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1000 watt PTC Heater in Air Filter slot produces 80 degree F vent air using recirc- increases range 1 mile per kWh WINTER RANGE

50K views 309 replies 39 participants last post by  ChiGuyGo 
#1 · (Edited)
1000 watt PTC Heater in Air Filter slot produces 80 degree F vent air using recirc- increases range 1 mile per kWh WINTER RANGE

Bottom line ...You CAN add 55+ miles of range(usable from Bolts 60kWh battery) (or rather prevent the loss of 55 miles) and do it for less than $150 and stay relatively warm. (80-degree air through vent ..probably 60-65 in the car(I'll locate my thermometer to check...but it was plenty warm..not HOT like the car's heater gets obviously think hotter than luke warm

I tried various settings and the best setting is (at Zero degree F) is : temp set to "LO" , heat/ac off and recirc ON. Just as you see in the Photo below..and Vent temp is 80 ..going down the road.


Range: 2.2 Using the Bolts Heater
Range: 3.2 Using the PTC heater in the air filter Vent


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I noticed a melting smell and pulled the heater ...had specks of melted plastic



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Put my hand down the slot to see if I could locate the part melting... (so this dumbarse) I dinged my fingers this so you don't need too !!


****..had the fan still running ouch.. anyway it was a fan blade.


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So the fan blades are less than 1 inch below the air filter slot so slide the Heater in with Fins facing UP ..not Down !!

Your welcome lol

No melting facing up


This is the right heater..

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and the Inverter I am using

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Dan

Evdriver.org
 
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#2 ·
IT WORKS ..and Soooo nice to have all the heat coming from the vents like "normal" instead of just the space heater I was using. The space heater because it is in the car you can get some really hot air pointing right at you but the heat wasn't even throughout the car.


and NO Window Fogging!


This REALLY works everyone. and you will see a 1-mile increase of range /kWh -or if you prefer you will stop the loss of 1 mile/kWh.


For me driving uber/Lyft this is really big...for those of you that have short commutes or only drive a few days a week, this Mod will not make much sense to you.


For Uber/Lyft drivers, for drivers will long commutes etc... DO IT !

It's a cheap mod that actually works, will reduce your winter range anxiety and the gains are huge.. 30% for less than $150
 
#104 ·
For Uber/Lyft drivers, for drivers will long commutes etc... DO IT !
Would you or a MODERATOR please delete this? While I'm admittedly very intrigued/amused by this thread, this is absolutely terrible advice, as no professional shop will do this modification for justifiable fear of liability, and as a diy by Joe Blow, it's probably not going to end well.

I believe what you're doing works (to what effectiveness is hard to quantify), what I don't know is:
-You've removed your cabin air filter, so you're no longer filtering air, are you going to end up with dust and/or other debris on the heater elements and start a fire possibly if not cleaned regularly?
-The "normal" load on the dc to dc converter is ~200-300 watts, how much (if any, to be fair) faster is it going to wear out/break with a substantially increased load.
I deserve an apology from all of you that refuse to admit that I have in fact demonstrated how to increase or not lose up to 1 mile of range in the Bolt (winter range)
:ROFLMAO:

Did you ever determine where the melted plastic bits came from?
 
#3 ·
1000 watt PTC Heater in Air Filter slot produces 80 degree F vent air using recirc- increases range 1 mile per kWh WINTER RANGE

I tried various settings and the best setting is (at Zero degree F) is : temp set to "LO" , heat/ac off and recirc ON. Just as you see in the Photo below..and Vent temp is 80 ..going down the road.

Range: 2.2 Using the Bolts Heater
Range: 3.2 Using the PTC heater in the air filter Vent

No melting facing up
That is friggin' awesome. You are the man. Seems like, with the HVAC button off/unlit, it shouldn't matter where you have the temp knob set.

Sorry about your fingers. Anything for science. :cool:
 
#4 · (Edited)
Did you find a place under the hood to mount the inverter?

I wonder how this would compare with using four 200w 12v PTCs, each with 12ga. wire, or two 400w 12v PTCs with 8ga wire. I'd been thinking of running the bundles of wire towards the battery, and connecting them through bimetal circuit breakers (which could be used as "off switches" once temps reach 40F).


nd
 
#5 ·
recirc is the key guys.. Vent Temp was 63 degrees (going down the road) when recirc was off. (pulling ZERO degree outside air across the heater). Recirc you get the inside air that keeps getting pulled across the heater. I thought I was going to have a fog issue using the recirc but apparently, it's pulling enough outside air through as well.


I am officially done with the Mod... It works, may not be the best at 20 below but at zero it's fine, and the normal winter temp for us at this time of year is 28 degrees.. thinking should be able be to get the interior up to 75-80 then.
 
#10 ·
YES , remove the air filter , mount the heater on 8x 9/12 (same size as filter) 1/8th inch wood (obviously cut hole out for the actual fins heating elements) and simply slide in. You'll still be able to close the Glove box..

You all know the air filter is behind the glove box ?




INVERTER is also just screwed down onto a 1/2 piece of wood and sits in the "engine" compartment next to the battery. Thought about bring the Invertor in the Cabin for extra heat but you really want it as close to the Battery as possible so it is as efficient as possible..besides the fan motor on the inverter probably drive you nuts anyways ;)
 
#11 · (Edited)
Thanks; one other ?: did the PTC heater come with a spec sheet listing its "target temperature"? As you described, a PTC is self-regulated to heat to a temperature which is fixed in the design/at the factory. I'm thinking it might be prudent to look for one with a bit lower temperature, because of that melting plastic you had.
 
#12 ·
Thanks; one other ?: did the PTC heater come with a spec sheet listing its "target temperature"? As you described, a PTC is self-regulated to heat to a temperature which is fixed in the design/at the factor. I'm thinking it might be prudent to look for one with a bit lower temperature, because of that melting plastic you had.
Anything warm enough to notice is going to melt plastic. You need to keep it far enough away...and use a fan activated relay to make sure you don't start the car on fire!!!
 
#14 ·
I drive to Northern Virginia (280 miles away) fairly regularly and a gain of 1 mile per KW would be significant to me. My first car was a VW Beetle and I still can't get a car warm enough for me in the winter time. I already have 1,200 watt inverter already mounted on top of the "engine" and have ordered the heater. What blower setting are you using?
 
#15 ·
Can I be skeptical here?

Show me energy used, miles, and the pie chart after driving 40-50 kWh of the battery. Then I will make my own decision if it really works.
I learnt one valuable lesson years ago - trust, but verify.

Any way to slide it somewhere near the heater core so that you are actually not warming it up? You see, the heater core is filled with cold liquid. In your case it will be a few degrees higher than ambient, so your initial hot air will be used to warm up the heater core. Then, without your approval, the coolant will start flowing freely in the system loosing all heat to the ambient. While it will not flow through the pump, it will use convection inside the about 1/2" tubing. Wide enough to create two layers of liquid and transfer the heat outside.
 
#16 ·
What I've seen about the Bolt EV's Energy Usage screen is that it doesn't clearly and consistently account for the energy drawn from the 12 V battery (which is what is powering the heater cores). I suppose it's possible that if the 12 V battery is only being recharged when you're plugged into a charger drawing juice from the grid, then there could be a real gain. Otherwise, you're mostly just shifting the energy burden to a different place.

Now, the recirculation trick is something that works even without these additional PTC heaters in the vents, so I don't know how much additional benefit these heater cores provide.
 
#21 ·
To the critics / naysayers of OneEV's hack - if you don't believe him or think there is a different way, do your own physical verification or your own hack and provide the same level of documentation that he did. All I see is cheap talk (typing) and 10 second knee jerk conjecture - I thought we (EV guys) were better than politicians.
 
#23 ·
I have no problem at all believing this works. My only concern is safety. How do you know the heater won't get hot enough to melt the plastic such as the tray the heater slides into or the sides of the HVAC unit? If it was hot enough to melt the fan blades when it was turned upside down, I'd worry. I also assume you run the fan for several minutes after turning off the heater to cool it down? A good precaution (if you can figure out how to do it) would be to add some type of relay or something that at least makes sure the heater can't come on unless the fan is running. Even better: a timer on top of that which keeps the fan running for 3 minutes after the heater shuts off. That could be harder because I'm not sure the fan has power when the car is off.

Just some ideas.

Mike
 
#24 ·
His results are interesting, and I'm glad he's sharing them, but I'd rather deal with the abysmal winter mileage I get of 1.7-2.0 mi/kWh, stated full charge range this morning of 109 miles, and a toasty warm car than go through the amount of effort involved here. But it's rare that I need to drive over 80 miles in a day unexpectedly. I suppose if my income was directly proportional to the amount of driving I did, I'd probably have a different outlook on it. Having that heater loose in the cabin was pretty concerning, this seems like a safer option.
 
#30 ·
All I see, as an amateur radio operator since age nine, is an extreme violation of warranty, and a continued electrical hazard. Stay with the basic design until heat reservoirs are used, and heat exchangers are used for slightly warmer temps. Like others who have responded, I question any savings at all, by drawing amps from still another circuit. I thought my answer was silly, but it now seems logical. THAT IS, I had an external lithium power pack (commercial, available everywhere at radically different outputs) and an external heater/defroster. It drew NOTHING from the car. And, it worked fine. Did absolutely no mod to the Bolt.
 
#31 ·
I believe the 12V battery used in the Bolt has 50 AH capacity, which at 12V should be approx 600 WH. So the 12V battery could run a 1 KW heater for about 30 minutes before needing recharging. You could easily drive 20-30 miles in that 30 minutes - which is 4-6 of those "5 mile" bars. I expect the car's computer really has no way to know that energy is being drained from the 12V battery. Hence the requests here for some longer term indication of the efficiency gains. I think it's great for OneEV to be hacking at his car and sharing his results. But I too am skeptical re: the physics.
 
#46 · (Edited)
For reference, these weigh just over 11 lbs per cell. $900 would get you 7 kWh and would weigh about 90 lbs.


If you pull 100% out of them, as he did, they will be junk in weeks. At 80% you will get 3 years easy. 12 V x 280 Ah = 3360 Wh x 0.80 = 2688 Wh usable x 3 will work. So for about $1500 you are pretty much sure to get a full three years.

I don't know how shipping from China is working these days. But back in 2011, when I had my LiFePO4 pack sent from China, it got stuck in customs for several weeks. They finally let it through, even though the shipper had it listed as electrical components instead of batteries. If he had listed it as batteries, there would have been a duty, as I recall..
 
#59 ·
I'm not sure exactly why, but it could have something to do with where the energy usage is tracked. The 12 V battery is recharged through the DC-DC converter, and if the Bolt EV's system is set up so that recharging the 12 V battery is not considered "accessory usage" because the accessories are powered through the high voltage junction box, it wouldn't fall under accessories.
 
#51 ·
So how am I getting up to an additional 1 Mile kWh/ or not losing that 1 mile/kWh of range.


The Bolt uses up to 7.5kWh to run the car's HVAC ..I am using just 1kWh heater.


I think that pretty much is the answer no matter which Battery it is coming from.


The Gains are real I have been testing for over a month.


Everyone knows running the Bolts heater = huge loss of range 20%-30%-40%

Turn your heat off and what kind of Gains would you expect to see? =20%-30%-40%

That is essentially all I am doing ..with the exception of 1000 watts
 
#53 ·
The Bolt uses up to 7.5kWh to run the car's HVAC ..I am using just 1kWh heater.
I just do not believe it is that simple as if it is, then it means GM engineers messed it up a lot.
I had 500e with PTC heater and believe me - summer I could get 80 usable miles, winter I could barely touch 50 with heat set at 68 F.
 
#58 · (Edited)
The most plausible scenario I can imagine to explain the difference in efficiency, is that the car is running heater when needed, + A/C to regulate the air temp (and perhaps humidity). And OneEV's heater is not running the A/C. I could believe that GM would be doing something stupid like that, but OTOH I'm sure the Bolt engineers had a strong incentive to maximize the range they could advertise for the car. So you'd think they wouldn't do something so stupid - unless humidity control was the driving factor. Of course, we've seen that the winter range is nowhere near the advertised range for the car. So maybe they were satisfied getting a good fair-weather range to put in the specs.

But I've seen no data from OneEV to convince me that the month of test results consists of anything more than looking at the last few energy bars on the display while turning the heater on and off, and that's not enough to overcome my skepticism. My opinion doesn't matter much anyway, because I live in the southeast and don't have to deal with cold much. Until this week, that is!

I don't know how the Bolt's energy accounting works, but a big difference between OneEV's heater and all the other "accessories", is that the accessories are turned on/off by the car's computer, so it knows when they are on/off and can estimate their energy consumption. The computer probably has no idea when he has plugged a 1KW load into the cigarette lighter, unless the fuse blows (and probably not then.)
 
#62 ·
I live in a mild climate so my observations might be bogus, but we do sometimes get temps in the 30's F. During those times, I've noticed that the heater starts at 6-7 kW but once the cabin gets heated up to near the set temp, it drops to 1-2 kW. So I'm thinking, what if you could find the right set temperature so the built-in heater just draws 1-2 kW instead of higher? My line of thinking is that if it is 0F outside and you have your set temp at say 65F, the heater might keep cycling back up to 5, 6, or 7 kW at times: to try to push the cabin temp up over the set temperature. Maybe reducing the set temperature to 55 instead of 65 would give the same amount of heat as a PTC heater?

The HVAC system in the Bolt is a bit squirrely anyway: the temperature sensor is down by the passenger's feet, possibly in the HVAC/fan unit itself. So you are essentially trying to warm up or cool off the passenger's feet to the set temp. Setting the vents to blow top vents only and setting a lower temperature could potentially yield similar results. IF you can find the right set temperature.

Mike
 
#66 ·
The HVAC system in the Bolt is a bit squirrely anyway: the temperature sensor is down by the passenger's feet, possibly in the HVAC/fan unit itself.
The main cabin HVAC thermistor is up behind the rearview mirror. There is also a humidity sensor up there. There are two thermistors in the HVAC ducts, one for the foot vent, and one for the chest/windshield vents. There is also a thermistor in the AC evaporator behind the glovebox.
 
#64 ·
If I would try to maximize EV range while keeping warm I would heat my body and not the air in the car.
I used a heated jacket and heated pants while was into street bikes and touring. It worked wonderfully. Cheap to buy, runs off 12V, safe, effective.
There is jacket, vest, pants , socks available.
heated jacket

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#65 ·
If I would try to maximize EV range while keeping warm I would heat my body and not the air in the car.
That won't help OP's rideshare passengers. But for most of us, sure, it would reduce the need for HVAC in cold winter months.
 
#69 · (Edited)
OK Guys went out for a Couple Hours.. .So what was it 15 below and I was able to get the cabin 60-65...well today at 7 degrees Above zero ...got 72 degrees in the Cabin. I had to turn the heat off my feet because it was getting too warm !! The highest temp coming out of the vent was 93 Degrees

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Range was 3.0 for Cars heater ands 3.5 for My Heater ... 1/2 mile today ...which is still very impressive. that would translate to 27.5 "extra" miles through the usable 55kWh of the Battery


Temp ranged from 60-72 in cabin today

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Uploading a Video to Youtube now.. I'll upload here soon..
 
#78 · (Edited)
OK Today's range test 6-8 degrees...also includes showing placement of PTC heater



The car has cooled down 50 degrees inside, I just went out and wanted to test one more thing...show you how at startup hope fast the heater blows hot air through the vents

Got to 80 in less than a minute

 
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