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Discussion Starter · #1 ·
We have a 1500/3000 watt power inverter, its got the standard positive (+) , negative (-), but its also got a ground?

This wont be in a car, it'll be sitting in a football field for halftime for a marching band powering the PA system, so it cant be grounded to a truck, and even so, wouldn't grounding it to the truck be the same as the negative is doing? Should I ground it at the negative at the battery along with the Negative on the inverter?
 

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That is a new one on me. I've been dealing with electrical issues for the past 25+ years, and I even worked as an electrician for the better part of 10 of those.

I've never encountered a piece of equipment that had both a negative and a ground.

The only thing that I can suggest is look to see if perhaps the ground is for some sort of chassis grounding, instead of the electrical portion.

Good luck

Exco
 

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Discussion Starter · #3 ·
There you go. There should be a picture attached. I'm doing it on my phone, so then again, there might not be a picture, haha
 

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Discussion Starter · #4 ·
There's not.. I'll have to figure it out when I get home. Haha.

Basically there's a big positive, and a big negative. But then on the corner there's a smaller terminal with the ground icon.
 

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Discussion Starter · #5 ·
What fuse should I use? It's 1500/3000
 

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We have a 1500/3000 watt power inverter, its got the standard positive (+) , negative (-), but its also got a ground?

This wont be in a car, it'll be sitting in a football field for halftime for a marching band powering the PA system, so it cant be grounded to a truck, and even so, wouldn't grounding it to the truck be the same as the negative is doing? Should I ground it at the negative at the battery along with the Negative on the inverter?
This is where people get mixed up, negative does not always equal ground. When dealing with power inverters and generators many systems don't transfer the negative of the DC side to the neutral of the AC outlet (or ground pin) and you are dealing with what is called separately derived systems.

So for some systems th ground wire is the same at the negative wire, in other cases its totally isolated and should never be connected to the negative battery wire. On side you have the battery the Positive voltage is positive with respect to the negative terminal, but on the other side you have an AC voltage that is +/- in respect to a neutral AC wire that in a separately derived system is not tied to negative wire on battery.

Many high wattage power inverters follow the separately derived system model as a high voltage/current feedback to negative terminal to battery can have bad consequences to the circuit. So negative from battery is isolated from neutral of AC outlets. This may or may not be the case with your inverter but often is the case on higher wattage ones. This creates a potential problems of ground differential between equipment that can be a severe safety issue under some conditions. Which is why the ground terminal is provided on these types of units.

Not grounding the AC side properly can causes major problems if you run two inverters on a cart with two pieces of equipment, as their AC neutrals will not have a common ground and if equipment is connected via an audio cable or someone is unfortunate to touch the wrong things you can get an pretty good shock. Often (but not always) in these types of systems you would leave the battery system not grounded to the cart, then make sure all AC equipment is grounded to a common ground such as the cart or the ground wire to a grounding rod.

Would need to have an electrician take a look at your specific configuration to be sure. When it doubt find yourself a good electrician to help out. Better yet find an electrician that specializes in Solar or alternative power as they will have the necessary experience with these types of inverters. A 1500/3000 watt is not something that should just be experimented with as you are potentially pulling hundreds of apps from your battery system and you will need it to be hooked up and safe.

You don't want someone getting zapped while trying to wheel in the cart during an unfortunately timed down pour.
 

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Discussion Starter · #7 ·
haha they will be well protected from the elements.

We used this same setup last year and it worked fine, but i noticed it, and im kinda fixing everything up since i know PA equipment, and more familiar with 12v DC stuff than anyone else there.

so where should i ground it at? its a rolling cart, and th [e battery has to be removed every day to charge since theres no alternator, haha.

thanks
 

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Discussion Starter · #8 ·
Just FYI, this system its as follwed:

BATTERY is connected to a 1500/3000 power inverter. It has 3 outlets. 2 of them are taken and the last is a 8 slot outlet strip. Or JUST the outlest strip is plugged in and everything is then plugged into that.

Things plugged in: 350(ish)watt bass head with a 210 cabinet.
212 guitar combo amp/speaker.
1 12 guitar combo amp/speaker.
ZED14 Allen and Heath Mixing board(not a powered board)
Then ONE(right now) but possibly 2 later, QSC 1000 watt powered 12in speakers.
and of course the random and occasional phone charger.

once again, this worked very well when we had it running last year, just hooked straight to the battery.
 

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Well you made an old EE professor cringe. Hank was over for dinner tonight and showed him the thread and first thing out of his mouth was "Oh my". As I said above you really need to get some assistance from an electrician or electrical engineer as you have some safety issues.

Per Hank:
At a minimum their should be a 12volt disconnect switch for quick disconnect of power supply to inverter and a properly sized fuse. Fuse will need to be rated to correct rating for inverters peek current draw AND rated to handle short circuit current of battery.

Battery(s) (ideally plural) should not be discharged at anything higher than a C/2 sustained discharge rate to eliminating heating and gassing. Which means an 100AH battery should only be discharged at 50AMPS for an hour. So batteries need to be sized to the inverter based on the measured load of the equipment.

And need to look at the manual for the inverter and make sure that its safely grounded per the manufacturers instructions.
 

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Discussion Starter · #10 ·
haha thank you. ill bring it up with my band director.
 
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