Low voltage auto engine start for 75 bucks, who has one?

My prostars has the factory version of this installed as an its 'APU'. It has an extra 4 batteries installed on a frame rail as a step and can auto start the truck when the batteries are low. When it kicks on I believe it runs for about 80 minutes. (Never timed it just going by what someone told me. It is a long time.) to recharge the batteries so I'm getting 20 minutes isn't long enough.

Its also setup so that the system disables if left in gear. Hood open. touch the clutch (I believe brake also but can't quite remember.) Or if the parking brake isn't set.

Even with the 8 batteries its hard for it to last full 10 hours with the heater on and only about 5 with the AC on, some times worse depending on heat.. (I also have a waeco fridge a long with a few electonics that are always pulling some power.

 

You still have to figure out what to do with the exhaust from the gasoline generator. This is not something to take lightly or figure that your cab is sealed well enough to prevent CO from getting in. By the time you know your getting CO in the cab your too dead to do anything about it. The fumes and associated CO from anything burning gasoline are much more toxic, faster acting and have detrimental effects sooner than diesel. Not only do you have your own health and safety to worry about, you have the people parked right next to you who may not have and APU and may be sleeping with their windows open while your running your A/C.

The best scenario would be for the exhaust to be routed above the roof line of the truck because anything lower than that and your just asking for trouble.

Personally I would NEVER even think of using a gasoline generator for a truck unless I had a 100' heavy gauge extension cord so I could put the generator out behind the trailer where it would get stolen anyway.

I know people are researching more economical ways to provide power and such to their trucks but there's a reason why RV's have only used propane or diesel in their units for 50 years. How much is your life worth? And how much value do you place on the lives of the people around you when your running your generator flooding the area with deadly CO??

Get yourself 4 to 6 deep cycle AGM batteries and the correct alternator for your truck, use the power wisely and sleep the night away with the quite hum of the air conditioner not the ruckus drone of a gasoline generator screaming right under your bunk. Yes this setup would be more than the gasoline generator but then there's no gas cans to carry, no oil/air filter changes, no noise and most of all, no chance of not waking up from CO poisoning.

I have run trucks with actual diesel APU units as well as the AGM battery system. Both have their strong points and weak points, The A/C on an APU most certainly did a better job but at a cost, the initial cost of the unit, the ongoing maintenance cost and the fuel burn. Then there's the noise, no matter the manufacturer there's going to be noise and vibration, some admittedly better than others but it's an internal combustion engine so there's going to be some period. The battery system doesn't cool as well but there's little to no ongoing maintenance and there's no noise/vibration from a running engine.

Some things to think about but if nothing else take the time to research the exhaust and associated CO from a gasoline engine and make sure you have taken every step to insure your own health and safety as well as those around you.

 

Running AC from batteries? Forget it.

My RV has 16 X 150ah AGM's which is 2400ah @ 12v (actually 600ah @ 48v in my case), and I can't run AC from those for more than maybe an hour in any fashion that will not destroy the batteries.

Believe me, there are tons of RV guys who have desired to do this, and very few have managed even with enormous battery banks (I carry nearly 2000lbs of batteries in mine).

Secondly, AGS is designed for 2 battery banks... 1 "house" (the one the inverter runs off of), and 1 starter (that the assumed generator starts from).

It is ill advised to try to have your "house" batteries also be your starter batteries. In order to do this, you would have to set your AGS to start at a relatively high voltage (enough to still start the generator).

High draw loads like AC will reduce that voltage while running, and it will rise when the AC is turned off.
What that means is that you may have 13v at rest, and the moment you turn on the AC, it will go to 12, or 11.5..etc.
When you turn the AC off, it will rise again to maybe...12.5v.
On a tractor sized bank, that voltage drop will be severe and the AGS will think your batteries are dead just because of the voltage under load and it will try to start the engine....which defeats the purpose.

What you'll end up with is a 10 minute on/off cycle, which is obviously not worth it.

Bottom line is that you will need a generator running to run A/C.

The AGS is still handy for things like starting your engine in response to a low battery situation caused by load (ie...the AC turn the generator on automatically if you forget), or by parasitic loads, or leaving your headlights on...etc.

Magnum Energy makes one that can be adapted. Just Google "Magnum Energy generator start" and you should find it.

 

To answer your question directly, the short answer is "no".

You have to understand that it's not just about voltage. Fast charging a battery can bring it to *voltage" rather quickly. This surface charge may even be enough to start your motor.
However, to run sustained loads requires that the batteries have gone through an *absorption" period. I suppose it's kind of like pouring syrup on a stack of pancakes... it takes awhile to make all the layers sweet.

Generally this is a matter of hours, not minutes (with a battery, not pancakes).

 

Something else that the future readers of this thread should consider is starter solenoids...
The relationship between the function of starter solenoids and the actual starter motor is not always linear, nor does it stay the same over time as the contacts of the solenoid wear.

Why does this matter?
Because solenoids are low draw devices that are more sensitive to voltage, where the starter motor turning is more dependent on *current*.

There is a general presumption that if you turn the key and the motor cranks, then you "have enough power", or that the "battery was good".

A battery can be quickly charged to the point to where the solenoid will respond and supply current to the starter motor, but that doesn't mean your battery is charged. Instead what you are doing is demanding a high current load from a mostly discharged battery where it is trying to do so at diminished voltage (it drops instantly).

You could equate this to the 100lb mom who lifts the 5000lb family wagon off of her child that is pinned under it...
She (um..the battery) has no choice but to put everything it has into it, but it isn't healthy and you won't be doing long on a daily basis.

 

They make high efficiency air conditioning units that run on 12v DC, some are specifically built for semis. They are a lot more expensive than a $100 walmart window-mount unit, but the trade-off is you'll get something much more suited for the job. It won't drain your batteries nearly as quickly.

You have to remember that the 12v Lead-Acid batteries in your truck are built to kick out high amps over a short period of time (starting the truck). They are not made for continuous power supply and deep discharge cycles. For that you should pick up a set of deep cycle batteries. They make lead-acid batteries that aren't a whole lot more expensive than starting batteries, that are built for deeper discharges, marine batteries for example. RV batteries are a bit of a hybrid design that can be deep discharged, and still kick over your engine. Sealed batteries such as Gel, AGM, and lithium-ion will have greater amp/hour capacity, can be discharged further without damaging the batteries, do not require maintenance, do not emit flammable gasses like Lead-Acid, and have a longer shelf-life. The drawback to these is that they are MUCH more expensive, and they have lower CCA.

You might also consider using solar to run the AC. If you can figure out how many watts the AC unit draws, you can calculate the size of solar panels you will need. They make solar "blankets" that can be placed over your windshield, and folded up when not being used. Even if you're not able to generate enough electricity to keep up with the AC, you can at the very least, extend the battery run-time.

12v Truck Sleeper AC (compressor only) --draws 850 watts
http://www.amazon.com/compressor-sl...65175523&sr=1-15&keywords=12v+air+conditioner

12v Flexible solar panel -- 100 watts
http://www.amazon.com/HQST-Monocrys...5175748&sr=1-10&keywords=foldable+solar+panel

If you want something "Ghetto-Rigged" you could stick with the portable 110v AC idea, and grab a portable generator. The drawback to using one of these would be that most of these units run on gasoline, not diesel. You would have to carry gas cans to the Auto/RV fuel isles, fill them up there, and haul them back to the truck. Generally the smaller units will run for about 10 hours before needing to be refueled. I'm not sure how DoT looks at gas cans though.
http://www.amazon.com/Honda-EU2000I...465176070&sr=1-11&keywords=portable+generator

There's also the option of getting a diesel fired generator. You could possibly mount one directly to the truck somewhere, and even run a fuel line directly to your main tanks.
http://www.amazon.com/DG4LE-Portabl...485&sr=1-3&keywords=portable+diesel+generator



My best advise would be to talk to a dealership that deals with trucks like yours, and talk to them about what options you might have.