Getting excessive charging voltage from Epever SCC

[JBennettBus]

My bus-mounted system seems to be working since I installed the new battery about a week ago. The battery charged up, and I've been running a small load (computer running Epever software, light, and fan, >100W) with no problem. Even the low-temp disconnect worked last night.

I just went out and found the computer was off. Turned it back on and started the Epever software. It showed the solar charging was cutout and a maximum battery voltage of 21.31, even though the overvoltage cutoff on the controller is set to 15. After getting everything running, the inverter made a long beep and turned off then back on.

With the inverter off, I was checking the SCC parameters with the MT-50 monitor when it threw an overvoltage disconnect error. I shut the breaker to the panels, then I checked the battery voltage at the terminals. It was 19V and dropping.

It looks to me like the SCC is kaput. I'm pretty sure I have all the charging parameters set properly for LiFePo4. Or is there something else that might make the charging voltage suddenly run that high? Any ideas/advice would be helpful.

System parts
6 HQST 100W panels, 3s2p
Epever Tracer 4210AN
Li Time 12V/300AH battery
Power Tech-On PS1003 inverter, 2000/4000W

 

[MisterSandals]

It showed the solar charging was cutout and a maximum battery voltage of 21.31, even though the overvoltage cutoff on the controller is set to 15.

I've seen something like this happen when the battery is disconnected and a powered array is connected.
I "think" when the SCC starts up with just solar, it assumes the battery voltage is similar to the solar voltage. So when the sun came up, the solar started powering the SCC and it saw something close to 24V and assumed you have a 24V battery and started charging it as such.

Its one of the reasons i like setting battery voltage in an SCC, if possible, rather than have it "auto detect".

Just a theory but I've had this happen. It did not kill my SCC or battery (caught it fairly early).

 

[Symbioquine]

There's not enough information here yet to do more than guess, but I have a wild guess what might have happened...

Many charge controllers including the Epever units come by default in an auto 12v/24v configuration where they'll detect the battery voltage and use charging parameters based on whether they think they're hooked up to a 12v or 24v battery system. I'm imagining that it might be possible for a glitch/bug in the controller to cause it to restart then have that detection logic get invoked and coincide with a transient ripple/spike on the DC battery side of the system. Once the charger thinks it is charging a 24v system, all the charging voltages/limits would be approximately doubled.

Obviously, if that can happen it's a pretty bad issue. I use lots of those Epever controllers, but I'm kind of paranoid about that sort of thing (and I suspect not the only one who is) and prefer to disable the auto mode - setting the charging voltage and limits/thresholds based on the battery I am hooking it up to.

 

[JBennettBus]

I've seen something like this happen when the battery is disconnected and a powered array is connected.

I haven't disconnected the battery since I installed it. Could a BMS shutting off make it look like the battery has been disconnected?

 

[Symbioquine]

I haven't disconnected the battery since I installed it. Could a BMS shutting off make it look like the battery has been disconnected?

Yes, that's what it would look like to the SCC.

 

[MisterSandals]

I haven't disconnected the battery since I installed it. Could a BMS shutting off make it look like the battery has been disconnected?

It is possible. Does your SCC "power off" when you hit low temp disconnect?

And continuing on, does it power on when sun hits your panels? If so, how would the SCC know what voltage your battery is? My theory is that it chooses between 12V and 24V based on which is closer to solar voltage.

 

[JBennettBus]

I use lots of those Epever controllers, but I'm kind of paranoid about that sort of thing (and I suspect not the only one who is) and prefer to disable the auto mode - setting the charging voltage and limits/thresholds based on the battery I am hooking it up to.

Yeah, when you open a parameters page in the software, it shows auto detect as the default. I just checked again, through both the MT-50 and the software, and it's set to 12V. Since this model doesn't have a specific profile for LiFePo4, I had to set all the charging numbers under the User setting.

Maybe I have something wrong in the settings, but I spent a couple of days making sure everything was set according to either the Li Time manual or various posts here that discuss such settings. I'll check them again just to be sure.

 

[Symbioquine]

Yeah, when you open a parameters page in the software, it shows auto detect as the default. I just checked again, through both the MT-50 and the software, and it's set to 12V. Since this model doesn't have a specific profile for LiFePo4, I had to set all the charging numbers under the User setting.

Maybe I have something wrong in the settings, but I spent a couple of days making sure everything was set according to either the Li Time manual or various posts here that discuss such settings. I'll check them again just to be sure.

Weird. If you have it set manually to 12v, then all the stuff we've been talking about regarding the "auto-detect" feature shouldn't be relevant.

 

[JBennettBus]

It is possible. Does your SCC "power off" when you hit low temp disconnect?

Last night was the first time it's been cold since I installed the new battery, and the low temp disconnect did indeed work. (Previous batteries were gel, so there was no low temperature protection on.) There was voltage at the panels, but the SCC didn't start charging until I warmed up the temp sensor.

This is still sounding like a glitch in the SCC, but I need to double and triple check all the charging parameters again to make sure I wasn't the glitch.

btw, thanks for the help. I forgot to mention that in my first reply.

 

[JBennettBus]

Yes, that's what it would look like to the SCC.

Sounds like it might be best to try another controller. (I can afford one that's not a Victron.) If it solves the problem, I'm good. If not, I still have a problem, but I'll have a spare SCC.

And thank you for your help too!

 

[MisterSandals]

I can afford one that's not a Victron

My philosophy is that i cannot afford one that is NOT a Victron.

Your SCC is the heart and brains of a solar system. Saving $100 and risking a $1500 (?) battery is pound foolish.
Hopefully your battery is ok!

The 5 year warranty, ease of use with bluetooth, and potentially many hours of tinkering saved make it a bargain.
A quality SCC is a great investment.

 

[JBennettBus]

Your SCC is the heart and brains of a solar system. Saving $100 and risking a $1500 (?) battery is pound foolish.
Hopefully your battery is ok!

There's a lot of wisdom in what you're saying. If I had a nickel for every time I got burned because I forgot or ignored that "you get what you pay for", I'd have a lotta nickels.

 

[Bud Martin]

There are threads about this issue with EPEVER.

A device that records max voltage?

What is the float voltage? That would be even lower around 26.8? Seems odd to get to 30+ in just a couple seconds while floating. Have you contacted epever? Quick google search indicates this is a general problem with this controller. Cloud edge effect or large change in load will effect the...

diysolarforum.com

Voltage spike read on SCC, inverter shutoff, voltage drop and inverter back on

Have seen some references to this issue on the forums. Today I noticed that my lithium 12v WEIZE brand batteries in series were sitting at 27 volt float. This seems to be normal. Although, the scc was reading no charging from my panels. This is off the grid no external power. I turned on my...

diysolarforum.com

inverter shut down. cuts off electricity.

let me start at the beginning: the set i have so far has been running about 6 months. 1. 4 Renogy 200 watt panels set up in series and parallel for 24 volt 2. epever tracer 4210AN controller w/ remote meter MT50 3. 2 12v 100ah ampere batteries in series for 24v 4. pure sine wave inverter...

diysolarforum.com

 

[JBennettBus]

There are threads about this issue with EPEVER.

Thanks. I didn't do a proper search before I posted. I know that's bad forum etiquette, and I'll try to avoid that mistake in the future.

 

[Bud Martin]

Thanks. I didn't do a proper search before I posted. I know that's bad forum etiquette, and I'll try to avoid that mistake in the future.

Not a problem at all.