Ability to view and/or set charge rate

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Astros

Well-known member
Joined
Oct 11, 2017
Messages
186
Location
Seattle, WA
I've had a 2018 Leaf for about six months, and in that time we've taken multiple trips of ~300 miles in a day and two ~500 mile days. On long trips like that, the battery heats up and the quick charges after the first are significantly throttled (rapidgate, as has been covered extensively elsewhere). In the summer I typically got ~45kW for the first charge, 20-25kW for the second, and ~16kW for the third or higher session. Since this charge rate is set by the car, I would really like to see the maximum current charge rate displayed in one of the dash screens, so it is easier to plan charging stops. Yes, I can use LeafSpy to get the temperature and calculate the expected charging rate, but that's not always easy while driving. And, it would really help out people who are new to the car.

Even better would be if we could set the maximum charging rate ourselves. I'm not even asking for the ability to set it higher than the throttled rate, since I assume if we could do that Nissan would find a way for that to void our battery warranty. I'd like the ability to set the maximum charge rate to, say, 30kW for the first charge. That way if I am on a long trip and know I'm going to be doing multiple charging sessions I can keep the battery from getting into the red so quickly, and maybe get a higher average charge rate.
 
Lowering the maximum charge rate in a controllable manner should be reasonably easy. A dash toggleswitch to cap charging around 25 kW by spoofing the temperature sensors seems like something Muxsan has done already. Make the car think the battery is 15-20 degrees C warmer than it is, just for the duration of the charge. Alternatively, just reduce charging rates directly through the CHAdeMO CANbus.

That should keep heat dissipation low enough that longer road trips are possible, even if they take longer to charge, without genuinely overheating and damaging the battery. Since resistive power dissipation is proportional to current squared, cutting the charge rate in half should cut total heating (i.e. degrees C temperature gain) over a full charge in half.

In a sense, this would be a reverse Rapidgate update. The only trouble seems to be that the newer ZE1 cars aren't as easy to hack on.

mux said:
Dala said:
Anybody working on this?
 
Bummer. I'm assuming the OP already has the rapidgate "fix" firmware applied (NTB19-056)?

Would be nice or if you could find slower DC chargers to use for your initial charges? That obviously might not be practical.... Liquid cooled Bolt has no problem like this except that it's slow to DC FC if the battery's cold.
 
Oh, yeah, we've got a product for that in final stages of development. Should be on sale starting beginning of August for MUXSAN-equipped cars (the mod requires a CAN bridge), and later in August for any other Leaf. The feature list right now includes:

- Little e-paper display + 3-button interface, so settings stay visible even if the car is off
- Setting AC charge rate (6-32A)
- Setting DC charge rate (5-100kW)
- Setting AC cutoff percentage (10-100%)
- Setting DC cutoff percentage (10-100%)

The location of the display is in principle flexible throughout the car, all you need is access to a 12V fuse position, a grounding point and EV-CAN through a CAN bridge. The display essentially just sends configuration commands to the CAN bridge, which already has these features built-in but as of now either hardcoded or requiring external tools.
 
I am also doing this, but in another way. I am going for no extra buttons, so the setup will rely on HVAC controls.
6djKeB2.png


It is a good time to be a Leaf owner these days :)
 
Astros said:
I've had a 2018 Leaf for about six months, and in that time we've taken multiple trips of ~300 miles in a day and two ~500 mile days. On long trips like that, the battery heats up and the quick charges after the first are significantly throttled (rapidgate, as has been covered extensively elsewhere). In the summer I typically got ~45kW for the first charge, 20-25kW for the second, and ~16kW for the third or higher session. Since this charge rate is set by the car, I would really like to see the maximum current charge rate displayed in one of the dash screens, so it is easier to plan charging stops. Yes, I can use LeafSpy to get the temperature and calculate the expected charging rate, but that's not always easy while driving. And, it would really help out people who are new to the car.

Even better would be if we could set the maximum charging rate ourselves. I'm not even asking for the ability to set it higher than the throttled rate, since I assume if we could do that Nissan would find a way for that to void our battery warranty. I'd like the ability to set the maximum charge rate to, say, 30kW for the first charge. That way if I am on a long trip and know I'm going to be doing multiple charging sessions I can keep the battery from getting into the red so quickly, and maybe get a higher average charge rate.

Having done the same with my 2018, I found the only real acceptable solution for me was shorter quicker stops initially planning the long hot charge stops with meals or "events". Unlike my E Plus, when the 40 kwh pack gets hot, it stays that way. With the much shorter range, it was hard to tell but with OAT in the mid 70's (currently the only temperature range I have to compare) my E Plus batt temps would settle into the mid to upper 90's with freeway driving being slightly cooler than typical city driving. I think the higher regen profile of the E Plus heats up the pack when there is a lot of acceleration over the more or less constant velocity typically seen on the highways.

The 40 kwh "probably" settles at a higher temp around 105ishº Now this is a guess and complicated by the shorter range and less time for pack temps to settle.

To elaborate; I charged my E Plus at Vancouver Plaza, pack temps were in the low to mid 100's. I take off for Olympia speeds around 70 mph and pack temps dropped and settled between 98 to 99º. But this was a 100 miles. Finding that length for my 40 kwh was all but impossible to do since a lot of my charging was taking advantage of the rate before it slowed significantly. In most cases, I was only charging until the rate dropped below 40 KW for first 1-2 charges, the 30 kw for 2-3 charges, etc so didn't charge above 75% that much.

BUT, I did see times when I would finish DC charging at a station ~ 100º and still see pack temps rise when I started driving. I always thought it was residual heat from charging simply not hitting the sensors right away but the temps always seemed to rise and stay there most of the time which is part of why I guessed the 105ish º number.
 
Pack temps do in fact rise just after a QC session - because the temperature sensors are located on the outer edge of the cells (and a bit out of the middle) while the majority of the heat is generated on the tab-end and middle of the cells.

This should only be prominent with the rear stack the rest of the cells only budge a few tenths of a centigrade (maybe 1F) normally. Also depends on SOH and SOC.
 
cwerdna said:
Bummer. I'm assuming the OP already has the rapidgate "fix" firmware applied (NTB19-056)?

This post was from back before the rapidgate fix was released. That fix would have helped a lot, but as Dave mentioned it's much less of an issue with the Plus. Now if I want to limit the charging speed at the beginning of a trip I just make sure to use the older ~45kW chargers instead of the ~70kW EA ones.
 
mux said:
Oh, yeah, we've got a product for that in final stages of development. Should be on sale starting beginning of August for MUXSAN-equipped cars (the mod requires a CAN bridge), and later in August for any other Leaf. The feature list right now includes:

- Little e-paper display + 3-button interface, so settings stay visible even if the car is off
- Setting AC charge rate (6-32A)
- Setting DC charge rate (5-100kW)
- Setting AC cutoff percentage (10-100%)
- Setting DC cutoff percentage (10-100%)

The location of the display is in principle flexible throughout the car, all you need is access to a 12V fuse position, a grounding point and EV-CAN through a CAN bridge. The display essentially just sends configuration commands to the CAN bridge, which already has these features built-in but as of now either hardcoded or requiring external tools.

That sounds really neat. I think I would be very interesting in getting one of these once it can work with any Leaf. How much will you be asking for it?
 
Astros said:
cwerdna said:
Bummer. I'm assuming the OP already has the rapidgate "fix" firmware applied (NTB19-056)?

This post was from back before the rapidgate fix was released. That fix would have helped a lot, but as Dave mentioned it's much less of an issue with the Plus. Now if I want to limit the charging speed at the beginning of a trip I just make sure to use the older ~45kW chargers instead of the ~70kW EA ones.

:lol:
 
mux said:
Pack temps do in fact rise just after a QC session - because the temperature sensors are located on the outer edge of the cells (and a bit out of the middle) while the majority of the heat is generated on the tab-end and middle of the cells.

This should only be prominent with the rear stack the rest of the cells only budge a few tenths of a centigrade (maybe 1F) normally. Also depends on SOH and SOC.

Not seeing the huge temperature difference in the cells anymore. All three are almost always within 2-3º of each other and frequently within 1º
 
Astros said:
That sounds really neat. I think I would be very interesting in getting one of these once it can work with any Leaf. How much will you be asking for it?

Just the display device is going to be a ~$100 upgrade for MUXSAN customers. Not sure about the final price for non-muxsan cars, because that has to include a wiring kit and CAN bridge which tends to get expensive - and really that's way too involved for what it does. We're probably making a revision for non-muxsan cars that effectively includes a can bridge and requires some soldering (to make it cheap and easy for us)
 
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