Block heater test and ohms

Hi, I have tested my block heater with a multimeter. I tested it by attaching it to the blades on the end of the block heater plug. I got 50 ohms. Is that too high? I know that a zero reading means my block heater is pooched, but I've also read a "good" reading is about 30 ohms. But I've also read that you multiply ohms by voltage to get the wattage, and I've read that the Tacoma block heater is 600 watts. Which would mean I'm all good.

I am trying to figure out why my battery froze. I had it plugged in on a -40C (-40F) night and that's usually more than enough to start it like nothing in the a.m. Love the 0W oil! I popped the cap on the battery and I could see ice forming in there.

I've tested all the plugs, from the outlet to the outlet on the extension cord, to the outlet on the end of the plug that plugs into the truck itself. I just had the servicing done and they said my battery was fine. It would hardly turn this a.m. and it was "only" -30C (-22F).

I bought a new battery, but I want to make sure it doesn't freeze, too!

 

I've been watching my scanguage the last few -20c mornings, truck is plugged in from 6am-8am.
Coolant temp at start up is 25c, Oil temp is -5c. Warm heat out of the vents in 3 minutes or so.

Block heater doesn't warm the battery at all, you'd want a battery blanket for that.

 

Yeah, I get that about the battery. I thought it warms the ambient temp of the engine compartment enough to keep it from getting cold enough to freeze the battery. Then again, it was so freaking cold that night. My battery is almost 3 years old now and it might not be carrying enough charge to keep from freezing when it's that cold. Anyhoo, I will put my hand on the engine block near where the block heater inserts later tonight. That the best test, I guess.

 

The block heater will do nothing for your battery. If you're in the cold often in the winter set yourself up with this stuff and you and your truck will be much happier in the morning.

https://www.amazon.com/Zerostart-28...ocphy=9028984&hvtargid=pla-492456125160&psc=1

$100 Zerostart 3400063 Silicone Pad Heater Engine Oil, Transmission Fluid, Reservoir and Hydraulic Fluid Heater, 3½" x 4½" | 120 Volts | 250 Watts

https://www.amazon.com/Zerostart-34...a-570830266523&psc=1&ref=&adgrpid=61179236814

DEWENWILS 2 FT Extension Cord Outdoor Tri-Tap Extension Cord Splitter, 12/3 Gauge Short Extension Cable with 3 Electrical Power Outlets, Heavy Duty Power Cable for Multiple Appliances, UL Listed

https://www.amazon.com/dp/B0861MD53...jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

 

Power = V^2/R


P=120*120/50 = ~300 watts
(assuming the resistance stays the same as it heats up, which is probably pretty close. Definitely not true for something that gets very hot like a light bulb, or something known to be non-linear like a diode)

But I doubt it is bad... (just me guessing, it was 73F this morning for me, so I am not an expert)

I would blanket the battery, as others said

 

Sometimes you can hear them hum, or hear the engine ticking. Might notice the hood staying clear of frost if it's on for a long time.

I use these lighted cords; That way I can confirm power at a glance. Also use an auto-timer so I don't need to run it all night long.

 

Thanks for the replies, folks. Yeah, the more I think about it ... it's not the block. She turns over really nice when I get a boost. Like nothing at all. Already looking at the blankets!