Customer Reviews

Cobra CPI 1575 1500 Watt 12 Volt DC to 120 Volt AC Power Inverter

5 star:		(43)
4 star:		(19)
3 star:		(6)
2 star:		(7)
1 star:		(19)

 

 

This review is in response to some comments regarding wire and fuse size selections for this inverter and others like it.

In response to other review quoting a table from the National Electric Code (NEC). While the table that was posted is correct for 115VAC (household voltage) is does not translate directly to 12VDC (automotive voltage). When dealing with a 12 volt system there is less concern with wires overheating, at least in the way that the NEC considers it, and far more concern with voltage drop. When running wiring a reasonable distance (a couple hundred feet or so) there is little concern with voltage drop with AC power. But when dealing with DC, simply increasing your wiring distance 5-10' can have a drastic effect on voltage drop. That is why this inverter should be wired with, at the very least, #4 wire and really should be installed with #2 or thicker, especially if you need to run wire 15 or 20 feet or more.

The purpose of a fuse in a DC system is to protect the rest of your electrical system in the event of a short. That is why you always want to install your fuse as close to the battery as possible (no more then 3' if you can help it). As far as the amperage goes, there is a really good quick reference chart for automotive wire size that can be found at Tessco's web site here:[Turns out I can't link to an outside page so I'll paste the contents of the table at the bottom]. But to boil it down, you can safely fuse a 12VDC circuit at 150, or 200 amps, or more on #4, #2 or #0 wire.

Now this unit at full load is something like 85% efficient. So if you do the math -- 1500 Watts / 12 Volts / .85 efficiency = ~147 amps, A 150 AMP FUSE IS REQUIRED. If you take peak power into account you would need to double that to a 300 amp fuse, but because the inverter cannot run at peak power for more then a moment, a slow-blow 150amp fuse may work just fine, or perhaps you could step up a 200amp. I wouldn't go all the way to a 300 amp fuse unless you really found that you needed it and had the inverted is wired in such a way that it could handle that level current (read: installed using very heavy gauge wire). Now if your vehicle is running while your inverter is working the amperage will be a little lower because your dealing with 14.4 VDC rather then 12 volts (watts = volts x amps -or- amps = watts / volts). But at the very least, a 150 amp ANL fuse is very good idea and not at all over sized.

Just a FYI on fuses, most car stereos are installed with AGU style fuses, but they only go up to 100 amps.

You will need an ANL style fuse to get one rated at 150 amps or more. See these links for examples:
Kicker 09ANL150 150 Amp ROHS Compliant ANL Fuse - Package of 2
Scosche EWFH Single ANL Fuse Holder

Wire Gauge Selection Table 12 Volt Circuit

Wire Distance
AMPS 3' 5' 7' 10' 15' 20' 25'
---------------------------
<5 18 18 18 18 18 18 18
6 18 18 18 18 18 18 18
7 18 18 18 18 18 18 18
8 18 18 18 18 18 16 16
10 18 18 18 18 16 16 16
11 18 18 18 18 16 16 14
12 18 18 18 18 16 16 14
15 18 18 18 18 14 14 12
18 18 18 16 16 14 14 12
20 18 18 16 16 14 12 10
22 18 18 16 16 12 12 10
24 18 18 16 16 12 12 10
30 18 16 16 14 10 10 10
40 18 16 14 12 10 10 8
50 16 14 12 12 10 10 8
100 12 12 10 10 6 6 4
150 10 10 8 8 4 4 2
200 10 8 8 6 4 4 2

This product works great, I have a microwave, flatscreen tv, and a toaster i hook up to it and there is no problems. One thing I wish would have been mentioned somewhere is that you need to purchase a 150 amp inline fuse to put in the power wire from the battery to the inverter. So plan on getting one of those and have it ready so you can install it. I didnt know about it and spent some time in North Dakota trying to find one. Enjoy.

Other reviewers don't seem to have had the problem I did, so this might be a good product but I must tell you my experience with it. I am very familiar with inverters and how to hook them up having lived off of solar power now for over ten years. When I first set up this inverter, the input voltage showed 12.3 volts, the same as my battery voltage but undr a 110 watt load the output wattage meter showed 0 (zero) watts. What I had plugged into the inverter was working fine (a small TV), so I assumed this meter was just broken. If that was all that was wrong I could have lived with it. The next morning I turned it on, turned on the same TV and within 20 minutes the picture on my TV slowly shrank down to a pinpoint and then shut off. There were no low voltage warning sounds. I checked my battery level and it was at 12.2 volts, the same 12.2 volts showed on the input meter on the inverter, output still showed zero, as it always did. I checked the output at all three of the outlets on the inverter and they showed zero. I turned the inverter off and then back on with the voltage meter still in one of the outlets and watched my meter go from 119 volts down to 30 volts, up to 80 volts and then back to zero. The whole time there were no warning sounds coming from the inverter. This fluctuation could very easily damage anything that was plugged into the inverter!!!!

The good news, Amazon's return system is very easy, didn't cost a penny to return it and I got a refund quickly. I thought of getting a replacement instead of a refund because of all the good reviews but decided not to press my luck, no equipment was damaged this time but why risk it again. If I could rate Amazon I would give them five stars but the inverter gets zero xtars since it didn't function as advertised, went dead under much lower load than it is rated for.

The inverter is working for me exactly as described and as I hoped. I drive a truck and have it installed to replace an older, smaller model. I run a number of things including my laptop, external speakers, printer, TV and a coffee pot. The low input warning works great, and will shut down the inverter if necessary. I will be adding things soon, such as a microwave.
The meter is a great feature which lets me see how much power is being drawn by each device attached as well as the input voltage.
I highly recommend this inverter.

I bought this unit to create a back up system for my home hot water steam heat radiator system. We are experiencing more and more power outages during our harsh winter months, and although we have natural gas and the pilot stays on during an electrical outage, there is a small gas valve that needs 25 volts of power to open to allow the gas to be lite by the pilot. There is a standard 120 line going to a small transformer that reduces the voltage on the furnance and without power no heat. BRRRRRRR lol, anyway talked with our plumber when he serviced the unit this year and we came up with the idea of an inverter to do the job. Amazon delivered the unit in 3 days, came well packed, and didn't take long to read the directions and figure out how to operate it. I have 3 vechicles and 2 extra batterys so I decided this was a better way to go than a generator, didnt want the smell, gasoline, or fumes. Have small trickle charger for the battery and when we hear a storm is on the way we will charge up the battery to be sure we have full charge, have operated the furnance unit for 30 minutes and IT WORKS OFF THE INVERTER MISSION ACCOMPLISHED, and the draw was so low the battery didnt lose any power during the 30 minute test. Also tested a house lamp with a 100 watt bulb and it ran for 30 minutes also with almost no lost of battery power. The unit looks good, is relatively silent, and does what it promises to do. I LOVE IT. My only comment is you need to be aware that it does not come with any cables to hook up to the battery, I split a pair of heavy duty jumper cables that I had laying around and use them. Short of that it is well worth the money, and I look forward to using the unit on remote job sites to power my electrical tools during the spring and summer. Again an excellent product.

I use this in the trunk of my 1982 Mercedes to power an immersion heater for a vegetable oil tank. I heat approximately 15 gallons of vegetable oil, which pretty much drains the deep cycle battery that is dedicated to the inverter. In the cold months, this inverter is handling 1.2 kW for about an hour everyday, and I haven't had a single problem.

I purchase the Cobra 1575 inverter in June 2010. It had pretty good reviews and a good price/feature ratio. I ordered it and installed it as soon as it arrived. I used two #4 two foot long copper cables for the positive and two for the negative side input. needless to say there was very little voltage drop with the power leads.
I measured .1vdc drop using a digital VOM. I also ordered a 150 amp fuse and holder to protect the unit and installed it into the positive lead. In short, with several
new high amp-hour batteries in parallel using #4 jumpers I had a very good installation. (Note that I am a life-long electronic technician with 55 years experience). Performance using various loads was encouraging. The unit would run an angle grinder,a 300 watt lamp, and a 100 watt fan all at once. This would be about 500-600 watts of load. I also tried my 1000 watt microwave oven, 1000 watt coffee maker and other similar type loads with great success. I was happy. Then I tried the washing machine.....too much starting load and the unit shut down (as it was designed to do). OK, it was just a little too much for this unit. Also, the 12" radial saw would not start due to the same high initial load problem. Maybe a larger unit with 2500 watts would work.
As I said, I was satisfied with the unit.....until about 4 hours ago when I pressed the START button on the inverter with NO load. Smoke, sparks, some flame (contained inside) and a FAILURE beep issued from the thing as if it were clammering for life.
IT IS DEAD. I'M sorry for it. I gave it everything it needed and still died.
What I am saying is that this Cobra inverter has been built with low-rated components to save a little construction cost. Now I am a disappointed customer.
This Cobra 1575 failed with just under one-half hour of use. Now I will send it back to Amazon and see what will happen. I'll post the results.

I have purchased 25 of these for one purpose: running laser printers in our sales team's vans. As you may or may not know, laser printers draw quite a few watts when they are warming up, so I wasn't even sure if these would do the trick. They always say you should have a power inverter with quite a few more watts available than you intend to use, so that's what I did.
This thing powers those laser printers without even breaking a sweat. I've had other inverters that are of much lower quality, and even a moderate draw on them causes the fans to kick into high gear, making it sound like a vacuum cleaner is running.
When it comes to electronics like this, my first impression is how heavy they are. Heavier (generally) = better quality... and these weigh a few pounds, nice and sturdy.

UPDATE: I had problems with 2 of the 25 units and Cobra sent out replacements ASAP, no questions asked. Excellent support.

I own a 16" electric chainsaw. There are times when I help friends that house power is just not available. I drive my truck close to where needed and connect the Cobra Power Inverter. It supplied power to my chainsaw with no problems what so ever. It also amazes folks that never knew such a great tool existed.

This inverter performs exactly as advertised. 1500 watts continuous,3000 watts surge. It is the final link in my solar system and does exactly as
I expect it to do. Very good product, highly recommended.