Over voltage alarm

[Dakotalee]

I have: (3) 375 watt panels
2 battleborn batteries wired to 24v
A epever 40a tracer model charge controller
2000w pure sine giandel 24v inverter

The issue Im running into is on sunny days the overvoltage alarm triggers on the inverter when the batteries are near full. Also, the charge controller trips over voltage protection and temporarily disconnects the array.

I have my panels wiired in parallel and they run at about 44v.

I tried playing around with tje controller parameters with no success. I also contacted battleborn and we havent been able to figure out the issue yet either.

Does anybody here have any ideas?

 

[bass_sears]

24v panels presumably, peak voltage ~44v, right?

Regardless, if controller is 4210AN, according to data sheet here:
https://www.epsolarpv.com/product/3.html
... max wattage it can handle is 1040@24v, you have 3x375 = 1,125w of panels

Probably only how over max input on nice clear sunny days with good angle... inverter has nothing to do with it.

-- Bass

 

[Dakotalee]

They are 44v or 42 vpanels.
The charge controller can be over paneled. Regardless my system tops off before I ever reach peak. Its usually charge by 10am.

 

[bass_sears]

What is the open circuit voltage of your panels (Voc)? Could you be catching ideal conditions that put you over the 92-100v maximum for your controller at same time your load is going to basically nothing because as you say your system is already topped up?

 

[Dakotalee]

The panels are 47.7 the controller is rated for 150v

 

[jonyjoe303]

something that might be happening is that one of the lifepo4 batteries might be getting full triggering the bms. When the bms triggers the controller will try to keep charging the battery causing voltage surges. Voltage surges might be causing the inverter to sound the alarm. What happens is the bms being used uses mosfets, mosfet leak voltage, when the bms triggers it stops accepting current but since it leaks voltage, the controller still reads a low battery and tries to force a charge into the battery. On my 4s lifepo4 battery when the bms activates, if I connect a voltmeter to the terminals they read about 11.7 volts even though its full.

If the controller is cycling back and forth, its probably whats going on. I encounter these voltage surges on my 12 volt solar system and lifepo4, i suspect it might occur also on a 24 volt system. On my 12 volt system I saw the voltage surges as high as 20 volts when the bms trigger, destroying equipment connected to the battery. Since each battleborn has its on bms, it adds complications if one gets full before the other. You might have to lower the bulk voltage low enough so neither battery ever gets a full charge. But even set low enough there is no guaranteed the bms won't activate if charging long enough, especially if the battery goes out of balance or is being fast charge.

To protect any devices connected to your battery that is sensitive to voltage surges, you can use a 24 volt voltage stabilizer, they react fast enough to protect your equipment. I tried using an overvoltage protection relay to protect from voltage surges but they react too slowly and destroyed equipment.

 

[bass_sears]

Is your controller the Tracer 4210AN? Say 92-100v max depending on temp in spec sheet.

 

[Dakotalee]

Ugh.

 

[Dakotalee]

4215BN

 

[Dakotalee]

something that might be happening is that one of the lifepo4 batteries might be getting full triggering the bms. When the bms triggers the controller will try to keep charging the battery causing voltage surges. Voltage surges might be causing the inverter to sound the alarm. What happens is the bms being used uses mosfets, mosfet leak voltage, when the bms triggers it stops accepting current but since it leaks voltage, the controller still reads a low battery and tries to force a charge into the battery. On my 4s lifepo4 battery when the bms activates, if I connect a voltmeter to the terminals they read about 11.7 volts even though its full.

If the controller is cycling back and forth, its probably whats going on. I encounter these voltage surges on my 12 volt solar system and lifepo4, i suspect it might occur also on a 24 volt system. On my 12 volt system I saw the voltage surges as high as 20 volts when the bms trigger, destroying equipment connected to the battery. Since each battleborn has its on bms, it adds complications if one gets full before the other. You might have to lower the bulk voltage low enough so neither battery ever gets a full charge. But even set low enough there is no guaranteed the bms won't activate if charging long enough, especially if the battery goes out of balance or is being fast charge.

To protect any devices connected to your battery that is sensitive to voltage surges, you can use a 24 volt voltage stabilizer, they react fast enough to protect your equipment. I tried using an overvoltage protection relay to protect from voltage surges but they react too slowly and destroyed equipment.

I tripped the bms shutdown when I was installing them. Accidently hit the post with my wrench. I disconeected the system and put the volt meter on. The volt meter had enough charge to turn the batteries back on. They read 13.3 and 13.2v. I reinstalled them. Think they cpuld be out and balance and causing the problem?

 

[jonyjoe303]

If they are new they should be in balance but with battleborn I don't think there is a way to check the cell voltage. Even if they are in balance when they are fast charge, one cell might reach the cutoff before the others.

I don't think there is anything wrong with the batteries, or the solar controller, it's just solar and mosfet bms don't work well together. I had many problems until I used a bms with mechanical relays. With battleborn (and other drop-in replacement batteries with built-in bms) those will always require adjusting the controller bulk voltage setting throughout the day. On my system I had to make sure the battery was in perfect balance and when it got close to full, I lowered the bulk setting to prevent it from triggering the bms, I also used a voltage stabilizer to protect my devices. Even with all the extra attention every couple of weeks the bms would trigger.

Something else that might work is put a smaller 24 volt lead acid battery in the system, this will let the controller always see 24 volts even if one of the lifepo4 has activated the bms.

 

[Trebor English]

The two 12 volt batteries could be at a different state of charge.  The bms goes open circuit when the first cell goes above the cutoff voltage. 

The usual process to balance cells is to parallel connect all of them and then charge all of them to 3.5 volts, or whatever your upper voltage is.  That process applied to a pair of battle born batteries might lower the state of charge of the higher voltage battery.  I would ask battle born and give them the wrench sparking story.  

The point of charging to 14.6 volts instead of only 14.0 volts is to get the last 2% of capacity in there.  Back off the charge voltage, give up the last 2% and don't damage your system.  

The battle born balancing circuitry doesn't actually function until you get to 14.2 volts.  You need to hold between 14.2 and 14.4 for 20 minutes for balancing to work.  If your charge rate is too high you could zip past balancing and get to bms overload shutdown very quickly.  You might  make that better by disconnecting a solar panel.

 

[jimindenver]

I have seen over voltage issues from a inverter on a system with a epever charge controller. It took a while to figure it out but on a day with partial clouds the cloud effect was causing the voltage to get above 15 volts. The charge controller just doesn't sample the voltages fast enough to respond to the cloud effect and can take seconds to recognize that the battery voltage has changed. The delay can be seen both in cloud effect and when a heavy load is applied. The inverters remote panel showed the difference in voltage a few seconds before the charge controller did.

Due to this I no longer suggest epever as a low cost alternative in my designs. Especially those with Lithium batteries that are not going to appreciate high voltage.

 

[Dakotalee]

Victron?

 

[Dakotalee]

Right now I have the charge set at 28.8 and float at 27.6

 

[jimindenver]

I do suggest Victron SmartSolar with the blue tooth built in.

 

[Weight]

What are the specifications on the inverter. I had difficulty finding an inverter that could operate at standard solar charging without going into high voltage alarm.

 

[bonvanroulez]

I have seen over voltage issues from a inverter on a system with a epever charge controller.

Yep, everything that Jimindenver said. I had two different Epever controllers and both did the same thing, allowing a voltage spike over the 15.6 volt input limit on my inverter and triggering its high voltage protection and alarm. The second controller was that BN4215. Happened with the cloud effect and also while driving when trees would momentarily shade the panels, also pulling out from under gas station canopies. Constantly having to stop to restart the inverter. The worst was taking off on a long hike or bike ride and returning hours later to hear that alarm and find the inverter shut down so the refrigerator lost power. I switched to Victron mppt 2 1/2 years ago, never had another problem. I had other issues with those Tracer/Epever controllers but that's another topic.

 

[Dakotalee]

I'm getting fed up with this controller already. I bought this because one of the main selling points was its fully programmable and evrytime I try to input paramaters it denies me saying its invalid.Trying to troubleshoot this thing is becoming impossible. I'm kinda pissed off with this thing and epever who also provided no support.

Side note. Battleborn instructed me to put a 10 hourish ( full day of light) absorpotion charge to make sure the batteries were balanced but yea guess what. Invalid parameter. Grrrrr. I should have known better than to get this chinese shit, man. But there were so many positive reviews and it seemed like a solid mid tier controller. Pffffffffftt

 

[future_vandweller]

I'm near 100% confident that this over-voltage alarm is due to a poor absorb stage algorithm in the Epever controller.  *All* solar charge controllers (MPPT or PWM) operate in a PWM mode during absorb.  During this stage, there's way more current/power available from the panels than what's needed by the batteries.  The controllers try to maintain a specific voltage by modulating the connection while the current tapers off.  If the PWM algorithm does not respond quickly to the battery voltage, it can cause the voltage to spike briefly and trigger the over-voltage alarm.

Try adding a load to the load terminals to make it easy for the controller to maintain voltage.  The proper fix is firmware revision by Epever.