Cobra CPI 875 800 Watt 12 Volt DC to 120 Volt AC Power Inverter with USB port
by Cobra
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List Price: Category: Car Audio or Theater See more product details |
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Customers in the UK,
Buy this product at amazon.co.uk
for British Pounds
Digital Cameras Photo Reviews of Cobra CPI 875 800 Watt 12 Volt DC to 120 Volt AC Power Inverter with USB port
Customer Review: Great
Summary: 5 Stars
Used it for my sons XBox360 in the car on a trip to florida.
Worked great.
Customer Review: Good Unit BUT you need to know a few things
Summary: 4 Stars
This is a very good unit, for what it is designed to do. It is up to Cobra's usual high quality standards. There are a few things you should know before you buy it though.
There are a couple of comments about the unit not putting out full voltage - however, if you go to the Cobra website and read up on this unit you will see that a standard voltage meter will not read the voltage correctly due to the sine wave configuration, instead it will read low voltage. Measurement requires a specialized meter, an RMS if I recall correctly. I have read also that some electronics work fine with the modified sine wave and some pick up some interference. It would probably be worth the time and energy to research which would be the case for your particular electronic application, before buying.
Another quite important thing to know is that this unit, while rated at 1600 watts, will only run at 800 watts continuously. The 1600 watts provides room for start up surge, but not for running more than a few seconds. I bought mine to use in my car. First thing I tried was a 1500 watt heater, and it would run for a few seconds and then stop. Then I tried a 750 watt heater and it ran just fine. So check your application and see if it will be 800 or less watts, if more, get a bigger unit.
Another important thing to watch for on automobile installations is the output of your alternator. Many cars have alternators with as little total output as 60 to 75 amps. You can calculate the amp draw by dividing the AC watts by 12 and then multitplying by 1.1 - so in my case the 750 watt heater draws 69 amps from the battery/alternator. If I had a 60 or 75 amp alternator then there would be a serious problem. Probably the battery would be drained while driving and I would end up with a dead battery, at night, in the middle of nowhere, surrounded by zombies pounding on the windows....
I have a 135 amp alternator, but since I am not sure exactly how much amp draw my car uses while running at night with headlights (most of my driving is after dark) then I am not completely sure how much reserve/overage I have for the inverter. As a result I only run the heater intermittently so the battery won't drain. If your application pulls enough amps to cause the charging system to run at system capacity so that the alternator continuously puts out 100%, the alternator will not last nearly as long as normal. I never run my heater when the engine is idling, at idle the alternator puts out about 40% less.
If you are going to use this in a running car, try and find the total amp draw needed for the car,(I found that my alternator runs at about roughly 60% when idling so I am guessing that my total draw would be about 50% of the total capacity of the alternator at full speed, or 68 amps in my case, but that is a guess) subtract that from the total output of your alternator, and then compare your alternator's power reserve with the draw from the inverter with your application, to make sure you have enough total capacity with some margin. Mine would, based on this theory, run a 2 amp deficit. Or do what I do and run the application only intermittently so the battery gets charged up and the alternator isn't running at 100% capacity all the time, and never while the engine is idling.
If you are going to use this in your car while driving, the supplied cables are not going to work for you, they are too short. The inverter is not weather proof so it can not be mounted under the hood where water can splash up on it, or dust get into it. It needs to be in a weather tight environment with good air circulation, it also doesn't like heat. I took a pair of heavy jumper cables and soldered bolt connectors on each end and ran these to my cars interior. I added an in line 100 amp fuse in case of a short in the cables.
If you are going to use this on a battery only, there are formulas to determine how long the battery will supply the load you need - you can find the info with a goole search easily. It would most likely be worth your time to run the formula before buying, to make sure that you are going to get sufficient run time from the battery you have or plan to get. If frequent recharging is in your future, consider deep cycle batteries.
In summary, this unit works, within it's limitations, and I am happy with it. I would have given it 5 stars, but the Amazon description of the unit's true continuous run capacity should be more detailed than it is.
August 2009 - I see that the description has been changed so that it better represents the 800 watt continuous capacity. Kudos to whoever made that honest change!
Customer Review: Great product
Summary: 4 Stars
I bought the cpi 875 to use in case of a power outage, and it seems to power what I need pretty well, although I haven't had to use it for an outage quite yet. I already hooked it up to run a lamp and a propane heater that requires electricity to operate, and it did very well. Has a pretty low profile, so it sits under the hood with it closed, so that should be nice in case the outage is in inclement weather (which they usually are). I figured, instead of buying a generator and dealing with all that comes with those, I would use the Inverter to run some essentials, and just run the car every once in a while to charge the battery back up. The only downside to this unit, I would say, is that it doesn't have a voltage readout, and it doesn't come with a cigarette lighter adapter, in case you wanted to use it for small devices in the car. But, other than that, it seems like it will be very handy in an outage, and should also be nice in case I go on a trip and need to power something. Overall, definitely recommended, and at the Amazon price, it can't be beat.Customer Review: First time shopper
Summary: 4 Stars
This was my first time ordering anything from Amazon.com I have to say that i was truly please with this produce. I Needed the inverter because the heat in my car doesn't work. SO i needed to use a house heater in my car to keep warm. The only way for it too work was for me to buy the inverter and convert the power. Now the inverter (1600 cobra) supplies enough power to run the heater and keep my kids and i warm for the winter. SO if your looking for a good product i give this one an 8.Customer Review: gross misrepresentation
Summary: 1 Stars
how can you label this as being a.....
"Cobra CPI 875 1600 Watt 12 Volt DC to 120 Volt AC Power Inverter" ......I have purchased many products from amazon and never have I felt ripped off like I did this time ( and I purchased 2 of these, LOL ) this is nothing but a 800 watt inverter and I suggest you represent it as such ! shame on you !!!!!!