Ok, just hear me out on this one,
I am looking at purchasing an 87 6.2 to drive back and forth to college and the dorms that I am staying at do not have any place to plug in the block heater in the winter (I am going to school near Chicago, so I will have to plug it in). I got an idea of putting a power inverter in the truck that would run the block heater with a timer. I thought that if I got an extra battery or two that I could run the inverter and essentially the block heater off of those batteries while maybe charging them with my alternator or some other means. My problem is that I don't know how big of an inverter to go since I don't know how much power the block heater would pull for say three to four hours. The inverters are rated by Watts and I don't know the voltage, let alone the wattage of the block heater. So my main questions are, can this even be done (I hope) and if it can how big of an inverter should I purchase. Any advice and insight into this is greatly appreciated.

What makes you so sure you will need the block heater? I live in Western NY, and if all my glow plugs were good, I would not need mine... ;-) If your glow plug system is in top notch shape, and the engine isnt that tired, you should be fine I would think, except maybe on the coldest of cold days... (like down near 0). just my 2 cents....

You will need to run the block heater for a minimum of 3 hours. I believe that it pulls around 600 watts. A 12 volt battery (or battery bank) would have to be able to provide 150 amp hours. You should use deep cycle batteries, not regular automotive batteries. And the amp hour rating should be double your expected load since you don't want to drain the batteries more than 50% (otherwise you will drastically shorten their life). So for instance, you could get two Trojan L-16 batteries (which are used in fork lifts and have become popular for solar electric systems). These are 6 volts, 350 amp hours, 113 lbs each. So wired at 12 volts, you get 350 amp hours. and a weight of 226 lbs. Unfortunately, batteries don't operate very efficiently at low temperatures, so you might have to increase the number of batteries. Golf cart batteries would also work. They are 12 volts each, and smaller than the L-16s. You would need quite a few them.

You will need a good inverter that is rated at more than 600 watts, and you will need a good charge controler so that you don't over charge the batteries. You want to keep them separate from the starting/operating batteries (i.e., not wired together)

It's probably doable, but quite cumbersome and expensive. I was going to ask why you need a 6.2 to commute back and forth to college, but now I realize you'll need it to carry around all those batteries.

Good job Thumbsmasher! You are "Right On" with needing a 6.2 to haul the load. The ideal is sound but the implementation is going to be a challange.

Most invertors are designed for less than full load. To successfully operate a block heater I would not go with less than a 1500 to 2000 watt invertor. I have several trucks at work that run power tools using invertors and my experience has been thus: They EAT batteries and charging systems!

A good, HD battery isolator would be necessary to separate the truck system from the auxillary system as well. With out it, the truck batteries would go dead helping the aux batteries run the invertor. The alternator would have to be upgraded to handle the increased charging load. Possibly, install and additional alternator to run the auxilliary system, like the ambulance/fire vehicles.

As stated, it would require a lot of battery reserve to power a block heater. I would work with the existing system and make sure the truck batteries, cables, cable ends, connections, alternator, glo-plugs, relay/controller, etc are in top shape. The truck should start well enough without the aid of the block heater.

If necessary, we could get into a manually operated glo-plug system, etc., to help it along, but the truck should start without the heater except under extreme conditions.

The main reason that I am looking at this 6.2 is from my previoius threads, it is a low mileage engine (around 40k original) 2wd that gets close to 20 mpg. I can get the truck fairly cheap and it is in great condition, the things a poor college kid is looking for. I assumed that you had to plug the block heater in cuz the temps will be around 0 if not below sometimes. Correct me if I am wrong but my dad had an old 6.2 that we had to plug in in the winters. Just going off of that.

It certainly helps cold starts to have a block heater. We were just saying that a properly adjusted and maintained 6.2 should start on the glo-plugs. This is entirely dependant on a good electrical system. The problem with most manufacturers is that they design things to work in conjunction with everything else. If one little thing gets weak, it affects everything. That's why I commented on all the electrical components and connections being in top shape.

One slightly corroded battery connection can keep it from starting when cold, where you may get lucky and it will start when warm. If there is a weak spot, it will manifest itself after sitting out in the cold overnight.

Same goes for the fuel system, trucks start fine after they get some heat in the system. Let them sit overnight and, if there are any bad hose connections, etc, the fuel will drain back to the tank, leaving a dry pump, lines, filter, etc and make for hard starting. Just food for thought...Fred

Thanks for the info Fred482. So I have a few more q's for you. So if the weather hits -10 outside in February in Chicago my truck would start with the proper equipment? Which leads me to my next q, what should I do for glow plugs? Our old 86 had a manual controller for them so I know what you are talking about there. Any advice is appreciated.

There are a couple of things that you can do to make cold weather start ups a little less painful. Plugging in helps but can be gotten around within limits. 1) Change oil to synthetic for winter, Rotella has a 5w-40 that is available a wally world for around 3.77 a quart. This will help the engine spin fast when it is cold. Next is keep your fuel dosed with a good additive. If the fuel doesn't flow through the filter, she isn't going to start. Wire in a manual glow plug switch and use 60g glow plugs or some of the self regulating fast heat plugs like Kennedy sells. With the ability to use extended glow cycles in cold weather and oil that will let the engine turn over fast, she should start. For emergencies, carry a can of starting fluid. Use it after the engine fails to start with glow plugs alone. Do not use glow plugs while using the starting fluid! Do not use a lot of starting fluid. Usually it takes just a small amount to get her fired up. These things work for me with my daughter in college with her 86 6.2 blazer. I just converted her to a manual glow plug switch two weeks ago, and I haven't got a phone call since, DAD MY TRUCK WON'T START:lol: Also, with the manual button, I like to use some after glow to help the engine smooth out when it is real cold.:cool2: