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Inverter / watts question

mcavoy33

mcavoy33

Seasoned Expediter
I bought a rice cooker but my inverter isn't strong enough to power it. I need to buy a new inverter but I'm not ready to spend on a 3000W inverter so I'm going to go as cheap as possible.

My rice cooker says 120V~60Hz 350W


Does the 350W mean that I can get away with buying a 400 watt inverter?

Any recommendations on brands to get / stay away from?
 
Wolfeman68

Wolfeman68

Veteran Expediter
Fleet Owner
US Marines
mcavoy33 said:
I bought a rice cooker but my inverter isn't strong enough to power it. I need to buy a new inverter but I'm not ready to spend on a 3000W inverter so I'm going to go as cheap as possible.

My rice cooker says 120V~60Hz 350W


Does the 350W mean that I can get away with buying a 400 watt inverter?

Any recommendations on brands to get / stay away from?
Click to expand...

No, 400W inverter is too low. There is a "surge" wattage, (when you first turn an appliance on, and when it powers up to maintain it's function) that is usually not listed. The 350W listing is the steady draw of the appliance. Most applications in trucks are in the 1800 to 2000W range. There is a 3000W inverter constantly on sale on Ebay for $199. It's called the Tiger Claw. I've had one in one of my sprinters for 2 years now and it's still going strong.
 
Turtle

Turtle

Administrator
Staff member
Retired Expediter
Surge Wattage is rarely more than double the steady draw. Exceptions being a refrigerator, air conditioner, sump pump and a few other things. A 350 Watt rice cooker will surge at most 700 Watts (probably more like 450-500, tho). A 400 Watt inverter should handle an 800 Watt surge. Most inverters can handle a surge of twice their rate Wattage. That's by design, for this very purpose.

I have used a 350 Watt rice cooker with a 400 Watt inverter, so it'll work, but it's really putting a strain on the inverter. A better alternative, especially if you have other appliances like lights or a computer hooked into it, would be a 1000 Watt or an 1500 Watt inverter.
 
asjssl

asjssl

Veteran Expediter
Fleet Owner
I have a 1000 w from harbor freight ...close to 5 yrs. Old....no problems w/ it...love that place...

Posted with my Droid EO Forum App
 
Camper

Camper

Not a Member
Depending on what other appliances you're using, I'd recommend a minimum of 1000 watts, especially if you're likely to have other items on in concert such as lights or another appliance, such as a coffee maker.

My suggestion would be to spend the extra bucks and opt for something more in the range of 1500 or 2000..In the long run the benefits will far outweigh the costs.

Posted with my Droid EO Forum App
 
matlack

matlack

Expert Expediter


It takes a really good connection and a light load on the

inverter not to overheat the cigarette plug, much better to use

cables directly to the battery IMO.


If you deal with Harbor Freight, be sure to sign up for their free

emails and mailing list as you will receive special discounts,

usually a coupon for 20% off any one item and a free Gift

(Flashlight,Work Gloves,ETC) with any purchase.

They also advertise monthly in the small magazine (American

Profile, Parade, etc) insert that is included inside most Sunday

Newspapers.
 
AMonger

AMonger

Veteran Expediter
matlack said:


It takes a really good connection and a light load on the

inverter not to overheat the cigarette plug, much better to use

cables directly to the battery IMO.
Click to expand...


Found that our the hard way, using a 300 watt inverter through a cigarette lighter socket to charge/power a laptop. Fried the socket.

The engine compartment on a Chevy van is a tight place. I'm finding it hard to work under there. Is there a way to hardwire an inverter into the electronics under the driver's seat? I know there's a lot of power going in there.
 
greg334

greg334

Veteran Expediter
MOST gm cargo vans have an upfitters connection behind the front drivers seat unless the van was ordered as part of a fleet package - like Ryder and Penske C/Vs.

Under the hood, I think on the left side is the power distribution center and under the cover is where the upfitter's connection gets power. There are two lugs for cabling, I think each has a 50 amp fuse on them, so you can use that point to power the inverter.
 
yayashas

yayashas

Seasoned Expediter
I connected my under the seat of gmc ther is plus that goes ther by the fuses and groundet to the seat frame or bolt thet holds seat had it for 1/2 year no problem run fridge and laptop.
 
Fr8 Shaker

Fr8 Shaker

Veteran Expediter
I had read on one inverter I had that if you use the cigarette adapter for power you only get 1/2 the wattage of the inverter and need to hook directly to battery for full power.

ie: 400 watt inverter through cigarette or power supply adapter will only give you 200 watts.
 
Turtle

Turtle

Administrator
Staff member
Retired Expediter
Fr8 Shaker said:
I had read on one inverter I had that if you use the cigarette adapter for power you only get 1/2 the wattage of the inverter and need to hook directly to battery for full power.

ie: 400 watt inverter through cigarette or power supply adapter will only give you 200 watts.
Click to expand...
Sort of, but not necessarily.

Watts divided by Volts equals Amps.

A 400 Watt inverter is 33.3 amps. Most cigarette lighter adapters are 10 amps so you're looking at a 120 Watt inverter max (Amps times Volts equals Watts). Some of the 12-volt power taps that look the same as a cigarette lighter plug are 15 Amps max, or 180 Watts. A 20 Amp tap (very rare on vans, not sure about trucks) will allow 240 Watts.

So the inverter will will give you only the maximum that the power tap puts out. Using a 400 Watt inverter with a 10 Amp cigarette lighter socket will only give you 120 Watts.

Keep in mind these 10, 15 and 20 amps draws, not to mention 33.3 amps of a 400 Watt inverter (or the potential 125 amp draw of a microwave on a 1500 Watt inverter) are relatively high amp draws, exactly the kind that a cranking battery is not designed for. Not a problem if the engine is running, but if you are parked and run those kinds of draws very often at all, you're turning a 60-month battery into a 12-month battery. You're much better off with an isolated auxiliary battery.

Power a 350 Watt rice cooker off a cranking battery, and you could be charged with assaulting a battery. <snicker>
 
mcavoy33

mcavoy33

Seasoned Expediter
matlack said:
There are some good deals on Power Inverters at Harbor

Freight Tools Stores, it would be faster to purchase one at one

of their stores and it could be returned easier if it did not work.

Most of their stores carry what is on their website and you can

find a list of their store locations there;

Power Inverters - Save on Power Inverters at Harbor Freight
Click to expand...

Thanks for this matlack, I'd much rather purchase one in person.


Also thanks turtle for sharing so much info.

I'm probably going to go with a $29.99 400w continuous / 800w peak Chicago Electric. I'll upgrade down the road if I ever add a fridge or microwave.
 
mcavoy33

mcavoy33

Seasoned Expediter
Ok I'm thinking about upgrading.

What do you guys with fridge & microwaves use for inverters? What is the smallest I can get away with?
 
cheri1122

cheri1122

Veteran Expediter
Driver
Mine's 2500 [upgraded when the 1500 died], has 3 AC outlets [1 for the fridge, 1 for the laptop, the 3rd for whatever is in use at the moment] and a USB port.
I've found that running the microwave requires running the truck [APU alone isn't enough, though it puts out more voltage than the truck batteries] on high [1100 rpm] idle, or it flashes 'LP' for low power.
Probably because of the big [apt size] fridge, but that's an option I won't give up, lol. :)
 
cheri1122

cheri1122

Veteran Expediter
Driver
I spose I could, just wasn't sure whether interrupted power might be an issue - seemed safer to add more battery power.
BTW: excellent choice, on the rice cooker - it's the single most versatile cooking utensil [besides the microwave] I've found. It boils, [water, pasta, veggies, soup], browns [meat, pierogis, grilled cheese sandwiches], steams [veggies] and the steamer insert works as a colander [or bowl full of holes, as my daughter calls it], warms the sauce for the pasta, water for washing up after you eat the pasta - and it cooks rice too, I guess. That's the one thing I haven't used it for, lol. :)
 
Turtle

Turtle

Administrator
Staff member
Retired Expediter
I've got a Microfridge where the fridge plugs into the microwave, and then the microwave plugs into the inverter. When the microwave is activated, the fridge is automatically shut down until about one minute after the microwave is finished. It's designed to never pull more than 10 amps AC due to the wiring in older apartments and college dorms. The microwave is a relatively low power model at 900 Watts, which is 7.5 amps AC (which is 75 amps DC, but it generally pulls closer to 50 amps when running), and the fridge 1.3 amps AC (13 amps DC, but pulls more like 10 amps), and both together is 8.8 amps AC (88 DC), but the microwave will pull more nearly 10 amps at startup, so it kills the fridge automatically.

The only way to know the smallest size inverter you can get away with is add up all the Watts of the appliances you plan to run at the same time, then, take that number and add 10% to itself to account for the 10% amp loss in the inverting process. For example, an appliance that draws 480 Watts, plus 10% (48 Watts) is 528 Watts.

Then, total Watts divided by volts will get you the amp draw. (amps X volts = Watts, and Watts / volts = amps).
 
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