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Electrical Guru's, Inverter Wiring

GRINCH

GRINCH

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I have a 2500 Watt (5000 Peak) inverter I'm putting in my rig. I will be running dual batteries with the Ryoken way ACR setup with a Blue Sea battery switch.
I plan on using tinned Marine 1/0 AWG cable to feed the inverter. I want to be able to break the power to the inverter through a relay controlled by a switch on my dash.

Finally the question.

What size relay will I need to handle the load. Basic electronics tells me 208 amps. That is if it takes that much to make the 2500 watts ouput on the AC side. If the inverter is able to handle 2500 watts how much draw is on the dc side to make that power through the inverter?
 
mr250twostroke said:
Why not just use the switch on the inverter to shut down? Putting it somewhere hard to get to?
Click to expand...
The inverter is going to tucked away. I thought about re-moting the switch on the inverter to the dash. I really want to break the DC circuit as far from the inverter as possible.
 
I would say running a relay inline with the switch on the inverter is going to be cheapest and easiest. I found this thread Inverter Remote Switch

Otherwise a relay that size is going to be costly.
 
Watts is watts.....
Doesn't matter what voltage you are running at, a watt is the amount of work done.

So, since as you have already figured, Watts is Volts times Amps,
Then using 12 volts for 2500w, you get the 208 amps..

But two problems with that.
Your converter has a peak of 5000 watts, which comes in at 416 amps at 12 volts.

Actually, since the currant goes up as the voltage goes down, you probably should figure it at 11.5 volts got get worst case.

Plus, you never get something for nothing. There will be some losses.

All total, figure 430-500 amps worst case.
Unless its a really short run, you might want to consider bigger than 1/0. Voltage loss is not your friend in this case.

So, you need a relay that will run on 12 volts, but be capable of switching 500 amps......

Lets see.....

Where oh where would you ever have to switch that kind of current in a K5......

I dunno, maybe.........The Starter??

Grab yourself a good heavy duty Ford starter relay, or a heavy duty winch relay, mount it on something that will help dissipate heat just in case, and go for it.

Given the cost, grab two, and have a spare if it fails.

I have run a winch with one until the battery failed, many times, and never had a relay fail from overheat.

Try to always switch the inverter on and off without a load, and not only will it last longer, plus what you are running will not see any funky voltage until it gets stabilized, and there will be a minimum switching load on the relay.

That will just about eliminate burned contacts.

J.
 
This thing will draw more like 230A at full load with peaks almost twice that. To switch the DC you will need a continuous duty solenoid, like a battery isolator setup would use. But I would recommend that you use the factory method of controlling power, by making the built-in power switch of the inverter remote mount.

You want the DC cables as short as possible, so mount the inverter as close to the batteries as possible. Then make the AC lines as long as you need to since the current is about 1/10. If you keep them short enough, the 1/0 should be enough, but it all comes down to how your terminate it and make the connections at both ends.
 
look at transportationsafetytechnologies.com or commonly called tst in the industry. They have systems that handle turning on and off the sensitive electronic equipment in ambulances, fire trucks, rapid assault equipment. There is a solenoid called COMMANDER 357 FINAL ASSY. This thing is bad ass! The great thing is if you have a problem you can talk to there tech support and if you are ase certified then the liability falls on their shoulder if it burns your **** up. The 357 is rated in the neighborhood of 300 amps, and it is salty, but if you can take a mobile field command system capable of multiple secure web connections and satellite downloads (realtime video) and flick a switch to turn it all off, then move out and not burn anything, yea, I think it will handle your inverter with no problems even if you would switch it off with the start up load applied to it! check em out! Remember it only costs more money if you have to pay for it twice! Look under the relay/solenoid tab
 
And don't forget to put fuses in it. I mean the big 250 amp inline fuses. Use 2 of them and on that inverter run 2 sets of power leads. It has a space on the back for them:wink1:

We install those in trucks fairly often.
 
Since I already have a bunch of 1/0 cable. I plan on running 2 of them with fuses on them. According to a chart I looked at, running 2 1/0 cables is like running 1 4/0 cable. Now to find some decent priced relays capable of handling 250 amps. Most of the starter relays I'm finding are only rated at 85 amps.

No price listing for the COMMANDER 357 on any website. Must be expensive.
 
Ok, a couple of comments.

First of all, 85 amps would not crank my lawnmower.

In looking around, I see where a lot of the starter relays are rated at that, but that has to be some kind of legal requirement.

We used heavy duty NAPA Ford starters on the winches we built for years, and never had one fail.
I think that after many years, they would wear out with heavy use, but that was after hours and hours of winching.

Also, I see on other sites that a Warn winch current draw approaches 450 amps, and their solenoids seem to take it, so one of theirs might be the way to go.
I have seen them listed in the 15-20 dollar range.

If you are still worried, check this out:

http://www.texasindustrialelectric.com/relays_1119865CD.asp

1500 amps continous duty. That oughta do her!

$165 is not too bad for that amount of power.

Look around their site, you might find something better.
http://www.texasindustrialelectric.com/relays.asp

If you go with that relay, I recommend you get the SCM that they sell for it.

That adds another $200 to the cost, but I think it would help in the long run.
The solenoid apparently draws about 20 amps all by its self.

Thats not surprising, when you are switching that much current, you need to bring the contacts together HARD.
(Think about the circuit breaker in Jurassic Park)

The SCM lets full current flow when the relay is closing, but then reduces it down after it is made.
It also controls the amount of current depending on how much load there is on the relay.

Either way, you should be able to find something that will work on that site.
Personally, I would go with the Warn solenoids, and keep a spare just in case.

If they don't do the job, then you can pony up for the big one..
You can buy a lot of $15 relays for $365. If they failed every other month, and were easy to change...........

J.
 
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