Cold Weather and the Harvester Engine

[Multihog]

I have noticed in a few EV owners manuals that the HV battery may not provide propulsion if it is not plugged into a level 2 charger to keep the HV battery warm. Since the Harvester generator will be able to charge the HV battery on the go then it should be able to precondition the HV battery in cold temperatures. My question is what will start the Harvester? Will it be a motor/generator and use the HV battery to start? Will a cold soaked HV battery be able to do that? Will the Harvester have a traditional 12v starter and be run off the 12v battery? Will it have block heater to keep the engine block warm? Could the block heater be powered from an external plug or from the HV battery? Most long term parking stalls I have seen have 110v ac plugs for block heaters in a gas/diesel vehicle. If I plug the Scout into a level 1 charger will it be able to maintain a charge on the HV battery while the HV keeps a block heater going for the harvester? Is the HV battery coolant loop going to be tied into the Harvester coolant loop? Long story short will I be out of luck if park at the cabin for a week in -30c weather? I know it’s to early to get all the details from Scout but I am curious about their cold weather plans. It’s been a while since I have had to light a fire under an engine to start it.

 

[Mr._Bill]

There is usually a 12v battery to power all the electronics, relays, and computers. The drive motor is the only external item powered directly from the HV battery pack. There will be a converter to charge the 12v battery and power all the devices when the vehicle is in the run state. The battery pack will have a heater to keep the cells from freezing. The BMS will manage the heater until the charge level drops too low.

The final design for the generator will determine if the engine has a block heater, but it probably will not. Heating pads, powered by a 120v outlet, can always be installed in very cold climates.

 

[Multihog]

What you say is true. I am overthinking about how integrated the Harvester will be. I still wonder what will physically crank it over. A 12v starter that I can boost with almost anything. Or the HV battery running a motor/generator, which will require me to have a Level 2 charger. To early to tell until the generator design is finalized.

 

[Mr._Bill]

Whatever the final design for the generator turns out to be, it will have a 12v starter. That is an accepted standard for vehicles. To use the HV battery pack to start the generator would require the vehicle to be in the run state to pull power from the 12v converter. The generator starter will be tied to the 12v system, since the intent of running it is to charge the HV battery pack. The models with the generator will likely have a higher capacity 12v battery.

The HV battery pack requires an external charger. The power to feed the charger comes from the wall outlet. The generator will be a power source carried with the vehicle to be used when a wall outlet is not available. The recommendation to have the wall outlet connected in cold climates, when not driving, is to keep the HV battery pack from being drained by the internal heater.

 

[JohnT]

This is my concern as well. We go hunting up in the mountains of Montana and can be -20 to -30 below zero. Need to have a reliable vehicle to get back out after a week.

 

[vrgruver]

Read about the 2013- BMW i3 REX. This had a range extender generator. System can be a little different, but it can answer a lot of questions with a 12 year old design.
https://en.wikipedia.org/wiki/BMW_i3#/media/File:BMW-i3-Electric_Drive_unit2.JPG

 

[Sunrack]

My prediction is that the Harvester engine starter cycle will utilize the (800v) generator and batteries as a generator/starter. No separate 12v starter is necessary.

 

[MadDirty]

I doubt they're going to try to reinvent the wheel here, so to speak.

The traditional 12V battery will likely be used to energize the starter on the Harvester engine, just like a traditional vehicle. How that will be manually triggered is going to be a bigger question, though I believe it'll just end up being a toggle switch in the UI. I don't expect there to be a separate start/stop button for the Harvester. If there is, I'd expect it to be mildly tucked away.

 

[Terrawatt]

I agree with most of what was said on this forum so far. I think Scout would, or rather should, stick with 12VDC for their auxiliary systems and the engine starter. I think the Rivians have one or two 12VDC lead acid batteries on deck for this purpose.

As for a block heater, I wonder if they could keep the block warm using the same heat pump that's going to precondition the battery. But I think this might be difficult and/or expensive, as I assume the generator and the battery will have seperate cooling loops, as seems to be the case for other vehicles:
https://www.fenderbender.com/runnin...33029710/hybrid-and-ev-cooling-system-service

Another option could be to use the existing 120VAC inverter to power a conventional block heater during the precondition process. It will be a bigger drain on the battery, but atleast they would be use tried and true components.

I would most like to see an engine block heating system that can heat the engine while driving or while parked. Rather than a block heater that you have to plug in separately while parked only. What I can see happening, with a system that has an independent block heater that heats the block only while parked, is trying to start a cold engine while traveling on the highway and it failing to turn over because no system was able to heat the block up while traveling for so long.

It also wouldn't surprise me if Scout straight up won't put a block heater in the system to avoid the extra complexity and cost. My VW Golf R doesn't have a block heater, nor can you install one, and it starts just fine in -40°C weather. Probably not good for the longevity of the engine, but so far so good. It's been 7 years so far being an outside vehicle during harsh winters and I haven't had a problem yet. As long as I keep the battery happy, the engine starts.

 

[Sunrack]

One other point is that the Harvester engine cooling system, during cold conditions and while changing, can be an efficient way to heat both the cabin and the 800v batteries without using the heat pump.

 

[Multihog]

Just hoping for the option to start the Harvester to condition the HV batteries, instead of getting the “To cold to move, please plug in” message. Bonus would be the ability to jump start the Harvester with another vehicle in the advent the 12v is also discharged and cold. Doesn’t need to be a separate button or switch. Just an option through the touchscreen in extreme cold.