So I'm planning on trying a little project this weekend with wiring up my engine block warmer to some batterys that im going to be storing in my toolbox. Remember this is just an idea currently, but I'm wanting to get some more details.

Ive learned that the engine block warmer pulls 1000watts, and the average battery can push around 500watts. So If I parallel three that will give me around 1500watts. But I dont know how long it could push that for.

I've got an 12V 1000 watt power inverter with 1800 peak, and two 120V AC outlets. So that should be fine.

And I was thinking I could use a battery isolator to charge the batterys with the alternator.

I'm not entirely sure that this is plausible, but I'd like some input from anyone who can provide some constructive information.

 

why? is this so you use the block heater when you are not at home (or not near an a/c outlet)? I guess if it were to work it might be more cost effective to instead of increasing your monthly electric bill! good idea and sounds like it would work, keep us updated!

 

Well a few reasons why. Im stationed in NY right now so obviously there is snow/ice/water everywhere, and my landlord feels that it is an electrical hazard to run an extension cord through the snow...I tried to explain to her that it is a brand new extension cord with not cuts or tears in the rubber surrounding the wiring so there is no chance, but she disagrees. So that is the reason I'm wanting to try this.

But back to my project does anyone know how long I could push 1000watts to the block warmers using the setup mentioned above?

 

I'm afraid you're mistaken. You don't increase wattage by stacking three 500 watt batteries. It doesn't work that way.

The wattage consumed by your current block heater is determined by the electrical resistance of the heater coil, and the voltage you hit it with. Even if you stack three 12 volt batteries in series, you'll only have 36 volts, maybe around a third of the house voltage, so you'll only get about a third of the wattage.

Still, 500 watts is about the same as the low setting on many electric heaters, so it might be better than nothing, and probably not adequate in subzero temps.

 

It all depends on the capacity spec of the batteries you're using... Lets look at an Optima Red Top for this example....

http://www.optimabatteries.com/_medi...ecs/34_34R.pdf

The spec says that it can deliver 50Ah (amp hours)

Having three of these batteries in parallel would give you 150Ah's

At 1000W and 12V, you'll be drawing I=1000/12 = 83.33333 amps.

So, with 150Ah to work with, you can run the heater for 150/83.33333 = 1.8hours.

Looks like less than two hours for that particular battery.

Edit -- good point by BareBones below... this is assuming a 100% efficient inverter, which it won't be.............

 

Regarding trying to do the same thing with your 1000 watt power inverter, you can get an idea from your battery's CCA. Say you have 1000 amps CCA. Given the inefficiencies of your power converter, you'll probably be consuming 100 amps in order to generate 1000 watts.

So you'll probably be able to run the block heater for about as long as you could run your starter constantly without the truck starting. I think you'd be lucky to get an hour.

 

There's another factor you really don't want to overlook. Your standard truck batteries are NOT deep cycle batteries. They'll be ruined if you discharge them down close to empty on a recurring basis.

 

if i was u i would just plug it in. but u could alway just buy a generator and put it in the bed of your truck and just plug in to that.

 

For the money/time, i would buy a small generator......and then plug your truck in to your apartment when no one is looking!

 

I would talk to the landlord and convince her to let you plug in for say three hours..It would cost her 10 cents per hour about. and as far as the cord being a problem have her call an electrician and have him come out and tell her..He may want to install a GFI outlet which will keep everyone safe...Or you could put one in for her..


Dick

 

Not trying to offend anyone here, but do you need to plug it in, or are you plugging it in because you can.
I'm in Mass and I dont believe its any colder where you are, and all the years I owned diesel I think I plugged it in maybe 4-5 times.

 

Using batteries and and inverter is gonna be such a hassle. If you can't convince her to let you do this, get yourself a little 1200 watt honda generator and chain the thing up in the truck. There was a kid with a crappy duramax that did that at the school I work at. His truck wouldn't start unless he left it plugged in all day. My brothers would screw with him and shut the thing off mid day.

 

Sounds cool too me... I think what these guys are saying is right as far as time goes, but what I would do is that since it seems that you won't get more than and hour or so outta the batteries, wire the heater in with a timer and have it come on about an hour before you have to start the truck. When my GP's were shot, in extreme cold, it only took 30 minutes to get the truck warm enough to fire. I think it'd be cool to be portable... a small Honda generator might work better, but it's still fun to play with stuff. Those new Hondas are pretty cool, though... they've got some about the size of a large lunchbox now and they're really quiet too! You could stick it in your bed and it wouldn't be very loud. Are gonna wire your batteries in the toolbox so that they have a switched connection to the alternator whenever the truck is on? If you did that, they'd charge when the truck is running, but be separate from the truck batteries when the truck is off and leave the truck's batteries nice and charged for the next morning's start. I would imagine a traditional starter relay would work good for that... just splice into the control wires that hook up to your existing solenoid (mine is on the inside of the passenger's fender) and then have the main terminals on the solenoid make or break the connection between your toolbox batteries and the alternator. I wonder if 4 to 5 batteries would overload the alternator?

SUBSCRIBED!!!

 

You would be drawing about 100 amps give or take depending on the efficiency of the inverter that you were using. Unfortunately its hard to find specs on battery worth a damn. But looking at the specs on the battery Here this looks comparable to the type and size you would find and need in say the optima stuff you buy at an auto store. Paralleling 3 of the batteries you could run them for about 1.5 hours before discharging them completely.

 

Another thing to consider, how long are you going to run the truck once its started? Those batteries won't charge up that fast with a stock alternator. You'd probably **** off the stocker and end up killing it with a load that large.