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Discussion Starter · #1 ·
I was wondering if anyone else had tried this, tell me what you think, I think that (depending on current draw) I might be able to make one of those Coolant heaters (used to help warm up an engine via heating up the coolant for 6+ hours) work on a battery with a DC to AC converter.

 

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Can you fit a battery that big in your vehicle?

I have not run the numbers, but the wattage of the heater, and 6 hours, (or even 1 hour), and any battery you can fit, looks like it equals a dead battery to me.


If you need a coolant heater that uses no or very little power, they make them that burn diesel fuel, and some that use propane, either one is expensive.

Grigg
 

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Discussion Starter · #3 ·
Correct me if I'm wrong here (I'm a little rusty on my electrical power math) but given the 2 constants here, 12 volt battery and a 750 watt/hour drain, the only variable is the current ultimately.

Given that, if current for the 120 volt device is 6.25 Amps an hour, wouldn't the current draw on the 12 volt system be 62.5 amps/hour? 6 hours at 62.5 amps comes out to 375 Amps. Given that DC-AC converts aren't perfect and typical conversion loss is about 10%-15%, I'd say that a 1,000 Amp battery would still be more than healthy enough to power said device for 6 hours. and given that I'd be recharging it every time I start the truck, it'd recharge enough to be used again.


Pantherman
 

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they do make 12volt heating elements- get rid of the power loss of an inverter.

I have seen 12v water heater elements on alt. energy webpages.

but I dont know that it would work. heat elements draw a lot of juice.
 

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Discussion Starter · #5 ·
they do make 12volt heating elements- get rid of the power loss of an inverter.

I have seen 12v water heater elements on alt. energy webpages.

but I dont know that it would work. heat elements draw a lot of juice.
I'm not so concerned about power loss, I need something mobile as I'm not always near an electrical outlet to plug the coolant heater into.


Pantherman
 

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A "1000 (cranking) amp" battery is good for about 90 amp/hr, so your plan could work if you have space for 5 batteries somewhere (the calcs say around 430 amp/hr of power used over 6 hours). You would also be running them down completely on each cycle, and would need substantial alternator capacity to recharge in a reasonable time. They would probably last 10 or 11 cycles before replacement was needed unless you use deep cycle type batteries (more $$$ and larger, heavier).

Consider a small portable generator. I used to have a 600w unit (about the size of a big lunch box)for that use. It would run my 500w block heater and also had a 12 volt DC output for battery charging. IIRC, a gallon of gasoline would run it for 4-5 hours. I had a vented tool box on my truck that it could be placed in for security.
 

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Discussion Starter · #7 ·
A "1000 (cranking) amp" battery is good for about 90 amp/hr, so your plan could work if you have space for 5 batteries somewhere (the calcs say around 430 amp/hr of power used over 6 hours). You would also be running them down completely on each cycle, and would need substantial alternator capacity to recharge in a reasonable time. They would probably last 10 or 11 cycles before replacement was needed unless you use deep cycle type batteries (more $$$ and larger, heavier).

Consider a small portable generator. I used to have a 600w unit (about the size of a big lunch box)for that use. It would run my 500w block heater and also had a 12 volt DC output for battery charging. IIRC, a gallon of gasoline would run it for 4-5 hours. I had a vented tool box on my truck that it could be placed in for security.
ok, where can I find one of these, or what search words could I use in a google search so that I'm not having to look at the much larger generators as well?
 

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A power inverter will likely not work with a resistive heating element.
At least mine doesn't anyways, it eve says in the manual that it won't work.
 

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Here are some links for diesel burning coolant heaters, not sure the relations between the company's, as the last two seem to be the same product?
From my research I decided the first one was best, but have no experience with any of them.

Webasto:
http://www.webastoshowroom.com/blueheat/blueheat_products_ttc1.htm
or http://www.webasto.us/am/en/am_rv_heaters_948.html

Espar:
http://www.espar.com/html/products/coolantheaters.html

Eberspächer:
http://www.eberspaecher.com/servlet/PB/menu/1004065_l2/index.html

They all make a number of different models. They also make air heaters, but what you want is a coolant heater.

Grigg
 

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those hondas are very nice- quiet, too. you can have a conversation standing over one. they only use about a gal/ 8 hours with a substantial load on 'em.
about $600, new...

the webastos are nice, too- set a timer, it fires up and can even trip a relay to warm the cabin once coolant temp is up. defrosted windows:)
timers can be set for multiple cycles. also, a "remote start" type function is an option. we had them on e few OTR trucks a while back.(when I was a grease monkey)
kept the trucks warm while the drivers slept to save fuel.
about $1k, new...+install.
New ones are bio-D compatible.

you would have to decide on which one would be more useful/ best ROI.



heres a few 12v water heater elements-

12v 25/50amp 300/600w $85
^very bottom of page...

50amp-600w for $35



whats the stock block heater rated at?? 400w??
maybe a 300 watt heater element would work. but the toll it would take on batteries/alt would cost ya in the long run.

what about a small weber grill and a bag of briquets??- $20

EDIT- I also recall seeing a manually operated webasto type diesel fired heater. It is an american made unit(cleveland?), mfg by perfection stove company. primary use is thawing remote stock water tanks.
seen a few on ebay for under $400.


good luck,mo
 

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I use my Honda generator. I work in Washington, DC from 7pm-3AM and at 1:30-2AM every night I plug my truck into the generator (gen is bolted to the back bumper permanently) and let it heat it up. I also put a 1500 watt household space heater in the cab and have that on the same extention cord.

I have the honda EU3000is so 1500 + the 790w my block heater draws is no problem. My fuel bill is like 2 gallons a week running the generator 1 hour a day. 1 hour is more than enough to get the block from 10-15F up to 45 or 50, hot enough for an instant start.

The honda eu1000 or eu2000 is super quiet, small enough to throw anywhere in a vehicle and much cheaper, lighter weight and more reliable than using batteries. Its also quiet enough that you could run it in a neighborhood and most likely nobody would even know it was on.

Keep in mind the hondas are inverter generators so for a 750w load, the eu2000 might be quieter than the 1000 because it only runs the engine fast enough to develop enough amps to run the inverter. example,. a 750 watt load would be close to full capacity for the 1000 watt generator but the 2000 watt unit would be running at half the speed.

Also, the eu2000 is great for running a refrigerator, microwave, and lights if the power goes out. its a good thing to have anyway.. use your block heater story as an excuse to buy it =)
 

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Ive run a window AC off the 1000. also fridge, lites, etc...

but if you go that route, get the most you can afford.
 

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Discussion Starter · #14 ·
Thanks for the info guys, I'll keep it in mind when I'm building my vehicle. This is all pre-planned stuff I wanted to get out of the way before I started the build. I have bookmarked this thread (like many others) for future reference when I'm actually building.

Pantherman
 

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I've got an Espar D5 in mine, makes a big difference. No extra batteries, no different fuel source or type, don't have to run out and start it like a generator. And it is small and doesn't take up any extra room like 5 big batteries or a gen. would. I have mine mounted on the frame rail under the cab.
 

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