Will it work? Take a look at the file attachment. A portable battery pack is connected to a 600 watt dc/ac inverter which is connected to the engine block heater.

It is 30 degrees here but sunny.

 

It will drain that battery in 10-15 minutes tops. 450W~40A@12V depending on efficiency, 40Ah is a big battery. That portable battery is at best 10Ah, and that is at least a 10 hour rate meaning 1 amp for 10 hours.

 

I actually have a 18A/hr portable battery but...there is a time limit on how long the juice will last. This is where input is needed from other posters. Could a deep-cycle (marine?) battery be rigged up to provide the needed power for the engine block heater? Once home, the deep-cycle battery is put on the 2amp trickle charger overnight for use on another day. I know marine batteries are not lightweight and not exactly easy to lug around. Is there other options? Do we have to wait for the developing plug-in battery chemistry (7 times the power?) to work its way down to portable power packs to make this a reality?

Do we mount a third battery in hybrid vehicles (new longated shape?) mounted inside the engine compartment (rear firewall?) with a retractable cord and plug that can be plugged into the engine block outlet so no one can steal your portable power pack?

 

Billy... you need ~500w x 2 hours = 83 Amp Hours.

To be best, you need 3 hours, or 125 Amp Hours.

A full size, lead acid (wet) battery, on the large end, such as for Semi's or Caterpillar would do it. They are 10" x 10" x 20" and weigh 132 pounds.

You need one of "8D" capacity.
There's not a price here ( I don't think, I didn't read it all ):
http://www.cat.com/cda/files/192183/7/PEHJ0073.pdf

But I'll bet they cost 4-digits ( $1,000 )

Or, you could put 3 regular car batteries in a row, in PARALLEL.
Parallel means you wire PLUS to PLUS to PLUS to device, and
NEGATIVE to NEGATIVE to NEGATIVE to device.

With 3 car batteries, you will be close to 100 pounds, but hey, you can get 3 for under $300.

Now that I think about it, 4 in a row might be better....
I just don't think it is worth it....
The Cost-Danger-Work to Benefit ratio is not good.

Do this:
Take 200 or 300 feet of extension cords ( $60? ) ( 20 pounds? ) with you where ever you go. Take them in 50 foot sections. I think you'll be able to find a plug in 99% of the places you go.

This is why 120 VAC plug-in hybrids are so much more attractive than the EV-1, which pretty much had to be at home to charge, since the charger was large, and specialized. ( And higher voltage ) You are rarely more than a couple hundred feet from a standard plug.

I plug mine in at work for what it's worth. 2.5 hours = 10 cents of power.
*( In rural America... in larger Cities it may cost 20 cents )
I make up for it by turning the lights off during lunch.
-John

 

Why do all that figuring?! just plug it into the ac outlet on the console! :wink:

Just kidding of course.

But what about some sort of solar aray on the roof, what kind of power could that produce for day time charging/warming while away?

 

I almost thought that was what Billy was going to do... almost.
( see "robbing Peter to pay Paul" )

Your ENTIRE roof covered with Solar Cells will give you ~ 75 watts.
100 watts if you cover the hood too.*

* Of course that is at high noon, on a clear day, you get less in the morning and afternoon, unless the panels can pivot to follow the sun.

 

This makes me wonder about my Jeep setup. A question for you electrical geniuses as I really struggle when it comes to things electrical. I have a dual battery setup on my Jeep, a deep cycle yellow top optima as the main battery with all accessories off of it and a back up red top optima. The latter has a controller so that it can be isolated if need be or joined up with the main battery for extra cranking/backup. Here is the question...one of the accessories I run off the yellow top is a 750w in(con)verter(??) for 120 accessories. In the event of an emergency if I'm stuck in the woods or some where without a place to plug in could I actually use my block heater off the main battery, isolating my backup battery of course? Would there be any issue given that both the block heater and the battery are using the same ground?

TIA

Darren

 

What is the purpose here?
I think ideas are getting out of hand.
The purpose is to make your car more efficient, not worse.

This only works if you plug into grid power.
Plugging one part of a car into another is working backwards, against you.
And if it is cold enough for your engine to benefit from a block heater, then it is also cold enough for your 12v battery(s) to be weak to begin with, and you really shouldn't be putting more stress on them in the first place.

A block heater is a good idea IF the electricity costs less than the gasoline it displaces. ( or if the electricity is wind power, etc. )

For example, I spend 10 cents on electricity from my home to get my car to 100 degrees. Right now, it will take 25 cents of gasoline to warm my car to 100 degrees. Thus, each morning, I can save a whopping 15 cents.

If the price of electricity goes up, and/or the price of gas goes down, before long, a block heater from the grid does not even make sense.
There is not much "margin" as it is.

Why spend $100's on elaborate methods to warm your car?
As it is, it will take about 700 days to "break even" with the most efficient method: House Plug.

 

I think I will disagree that most work parking locations have a 120V outlet near by. Even if they did your cord may be taken without your consent! (let alone allowed by your employer or facility owners)

Not that I am looking to do what this thread is about, but if you were to take an Optima Yellow top:
http://www.optimabatteries.com/optim...cs.php#yellow1

and create a setup where you can power the block heater with 1 battery, why couldn't you go out to your car 2 - 4 hours before you are going to head home, flip the switch to power the block heater & then charge up the battery when you get home overnight so you can do this again tomorrrow? Yes you would need an inverter that could handle the current draw & so what if you drain the battery in those 2 - 4 hours, it is not connected to anything else in the system & you top it back off when you get home?!?

Just a thought.

 

John, all of those Optima batteries, even the largest, would power the heater for 1 hour tops. So again, you would need at least 3 batteries, perhaps 4, chained together in parallel.

The risk of disaster doing this, if something goes wrong, is huge.

You can get long extension cords pretty cheap.
And no, not EVERY parking space would have an outlet within reach, but most would... If... you seek out those spaces. The power use is trivial. 10 cents? a day. Turn off the lights and computer monitor when you leave the room for lunch and breaks, and you'll make that power up... IF your boss cares about 10 cents per day. He/She will probably be impressed at the effort you are taking to help clean the air, and encourage more of this!