OK. How Crazy of an Idea is This...

[Hans13]

Is that a crazy idea?
yes.
is it doable, Hell yes. Simple in fact, here's how I would do it:

Figure you're inverter will have around a 95% power factor. (actually a very reasonable estimate with today's power supplies.) and you will want at least a 1500w inverter to run the 1000w block heater at 100% duty cycle without issue.

So now it's simple math. The block heater will draw 87.5A from a 12v system. (heater + power-factor / 12v) From a simple search on this board, depending on climate and wind, morning starts in extreme cold need you should set your plug in timer for 1-4 hours.

So you will need 88-355 amp hours of 12v battery to run your block heater. (also a simple timer.)

Lithium batteries for this would be light and cheap, but the charging system very expensive and there is always the risk of a class D fire when rapid charging lithium batteries. So I personally would go with deep cycle led acid. Little maintenance, and can simply be linked parallel to the starting batteries for recharge. 30 second google search gives me these: http://www.amazon.com/Vmaxtanks-VMA...TF8&qid=1424401618&sr=8-5&keywords=deep+cycle I know for certain you can find comparable batteries cheaper, buuuut I live in Vegas, (we don't have cold here) so I won't bother looking.

So a pair of those will cover you for 3.5 hours of block heater (numbers include some padding) That's enough for almost the max forum recommended heating time. Keep in mind 35A is that battery's regulated max charge rate. So unless you have a 6 hour commute, you will need to plug them in overnight each night to fully recharge them from 0.

I would add an RV battery isolator, and at minimum a 3g alternator. However this is totally doable. Cost might be steep, but then the batteries will likely last 3 years, and to have 3+ hours of 15A 120V on demand when not needing the heater. That really does make the idea a little attractive. Especially when you consider mounting the deep cycles in the stock battery locations and running a super capacitor array to start the truck. The batteries will keep the capacitors topped at 12v, and the isolator would keep the inverter from drawing down the cap bank. So you'd step into a truck that had a warm block, and the starter would still spin the flywheel off. All from that one pair of batteries. G31's really aren't that much cheaper, brand new retail, than the ones in the link I posted, and a Super Cap array is only $120ish for the capacity I would want. Crap, I'm talking myself into it.....

After some thought, it's still a crazy idea, and wouldn't be cheap.... But it's also not, all things considered, a bad idea.




When I joined this forum, replies to "crazy idea" titled posts had the tone of: "well I wouldn't do it, but if I did, here's how:" Not: "That won't work, and here's why:"

I miss the forum I joined. It was alot more fun.
Just sayin...

Great post! I appreciate the positive words at the end.

Like I said before, the likelihood of me doing this is nearly 0%. I just tossed an idea to ponder. I believe that I will be hooking up a third battery.

 

[G. Mann]

I think this a battle that has been fought many times over the years by folks that operate in the frozen north. The hands down winner of the battle are the diesel fired heaters like Webasco and Espar, simply because of reserve battery power.

It takes an ignition source [low current demand to get fire started] and then a 12 Volt pump to circulate the hot coolant once the boiler is hot. Keep in mind when it's cold, batteries don't work as well either, so less "cold cranking amps" are available.

I have a Wabasco heater on my diesel pusher 40 ft motor home to pre heat the Detroit 8V92 and the run time on that heater has limits based on reserve battery power to run the pump and still crank the engine.
So, even there, no free ride.

 

[Agnem]

Keep in mind that the block heater is only 110v AC for convenience. Not because it has to be. All these conversations about inverters are not necessary. A block heater will run as good on DC as it does AC. Just get yourself 9 12 volt batteries and hook them in series. Be careful not to get hooked up to the final product! Should give you a little bit of heat for an hour or two.

 

[TahoeTom]

https://www.youtube.com/watch?v=_ELxfImQ3bo
How about something like this? Maybe your boss could help.

 

[Brad S.]

Hey, hey i got it, low buck, low power idea, a bunch of those pocket/hand warmers all stuck to the side of the engine about 20 mins before you start it.(just kidding)

It would be very ironic if your boss had troubles getting his vehicle started after he told you no plugging in.
(God does have a sense of humor ya know)

 

[G. Mann]

Now that is a glow plug system that won't swell up.. Hahahahha.. Russians.. what can you say.. they make rednecks look like sissy boys.

I don't know how you say "Get`ter Done" in Russian, but they do it.