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Power Inverters

Hey everybody.......I just had a quick question regarding a power inverter. I know they have been discussed on here before, but what I was wondering hasnt been talked about in previous threads.

I am going to get a 750/1500 watt inverter and I know that the best way to power it is via the battery. I am also going to get a ham radio (icom v8000 probably) as well. I have read that it is best to hook the ham up to the battery as well. Can I run one wire from the battery into the inside of the car then use some sort of a splitter to run the ham radio and inverter? Or would I need to run a seperate wire for each of them?

Also, would it be safe to run a laptop with wx worx and a gps unit to the inverter without causing any problems? I may be charging my camcorder and digital camera at times via the inverter too. Is all of this too much overload on the inverter or should I be fine? I will probably keep the car running to avoid sapping the battery and if I dont have the car running I will just simply turn the inverter to off. I am new to the equipment I am going to get and I want to make sure I hook everything up right to avoid any problems. Any info. would be greatly appreciated.

Thanks,
Chris
 
Originally posted by Chris Wilburn

I am going to get a 750/1500 watt inverter and I know that the best way to power it is via the battery. I am also going to get a ham radio (icom v8000 probably) as well. I have read that it is best to hook the ham up to the battery as well. Can I run one wire from the battery into the inside of the car then use some sort of a splitter to run the ham radio and inverter? Or would I need to run a seperate wire for each of them?

Absolutely run two separate feeds for this Chris, for a variety of reasons. I have set this similar setup several times, the two separate feeds works well. Additionally, if you have a bunch of other 12v stuff, like scanners, CB etc, I would run a THIRD feed just for them and use a junction/fuse block.

Also, would it be safe to run a laptop with wx worx and a gps unit to the inverter without causing any problems? I may be charging my camcorder and digital camera at times via the inverter too. Is all of this too much overload on the inverter or should I be fine? I will probably keep the car running to avoid sapping the battery and if I dont have the car running I will just simply turn the inverter to off.

As long as you have a dedicated feed of sufficient gauge wire and your vehicles charging system is in good shape, you should be able to run that stuff just fine. I have run a built in computer and as many as TWO laptops, a 110v plugin for charging cameras as well as a TV and DirecTV receiver all at the same time off a 1500w inverter. You are correct in thinking about keeping your car running when you have a lot of stuff on it. If your going with a single battery setup, you won't want to leave the engine off very long or it WILL sap the battery. I got around that with a dual battery isolated system so I can leave it running with the car off for quite a while depending on what I have hooked up to it.

I am new to the equipment I am going to get and I want to make sure I hook everything up right to avoid any problems. Any info. would be greatly appreciated.


Thanks,
Chris

Here is an old thread I started that might help you out. The thread isn't finished (got caught up in the ST site overhaul) put it should help you some.

http://www.stormtrack.org/forum/viewtopic.php?t=5765

EDIT: To fix the link after Jeff moved it.
 
Chris,

That inverter should be big enough to run what you mentioned. Most laptops (not the desktop replacement beasts) probably use something along the lines of 40-50W (maybe 60-70W when the laptop battery needs to be charged -- just a guess), and most GPS devices don't require a whole lot of power. So in terms of inverter capability, I'd think you'd be fine.

I would make sure, however, that your car's electrical system is up to par. The inverter may be able to put out 750W for an extended period of time, but your car's electrical system may not -- it depends on your alternator capacity and your battery size. If your alternator is only rated for 70A, you're going to have a tough time doing what you want should you ever end up putting a full load on the inverter. From what I've gathered, for most cars, the alternators are chosen (by the manufacturers) such that about 50-70% of their rated output is used in normal operation (by the engine, OEM electronics, etc). For a 70A alternator (which is pretty common for cars, particularly among imports in my experience), that leaves about 20A for accessories. A 750w load through your inverter will require about 50A for a 14v charging system (typical for a car that's running -- 750W/14V = 50A). Actually, it may be considerably more than that since that assumes that the inverter is 100% efficient -- most inverters are ~70% efficient. Now, you likely won't be putting 750W sustained through your inverter, so I don't think you need to worry too much, but just keep tabs on it.

A larger capacity battery may help you (a) keep things powered on when the car is off, and (B) provide some capacity should you briefly use more amperage than your alternator can put out.

As for wiring... I'd bring a 2awg cable from the battery to feed the inverter (if the inverter is in the trunk). You'd probably be okay with 4awg, especially if the cable doesn't need to be too long, but bigger won't hurt.

I run a 600W inverter in my car, along with a couple of ham radios (and car audio equipment). I recently bought a larger battery, and my alternator does 130A (+/- 10A -- can't remember the exact rating), so I don't have too many problems. I did burn out an alternator and battery (though the bat probably died becaues the alt died, meaning that my car was running for 15-20 minutes straight off the battery -- talk about a tough load!) in an old car that had a 90A alt several years ago, however. I run a 2awg cable from my battery up front to the trunk. I then have a fused power distribution block, which splits the 2awg cable into 4 smaller cables, one of which is an 4awg cable that feeds the + of the inverter (the others will soon feed a couple of amplifiers and a computer). For my ham radios, I run a seperate 4awg cable from the battery to another fused distribution block that's located in the dash above the passenger's feet. Here, I split the 4awg cable into a couple smaller cables for each of my ham radios.

Remember to fuse any cable that you connect to the + terminal of the car battery within 18" of that battery! Why so short? If you get into an accident, and something metal in the engine compartment is able to pierce the shielding of the cable, you could be in for some big trouble (fire, explosion, lots of fun). In addition, make sure to fuse at any location where you change to a smaller-sized cable! You may have a situation (like a semi-short) where you pull enough current that's SAFE for the 4awg but not for the 8awg (or some smaller cable). You're not just fusing to protect the electronics (many of which have bulit-in fuses or protection to begin with) -- you're also fusing to protect the cable! Too much current means lots of heat and the definite potential for fire.

EDIT: David's "Making of a Chase Vehicle" thread has been moved out of the archives and into the equipment forum --> http://www.stormtrack.org/forum/viewtopic.php?t=5765 ...
 
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