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Discussion Starter #181
So because it was too hot, you went and crippled the Bolt's HVAC system by turning on recirc.

Which I've already established will IMMEDIATELY (within seconds of pushing the button) spike the heater's power way up.

Thus making comparison of the Bolt's system against your setup COMPLETELY invalid.

In your shot, you've got an ambient temperature of 43F ambient. There's no way in **** you're seeing 2400W average unless you either opened the windows or disabled recirc.

I get far lower average power consumption at only 20F ambient.

what the h are you talking about ... I have tried with recirc without recirc...the only thing recirc does is uses the interior air and "recirculates" it . Using LESS energy to maintain heat best it can


When I turn off recirc on PTC then I also leave it off Cars heater... all things equal.
 

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I happen to be the only person that has provided proof on something that isn't exactly rocket science. I max out at 1,000 watts... the Bolt max es out at 7,500 watts... so no shaat sherlock I am going to get better range.
But you are not comparing same scenarios. That where it hurts most folks here.
You will shout in ALL CAPS, with large Bold letters that you accomplished something, but the data you compare between OEM setup and your PTC are two different scenarios.

Besides, however you want to word it - there is no logical explanation why your 1 kW would be enough for doing same job what 7.5 kW does.
Energy of 6500 W is huge loss. There is no explanation for it, meaning I cannot find any plausible explanation for it.
Even assuming OEM system is poor design, and it is, it is still not as bad to simply drop 6500 W somewhere in between.

Yes, I see, you gained 18 miles on full charge. Is it a lot or not? That is debatable. One could say - drive a bit slower. No can do here. I get it.

All possible problems you created with your setup (strains on the DC/DC converter, OEM 12 V battery, lack of filter, possible melting of the blower, no cabin filter...).
And the investment of time and money.
Yes, that is how great ideas are born.

To really prove it, you would have to spend at least two days of same driving, same weather and settings, one with PTC the other with OEM, while doing extensive data tracking and logging.
Almost laboratory setup like.
I can see that even with -10 C (+14 F) on a longer day of driving I get the OEM system down to 1500-2000 W on most times. Sure, hard to prove a point here.
 

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I max out at 1,000 watts... the Bolt max es out at 7,500 watts
Sounds like you are doing the equivalent of forcing the stock system to run at only 1,000 watts, which uses less energy, of course. With an additional side benefit of more instant heat.

I wonder if limiting the power of the stock system would create similar results with less possible issues.
 

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Sounds like you are doing the equivalent of forcing the stock system to run at only 1,000 watts, which uses less energy, of course.
But that is the bad side of it.
Any power to OEM heating system is a big waste due to the fact it must first warm up the whole system and coolant within. This is a big heatsink.
Surely, at lower power load the coolant is at lower temp, so you experience less heat exchange with ambient, what overall results in less losses. Yet still, ideal would be NOT to deploy OEM at all.
Use PTC only.
 

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I have wondered - might propane be simpler for this application? (no need for a pump for example). Biggest issue with any combustion approach is you need to add some exhaust plumbing, and also potentially air intake plumbing.

Also probably some condensate plumbing for a highly efficient system - acidic condensation is a problem for high-efficiency condensing systems.

Solve the exhaust/combustion air intake challenge and you've probably also got an opportunity to use the same solution for a less effective (but also much less extreme) HRV system to maximize ability to stay on recirc without fogging.
That is what I'm working on using fuel exhaust as heater for battery... it will not have a lot of power but it will keep more than happy battery in cold weather....flow true coolant something similar to what boiler is doing but I will be using venture pipes for maximum exhaust heat transfer and I have already variable pump that will keep coolant flow for battery in check....
Propane is not my favorite fuel....living in the Midwest bio diesel is easily obtained....Unit I will be using has altitude and combustion chamber sensors for optimal burn rate....and it is certified for all 50 states....also it has catalyst converter for near zero emissions. It is very expensive Unit that I use for other projects and marine applications....
Pump will still be necessary for cabin heater and battery heater... I will have independent control over my setup and it will not interfere with my setup.... For now I'm playing with when air conditioning is called to cool down battery....and once I find it I will adjust my calibration for battery heater loop. Exhaust when pushing 5000 watts of heat to coolant is producing on exhaust side 6 inches from exhaust outlet 128°F hot air and from my calculations it is giving around 400-750 watts of heat transfer to coolant using exhaust heat... I could get even more but I don’t want to eliminate catalyst converter....
 

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If I did the math right, we are talking about 85% efficiency.
Biodiesel is about 34 MJ/l and from the above it looks like 8000 W from a liter of fuel.
Joules per s is a W, 3600 seconds per hour, and here and there - about 29 MJ in 8000 W during 60 minutes.
28.8/34.0=84.7%.

That is quite good.
If it is quiet and does not smell badly, might be a decent alternative to electric energy.
Reason for not getting over 85% efficiency is because this unit uses catalyst converter and for this to operate properly they have to make it less efficient ( more heat to exhaust instead of combustion chamber coolant heater)
It has no fumes and no smell ( but what they say it is not killing you what you can smell but what you can't)
And you are right on the money with your calculations.... I could get better efficiency with dinosaur diesel or kerosene...but bio diesel is what my setup will be running.....
I do still agree that cleanest heating is electricity but using 5-8 kWh for 2 hours of driving is no go with battery size in Bolt EV.
I have 4 EV projects done this way for customers ...
Now my new idea is to harvest exhaust heat on top of fuel coolant heater .
 

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A test I have not seen trotted out to distinguish stock heater range vs PTC heater range would be run the car all day from full to empty with stock heater, and again with PTC heater. Taking notes each day, even better with multiple days of each, along with ambient temp and cabin temp noted (hopefully identical for each run). Do that and report back, please. Using the infotainment display for short runs tells nearly nothing.
 

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Discussion Starter #188
Yes, I see, you gained 18 miles on full charge. Is it a lot or not? That is debatable. One could say - drive a bit slower. No can do here. I get it.
No not debatable.. 18 Miles and NOT having to slow down is significant.


BTW Looks like once we get temps near 50 then the PC heater won't make as much difference because running either heater will only be for short time anyway.
 

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Discussion Starter #189
A test I have not seen trotted out to distinguish stock heater range vs PTC heater range would be run the car all day from full to empty with stock heater, and again with PTC heater. Taking notes each day, even better with multiple days of each, along with ambient temp and cabin temp noted (hopefully identical for each run). Do that and report back, please. Using the infotainment display for short runs tells nearly nothing.
So we can ignore everyone's Posts about their range then unless they ran their Bolt to empty..yeah OK then
 

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A test I have not seen trotted out to distinguish stock heater range vs PTC heater range would be run the car all day from full to empty with stock heater, and again with PTC heater. Taking notes each day, even better with multiple days of each, along with ambient temp and cabin temp noted (hopefully identical for each run). Do that and report back, please. Using the infotainment display for short runs tells nearly nothing.
Yup, and running the Bolt in the most efficient manner possible when using the builtin heat. For example, recirc on and only tapping the defrost/defog button when fog appears just long enough to clear the condensation. Log heater wattage used by the Bolt for the entire run, and also monitor AC wattage in case the AC kicks on for whatever reason.

Reason for not getting over 85% efficiency is because this unit uses catalyst converter and for this to operate properly they have to make it less efficient ( more heat to exhaust instead of combustion chamber coolant heater)
It has no fumes and no smell ( but what they say it is not killing you what you can smell but what you can't)
And you are right on the money with your calculations.... I could get better efficiency with dinosaur diesel or kerosene...but bio diesel is what my setup will be running.....
I do still agree that cleanest heating is electricity but using 5-8 kWh for 2 hours of driving is no go with battery size in Bolt EV.
I have 4 EV projects done this way for customers ...
Now my new idea is to harvest exhaust heat on top of fuel coolant heater .
Based on how I understand how you're describing it:
The coolant heat exchanger and the combustion chamber are integrated with each other, then followed by a catalytic converter, then by exhaust with no further HX?

Yeah, putting an HX that preheats the coolant from the cat exhaust should increase efficiency, but you need to be careful that when starting to condense out the exhaust, you handle the rather acidic condensate properly. (This is a challenge with high-efficiency condensing boilers that are so efficient they condense the water vapor out of the exhaust.)

You might possibly find better efficiency improvements at that point for total system effiiciency than just making the combustor more efficiency - most notably as I've mentioned before by maximizing recirc by finding ways to control humidity without losing heat. As I've mentioned, either a dehumidifier or an HRV ( see DIY Heat Recovery Ventilator (HRV) Plans for one example of an HRV - one to handle the Bolt efficiently would likely be much smaller. Take a look at Dan Achim's setup in the comments that was coincidentally posted only a day or two ago, I like his geometry that gets proper counterflow over a greater percentage of the unit, although I wonder if the tape he's using to seal the joints is going to create gaps that kill efficiency without a huge amount of thermal paste or similar material...
 

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Yup, and running the Bolt in the most efficient manner possible when using the builtin heat. For example, recirc on and only tapping the defrost/defog button when fog appears just long enough to clear the condensation. Log heater wattage used by the Bolt for the entire run, and also monitor AC wattage in case the AC kicks on for whatever reason.


Based on how I understand how you're describing it:
The coolant heat exchanger and the combustion chamber are integrated with each other, then followed by a catalytic converter, then by exhaust with no further HX?

Yeah, putting an HX that preheats the coolant from the cat exhaust should increase efficiency, but you need to be careful that when starting to condense out the exhaust, you handle the rather acidic condensate properly. (This is a challenge with high-efficiency condensing boilers that are so efficient they condense the water vapor out of the exhaust.)

You might possibly find better efficiency improvements at that point for total system effiiciency than just making the combustor more efficiency - most notably as I've mentioned before by maximizing recirc by finding ways to control humidity without losing heat. As I've mentioned, either a dehumidifier or an HRV ( see DIY Heat Recovery Ventilator (HRV) Plans for one example of an HRV - one to handle the Bolt efficiently would likely be much smaller. Take a look at Dan Achim's setup in the comments that was coincidentally posted only a day or two ago, I like his geometry that gets proper counterflow over a greater percentage of the unit, although I wonder if the tape he's using to seal the joints is going to create gaps that kill efficiency without a huge amount of thermal paste or similar material...
Thanks I will look into it...
 

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Discussion Starter #192
So 121.8 / 36.7 = 3.31 miles/kWh I ran Just the PTC today. As you can see plenty warm inside the vehicle at 78 degrees. (Climate settings 1%)


I had 26 total Stops, passengers getting in and out, and waiting for passengers. so 3.3. excellent ..temp was 32 when I started 38 when I ended

On a Ful 60kWh battery I could have gottne a total range of 60 - 36.7 = 23.3 kWh left = 23.3 x 3.1 = 72 More miles . 121.8 + 72= 193.8 ...for a average 35 degree day , 26 stops and running snow tires.


So I took photo of my home charger 3783 kWh ...lets see what it says in the morning /later tonight .. it should ad 36.7 or thereabouts ...total 3819.7


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