Originally Posted by DiggerD

I have a roadpro rppi-2500W that i bought off craiglist from a guy who said he used to drive truck. I need help with either an instruction manual or by someone who really knows this subject. The back of the inverter has 2 pos and 2 neg connections. Do I need to connect to all 4 or can I just use 1 of each? I have 1 pos cable with 2 60amp fuses built into the line and 1 neg cable. I'll only be using it for 1000w cooker and my laptop. Any help would be greaty appreciated Happy New Year

I think that inverter might have the option for being able to join multiple inverters together. one inverter is the master and the rest act as slaves. the master sets the wave pattern and the slaves follow the master. see if theres a marking on the terminal as far as MAS or SLA if there is you only hook your cable to the MAS since you arent using it to control a secondary inverter.

I have all four hooked up just because I thought it might provide more power and stability.

I would like to get some better cables because I think I'm losing power as my cables are about 12 ft long, maybe a little less. Our shop requires you to buy 12 ft, and they run them all the way from the batteries on the catwalk up to the holes behind the driver's seat and mount on the side of the cabinet.

The problem is that the recommendation on the inverter instruction manual says the cables should be only 4ft long for maximum performance with a rating of 4 awg. I have the 4 awg but I think the length is giving me problems.

If I run the microwave continuously for than a couple of minutes it will trip out. If I'm cooking something for very long, I have to do it a couple of minutes at a time.

I wonder if getting 2 or 1 gage awg wires would be any help. That wire is really expensive, but I may be able to get a good deal on Amazon. But I would like to know if that would likely help if anyone knows.

It is a Cobra 2500.

i doubt its the wire length doing it 4ft vs 12 ft with 4 ga isnt all that much, once your get over 15-20ft like on a stick welder then yeah it starts to be a factor. i think its more of a battery voltage drop issue or something over heating inside the inverter.

What you may want to try is take a set of jumper cables and run from you battery box thru your drvr door and hook them up to your inverter along with your power cords to the inverter. that will tell you for sure if its a cable size problem. If that dont change anything disconnect the jumper cables from the battery box and hook the jumper cables up to an idling personal vehicle (a seperate battery system) and try the microwave again. This will tell you if theres something wrong with your battery or charger system in the truck.

Are you idling when you are using your microwave or is the truck shut off. If its shut off then that is probably the problem cause of overall voltage drop causing the inverter to trip out.

Originally Posted by Elvenhome21

Are you idling when you are using your microwave or is the truck shut off. If its shut off then that is probably the problem cause of overall voltage drop causing the inverter to trip out.

It does it whether I am idling or not. I'll try some of the things you mentioned here when I get home.

At least now I now it is not the inverter as I have a new one now. But it's about the same duration of time. Over 2 minutes on the microwave. But all I have to do is let it sit for about 10 seconds and it will run another 2 minutes before it trips out again.

I'm beginning to think it may be a problem with the batteries or truck alternator. Its getting serviced over the next couple of days so I'll have them check out all the power points. They won't do any troubleshooting on the inverter itself though, so I'll have to take it from there. Thanks for the info.

I've been told to keep the power cables to 4ft or less. I used 4 gauge battery cables from advance auto

It turns out, the problem is the alternator on my APU is not putting out enough. When I said before that the inverter was tripping out even while I was idling, I meant, while the APU was running. I try to idle so little I didn't want to idle long enough to test it, but I did.

With the engine running, I can brew an entire 12 cups of coffee without the inverter shutting down and run the microwave for more than a couple of minutes (didn't test much longer so it's probably limitless). But now my idle time is up to 5% from 3%. I don't know if I'm going to get the fuel bonus.

But here's the solution. I discovered that if the air conditioner, on the APU, is running it puts out more power and keeps the inverter running with high output. Those of you who have APU's will notice that when the AC is running, the APU is louder and working harder. This apparently gets more power flowing from the alternator and into the batteries. I'm just guessing but it works. I just don't know if I'll be able to get the AC to come on in freezing temps, or if I'd want to.