Safety tips for all-in-one inverters

[dileepa]

Hi All,

Are there any safety methods that you know for the longer life of all-in-one inverters?

For example, one method I heard was, "Don't cut the battery power while the inverter is powering the loads".

Likewise are there any other small tips that you know?

Thank you.

 

[svetz]

Interesting topic! But the Beginner's Corner might not be the best sub-forum for it as a lot of folks don't check it out.

 

[dileepa]

Interesting topic! But the Beginner's Corner might not be the best sub-forum for it as a lot of folks don't check it out.

Yes. looks like you are correct.

 

[EastTexCowboy]

I'm gonna say following the recommended shutdown and power up sequences would be a good practice. MPP recommends shutdown sequence as battery, then inverter, then PV disconnect. Which is the opposite of what you heard about not shutting the battery down first. it would be interesting to hear what shutdown and power up sequence some of the other folks here follow. There are likely some threads on that already.

Beyond that some of the obvious stuff would be to avoid overload situations, maintain room temps within recommendations, and keep the environment as dust free as you can. I need to blow mine out again after installing conduit that generated some drywall dust. Like any electronic circuitry and especially with fans, that stuff is gonna get all up in there.

Change the oil and grease it - oh, wait - wrong piece of equipment. Scratch that.

 

[StuartV]

Dont most AIO's have a main power switch tho? The 2 I've had have had a main power switch.

 

[EastTexCowboy]

Dont most AIO's have a main power switch tho? The 2 I've had have had a main power switch.

Yes, the AIO has a power switch. But there is still a recommended sequence for shutting down battery/PV/inverter. I'm guessing that's what you were referencing.

 

[StuartV]

I would turn off all loads at the sockets (I'm in the UK), then turn the power switch off on the AIO, then solar panels (if its daylight), then battery if I ever needed to do that.

 

[meetyg]

I would turn off all loads at the sockets (I'm in the UK), then turn the power switch off on the AIO, then solar panels (if its daylight), then battery if I ever needed to do that.

I think this is the way to go...

Reconnection procedure should be this in reverse.

Also, as with any inverter, whether AIO or not, don't forget to connect battery with a pre-charge resistor first! Otherwise you get big sparks from the current inrush that charges the capacitors.
This will prevent many issues with inverter and batteries in the long run.

 

[OffGridInTheCity]

I have an MPP Solar 3048LV (48v battery) in the trailer. It has an on/off switch, however....

With the MPP Solar switch in the off position, the display lights up when the battery is 'on'. It won't start delivering power until I turn on the MPP Solar switch. So I have to turn 1) turn off the MPP Solar and 2) disconnect the battery to completely turn it off and reverse to turn it on.

 

[Shimmy]

For best practices I would add torquing connections, or at least IR Scanning to make sure there is no excess heat. Also, make sure current is balanced between strings every few months both in charge and discharge.

Other than that, keep it dry and clean!

 

[EastTexCowboy]

I think this is the way to go...

Reconnection procedure should be this in reverse.

Also, as with any inverter, whether AIO or not, don't forget to connect battery with a pre-charge resistor first! Otherwise you get big sparks from the current inrush that charges the capacitors.
This will prevent many issues with inverter and batteries in the long run.

I stand corrected on my previous post on the sequence. I was quoting it from memory. This sequence @StuartV posted is the proper sequence.

On the pre-charge resistor, I did that the first few times but my EG4 Lifepower batteries have a constant low current even when turned off (I'm guessing for this specific reason) so it isn't really necessary. I suppose you could use a resistor just to be safe but as long as I can see the low current I haven't worried much about it.

 

[Hedges]

Are there any safety methods that you know for the longer life of all-in-one inverters?

Lithium batteries degrade when stored in hot temperatures, especially at full charge.
Ideally, keep around 50% +/- charge most of the time. Fully charge just before use if possible.

Do not charge below freezing.

Does it have forced-air cooling? Any filters? Could put a screen over inlet to catch hair. My computers and refrigerators really get plugged with cat hair.

 

[StuartV]

I have an MPP Solar 3048LV (48v battery) in the trailer. It has an on/off switch, however....

With the MPP Solar switch in the off position, the display lights up when the battery is 'on'. It won't start delivering power until I turn on the MPP Solar switch. So I have to turn 1) turn off the MPP Solar and 2) disconnect the battery to completely turn it off and reverse to turn it on.

Do you have panels connected as well?

When I had panels connected to my AIO, it would stay lit up when daylight was on them. Now I dont have panels connected up to it, the light/screen is off when the main power switch is off. When I had panels connected but the main power switch was off (saving battery), It would wake up in the morning when it had more than 26v coming through from the panels.

 

[EastTexCowboy]

I have an MPP Solar 3048LV (48v battery) in the trailer. It has an on/off switch, however....

With the MPP Solar switch in the off position, the display lights up when the battery is 'on'. It won't start delivering power until I turn on the MPP Solar switch. So I have to turn 1) turn off the MPP Solar and 2) disconnect the battery to completely turn it off and reverse to turn it on.

Mine works the same way, as long as there is enough PV to light up the display. As @StuartV mentioned, it's low voltage - on mine somewhere around 22v to 24v. But no matter how much sunshine I have it doesn't charge the battery unless I power up the AIO.

 

[OffGridInTheCity]

@StuartV
>Do you have panels connected as well?
Yes, I have panels. But its seems to be the battery on that lights it up (not panels) even when the MPP Solar switch is off.

@EastTexCowboy
>mine somewhere around 22v to 24v. But no matter how much sunshine I have it doesn't charge the battery unless I power up the AIO.
I was revisiting the specs the other day and on mine (48v system) it says there must be at least 60v for PV. In my case I have 2s2p 300w panels - and the voltage shows 61v at the unit and I'm thinking this is why my charge power so dismal.

It could be you're string voltage is too low?

 

[Rednecktek]

Nevah Wick da Wed Wire...

 

[EastTexCowboy]

>Do you have panels connected as well?
Yes, I have panels. But its seems to be the battery on that lights it up (not panels) even when the MPP Solar switch is off.

>mine somewhere around 22v to 24v. But no matter how much sunshine I have it doesn't charge the battery unless I power up the AIO.
I was revisiting the specs the other day and on mine (48v system) it says there must be at least 60v for PV. In my case I have 2s2p 300w panels - and the voltage shows 61v at the unit and I'm thinking this is why my charge power so dismal.

It could be you're string voltage is too low?

Huh. Well, I guess I'm going to have to test that again. But I had it turned off for several hours the last time I tested it and even though it was cloudy there were multiple times when it should have been producing more than 60v. I'm going to let this dismal weather move out then test it when I have plenty of sun.

 

[RCinFLA]

Most of the low cost HF AIO inverters do not isolate their PV inputs from H-bridge AC PWM sinewave converter. The PV inputs are riding on top of a HV squarewave caused by sinewave H-bridge polarity switching of HV DC.

If you have inverter active with AC output and neutral grounded, and accidentally let a wire from either AIO PV input touch ground it can blow out H-bridge IGBT devices in inverter.

Needless to say, if you touch one of the AIO's PV inputs while AC output is active you will get a nasty shock. Because both pos and neg PV inputs have the squarewave so you need double pole breakers to break panels pos and neg lines to totally remove the HV squarewave from PV wires.

Sometimes a PV panel can develop a migration leakage path from interconnect flat wire strips near the edge of glass to grounded panel metal frame when humidity has intruded because of poor edge sealing of PV panel lamination. This creates a problem with the HF AIO PV squarewave present on PV lines.

 

[OffGridInTheCity]

Huh. Well, I guess I'm going to have to test that again. But I had it turned off for several hours the last time I tested it and even though it was cloudy there were multiple times when it should have been producing more than 60v. I'm going to let this dismal weather move out then test it when I have plenty of sun

Assuming PV is OK then some things to check / experiment with. You're manual might be a little different - this is from my 3048LV manual - but you'll have similar options for sure.

1) Max battery voltage setting / is the battery full? If full, then it won't accept charge.


2) Max charging amps allowed. There's DC (02) and AC (11) settings.



3) Not as likely, but there's some options for Charger Source Priority. Mine manual is like this... Check for SbL .. "Solar energy for battery first".


4) And very unlikely - I assume you're not in bypass .... I do"Bypass Forbidden".

 

[EastTexCowboy]

Assuming PV is OK then some things to check / experiment with. You're manual might be a little different - this is from my 3048LV manual - but you'll have similar options for sure.

1) Max battery voltage setting / is the battery full? If full, then it won't accept charge.
View attachment 132774

2) Max charging amps allowed. There's DC (02) and AC (11) settings.
View attachment 132772
View attachment 132773

3) Not as likely, but there's some options for Charger Source Priority. Mine manual is like this... Check for SbL .. "Solar energy for battery first".
View attachment 132771

Thanks. I think I have all those set like yours but I'll check. Batteries are all around 52.7V so over 60% charged. I have everything else down now because I'm redoing a lot of the cabling to clean it up some and partly because I just can't keep from messing with it. Not like it would be generating any power now with this non-stop rain. Ugh.