Preheat car power

[MountainGoat]

As the winter comes and I find myself at an airport without convienent plugins  I thought about buying an external power source for preheat.   Then I remembered I already paid a lot of money for a portable 220kW power source.   I looked online and I saw 110v/3amp inverter for a car.   As best I can tell,  my tanis is supposed to take 115v at 2amps.  It seems like the power is there,  does anyone know a reason why the volt mismatch would matter?

Given where I am (dc area instead of vermont),  I figure 30 min to an hour should be enough to warm engine to near 40 F.  Since this is a temporary arrangement,  idling my car for up to an hour a handful of times seems better than springing for a power source. 

[Fritz1]

Inverter will do, maybe go a tad bigger on the amperage, clamp inverter directly to car battery, plan for about an hour on the tanis, cowl plugs can't hurt

[Fly Boomer]

13 hours ago, MountainGoat said:

 I looked online and I saw 110v/3amp inverter for a car.   As best I can tell,  my tanis is supposed to take 115v at 2amps.  It seems like the power is there,  does anyone know a reason why the volt mismatch would matter?

Voltage "mismatch" won't matter.  It's all the same 110, 115, 120 -- different names for the same thing.

I agree with Fritz on the amperage -- don't try to cut it close.  Many if these Chinese-made devices won't quite do what they are advertised to do.

[larryb]

It's best to measure your power draw and then buy an inverter that can handle 50% more. Amazon sells a number of inexpensive watt meters. After you use it to measure your engine heater you can use it to tell you how much it costs to keep that old spare fridge in the garage.

 

My Reiff is 700 watts. So 115 volts X 2 amps = 230 watts for the tanis sounds a bit low. At that low power it would take a long time to heat the engine up. 

 

https://www.amazon.com/P3-P4400-Electricity-Usage-Monitor/dp/B00009MDBU/ref=sr_1_5?crid=10B9NCA802ADA&keywords=kill%2Ba%2Bwatt&qid=1701709994&sprefix=kill%2Ba%2Bwatt%2Caps%2C135&sr=8-5&th=1

[Pinecone]

Since he has a 220kW source, I am thinking electric car.  So not so simple to connect to the car battery.

115 volts at 2 amps is only 230 watts.  That will not warm up an engine in 30 minutes.  It will take hours.

FYI, Tanis website was 460 watts, so 4 amps at 115 volts.

 

 

[PeteMc]

1 hour ago, larryb said:

So 115 volts X 2 amps = 230 watts for the tanis sounds a bit low.

I guess Tanis doesn't pull as much because they expect you to leave it plugged in vs. using it as a pre-heater (or even an occasional pre-heater).

Their website does say the 4 cylinder = 240 watts/ 2.1 amps and the 6 cylinder = 460 watts/ 4.0 amps.

ADDED:  Interesting that the Tanis Operating Guide does not have pre-printed specs on the power consumption.  There is a place at the top of the fist page for the installer to handwrite in the Voltage, Wattage & Amperage.  But there are no Specs that show Max draw.  However, the fuse is spec'd at 12A and they also call for "...A 12-gauge extension cord is recommended for system loads up to 12-Amps..."  They also list the appropriate wire gauges for different lengths of the extension cord (e.g. you can use 16 gauge if you're only going 50ft/15m or less).

 

 

Edited December 4, 2023 by PeteMc

[Hank]

1 minute ago, PeteMc said:

I guess Tanis doesn't pull as much because they expect you to leave it plugged in vs. using it as a pre-heater (or even an occasional pre-heater).

I generally plug mine in for an hour when it's cold. For a while in West-by-Gawd, Virginny, I had a cellular switch and would turn it on after I got up in the morning and called ATIS. By the time I was dressed and at the airport to fly to breakfast, it was good and warm. Alas, it was a 2G switch . . . . but very convenient in the cold climate!

[Utah20Gflyer]

I use a small inverter generator and an electric heater I converted to aircraft heating duty,  it uses 1500 watts and takes about an hour to warm the plane to starting temperature on a very cold morning.    
 

I would suggest trying your current plan and see how it works out.   You won’t be out much of anything if it doesn’t work other than a possibly delayed flight.  
 

If it doesn’t work then you’ll just have to escalate the issue to something more capable.  

[MountainGoat]

Thanks for all the thoughts.  It seems that the cigarette lighter is limited to about 120W, so I'll have to go for direct battery connection and make sure I can use it while the car is running.  I'll look for something up Watts, hopefully something that can no kidding supply 500-1 kW.  One thing I'd like to know, and product descriptions don't exactly say, is if an i.e. 1000W continuous power inverter with two outlets can supply 1kw to one outlet, or split between the two. 

Not an electric car, just converting real units to metric units.  (There are two types of countries in the world.  Those that use the metric system and those that have walked on the moon).

Edited December 9, 2023 by MountainGoat

[larryb]

If it says 1000 watts that is the total for the whole unit. And it’ll probably struggle to get that 1000 watts. Also remember that 1000 watts at 13.8 volts is 72 amps. Add 10% for inefficiency. 80 amps is a big number. You won’t make that number with a car alternator at idle. I’d just buy a 2000 watt inverter generator and be done with it.

[MountainGoat]

Hmm, perhaps.  I initially saw generators at about $1000 or so, now I think I've seen some for a few hundred, and a car plugin would be $50-$100 or so.  However, it might be worth trying the car one for the Sake of Science. 

Also, I've done some maths (like James May).  With only 150W available to heat an engine of 117kg AL and 5 kg mineral oil, its temperature would go up about 5 kelvin/hour.  Yes, I know there would be environmental losses, so I cut the available power down by more than a third.  Might still be worth a try, at least in chilly places rather than downright cold ones. 

[mhrivnak]

If you're comfortable with just a little bit of wiring, you can put together your own portable kit for a few hundred bucks and leave the car out of it. Then you can even bring the kit with you on trips. LiFePO4 batteries are an amazing innovation; they're lightweight, can be deeply discharged every day for a decade, and are affordable. Here's an example:

$50 - 10A charger (I have this one and like it): https://ampedoutdoors.com/products/10a-fast-lithium-charger-lifepo4

$130 (after coupon) - 50Ah LiFePO4 battery: https://www.amazon.com/Ampere-Time-Phosphate-Trolling-Sweepers/dp/B08K7MKRF7/

$100 - 1100W inverter (oversizing because you'll find other uses for this portable kit): https://www.amazon.com/dp/B00T564EIY/

Put all three in a milk crate secured with a luggage strap (for the battery) and zip ties.

For your 240W heater, you should get 2+ hours out of this setup. Or go for a bigger battery to heat for longer.

[Pinecone]

That would give you about 15 degrees C temp rise max, but less because the inverter has losses.

[FlyingDude]

On 12/8/2023 at 9:18 PM, MountainGoat said:

There are two types of countries in the world.  Those that use the metric system and those that have walked on the moon)

"With respect to units, the LGC was eclectic. Inside the computer we used metric units, at least in the case of powered-flight navigation and guidance. At the operational level NASA, and especially the astronauts, preferred English units. This meant that before being displayed, altitude and altitude-rate (for example) were calculated from the metric state vector maintained by navigation, and then were converted to feet and ft/sec."

https://www.doneyles.com/LM/Tales.html

[FlyingDude]

I've read about bush pilots who drain the oil from their planes and take it indoors with them so that it stays warm for their next flight.

They also make gas-powered engine heaters. It might be an option for those areas with no electricity.

Tanis heaters are pads that are glued on the outside of the sump as well as special heating bolts. You could try dipsticks with heating elements that go into the oil for faster action - make sure you don't apply heat on the plastic dipstick neck, though.

If I were you, I'd measure the resistance of the heating system at its connectors. 30 ohms? 40 ohms? 50 ohms? Divide your inverter output voltage by that, you find the current in amps. That'll factor in any factors, like additional pads glued on or presence/absence of heated intake bolts. Though, as others said, it'll be wise to get an inverter that can handle 50% more power than what you need. 

If this is something you're going to do often, you could get a truck battery and power the inverter with that. You can charge the battery at home. I wouldn't want to leave my car engine idling for an hour.

Safe flights.

[Pinecone]

Red Dragon was the propane aircraft engine heater.  You hooked it up to a 12 volt battery to run the fan and either the small torch bottles or a larger propane bottle.

They worked very well and quickly warmed the engine.

Airport I worked at in the early 80s have one in a Radio Flyer. Used an old car battery and a 5 gallon propane bottle.

[A64Pilot]

Back in the day it’s true that bush flying in the cold you immediately drained the oil, then in the morning heated it on your camp stove, dumped it into the engine and hoped it would quickly start.

Now days most I know that fly the bush bring a Honda generator with them, it can both keep them warm and pre-heat the airplane much better than a camp stove, runs fine on Avgas.

I’ve seen sheet metal ducts made for camp stoves for pre-heating. By camp stove I’m not talking about the suitcase Coleman stoves but the smaller single burner stoves.

Not that I live where it’s real cold, but I used to take a piece of sheet metal and put it against the cowl of my Maule and use my 55,000 BTU kerosene hangar heater and blow it at the sheet metal, that heated the engine and the hangar and therefore the whole airplane given an hour or two if real cold. That was only a couple of times a year and not at all a regular thing.