer is appropriate.

Today i was able to use a pair of jumpers to close the dcqc contactors and read the pack voltage (360.7vdc) thru the big 9mm sockets of the chademo port, positive on the right and negative on the left, so my chademo port appears to have the correct polarity.

Also i tested the small relay under the rear seat that controls the dcqc contactors and it was good. It is marked Omron MB627895, which i think is a Mitsubishi number. The nearest omron number i could find was a G8HN, general purpose automotive ISO relay, 12V coil 95 Ohms.

i haven't tried dcqc locally since my car would cause it to throw a main breaker and disable the charger for everyone else. The local dealer doesn't even have a level 2 evse, so i'm not very confident they could troubleshoot this without a way to test the chademo port. The FSM is not very detailed about this either.

My testing has verified that at least the mechanical connections are intact and electrically the port can access the pack, so it looks like a CAN buss control or some sort of sensor issue to me.

kiev said:

Today i was able to use a pair of jumpers to close the dcqc contactors and read the pack voltage (360.7vdc) thru the big 8mm sockets of the chademo port, positive on the right and negative on the left, so my chademo port appears to have the correct polarity.

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So, Kenny, in all this time, I take it that you never got your i-MiEV to DCQC, even using a different CHAdeMO charging station? If it weren't for the fear that the dealer might mess something up, this could perhaps still be a warranty repair item? More significantly, I don't think the dealers have any means of testing DCQC(?).

kiev said:

Today i was able to use a pair of jumpers to close the dcqc contactors and read the pack voltage (360.7vdc) thru the big 9mm sockets of the chademo port, positive on the right and negative on the left,

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Could you tell how you close dcdq contactors by jumpers?