Inverter and Battery is fried

[Hoop33]

It's a long story, but I will try to keep it short. I have been working with a solar company in my area for the past three years to install an off-grid solar system for my pole barn. I am only using the solar to run a few LED lights and maybe a fan, three or four days a week for a few hours. Not much of a demand on the system. During this time I have replaced 4 inverters and 4 lithium batteries. Each time we replaced the components, the system would work about a week, tops. The last time was about four weeks ago. I never really got involved because I paid them and it was there job to get it right. Until this last time. I am not an electrician or a solar system installer, but fairly handy and most of time I can figure it out.

Four weeks ago, the system worked fine for about a week. Then I noticed the inverter would not power up, again. The battery was fine at the time. Showing 100% charged and 13.9v. About three or four days later I notice a light blinking on the charge controller. It would blink and then stop blinking. I checked the charge controller and there was an error code E2. Battery over charge. The battery was warm, but not hot. Later that day the light was still blinking. I checked it and the battery was very hot and began to bulge on the sides. I disconnected the solar panels and then the battery. Again, dead inverter and battery.

So, basically I have taken inventory of all the components used to build my solar system. Also, I may note of the wiring sequence. Here's my list of parts used. 6 - 200 watt / 24 v solar panels, 1 - Renogy Rover 100A MTTP charge controller, 1 - aims power 3000w / 6000w Pure Sine Power Inverter, and 1 - 12.8v 300ah LiFePO4 Lithium Battery. After checking the wire sequence I noticed something that didn't look right to me. Here's how it is wired. Solar Panel to Charge Controller then the battery leads at the charge controller go to the inverter and the battery goes to the inverter as well. At this point I research wire diagrams for an off grid solar system. I found no one had wired their system that way. It should be Solar panels to Charge Controller to Battery to Inverter.

It appears I'm going to replace the inverter and the battery, again. My question is the charge controller damaged? Through this whole process, I have never replaced the charge controller. Or is it simply the wiring sequence that's the problem? The Renogy charge controller manual clearly states to not connect the charge controller to the inverter. I am open to all tips or suggestions. I want to make sure it's right this time before I put everything back together. Thanks for your help!

 

[seneysolar]

What are the settings on the Rover?

Pictures of the system?

Wiring should be ok. The inverter studs acting as bus bars if i understood your description

 

[Mattb4]

Typically you do not destroy SCC's without having too high of a voltage from the panels. The battery being overcharged and bloating would seem to indicate the wrong charging parameters or a faulty SCC. The inverter being toasted is a rarity and hard to diagnose without knowing the entire wiring/loads/battery setup.

Need to know a bit more such as your panels wiring arrangement (XS,YP). their specs and your Rover settings and specifications.

 

[Hoop33]

Not sure what settings you want. It’s set for a 12v Lithium battery. I’ll send a short video I did. I shot this video after the inverter went out and before the battery went bad. https://share.icloud.com/photos/0aeNbnRIZQAeH09uReZCVAtQg

Thanks for your help!

 

[Hoop33]

Typically you do not destroy SCC's without having too high of a voltage from the panels. The battery being overcharged and bloating would seem to indicate the wrong charging parameters or a faulty SCC. The inverter being toasted is a rarity and hard to diagnose without knowing the entire wiring/loads/battery setup.

Need to know a bit more such as your panels wiring arrangement (XS,YP). their specs and your Rover settings and specifications.

The voltage coming from the panels is 122v. The charge controller is rated for 150v. I'm good there. The panels are wired in series.

 

[Mattb4]

The voltage coming from the panels is 122v. The charge controller is rated for 150v. I'm good there. The panels are wired in series.

What is the panels Voc? Typically 24vDC panels are in the 36Voc range. 6 of them in series would be way more than 150Voc of the SCC. If they instead are 22Voc (12 volt RV panels) than 6 in series would be 132Voc which other than very cold days should not be an issue.

 

[Hoop33]

What is the panels Voc? Typically 24vDC panels are in the 36Voc range. 6 of them in series would be way more than 150Voc of the SCC. If they instead are 22Voc (12 volt RV panels) than 6 in series would be 132Voc which other than very cold days should not be an issue.

24 VOC per panel

 

[Hoop33]

Renogy Technical Department said my panels should be fine at 144Voc. The charge controller is rated at 150Voc / 1300 watts for a 12v system.

 

[Q-Dog]

144 VOC into a 150 VOC controller? I wouldn't.

 

[MisterSandals]

144Voc. The charge controller is rated at 150Voc

As the temp drops below 25C or 77F, the voltage rises by around ~.35% (what is your panel temp coefficient?) per deg C.

So if the temp drops 10 deg C (59F):


6 x 24Voc x 10 deg C x .0035 = 5.04V increase. Anything colder and you hit/exceed 150V

 

[Mattb4]

Looking up Renogy specs it states "Max. PV Input Voltage: 150VDC (25°C), 140VDC(-25°C)" So not knowing your location's operating conditions I can not say this is OK or not.

Assume it is and the SCC is not toasted. The settings for a 12 volt lithium battery does not tell me much. Does it give you voltages for charge, Absorption times and any other information? The extreme bloating gets me to wonder if an equalization charge was attempted by the SCC based on the wrong charge parameters. If this happened it also could raise voltage so high at the inverter which could damage it.

 

[Hoop33]

As the temp drops below 25C or 77F, the voltage rises by around ~.35% (what is your panel temp coefficient?) per deg C.

So if the temp drops 10 deg C (59F):


6 x 24Voc x 10 deg C x .0035 = 5.04V increase. Anything colder and you hit/exceed 150V

Good to know. That make since to me. I haven't thought about that. Maybe I need to disconnect one of the panels to have a little wiggle room.

 

[MisterSandals]

Maybe I need to disconnect one of the panels to have a little wiggle room.

Or configure array to 3S2P (3 in series, twice and connect the 2 strings in parallel)

 

[Hoop33]

Looking up Renogy specs it states "Max. PV Input Voltage: 150VDC (25°C), 140VDC(-25°C)" So not knowing your location's operating conditions I can not say this is OK or not.

Assume it is and the SCC is not toasted. The settings for a 12 volt lithium battery does not tell me much. Does it give you voltages for charge, Absorption times and any other information? The extreme bloating gets me to wonder if an equalization charge was attempted by the SCC based on the wrong charge parameters. If this happened it also could raise voltage so high at the inverter which could damage it.

Last weekend I re-connected the solar panels and the battery to get some reading. The solar panels were sending 122v to the charge controller. I verified that with a multi meter. The output on the battery lugs were 13.9v. Both numbers seem normal. The day the battery over charged / over heated was a bright sunny day. I didn't check the max / min. for the voltage coming from the panels. It could of been higher than 122v at some point and fried the battery. Which gets back to my original question? Is the charge controller fried too? Shouldn't the charge controller regulate the voltage going to the battery, regardless what the voltage is coming from the panels. It seems to me the charge controller should shut everything down until the voltage input is normal again. To protect the battery. Renogy sent me this morning some instructions on how to check the resistance on the charge controller. To verify if it's good or bad.

 

[Hoop33]

Or configure array to 3S2P (3 in series, twice and connect the 2 strings in parallel)

Thought about that too.

 

[pollenface]

it shouldn't matter if it's a bright sunny day, that is the whole point of solar.

What are your charge controller settings?

 

[Hoop33]

it shouldn't matter if it's a bright sunny day, that is the whole point of solar.

What are your charge controller settings?

To be honest, I'm not sure of all the setting. I will get that information and repost soon. Thanks for your help!

 

[MisterSandals]

I shot this video after the inverter went out and before the battery went bad.

Why is the PV only 13V?

 

[Kornbread]

Last weekend I re-connected the solar panels and the battery to get some reading. The solar panels were sending 122v to the charge controller. I verified that with a multi meter. The output on the battery lugs were 13.9v. Both numbers seem normal. The day the battery over charged / over heated was a bright sunny day. I didn't check the max / min. for the voltage coming from the panels. It could of been higher than 122v at some point and fried the battery. Which gets back to my original question? Is the charge controller fried too? Shouldn't the charge controller regulate the voltage going to the battery, regardless what the voltage is coming from the panels. It seems to me the charge controller should shut everything down until the voltage input is normal again. To protect the battery. Renogy sent me this morning some instructions on how to check the resistance on the charge controller. To verify if it's good or bad.

VOC will generally be higher than what the mppt section of the solar charge controller demands. Measure voltage the solar panels are producing disconnected from the charge controller.

Not sure why a lifepo4 would swell unless it had no bms to protect it, or the bms's protection was not set/functioning properly. Does the battery have bluetooth?

A small system like that should be a no-brainer.

 

[mikefitz]

I paid them and it was there job to get it right.

It's difficult to understand how any organisation would replace parts 4 times without investigating and discovering the issue that's destroying components.
Unfortunately the video you provided is no help. A set of photos and a ciruit diagram would be useful.

The only indicator that there are problems is that the charge MOS had switched off, suggesting a too high charge voltage.

My guess is that the Renogy Rover is producing a high voltage. This is higher than the battery BMS and Inverter can tollerate.
The failed BMS is allowing the battery to over charge.

The Renogy Rover setup is not intuitive and may have been set to the wrong battery setting, or failed to detect the correct battery voltage. You have a number of settings, 12,24,36,48, Auto.
The design seems to protect against PV overvolts, so I don't think that's the problem.

 

[sunshine_eggo]

I didn't see said, so I'm going to be the dick here.

No company that would charge you and install Renogy charge controllers is worth a shit.

A company that would put 6S 24Voc panels on a 150V MPPT is incompetent and not worth a shit.

Whoever you have been working with is a complete and total hack.

Speculation:

1. Inverters killed due to LFP BMS protection induced voltage spike.
2. Batteries replaced because "idiot" couldn't figure out what was going on, and replaced it, "just in case."

Surprised MPPT made it through the winter. You got lucky as shit.

Please let the people here help you for free. You will get vastly better results and actually be more competent that the paid jackass.

 

[seneysolar]

It's a long story, but I will try to keep it short. I have been working with a solar company in my area for the past three years to install an off-grid solar system for my pole barn. I am only using the solar to run a few LED lights and maybe a fan, three or four days a week for a few hours. Not much of a demand on the system. During this time I have replaced 4 inverters and 4 lithium batteries. Each time we replaced the components, the system would work about a week, tops. The last time was about four weeks ago. I never really got involved because I paid them and it was there job to get it right. Until this last time. I am not an electrician or a solar system installer, but fairly handy and most of time I can figure it out.

Good move, dump the installer. Give him all that stuff back and ask for a refund.

Whats the other stuff on the wall? Transfer switch? This is off grid?

Four weeks ago, the system worked fine for about a week. Then I noticed the inverter would not power up, again. The battery was fine at the time. Showing 100% charged and 13.9v. About three or four days later I notice a light blinking on the charge controller. It would blink and then stop blinking. I checked the charge controller and there was an error code E2. Battery over charge. The battery was warm, but not hot. Later that day the light was still blinking. I checked it and the battery was very hot and began to bulge on the sides.

picture of the bulging battery? The display indicates battery is ok? The charge controller display shows the same voltage so ill assume 2 broken things wouldn't read the same.

I disconnected the solar panels and then the battery. Again, dead inverter and battery.

Have you verified with a test meter that you have power (13v) at the inverter and it wont turn on?

Any fuse between them?

6 - 200 watt / 24 v solar panels

3 in series, then parallel the 2 strings

1 - Renogy Rover 100A MTTP charge controller,

My experience with Renogy has not been good and this is the most suspect problem here. For arguments sake im going to say get a new MPPT of a different brand.
The 13v pv coming in is suspect. Disconnect pv wires and measure while disconnected. Then reconnect to mppt. If disconnected V is 100v+ but then its dropped to battery V when connected, the mppt has just shorted the pv to the battery and could explain the runaway charging.

1 - aims power 3000w / 6000w Pure Sine Power Inverter

Hook this up to another 12v battery and verify its dead. A car battery or something.

12.8v 300ah LiFePO4 Lithium Battery.

TBD, the bulging sounds odd. Need pics.

After checking the wire sequence I noticed something that didn't look right to me. Here's how it is wired. Solar Panel to Charge Controller then the battery leads at the charge controller go to the inverter and the battery goes to the inverter as well.

Should be fine, the components wont know the difference. They just see battery line voltage

It appears I'm going to replace the inverter and the battery, again. My question is the charge controller damaged? Through this whole process, I have never replaced the charge controller. Or is it simply the wiring sequence that's the problem? The Renogy charge controller manual clearly states to not connect the charge controller to the inverter.

They mean connect to inverter without a battery. The mppt cant power it directly.

I am open to all tips or suggestions. I want to make sure it's right this time before I put everything back together. Thanks for your help!

Its likely the panels and battery are useful yet. Ive never seen or heard of a MPPT raising voltage high enough to damage a bms. The bms should have simply went into protection mode at the upper limit. Even the cheapest of Chinese crap will do this without harm. Having 13.xx at the battery terminals is a good sign for now.

 

[Hoop33]

Why is the PV only 13V?

View attachment 294682

The video was taken after the system started acting up. 13V from the panels is not the true reading. I have checked it several times and each time it's reading 120V-122V. The last time I checked was yesterday. Same number.

 

[Hoop33]

VOC will generally be higher than what the mppt section of the solar charge controller demands. Measure voltage the solar panels are producing disconnected from the charge controller.

Not sure why a lifepo4 would swell unless it had no bms to protect it, or the bms's protection was not set/functioning properly. Does the battery have bluetooth?

A small system like that should be a no-brainer.

I haven't check the panels disconnected. I will do that. Not sure about the bluetooth. I say no though.

 

[Hoop33]

It's difficult to understand how any organisation would replace parts 4 times without investigating and discovering the issue that's destroying components.
Unfortunately the video you provided is no help. A set of photos and a ciruit diagram would be useful.

The only indicator that there are problems is that the charge MOS had switched off, suggesting a too high charge voltage.

My guess is that the Renogy Rover is producing a high voltage. This is higher than the battery BMS and Inverter can tollerate.
The failed BMS is allowing the battery to over charge.

The Renogy Rover setup is not intuitive and may have been set to the wrong battery setting, or failed to detect the correct battery voltage. You have a number of settings, 12,24,36,48, Auto.
The design seems to protect against PV overvolts, so I don't think that's the problem.

I'm new to this. What is MOS and BMs? I tried to check the setting yesterday and the controller screen would not move to any other screens. The only thing the screen said was "12V Li Batt Active...". I do know it was set for 12V Lithium battery. That's about it.