Pure sine wave inverter

[joeExotic]

So I’ve had my system for about 7 years now and today I heard a beeping sound going on and off two or three times and then everything connected to my solar system turned off. Initially I thought it was the 1000 psw inverter but then I noticed the fuse burnt out. In short, covered the panels and switches out the 100 Amp ANL fuse and put in 150 Amp ANL fuse. Not sure if I’m using the right fuses? Should I be using another kind of fuse?

After 7 years is there any kind of maintenance I should be doing?

 

[HRTKD]

Where is the fuse located?

If this is a 12 volt system that fuse may be undersized. 1000 watts / 12 volt system / .85 inverter efficiency = 98 amps. On that system, the fuse would be sized at 125 amps (98 amps x 1.25 fudge factor).

I use MEGA fuses between the inverter and the common bus bar and a Class T fuse between the LiFePO4 battery bank and the common bus bar.

 

[MichaelK]

Can you go into a bit more detail as to what was being powered by the inverter when the fuse blew? I'd expect the inverter itself to be drawing just 2-5A powering itself? Were you trying to run a toaster when the fuse blew? Depending on what you were powering at that moment will give us clues as to whether this was a simple overload, or indicative off another problem?

 

[featherlite]

I picture of your system would also help

 

[joeExotic]

My setup is 3S 2P. All 100w panels. 40A charge controller Renogy Li. 1000W psw inverter. 360AH LFP 12V Battery system.

The thing is that I’ve been charging this way for years now so not sure why the fuse blew? Maybe because overtime fuses blow? Anyways, was charging big fridge (150w), chest freezer (65w), bug zapper (20w), iPad (10w), cell phone (10w), portable solar battery bank (80w), portable vacuum (65w), small fan (5w), modem (10w), router (10w), air purifier (10w), other small electronics (20w) and most of the time I also have my monitor and desktop on (85w my desktop uses very little). But when the fuse blew I did not have desktop and monitor on.

It was a 100A that blew and I put in 150A so this is better right?

This is the first hiccup in 7 years so now I’m asking for preventative care? Does anything need replacing overtime? How long do inverters last?

 

[MichaelK]

The frig, freezer, and vacumn, all powered via electric motors, may have had starting surges significantly higher than their running numbers would suggest. Assuming that the starting surge of the motors might be around 4X, they correspond to 600W + 260W. The rest of the loads add up to ~165W, so that works out to be 600 + 260 + 165 =1025W.

If you assume the voltage of your battery might have been dipping under the load, and the frig and freezer turned on at the same moment, that could pull 100A out of the battery. If that fuse happens to be a little out of spec, then the fuse goes poof.

Might be time to start shopping for a larger inverter.

 

[Supervstech]

What size wires do you have connected to the fuse and battery?

 

[joeExotic]

it’s 1000 w inverter but can surge to 2000 w.

Wires are 4awg

 

[HRTKD]

4 gauge wire is OK. I used conservative numbers of 100 amps, 8' round trip length of cable and 12.0 volts to get a 1.7% voltage drop.

As I stated earlier, that fuse was just barely big enough. A 125 amp fuse is more appropriate.

 

[joeExotic]

Cool thanks man. I put a 150A fuse so hopefully it will never burn out.

 

[Supervstech]

it’s 1000 w inverter but can surge to 2000 w.

Wires are 4awg

I wouldn't use smaller than #2 wire on a 1000W inverter.
And #2 is small if the wires are over 2' long...
Especially since you now have a 150A fuse.

 

[MichaelK]

it’s 1000 w inverter but can surge to 2000 w.

Have you looked at the fine print in the specifications? What you will find with many of the lower-end inverters, they will claim a surge capacity to 200%, but that surge is limited to only one single AC cycle, or ~16.6 milliseconds. An electric motor might pull surge starting current for 250-500 milliseconds, far more than some cheaper inverters can handle.

If it's a quality inverter, they will go out of their way to proclaim how long it can handle starting surges. If they keep completely quiet on that detail, then that pretty much gives you the answer, no meaningful surge.

 

[joeExotic]

I guess I’m pushing this inverter to its max limits sometimes. I decided on 1000w to get the low wattage draw. Looks like I didn’t plan accordingly

 

[AHTrimble]

it’s 1000 w inverter but can surge to 2000 w.

Wires are 4awg

2000w surge could draw 167amps at 12v.
With only a 10' round trip wire run you would need 1/0 cable.
For that set-up you would use a 200amp fuse on the 1/0 cable.

Here is the calculator that you need to use to figure this out for your specifics https://explorist.life/wire-sizing-calculator/