2011/12 Upgrade to dual stock chargers or 2013 charger?

I know there has been some discussion of this in the past, but the conversation seems to quickly devolve into "just buy a Brusa" I get why that may make more sense in many cases, but with the availability of used Leaf parts picking up it still seems like this could be a path to faster charging for a lot less money in the 3.3kW limited Leafs.

As the title indicates, it seems like there might be two main approaches to a budget upgrade for 2011-2012 charge rate.

1) Add a second 2011-2012 charger in parallel to the stock charger, presumably with the addition of a dual bus CAN controller to arbitrate between the two. It would seem like you could set this up so one charger is a "master" that communicates bidirectionally with the EV_CAN and the other a "slave" unit that doesn't get to talk on the bus but gets relayed the appropriate CAN instructions. The second unit could be directed to charge at the LBCs charge request power minus whatever the stock OBCs current charge power is. The I guess you'd be back to needing to modify the communication to the EVSE or use two separate power sources for the two chargers as with the Brusa upgrade.

2) Replace the stock charger with a 2013+ unit, presumably would also require a dual bus CAN controller to sit between the charger and EV_CAN and translate between the 2011/12 and 2013+ messages. In this case I would assume the 2013+ charger would communicate the correct increased charge rate to the EVSE?

Any thoughts on how feasible this is, and whether the charging CAN messages are well enough understood at this point to make it work?

Thanks,
Rob

Well, nothing gets communicated to the EVSE. The EVSE indicates the maximum amperage via the pilot signal duty cycle, and the charger pulls the pilot down to indicate that the EVSE should close it's contactors to let the power through. No bits go back and forth at all. Since the Nissan unit isn't designed to be a slave, you might have to fake a pilot and a proximity signal to get it think it's plugged in.

If you try and put the 2013 charger (or a second 2011/12 charger) back under the hump, you're going to have problems with the AC wiring going back there not being beefy enough, and maybe the DC wiring as well. Running a second set of wires back there would be no fun at all. So given that, I'd plan on leaving the current charger in place and placing the new unit as a second charger under the hood as the Brusa effort did whether you go with 2011/12 or 2013+. That way it continues to handle the J1772 connection and all the talking to the rest of the car, and all you have to do is convince the second charger to run with the proper charge limit.

Another problem is that the 2013 charger is intended to be stacked with the inverter and motor, so you would have to create plates to turn it into a properly closed unit, and it may have extra connections that you would have to deal with. Start by downloading the service manual for the 2013 I would suppose.

I would think the CAN messages would be well understood since they are the same ones that the Brusa guys had to interpret to tell the Brusa what to do. It should just be a matter of replicating messages to the charger except for replacing the max charge rate requested the rate you need it to respect. See if the Brusa guys will give you their docs and/or software as a starting point.

Unless you have one of these OEM chargers literally laying around, I don't know why you would try to pull this off.

As it was pointed out, the OEM unit has no proper housing, there are going to be serious issues with isolation, It's not designed to be programmable, not meant to be used as a slave, there are probably going to be cooling issues, and where are you going to mount it?

If someone put a gun to my head (which is what it would take), and made me use OEM charger parts, I think I would change over enough of the system from a stock 6.6 kW charger equipped car to make it work as Nissan intended.

It's just sooo much easier to install one or more Parallel configurable programmable chargers that were designed to be used in this way.

That Isolation thing is really going to trip you up.

For all intents and purposes, the additional charger(s) need to be completely invisible to the car.

The CAN signals need to be USED by the parallel charger, but just passively. It can't add its own input.

To echo some of the comments here and for more perspective, here's the OBC under the hump in the back of the '11 and '12:
http://www.mynissanleaf.com/viewtopic.php?p=69224" onclick="window.open(this.href);return false;

http://www.mynissanleaf.com/viewtopic.php?f=38&t=3896" onclick="window.open(this.href);return false; is underneath.

There are high voltage and cooling lines that run from the front to the back.

http://articles.sae.org/11993/" onclick="window.open(this.href);return false; shows the whole stack of the '13+ and describes what was changed. It needs cooling too. You can hear pump(s?) running while charging and can feel coolant going thru the hoses.

How much is this going to cost to do right and how much of a hit would you take on trading in for a used 2013? Wait a few more months when more 24 lease 2103s will come back and you might get a good deal.

Thanks all for the feedback!

First, my constraints are admittedly a bit different as I'm using the Leaf drive system outside a Leaf, so all of the physical integration issues are pretty much a wash as I have to find a new home for everything anyway. Although in general I'm not sure why the physical integration would be significantly more challenging for a stock unit than for adding a non-stock charger like the Brusa. The procedure for doing that looked pretty involved to me.

Second, I think cost is the primary consideration here. From what I've gathered a Brusa costs ~$2300 and still has a lot of integration challenges and additional costs associated. While admittedly an extreme example, I just picked up a 2013 charger/dcjb box from a local scrap yard for $75. The 2011/12 charger can be bought new through online parts retailers for ~$1300, and there are also new ones on ebay for $850 currently. The 2013+ combined dcjb/charger can be had for $900 new. Used prices should be somewhere in between scrap value and new price I would expect.

2013-15 6.6kW w/QC $880.25: http://www.quirkparts.com/nissan/leaf/292c03nf3d/2014-year/s-trim/electric-engine/electrical-cat/electrical-components-scat/?part_name=junction-block" onclick="window.open(this.href);return false;

2011-12 $1285.96: http://www.autonationpartsdirect.com/nissan/leaf/296a03na7a" onclick="window.open(this.href);return false;
ebay $850 (new, but earlier version): http://www.ebay.com/itm/296A0-3NA2A-Plug-In-Hybrid-Battery-Charger-Assembly-fits-2011-Nissan-Leaf-/231126845418?fits=Make%3ANissan|Model%3ALeaf&hash=item35d03bc7ea&vxp=mtr" onclick="window.open(this.href);return false;

The cost of the Brusa installation might be in the noise for a brand new Leaf, but for someone buying a ~$10k used 2011/12 its probably a little more of a stretch. Nor is just choosing to buy a new 2015 instead likely an option for many shopping in this price range.

Hey cwerdna, nice to see another Priuschatter over here

Ok, some more thoughts on details/issues raised above...

Yes there are fundamental challenges to both approaches proposed, but aren't most of the same challenges present when trying to add a non-stock charger? Other than the potential need for a separate CAN controller I suppose, but then again I would imagine there are some things about adding a non-stock charger that would be more complicated as well.

Physical: The 2011/12 is rear mounted, the 2013 is up under the hood and integrated into the motor stack. For a second 11/12 charger either in the mirror of its intended location (requires relo of brake backup power unit?, modified bracket?) or stacked with the original might be attractive as that's closer to how they were meant to be installed. Not sure how much room there is to work with back there, or if it might have to "stick out" into the trunk area a bit? Trying to put the 2013 in the back would likely be more challenging.

Case: 2011/12 was intended to be "indoors", so may not be up to the challenge of living in the engine room. 2013 looks self contained to me, I believe its contains the cooling plate that supports cooling both the charger/dcjb and inverter. The top is a bit bulky, could probably be replaced with a slimmer cover. If placed in rear "indoors" probably does not even need to be fully sealed. 2013 is meant to connect to inverter via bus bars, but I believe the charging ins and outs are both via wiring harness?

Cooling: Both 2011/12 and 2013 chargers are liquid cooled. On 2011/12 cars liquid cooling lines are run to the back, and can presumably be used to support the second charger and/or single larger charger.

Wiring: As noted, trying to mount a second charger (or single larger charger) in the back could overload the charger wiring. Though even with at 6.6kW, we're only talking about ~16A? It would seem like that's still in the ~14-16 gauge territory for this <10' sort of run. I guess I'd be a bit surprised if Nissan went even that thin on the charge harness. Anybody have an idea what it is back there? Adding to the front could probably be done in a similar manner to the Brusa?

Isolation: I assume the charger chassis is meant to be isolated form the vehicle chassis as part of the HV system? For the 2011/12 charger presumably there is already a mounting bracket that takes this into account, which should provide a basis for a strategy. Although looking at mounting graphic in the service manual It doesn't look like the charger box is isolated, perhaps the HV electronics are simply isolated form the box internally?

Programmability/control: For the relatively simple task of doubling the charge capacity on the 2011/12 I'm not sure programmability offers much. My understanding is the LBC tells the chargers how much power to put out, which is often well above the max output of the charger. Ideally you'd want the "slave" controller to just put out that amount minus 3.3kW. Other than that wouldn't you just want it to stop/start/fail just as if it were the only charger? Although less elegant, it might be interesting to see what would happen if you literally just paralleled the two chargers. It seems like the charger does more listening than it does talking, and when they do talk if they are both saying more or less the same thing it might not actually cause issues. That would cause it to charge at twice the expected rate once it starts throttling down, but honestly the current out of these chargers is so small relative to the battery capacity I wonder how much that would really matter. At least under reasonably moderate temperature conditions. As far as the 2013 charger goes, anyone have any idea how different the charge related CAN messages are?

As mentioned above, I am planning to transplant a Leaf drive system into another vehicle. But in the mean time, I have a running/driving 2012 that I'm planning to test all the modifications on first. I'm planning to start stripping my interior soon, I'll probably have a better idea of how feasible that rear space is to work with once I can see it first hand.

Rob

BTW, here is a shot of my rear exposed :roll:



There is a decent amount of room back there, but its split by a structural brace that runs through the middle. I'm guessing the noise filter to the right of the charger would be sufficient to supply both chargers (if going the dual 3.3kW route), so it would just be the second charger box itself that would need a home. If I can do so without causing too much damage, I'm going to try and peel back the outer covering on the AC and DC wiring and get a sense of the wire gauge to see if it could reasonably support double the currents.

Rob

You are better buying a new LEAF than trying to install an OEM charger. I have Brusa that is programmed for LEAF second charger. I removed from my car and since I'm not using it I will likely post it in the for sale section with the adapter plate for those determined to do this. There will be no tech support or instructions of any kind however.

I know nobody seems to like the idea, but I'm still thinking about it. At the moment adding a second 2011/12 3.3kW charger in parallel seems like the simpler option functionality wise. Again how to mount it in the Leaf is not really a concern in this case as it won't end up in a Leaf, but if it ends up working someone might be motivated to figure that out. I've just ordered a cheap dual-channel CAN interface, and am snooping around for a cheap stock charger to play with if anyone has any leads.

Looking at it some more, it really seems like it should be pretty simple to "slave" a stock 11/12 charger. One of the options in the CAN interface I ordered is supposed to be the ability for it to relay messages directly from one CAN port to the other either bi-directionally, or in just one direction or the other while also being able to monitor both ports interdependently. As a first test, it might be enough to simply tap into the EV-CAN with one port and relay all the EV-CAN messages to the slave charger connected to the second port, but not let it talk back onto the bus. It doesn't seem to say much to begin with. Here are the CAN messages related to the OBC (ignoring QC) according to the LAN section of the manual:

R: F/S CHG Relay Status from VCM - pass unmodified to slave?
R: Max Charge Power from VCM - initially pass unmodified, eventually reduce by 3.3kW or do something more sophisticated with battery current/voltage messages?
R: Charge Type Signal from LBC - pass unmodified to slave?
R: Battery Capacity from LBC- pass unmodified to slave?
R: Battery Current from LBC - pass unmodified to slave?
R: Battery Voltage from LBC - pass unmodified to slave?
R: Remaining Time to Charge Complete - pass unmodified to slave?

T: DTCs - ignore initially, eventually add handling to shut down slave?
T: EV Warning Lamp Request - ignore initially, eventually add handling to shut down slave?
T: AC input Type - should be ok to just let the master charger report this?
T: EVSE PWM Com to VCM - should be ok to just let the master charger report this?
T: HV Harness Interlock - should be ok to just let the master charger report this?

In addition there are a number of direct signals in/out, most of which seem like they could simply be paralleled with the master?
In: EVSE PWM from charge port on pin 9 - connect in parallel?
In: EVSE Connected from charge port on pin 10 - connect in parallel?
In: 12V battery power from fuse on pin 11 - connect in parallel?
In: 12V Power On from fuse on pin 12/13 - connect in parallel?
Out: Charge relay + to DCJB on pin 14 - initially NC (may need dummy load?), eventually AND with master?
Out: Charge relay - to DCJB on pin 15 - initially NC (may need dummy load?), eventually AND with master?
Out: EV Activation Request - NC, let master request
Out: Plug-in Signal to Comb Meter on pin 21 - NC, let master request
Out: HV Harness Detect to Charge Port on pin 40 - NC, let master supply
In: HV Harness Detect from Charge Port on pin 41 - connect in parallel?
Out: HV Harness Detect to Self on pin 42 - connect in loopback as usual
In: HV Harness Detect from Self on pin 43 - connect in loopback as usual

Rob

Hmmm... here's another consideration I haven't heard yet... if you use dual chargers, you're probably going to trip some breakers. Here's why: say you plug into an EVSE that says its max current that can be supplied is 20A. One or both of the chargers will see that, and say "yay, I can pull my max 16A" and both will try to draw 16A, which ends up drawing 32A on a 20A EVSE.
Therefore, you'd probably need some sort of mechanism to:
1) switch to a single charger when 16A or less is offered by the EVSE
2) halve the pilot's duty cycle seen by the chargers when the EVSE indicates > 16A is available

ishiyakazuo said:

Hmmm... here's another consideration I haven't heard yet... if you use dual chargers, you're probably going to trip some breakers. Here's why: say you plug into an EVSE that says its max current that can be supplied is 20A. One or both of the chargers will see that, and say "yay, I can pull my max 16A" and both will try to draw 16A, which ends up drawing 32A on a 20A EVSE.
Therefore, you'd probably need some sort of mechanism to:
1) switch to a single charger when 16A or less is offered by the EVSE
2) halve the pilot's duty cycle seen by the chargers when the EVSE indicates > 16A is available

Click to expand...

It can blow an EVSE not just a breaker. I have seen people do this on home built EVs.

miscrms said:

Thanks all for the feedback!

First, my constraints are admittedly a bit different as I'm using the Leaf drive system outside a Leaf, so all of the physical integration issues are pretty much a wash as I have to find a new home for everything anyway.
The cost of the Brusa installation might be in the noise for a brand new Leaf, but for someone buying a ~$10k used 2011/12 its probably a little more of a stretch. Nor is just choosing to buy a new 2015 instead likely an option for many shopping in this price range.

Click to expand...

Since you are potentially not constrained to the wire size to the pack and can mount anywhere a "LEAF programmed" Brusa is very easy, you simply parallel it to the system and you are done. You will need a new J1772 inlet rated for the higher amp draw and a connection to the pack to handle the same and you won't need to mess with the stock charger and any related integration issues.

EVDRIVER said:

ishiyakazuo said:

Hmmm... here's another consideration I haven't heard yet... if you use dual chargers, you're probably going to trip some breakers. Here's why: say you plug into an EVSE that says its max current that can be supplied is 20A. One or both of the chargers will see that, and say "yay, I can pull my max 16A" and both will try to draw 16A, which ends up drawing 32A on a 20A EVSE.
Therefore, you'd probably need some sort of mechanism to:
1) switch to a single charger when 16A or less is offered by the EVSE
2) halve the pilot's duty cycle seen by the chargers when the EVSE indicates > 16A is available

Click to expand...

It can blow an EVSE not just a breaker. I have seen people do this on home built EVs.

Click to expand...

Indeed, that can happen as well. I was assuming (probably wrongly) that most EVSEs now can probably handle 30A, at least for long enough that the breaker trips. Regardless, this could quickly become quite the science fair project.

ishiyakazuo said:

EVDRIVER said:

ishiyakazuo said:

Hmmm... here's another consideration I haven't heard yet... if you use dual chargers, you're probably going to trip some breakers. Here's why: say you plug into an EVSE that says its max current that can be supplied is 20A. One or both of the chargers will see that, and say "yay, I can pull my max 16A" and both will try to draw 16A, which ends up drawing 32A on a 20A EVSE.
Therefore, you'd probably need some sort of mechanism to:
1) switch to a single charger when 16A or less is offered by the EVSE
2) halve the pilot's duty cycle seen by the chargers when the EVSE indicates > 16A is available

Click to expand...

It can blow an EVSE not just a breaker. I have seen people do this on home built EVs.

Click to expand...

Indeed, that can happen as well. I was assuming (probably wrongly) that most EVSEs now can probably handle 30A, at least for long enough that the breaker trips. Regardless, this could quickly become quite the science fair project.

Click to expand...

A 40A EVSE can handle the 32A load. On a home built project the owner usually knows the restrictions and simply does not use one rated for less without dialing back the amp level.

miscrms said:

BTW, here is a shot of my rear exposed

Click to expand...

So that is why there is a big space in my Wife's 2015 and it's used up and covered in my 2012. thanks for sharing the photo. I like to learn through observing others projects. I have no idea what you guys are all talking about, you are way smarter than I, but I get the jist of it.

ishiyakazuo said:

Hmmm... here's another consideration I haven't heard yet...

Therefore, you'd probably need some sort of mechanism to:
1) switch to a single charger when 16A or less is offered by the EVSE
2) halve the pilot's duty cycle seen by the chargers when the EVSE indicates > 16A is available

Click to expand...

I had talked about it. He's going to have either fake, or relay the pilot signal to the 2nd charger anyway. If he has control over it, he can simply stop it and the 2nd charger will shut down. Ultimately, he's going to have to read the pilot signal so that he can throttle the 2nd charger properly, so I'd go for generating a new one and subtracting the 16a for the first charger at that point.

These are issues because the Nissan charger isn't designed to be a slave. The Brusa can simply be connected to the AC and DC busses and told it's a slave, be sent a CAN message indicating the max amperage, and go, as I understand it. Anyway, this stuff is actually fairly straightforward. It's the isolation issues I'm curious about. Being a software guy I understand the logic and interface issues, but not the isolation issue. From just the interfacing side, this isn't too bad, really.

Rather than intercepting / modifying the pilot, can't this just be done with CAN? I'm assuming that this is how its done with the Brusa?

I'm still getting up to speed on all this so perhaps I'm still missing something, but here's my understanding:

1) The OBC detects the charge cable is connected, and sends an EV System Activation Request via pin 18 to the VCM
2) The VCM activates the M/C Relay and closes the MSRs to activate the EV System.
3) The EVSE sends a PWM / pilot signal to the OBC indicating its current capability.
4) The OBC interprets the PWM signal and sends the EVSE current limit to the VCM via CAN.
5) The LBC tells the VCM via CAN the battery SOC, temp, etc
6) The VCM tells the OBC via CAN what the max safe charge power is based on 4 and 5.
7) The OBC begins charging at a power up to the max safe power reported by the VCM.
8) The VCM continues to update max safe charge power, throttling down until charge is complete.
9) After charge complete, the VCM deactivates the MSRs shutting down the HV system.

If this is accurate it seems to me like the OBC is already basically operating as a slave to the VCM, and just delivering the the power the VCM requests to the best of its ability. If that's true, and the VCM max safe charge power takes the EVSE current limit into account then it would seem like as long as that message is modified to derate it by 3.3kW before passing it on to the second charger then there shouldn't be an issue with stressing the EVSE.

Can anyone provide any more detail about how the LeafDD/Brusa control is executed? Does anyone know for sure if the VCM limits max safe charge power CAN message based on EVSE current limit?

Thanks,
Rob

ishiyakazuo said:

Hmmm... here's another consideration I haven't heard yet... if you use dual chargers, you're probably going to trip some breakers. Here's why: say you plug into an EVSE that says its max current that can be supplied is 20A. One or both of the chargers will see that, and say "yay, I can pull my max 16A" and both will try to draw 16A, which ends up drawing 32A on a 20A EVSE.
Therefore, you'd probably need some sort of mechanism to:
1) switch to a single charger when 16A or less is offered by the EVSE
2) halve the pilot's duty cycle seen by the chargers when the EVSE indicates > 16A is available

Click to expand...

Not on ours

All of our Brusa's are CAN controlled and look at the EVSE/pilot to see what the Leaf is getting and then ramps up to the max amount avail to the pilot.

If you plug into a 32a EVSE... the Leaf pulls 16 and the Brusa ramps up to 16a as well.

Plug into a junky Blink (at 24a) the Leaf pulls 16a and then the Brusa ramps up to 8a.

Charging to 100%??? Once the Leaf starts to taper, it tells the Brusa to shut down...

Easy Peasy.. it's all auto! Greg's the best!

And I've done a liquid cooled Brusa on a 13 (have duals on mine up front)... but you need to know what you are doing.

P.S. Do NOT try and screw around with the factory charger.. it's NOT worth it... get a Brusa or something else aftermarket that's ISOLATED and run in automatic mode...

JasonA said:

And I've done a liquid cooled Brusa on a 13 (have duals on mine up front)... but you need to know what you are doing.

Click to expand...

Would love to see some photos of how you've done this - It'd be really nice to get up to 32A charging as in many cases where you're parked for an hour it's much more cost effective than QC and you don't have to worry about staying with your car or coming back after 30 minutes in case someone else needs QC - never mind that L2 stations are far more available than QC stations in general.