Testing the Engine Block Heater

I don't think mine worked this year. For the electrically deprived like me, please show a photo of your set up. Or draw a couple of non-geek pictures.

 

Mind explaining how exactly you perform that little trick, without the use of a jumper wire? A lot of folks on this forum are not very well versed in electrical safety, and I would not approve of your method for those who are neophytes to electrical safety

For simple resistive loads, P = V^2/R

Assume the wall voltage is 120 vac, so 120*120 = 14,400

With the block heater cord unplugged, set the voltmeter to ohms, and measure across the live and neutral of the block heater plug on the car. A correct reading should be around 35 ohms, at least it is for my Prius and even my FJ

14,400 / 35 = 411 watts, which is close enough for government work

For under $40 you can pick up a single phase, 120 vac, plug in powermeter. I got one through Manitoba Hydro for $5, some sort of promotion. You can plug in a fridge, freezer, block heater, etc, and determine how much power the device is using

As an example, if I use that cheapie power meter I got, it claims the block heater is using 406 watts. I cannot verify the little device compensates for inductive loads, like a fridge or freezer. Probably not

 

If you don't mind waiting until tomorrow, I will take a photo of how to measure the resistance at the plug. You can then use the formula above to determine how much power

It's common for the plug to go bad, due to repeated flexing of the stranded wire cordset. You have two options:

1. Chop off the plug, and perhaps 2-4 inches above. Get a new plug and wire it up

2. Replace the entire cordset. It can be a bit difficult to unplug from the block end

Don't forget the basics, check the extension cordset first

 

Another device you can buy for testing loads is a "Killawatt". Available on the net, ebay, etc. Just do a search and choose your supplier. This device -will- give you indications of inductive or capacitive loads, as it will display Watts, Volt-Amps, Power Factor, as well as Volts, Amps, and time accumulation power consumption.

This is the only safe way to test the block heater. No exposed voltages, no arcing.

 

Or perhaps a clamp on ammeter.

 

Why don't I help those who don't want to slice and dice cables and connectors
For about $25, you can buy a neat meter that can be used around the house rather easily, to check what different equipment like your computer, washer, dryer, EBH draws or when is to buy a KillAWatt meter
Newegg.com - Computer Parts, PC Components, Laptop Computers, Digital Cameras and more!

It can show amps, voltage, Hertz, power factor, VA, watts and KWH. Simple to operate and connect I bought one, lots of fun around the house and an eye opener.

 

Waiting for photos!

 

I've exceeded my 50 MB attachment limit here. Am in the process of setting up an account at an online photo hosting site. Stay tuned

 

The cheap one I got from Manitoba Hydro isn't as accurate, compared to my AEMC it's always 5-10% off on the low side. Still, close enough for guvment work!

For example, here is what the gadget claims the amps are when my FJ heater is plugged in

http://i653.photobucket.com/albums/uu256/jayman_photo/Electrical/DSCF0846.jpg

Here is what the gadget claims the power consumption of my FJ heater is

http://i653.photobucket.com/albums/uu256/jayman_photo/Electrical/DSCF0848.jpg

It should be closer to around 418 watts, but initially it claims 391 watts. Again, close enough for guvment work

 

You still have to split the outer insulating sheath off the extension cord. You can't just clamp it on like this

http://i653.photobucket.com/albums/uu256/jayman_photo/Electrical/DSCF0852.jpg

or like this

http://i653.photobucket.com/albums/uu256/jayman_photo/Electrical/DSCF0853.jpg

as the meter will reliably indicate 0.0 amps

The only correct way to measure current with a clamp-on ammeter is like this

http://i653.photobucket.com/albums/uu256/jayman_photo/Electrical/DSCF0854.jpg

You will notice there were no sparks or arcs flying around while I was digging around inside the panel.

 

If you are "electrically deprived" as you claim to be, then never, ever attempt to put an ammeter inline, as you could electrocute yourself.

Take your DMM (Digital Multi Meter) and set it on ohms. Place the two leads across the plug as follows

http://i653.photobucket.com/albums/uu256/jayman_photo/Electrical/DSCF0844.jpg

For example, 35 ohms is the reading. To find power = V squared, divided by ohms. Assume 120 vac, close enough for a rough calculation

120 times 120 = 14,400.

14,400 divided by 35 = 411 watts

 

The only correct way to measure current with a clamp-on ammeter is like this

http://i653.photobucket.com/albums/u...l/DSCF0854.jpg


Or, this is is what I use----

 

Yep, remove the outer insulation from an extension cord. That way, you can properly apply the clamp on ammeter

 

Thanks -- I hadn't heard this before -- but I knew that in the past few days I was starting cold. I suppose it is due to brittle wires in cold weather. Does anyone have any thoughts on how to avoid this recurring repeatedly?

 

Sometimes it's best to have the heater plug in the engine bay, plugged into an extension cord that is routed out the grille. That way, you're only out an extension cord if worse comes to worse.

 

You've tried flexing the plug with it plugged into the extension cord? Sometimes that will briefly make contact. If you have a power meter plugged in, as I suggested a few posts ago, you will see when it comes to life

 

If you are looking for another block heater tester, a company from BC makes one and sells them on ebay for about 20 bucks with free shipping.

just type in "block heater status" tester in ebay.

Jason

 

The "Kill-a-Watt" is now only $21 Can. Much more useful than a block heater status checker.