[joeaax1j]

Honestly it probably makes more sense for LiBCM to stay on for 24 hours after keyOFF. During this time, LiBCM will consume ~1% SoC, but that will give you plenty of time to plug in the grid charger at your leisure. It will also give LiBCM time to balance the cells (if needed).

I agree - at least 24 hours. At my office, there are two public grid chargers and currently four cars that can be plugged in. I may have to wait several hours before I have access to one of the chargers. Of course, it would be nice if plugging in a grid charger worked for turning on the charging system, regardless of how long the car had sat.

After reviewing the code, I don't see anything that would prevent the heater from activating when the grid charger is plugged in, but not charging. If someone else with C experience wants to review the logic, start at heater.c>heater_handler().

Please verify that LiBCM thinks the heater is present. Each time LiBCM boots, it sends a one-line hardware debug statement:
HW:D/5AhG3/48S/Vs=ast/Heat:N
If LiBCM reports "HEAT:N", then LiBCM doesn't think the heater is installed.
If LiBCM reports "HEAT:Y", then LiBCM sees the heater, and should use it.

I'm fairly certain that LiBCM is not thinking the heater is absent. I haven't had any trouble with the heater after plugging in. Saturday morning when I saw that the pack temp was 13 deg C, that was a significantly warmer battery temp than Friday night when I had plugged in so I'm confident that the heaters had been working earlier during my charging session. I'll pay closer attention and see if I missed something and I'll watch more closely the next few times that the battery gets to full to see what happens with battery temp after that point. Thanks!

 

[bbcb]

@mudder , did the length of the bay 2 - bay 3 cable length change during the past year?

I finally got a break from work to install the heating elements and the outside foam pad didn't fit without allowing for more of an "S" curve. To wit:

With the rain coming in, it will have to sit on the bench until next weekend, but 0.8.5e is installed and appears happy.

 

[mudder]

Of course, it would be nice if plugging in a grid charger worked for turning on the charging system, regardless of how long the car had sat.

Unfortunately this is a hardware limitation.
Once LiBCM turns itself off, the 5 volt rail remains unpowered until one of the following hardware events turns it back on:
-Plug the USB cable into a powered USB port. The USB_5V rail powers LiBCM's 5V rail until the microcontroller boots and turns the onboard LVDC->5V buck converter on, or;
-Turn the key to the 'ON' position. The 12V keyON signal across R32 enables the LVDC->5V buck converter, or;
-Turn the IMA switch off, wait five seconds, and then turn the IMA switch back on. The resulting pulse across C165 enables the LVDC->5V buck converter.

As you can see, in all three cases there's specific hardware that turns LiBCM on. There is no such hardware interface to the grid charger. I certainly wanted to add the grid charger as a fourth "turn LiBCM back on" option, but I was unable to figure out a simple method to do so safely. Assuming there is a valid solution to this problem, at this point it's a bad too late to add it to the design.

I'm fairly certain that LiBCM is not thinking the heater is absent. I haven't had any trouble with the heater after plugging in. Saturday morning when I saw that the pack temp was 13 deg C, that was a significantly warmer battery temp than Friday night when I had plugged in so I'm confident that the heaters had been working earlier during my charging session.

What does LiBCM say when you plug in the USB cable and open the Arduino Serial Monitor window?

I'll pay closer attention and see if I missed something and I'll watch more closely the next few times that the battery gets to full to see what happens with battery temp after that point. Thanks!

If you have a spare laptop with decent battery life, I recommend plugging it in, opening the Arduino Serial Monitor window, turning the laptop backlight off, and then leaving the computer on overnight. LiBCM will spit out pack temperature every ten minutes, along with other troubleshooting information I might find useful.

 

[mudder]

did the length of the bay 2 - bay 3 cable length change during the past year?

I finally got a break from work to install the heating elements and the outside foam pad didn't fit without allowing for more of an "S" curve.

The alpha units didn't have RED Anderson contacts at all. To my knowledge, all beta cables are the same length. I make them all from the same template, so unless I made a one-off mistake, all beta cables should be the same length.

At the 9:00 mark in the third video, I'm pulling any slack out of the cable (just out of frame to the left). For your convenience, here is the third video from the heater install page:

Is your cable so long that there's simply too much slack outside the enclosure?

It's not the end of the world if you do end up having to remove more foam to make the cable fit.

 

[bbcb]

It's all good, just wondered and I do appreciate all of the effort you've put into this.

 

[davismltc]

One thing I have noticed this morning... it appears that the heater PCBs only work when the grid charger is actually charging -- not when balancing. Does this sound plausible? My SoC is 76, but the pack temperature appears to be dropping and is down to 13 deg C (even though I have it the gridcharging temp set to 20 deg C. Should the heater PCBs be working during balancing? If not, I may need to rethink when I want to grid charge during longer stints of being parked in the garage.)

Is it possible this is the case of plugging the charger in outside of the one hour window after key off?
Or maybe a 120vac power interuption of some duration?

 

[joeaax1j]

Is it possible this is the case of plugging the charger in outside of the one hour window after key off?
Or maybe a 120vac power interuption of some duration?

Thanks for the reply, but no. I had plugged in less than a minute after turning off the car. Grid charging was definitely working. As I mentioned, the battery was charged up when I saw the temp start dropping. Also, no power outages.

I saw the same behavior this morning. Came out and the battery SoC was at 75 (full charge is typically 76 for me), and the temp was 16 deg C (when it is configured for 20). I'll have to setup the laptop debugging like Mudder is requesting. However, it is too cold right now for me to be willing to leave my laptop running through the night (tonight it is supposed be -21 deg C). But I'll get around to it at some point.

-Bryan

 

[davismltc]

However, saying that a cell can retain energy while continuously frozen is different than saying repeated thermal cycling won't damage the cell (e.g. frozen each night, thawed each day). Each time a cell freezes (not necessarily 0 degC), the inorganic salts separate from the water, which results in volume expansion inside the cell. This repeated freeze/thaw behavior slowly degrades the internal structure. "Thus, the storage density becomes difficult to maintain and generally starts to decrease with [thermal] cycling."

Just so folks don't worry needlessly about daily freezing degradation in cold weather storage:
"The electrolyte in commercial lithium-ion cells generally consists of a 1.0-molar solution of LiPF6 in 1:1 EC-DMC (50:50 vol.%). The electrolyte freezes at about -30 °C"
Link: apps.dtic.mil/sti/pdfs/ADA351962.pdf

Report:
I've set my battsci.cpp regen disable to +5*C, but don't have experience yet on depleting the HV battery while driving from lack of regen from this setting. The heater boards are doing there job, and the weather hasn't been that extreme for me. However, my Insight is a CVT, and it typically fairs better than a stick when the HV battery is turned off (e.g. no regen). I suspect the only situation I'll run into now with heater boards installed is by not plugging into 120vac when the ambient temp drops low and the HV battery depletes to the point where LiBCM turns the heaters off.

The heater boards are a welcome addition for battery longevity, and Mudder has made it all possible. I think it's awesome!!

 

[100percentjake]

Re: G3 Insight packs

There is no form of direct-contact heating elements in the lithium 3rd gen packs, though there is a significant amount of circuitry (DC-DC converter?) in the same plastic case as the batteries that may serve as a warm-up heat source depending on how the fans run. I am also not sure if the 3rd gen packs intake air from inside of the cabin or outside; it always struck me as a bit strange that the G1 Insight IMA air intake is the outside of the car (just above the fuel tank, I believe) instead of the air-conditioned (or heated), filtered air from inside the cabin.


Side note, Mudder, what size/PN are the Anderson connectors that get spliced into the car-side IMA harness? I need to buy a set for whatever car I end up buying to replace mine.

Though, more pressingly, I need to cut my hatch open and liberate the IMA battery. It's 17 degrees outside right now and it's been sitting for a month. I'm worried, but I didn't want to cut the car open until I had a decision from insurance.

 

[joeaax1j]

Jake, if you haven't already, can you at least crawl in the back and flip the switch to turn off LiBCM?

 

[davismltc]

it always struck me as a bit strange that the G1 Insight IMA air intake is the outside of the car (just above the fuel tank, I believe) instead of the air-conditioned (or heated), filtered air from inside the cabin.

The Insight G1 IPU air intake is from inside the cabin (small plastic vent behind the passenger seat) and the cabin's conditioned air is drawn in across the HV battery pack by the 80mm 120mm Panasonic computer style fan. The air intake above the fuel tank you referred to is cooling the DC-DC converter via the squirrel cage blower and exhausts above the muffler.

Edit: (Oops...fixed the fan size...thanks Bull Dog!)

 

[Bull Dog]

That isn't quite correct.

The Power Delivery Unit (PDU), which includes the Motor Drive Module (MDM) and the DC-DC Converter is cooled by outside air.

The IMA battery is cooled with cabin air. A 120x38mm fan is responsible for moving air through the battery pack.

 

[joeaax1j]

I'm wondering if the issue might just be the temperature differential. I've been plugged in at the office since 7:30AM this morning and it is now almost 2PM. This is outside in a parking lot. The SoC was 56 when I plugged in and the pack temperature was 16 deg C. The outside temperature at that time was -13 deg C. I've been checking on the charge every hour or so. I've not seen the pack temp reach 20 deg C, yet. For several hours it seemed to be stuck on 19 deg C (although maybe it was going back and forth between 19 and 20, and I just didn't catch it.) However, right now it is showing 18 deg C and the SoC is only up to 69. So, it hasn't gotten to pack balancing mode, yet. Outside temps right now are -11 deg C, so the differential is about 30 deg C. I know without debugging info, this is all speculation. Just wondering.

 

[mudder]

Is it possible this is the case of plugging the charger in outside of the one hour window after key off?
Or maybe a 120vac power interuption of some duration?

Right now LiBCM always stays on, until SoC drops below 10%.
Assuming the power comes back up, 120 VAC interruptions won't affect LiBCM's heater behavior. By default, the heater will stay as needed, until SoC drops below 50%.

Side note, Mudder, what size/PN are the Anderson connectors that get spliced into the car-side IMA harness? I need to buy a set for whatever car I end up buying to replace mine.

I'll send you another set... you cover the shipping. Paypal request sent.
However, note that you can just swap the entire IMA harness from one car to the other. All you have to do is unplug the connectors in the IMA bay and then two more connectors behind the middle mat. If you decide to do that, just don't send the paypal payment.

FYI: LiBCM's entire parts list is located here. I'm using PP15 Anderson terminals, with PP15/30/45 housings.

Though, more pressingly, I need to cut my hatch open and liberate the IMA battery. It's 17 degrees outside right now and it's been sitting for a month. I'm worried, but I didn't want to cut the car open until I had a decision from insurance.

If it's going to be much longer before you remove the pack, please turn the IMA switch off.

I'm certainly interested to see how well LiBCM held up mechanical. Please take pictures/video before you remove it from the car, and also pictures of the LiBCM PCB with the cover off.

 

[mudder]

I'm wondering if the issue might just be the temperature differential. I've been plugged in at the office since 7:30AM this morning and it is now almost 2PM. This is outside in a parking lot. The SoC was 56 when I plugged in and the pack temperature was 16 deg C. The outside temperature at that time was -13 deg C. I've been checking on the charge every hour or so. I've not seen the pack temp reach 20 deg C, yet. For several hours it seemed to be stuck on 19 deg C (although maybe it was going back and forth between 19 and 20, and I just didn't catch it.) However, right now it is showing 18 deg C and the SoC is only up to 69. So, it hasn't gotten to pack balancing mode, yet. Outside temps right now are -11 deg C, so the differential is about 30 deg C. I know without debugging info, this is all speculation. Just wondering.

It's certainly possible that if you're parked outside and it's windy, then the aluminum chassis could be sucking air out of the IMA bay faster. A 30 degC delta is still less than what I observed in my testing (40 degC delta), but it's a similar ballpark, so that might be the case.

If you don't want to leave a computer in the car overnight (as you stated previously), another method to see if the pack heater is working is to just leave the car plugged in for a couple days and then see if the pack stays much warmer than outside.

Also, just FYI: When the grid charger is plugged in, LiBCM allows cell balancing regardless of SoC.

...

Issues like this are why I'm excited the (optional) daughterboard PCB I'm designing right now has a 512 MB flash drive on it... with this PCB installed, LiBCM will continuously log every decision it makes. Given the memory size, I suspect LiBCM will be able to recall at least the prior 48 hours. Obviously not helpful now.

 

[mudder]

Just wanted to give an update on what I'm working on:
Right now I'm rewriting the 4x20 LCD code. It has some major issues that prevent LiBCM from turning off. The most important goals are to:
-remove the blocking delay() functions that are called whenever LiBCM displays a user message. delay() is a terrible function because it prevents any other code from running until the specified period elapses. Because I didn't initially write an lcd_handler() function, I originally opted to use delay() functions whenever messages are displayed to the user.

-Redesign the lcd communication code so that that LiBCM can initialize the lcd during keyON events, rather than each time the key turns off. As I've mentioned previously, communicating with the 4x20 display is very slow, and has silly tight timing requirements due to how the lcd's 4b bus interfaces with a standard 8b serial I2C bus.

-Once I finish this, my next goal is to pull @Natalya's LiDisplay code into Prerelease, and then ultimately into Main.

 

[davismltc]

I'm logging info while grid charging to monitor the heater and SOC. This is the first time I've tried to actually save the data.
I get the data okay in the serial monitor, but when I try to copy then paste the data into a text file, my laptop only copies what's visible in the monitor window.

To save the data:
If I press Control A, it highlights only the upper half the screen (LiBCM code)

If I highlight all the data within the monitor screen and then press Control C with my cursor on the highlighted data, when I try to paste the data (Control V) into Notepad, I only get the highlighted portion visible in the lower half of the screen (what's immediately visible in the monitor window) pasted into Notepad, not the entire amount of data I highlighted.

Anyone else have this issue, or some idea of what I might be doing wrong, or how to preserve the data into a file?

My version of Arduino is 2.0.0

 

[mudder]

I've seen similar behavior when the "Autoscroll" box is checked. I always uncheck that box before copying text.
I haven't used Arduino 2.0.0 yet, but maybe this is still required?

If I press Control A, it highlights only the upper half the screen (LiBCM code)

Does this behavior persist if you first click on the Serial Monitor window (so it's the active window)?

 

[davismltc]

Yes. But I may be having issues with my computer. I just switched to my phone to respond b/c I couldn't get on the internet with the laptop. I'll advise once I sort out the laptop issue.

 

[bbcb]

I will pull logs tonight as well.

@6A this morning, the pack is still on my bench in my unheated garage after the heater kit install on Sunday with the grid charger still plugged in. That said, it would appear not heating as the temp shown below matches ambient:

let me know if you want me to grab anything more than instructed to @davismltc