[thestigmachI]

I went out to start my ramcharger this morning and found that it would barely even crank. Was -20 without windchill this morning. Tried jumping it, better but still not enough. Im going to swap out to a magnum starter soon just need to get around to it. My question is how long will one of those 80watt heating pads for a battery take to get the battery to an acceptable temp? Same question for the average block heater. I live in an apartment so I cant just plug up it go. Can only have a cord ran for a little while. thanks in advance

 

[fenrir]

-20 is -29C roughly.
Q=mc(DELTA)T

T=-29C to 0C or 29
c= 2000 (stab in the dark of the specific heat capacity of a battery)
m= mass of battery (15 pounds?) = 6.8Kg
Q=6.8*2000*29 or 394,400 joules
1 joule = .000947 btus or 373 btus
Assuming (based on a space heater, sorry, didn't spend time to
1 watt = 3.4 btus, so battery heater=80*3.4 or 272
373/272=1.37 hours

Of course, this is just a guess...   

 

[KurtfromLaQuinta]

-20 is -29C roughly.
Q=mc(DELTA)T

T=-29C to 0C or 29
c= 2000 (stab in the dark of the specific heat capacity of a battery)
m= mass of battery (15 pounds?) = 6.8Kg
Q=6.8*2000*29 or 394,400 joules
1 joule = .000947 btus or 373 btus
Assuming (based on a space heater, sorry, didn't spend time to
1 watt = 3.4 btus, so battery heater=80*3.4 or 272
373/272=1.37 hours

Of course, this is just a guess...

Oh. A wise guy!
Nyucckk! Nyucckk!

 

[SuperBurban]

Even with a warm battery, you still need to get around the cold engine and thick oil. I have found that engine warmers do better then a warm battery.

 

[4x4 440]

Even with a warm battery, you still need to get around the cold engine and thick oil. I have found that engine warmers do better then a warm battery.

I agree. You can get a battery insulating pad like the Cummins trucks have.

 

[thestigmachI]

Even with a warm battery, you still need to get around the cold engine and thick oil. I have found that engine warmers do better then a warm battery.

Its got a block heater as well. I figure it should get it warm enough to crank within the same time as the battery heater and ill plug them both in at the same time. Or do you think that a battery heater is a waste as a whole?

 

[thestigmachI]

-20 is -29C roughly.
Q=mc(DELTA)T

T=-29C to 0C or 29
c= 2000 (stab in the dark of the specific heat capacity of a battery)
m= mass of battery (15 pounds?) = 6.8Kg
Q=6.8*2000*29 or 394,400 joules
1 joule = .000947 btus or 373 btus
Assuming (based on a space heater, sorry, didn't spend time to
1 watt = 3.4 btus, so battery heater=80*3.4 or 272
373/272=1.37 hours

Of course, this is just a guess...

now thats an answer! what temperature is that getting it to? that might be within the realm of the length of time I could have it plugged in as well. out of curiosity how would I use the same formula to find how long it would take for the block heater to do the same job? Not sure how I would find the specific heat capacity of it, or anything for that matter.

 

[fenrir]

-29c to 0c or 32F

specific heat capacity of a motor would be less than a battery, but more mass.  You'd have to know the wattage of the block heater. 

I'm not a scientist, just have a basic understanding of science.  A lot of this info is on the googly thingy. 

If it were me, I'd turn it on 2 hours before but I don't like to cut things close.

 

[dodge82273]

lol , yeah , block heater , the ones that go in the freeze plugs , only help a little , even left plugged in overnite , the canister ones IIRC 1500 watt are better at sub zero , need about 3 hours , the battery needs the insulation wrap AND the heating pad to do much of anything , NONE of this is computed , its real world tried / true . You can also put a heat pad on the trans and engine oil pans .  I have 1 truck with a freeze plug heater on BOTH banks , it is no better than the truck with 1 , the plow truck has the tank type in heater hose/ block drain plug , works much better with less time .  understand , trucker's pull in , plug their truck in , and go home / inside for the nite , truck stays plugged in , heaters have a max temp , which shut's them off . always unplug before starting , the really cold moving water keeping the element cold will burn it out . 

 

[jungle]

We use to put a Old style leadlight  with a 60-75  watt bulb up on the intake manifold to keep the top of the motor a little warmer.
Jim

 

[pir2]

Being up here in the cold North, I would plug it in a couple hours before use, and even though it may not be warm by then, it should be warmer, enough to ease the starting.The wife's truck has both block heater and battery blanket that is very effective.My 

 

[thestigmachI]

If I could plug it in and leave it alone I would put it on a timer so it would turn on the night before I want to drive it and all would be well. But the apartment people would freak out about that. I hate apartment life. I suppose Ill try the battery heater and the block heater a few hrs before I want to drive it and swap out for the magnum starter. If that doesn't work I may upgrade to the in hose pump style. Good to know that it will take a little over an hr to get the battery to operating temp. Hopefully in spring I can buy a house with more than one garage bay and wont have this problem anymore.

 

[fenrir]

We use to put a Old style leadlight with a 60-75 watt bulb up on the intake manifold to keep the top of the motor a little warmer.
Jim

Yeah we would do the same thing with a high watt bulb on a trouble light...of course, that was back before led bulbs. That would be funny to see someone try that with a swapped out 100watt LED in a trouble light!

 

[712edf]

I hate apartment life. Hopefully in spring I can buy a house with more than one garage bay and wont have this problem anymore.

Here is your answer. Just don't get one with a pool.

Bucky

 

[thestigmachI]

Here is your answer. Just don't get one with a pool.

Bucky

Nah surrounded nearly completely by water on the peninsula of Wisconsin. No need for a pool when I have a boat and endless water

 

[gremlinmt]

OK, actual data from Montana winter:

I have my block heater, battery tender, and battery heater all plugged into a 3 way plug.  These are attached to the house with a timer.

At 10F I can have the timer come on at 4am and have an engine temp of 65F by 6:15AM.  At 0F it will only reach 28F by 6:15AM.  I'd have to go pull an amp draw on the block heater to verify size.  600w seems to be what the parts house says it should have.  Short answer, 3 hours will cause engine to reach drive away start, 2 hours will get you to easy start.  1 hour will get you to MIGHT start at -20F

 

[SuperBurban]

If you can get an old quilt, or moving blanket, put it on top of the engine. Even if its been a few days, that the engine has lost all it heat, it helps the engine retain the heat the heaters pump into the engine. A simple piece of plastic hung in front of the grill, will block the majority of the wind, and also help.

 

[dodge82273]

agreed , ounce you supply heat of any kind , battery , coolent , engine oil , insulation will help keep it . The freeze plug heaters seem regulated too low , try installing a 1500 w tank type . They plumb from the block drain 1/4 pipe plug just above the oil pan , to a Y installed in ..... the heater hose ,  will a ball check valve ... I have 1 truck with 2 freeze plug types , with both plugged in , its cold , 1 truck has the tank type , same time , much warmer ... yes at 20F below .Its tbi ,  the efi mags start with nothing ...

 

[gremlinmt]

I have a 1500 w heater on the big block chevy motor on the generator at work.  It's got a hose that comes off low on one side and cross the motor and plugs in high on the other side.  I need to look closer, it might actually reenter on the intake manifold. It's got a thermostat on the entry hose to the heater.  When it reaches 120F it shuts off.  The big problem with these heaters is amp draw.  12ish amps will often overwhelm a standard outlet if anything else is plugged in and trip the breaker.

I actually prefer the smaller freeze plug heaters because they won't overheat the engine in normal use.  This morning it was -10F.  Engine was 45F on startup this morning.

 

[dodge82273]

tanks types from napa etc won't overheat them either , both have on/off stat built in . the gen sen one runs from drain plug to drain plug or should ... gen sets , as you know , go from off not running , directly to run speed , so they may like to be kept at operating temp because they have NO warm up idle time at all , they are suddenly at speed and under load  .