Inverter Question

Topic 22261 | Page 1

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Bryan Q.'s Comment
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So when I get my own truck with swift after I’m done with my mentor. Will those cigarette plug inverters work for a crock pot ? Or maybe my lap top ? I know I can really idle my truck with swift. But idk if those would mess up the battery or anything


Hours Of Service

HOS refers to the logbook hours of service regulations.
Brian G.'s Comment
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I can't speak to an individual truck's electrical system..... and in fair disclosure I want to get into trucking, so I am by no means a trucking expert.

I can however, speak knowledgeably about electricity.

There is no free lunch in electricity. I'll use a water analogy to help for a second, even though water is not a good substitute (or companion) with electricity.

If I have 1 gallon of water in a jug, it's 1 gallon of water. If I divide that into 64 shot glasses that are one ounce each, I still have 1 gallon of water, but now it's in 64 little places. If I combine those into 1 cup containers I now have 8 of them, each one being 8 ounces. For this visualization, pretend I don't spill any and that the container doesn't "keep" any.

So back to electricity. In fact, let's work backwards.

Your CrockPot® is a hungry inductive electrical load. Inductive loads are things like an incandescent bulb, a little space heater, or in this case a Crock Pot. On that appliance it's going to say one of two things, that mean the same thing. It's going to say 120v 1200W or 120v 10A. I know, you are going, "hey those are different." Yes, they are written differently but they mean the same thing. It's like 65 mph and XX Km/h. You need to break it down to Watts. Amps* Volts = Watts. This is key. So a 10A Crockpot using 120V needs 1200 Watts. (10*120=1200). Great, so now you know what the "draw" is for your appliance.

Assuming your inverter can supply that load you now need to think about efficiency. Some inverters are more efficient than others. No inverter is 100% efficient. For the most part, lost efficiency takes the form of heat. Your inverter will either say on it or in it's manual how efficient it is. If you spent alot of money you can expect it to be closer to 99% and if it's a cheap WallyWonder® then it's going to be a lower number like 80%. By the way, there are different kinds of inverters..... the cheaper ones tend to be what is called "square wave" and the expensive ones tend to be "modified sine wave". To make it really simple - electronics like Sine Wave which is what they get from the power company. Cheap Power tools and inductive loads don't really care. A toaster will run on anything you throw at it including DC, but that might get very exciting in a bad way.

So what do you do with efficiency? Well, it tells you how much more power the inverter is using to produce the power your device needs. Let's go with a 90% efficiency inverter. We'll call it a Dockside Special and pretend you found it in the Harbor of Good deals. :) So a 90% efficient inverter needs 10% more power to produce a given amount of power. Our 1200 Watt device will consume 1320 watts from the power source that supplies the inverter.

PowerSource ---> Inverter ----> Hot Fresh Tasty Food Device.

Now you get to look at the power source voltage to convert it back to Amps to see if the circuit can supply that amount. Your truck is either going to be 24v or 12v. For a convenience outlet 12V is what I would expect to find. So how do we get back to Amps? Easy, 1320 Watts / 12v = Amps. In this case 1320 watts / 12 volts = 110 Amps. That is a tremendous amount of power for a 12 v circuit.

Most 12v cigarette lighters are on a 15Amp circuit. They have 60 Watts to provide on a nice day. That's 1/2A at 120v with a 100% efficient inverter.

Now, it's not out of the realm of possibility that your truck has been setup to directly cable an inverter to the battery. In the RV world you usually have isolated batteries to run everything but the engine and road lights. It's not out of the possibility to do this on a truck. It would come down to how that truck was spec'd. I would expect economy to rule the day here. A profitable truck should be running down the road and usually have plenty of electrical power to spare.

On my Motorcoach RV I have an 800A 24V alternator bolted to the engine. That's a 20 kilowatt (20,000) alternator... and can in theory provide 160A of power at 120V. I have no idea what is "normal" for a OTR truck alternator... but I'd guess 100+ to 200 amps at 12 or 24V depending on the truck configuration.

I hope that helps.

Btw, you might be able to find a lower powered crock pot or put your crock pot on "low" and it shouldn't draw as much power. The equations still apply. If you have multiple things plugged in you need to add up the power draw. When buying an inverter, be sure to get one with a circuit breaker unless you enjoy buying little glass or plastic fuses. Try not to overload the power source as bad things can happen when you overload vehicle wiring. The wires get warm and the magic smoke will escape.


Over The Road

OTR driving normally means you'll be hauling freight to various customers throughout your company's hauling region. It often entails being gone from home for two to three weeks at a time.


Hours Of Service

HOS refers to the logbook hours of service regulations.
Errol V.'s Comment
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Swift does not allow installed inverters. You are limited to the 12 plug-in kind. (Note: If you require a CPAP machine, the Swift shop will install your inverter for you.)

Truck stops and online you can find 12 volt coffee makers and an oven the size of a loaf of bread that works very well. I used a 12 volt cooler that will keep things cold, but it's not cold enough to make ice.

As Brian points out, the little ones are not powerful enough for a crock pot, plug-in refrigerator or flat screen. You can run a laptop using the 300w plug-in converter. I'm not saying these don't exist in Freightliners, but the solution is not simple.


Constant Positive Airway Pressure

CPAP is a breathing assist device which is worn over the mouth or nose. It provides nighttime relief for individuals who suffer from Sleep Apnea.

PJ's Comment
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I bought a 1500w at Harbor Freight. Its 1500 continous and 2k peak wired it with their 6’ cables designed for it and never had a problem. I just make sure the truck is running when using the microwave or kerig coffee pot

Chris M's Comment
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Swift is putting inverters in all company trucks. A large percentage have them already, and if you get assigned a truck that doesn't have one, you can go to the shop to get one installed, but you are low on priority list. But they will not allow you to buy your own and connect to the battery.

And as far as idling, if you're a good driver, you'll find that as long as you're not completely over the top with it, you won't get much grief for idling. Contrary to popular belief, Swift management does not want you to be miserable in the truck lol

LDRSHIP's Comment
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My $10 Wally World special crockpot pulls about 120 watts on high and 80 watts on low. 300 watts is the biggest you can go on a 12v plug in inverter. I would say you would need at least 200 watt inverter to power the crockpot with no issue. Idk if you have Opti Idle or not. If you do just set the Opti Idle up and the truck will turn on as need be to keep the batteries charged.

IMHO, those Road Pro 12V crockpots are junk. Don't waste your $40 for one. Overpriced and the heating element doesn't last.


Hours Of Service

HOS refers to the logbook hours of service regulations.
Pete B.'s Comment
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That’s my 200W Bestek power inverter, purchased from Amazon; it got great reviews, and hasn’t failed me yet. We’re not allowed to install inverters at Schneider either, and 200W is the largest we’re supposed to get/plug in. It powers my 2 or 2 1/2-qt Crock Pot (model SCR 200 B) I bought from; this particular model is available online only. It is the Crock Pot brand, and uses less than 200W. I use it on low mostly, but have put it on high, even while the truck is off. However, the inverter won’t really charge my laptop unless the truck is running.

Brian G.'s Comment
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That's odd that the laptop won't charge without the truck running. That suggests your laptop is pulling right around 200 Watts. Most laptops have an 80 watt power supply give or take. Some of the big ones have larger power supplies. Almost every laptop maker offers multiple power supplies. The bigger the supply the faster it will charge the batteries.

You can also order usually 2 to 3 sizes of batteries. It will be listed as 2, 3, or 4 cells usually. More cells equals more run time. Sometimes dramatically more.

As an aside: I evaluated a Lenovo El Cheapo latop (N3050) last year and was really impressed with it. It's only shortfall was not enough storage. It was a $300 laptop and I didn't expect much. Yes, it's a bit slow, but it would run for 8 hours on a charge and was fine for surfing the web, watching YouTube, or running Microsoft Office.

On the subject of Office - Check out LibreOffice. It's a free alternative to Microsoft Office that works virtually the same.

The current equivalent of that laptop is this:

I tried putting the link in and the site kept complaining about it. Again this laptop lacks sufficient storage to be viable, but would be great for email. The reason it has 2GB of Ram and 32GB of storage is that it gets them the Windows license for free... which is why it's $220. You really need 128GB of storage on a laptop....

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