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Battery stopped charging at 74%

ScottishBadger

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Solis RAI-3K-48ES-5G charger, with Fox-ESS LV5200 battery.

Latest problem, battery has stopped charging. System was "disabled" around 3 weeks ago by disconnecting the grid meter signal whilst investigating a totally different issue, today I reinstated the grid meter. Battery is at 74% SOC, I'm currently exporting over 1.3kW to the grid, but the battery won't charge. So far, I've checked all programming settings on the Solis, done a full power-down and reset on both the Solis and the LV5200 battery, all BMS settings are as they should be. I changed the time on the Solis to put it into timer-charging mode and it still wouldn't charge... time now back to normal.
I applied a considerable load, to "force" a discharge, this dropped the battery to 72% and when I removed the load, it started to charge from the available solar. Yes, I thought, it just needed to do some sort of internal kick-start, but then when it got to 74%, it stopped charging again!

I previously had a problem of the Solis giving an alarm and tripping off-line when any reasonable load was applied, with the message "ACOvercurrent". Weirdly, when the unit self-reset after a couple of minutes, it would ramp-up to match the load without further issue. Today, when I applied the loads, it worked properly and didn't trip out, but now I have this charging fault.....

The Solis software on my PC shows the inverter and what it's doing, but it isn't showing any information for grid , battery or solar power....

Anyone have any clues??
 
A fully charged battery will be an unloaded battery terminal voltage at or above 54.5 vdc. This is 3.4v per cell at rested unloaded open terminal voltage.

Possibility is battery cells are not balanced enough causing a cell overvoltage charging shutdown on BMS when attempting a full charge. Remedy for that is to hold absorb charging until BMS balances cells. BMS's typically do not balance until a cell gets above 3.4v, so for a 16s battery that requires an absorb voltage of about 56.0v. If severely out of balance it may take tens of hours to get cells back in balance.
 
Are there any alarm messages on the Solis or, more likely, that you can get from the FOX battery? As @RCinFLA said, the battery's BMS may be keeping the cells safe and triggering a cell overvoltage condition.

Unless the Solis SOC charge limit has been set to 74%, then it will be the battery telling the Solis at what rate to charge. The charge rate should be visible on the info screen (the 2nd or 3rd page of info AFAIKR), if you can't read it directly from the FOX.
 
A SoC indication based solely on battery voltage is pretty much useless.

A Columb counter SoC indicator has to periodically get a reference full charge state reset to clear out accumulated errors in the Columb (amp-seconds) count.

Failure to periodically fully charge battery to reset Columb counter in battery monitor will result in progressive greater inaccuracy in the SoC indicator. Since you also need to fully charge battery periodically to get LFP cell balancing by BMS there are a couple of reasons why a full charge periodically is necessary.

Many folks think reducing the full charge voltage on their battery will help them last longer but end up with out of balance cells and highly inaccurate SoC indication.

LFP cell cathode is much more rugged than nickel based cathode cells used in EV's. LFP can tolerate full charge with little wear on LFP cathode material.
 
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A SoC indication based solely on battery voltage is pretty much useless.

A Columb counter SoC indicator has to periodically get a reference full charge state reset to clear out accumulated errors in the Columb (amp-seconds) count.

Failure to periodically fully charge battery to reset Columb counter in battery monitor will result in progressive greater inaccuracy in the SoC indicator. Since you also need to fully charge battery periodically to get LFP cell balancing by BMS there are a couple of reasons why a full charge periodically is necessary.

Many folks think reducing the full charge voltage on their battery will help them last longer but end up with out of balance cells and highly inaccurate SoC indication.

LFP cell cathode is much more rugged than nickel based cathode cells used in EV's. LFP can tolerate full charge with little wear on LFP cathode material.
The system was always set to do a top-up charge overnight, so the battery was kept at 100% to maintain cell balance.
Weirdly, on Thursday afternoon (with overcast skies and no solar) it started to charge from the grid despite it not being set up to do so, and the battery reached 100% once more - but there are other issues!
As per my other post today, Solis Cloud is telling me that my inverter is online, but that my plant is offline! I've tried to reset by turning the inverter off then back on, but it hasn't worked. The sun was shining this afternoon, my solar input was around 3kW and the Solis inverter just sat there doing nothing - no fault warnings or alarms, and wouldn't charge the battery which was sitting at 73% again, having partially discharged to the house earlier in the morning before the sun came up. Since then, the sun has gone down, and the Solis has started to give out power from the battery - which is now down to 40%.
I'll see what it does overnight tonight, as it failed to charge from the grid last night despite all timer settings being double-checked and accurate. Tomorrow is meant to be a good sunny day as well, so we'll see if it takes any charge from solar as the day goes on......
 
Are there any alarm messages on the Solis or, more likely, that you can get from the FOX battery? As @RCinFLA said, the battery's BMS may be keeping the cells safe and triggering a cell overvoltage condition.

Unless the Solis SOC charge limit has been set to 74%, then it will be the battery telling the Solis at what rate to charge. The charge rate should be visible on the info screen (the 2nd or 3rd page of info AFAIKR), if you can't read it directly from the FOX.
No alarms other than the occasional inverter "ACOvercurrent", which self-resets after a couple of minutes and it's been doing this since the day it was installed. This is the main reason why I have fallen out with the installer and refused to pay the balance on the installation, as they are refusing to come and look at it until I pay them, despite the contract clearly stating "balance on completion". Completion, to me, means a working, fault-free system!
I had a steady 3kW of solar this afternoon, but still no charge into battery.
 
List the cell voltages readout. Just stating state of charge numbers is not very helpful.
 
List the cell voltages readout. Just stating state of charge numbers is not very helpful.
I have no way of seeing individual cell voltages. Present overall battery voltage reported from BMS is 52.9v / 20% SOC.
The sun is shining, I have over 3kW generation and this useless pile of junk won't charge, either from solar or grid!
It randomly charged from grid on the afternoon of the 11th - outwith the manual charging times set and with no solar present - so I can't see it being a cell imbalance issue? From that point, it slowly discharged until yesterday evening when it responded perfectly to house loads and it discharged from 70% down to 20%, it's programmed minimum.
 
It randomly charged from grid on the afternoont - so I can't see it being a cell imbalance issue?
That is what happens when cells are out of balance.

Under charging, one cell hits overvoltage and shuts down charging. BMS slowly bleeds that cell down and eventually resets BMS charging enable again.

This process can repeat many times until cells eventually get balanced. It can take a few hours to a few weeks held at absorb pack voltage depending on how misbalanced the cells are. It only takes about 1% misbalance to cause a BMS cell overvoltage trip to happen when attempting a full charge.

BMS bleed balance current is likely only 50-150 mA, so 1% misbalance (1 AH on 100 AH battery) can take about ten hours held at absorb level voltage to correct. It may shut down charging due to cell overvoltage several times during this time period. Lowering the charge current will reduce the number of overvoltage shutdowns until it gets balanced again. Then you can raise charging current again.

You need to hook up PC comm with battery to read out battery status and individual cell voltages. Manual says first three LED's blink when there is an overvoltage condition.
 
That is what happens when cells are out of balance.

Under charging, one cell hits overvoltage and shuts down charging. BMS slowly bleeds that cell down and eventually resets BMS charging enable again.

This process can repeat many times until cells eventually get balanced. It can take a few hours to a few weeks held at absorb pack voltage depending on how misbalanced the cells are. It only takes about 1% misbalance to cause a BMS cell overvoltage trip to happen when attempting a full charge.

BMS bleed balance current is likely only 50-150 mA, so 1% misbalance (1 AH on 100 AH battery) can take about ten hours held at absorb level voltage to correct. It may shut down charging due to cell overvoltage several times during this time period. Lowering the charge current will reduce the number of overvoltage shutdowns until it gets balanced again. Then you can raise charging current again.

You need to hook up PC comm with battery to read out battery status and individual cell voltages. Manual says first three LED's blink when there is an overvoltage condition.
There are no faults showing on the battery lights. Had another look today, from what we can see on the charger display, everything suggests it should be charging, but measuring the volts direct at the battery cables, the charger does not increase voltage when charge is selected on timer even though the charger screen says it is charging. it's looking more and more like a charger internal fault I think.
 
Surely there is a way to get more detailed info from the Fox? e.g. alarm conditions and individual cells voltages? Or at least max-min cell voltages at any one instance.

What does the Solis show on the info screen I mentioned in post #3, to indicate what the Fox batteries are asking for, charge-wise?

Totally agree on withholding payment, it is not fully commissioned as that fault has existed from day 1.
 
Surely there is a way to get more detailed info from the Fox? e.g. alarm conditions and individual cells voltages? Or at least max-min cell voltages at any one instance.

What does the Solis show on the info screen I mentioned in post #3, to indicate what the Fox batteries are asking for, charge-wise?

Totally agree on withholding payment, it is not fully commissioned as that fault has existed from day 1.
The Fox battery only communicates any faults to the outside world via coded led light indications, and at no time has it given any fault indications. I can't find any way to milk any further info out via the Solis - in fact I can't do anything now, events took a turn yesterday morning.....
I went out to the workshop to find the solis in alarm mode, but the display had locked-up on "grid-normal" and the fox battery had only the flashing "operating" light, no contents lights showing. Pressing the buttons on the solis panel would not allow me to cycle through the display to see what the fault was, so I turned off the mains isolator to reset things. At this point, the display remained showing "grid-normal", even though the grid had been disconnected from it! I had to force a full shutdown by turning the battery off by powering it down (the installers never put any master switch between battery and solis charger), when I powered the battery down the solis then went blank. I can't power it back up, I don't know id this is due to an internal fault within the solis or a lack of battery power and I have no means of charging the battery without the solis charger, plus an installer that has allegedly ceased trading and refuses to come and look at it unless I pay an outstanding balance on a job that hasn't been completed......
 
Oh no.. that's not good :( The Solis will need d.c. to power itself, so either battery or PV if you have them.

Sadly sounds like a very dodgy installer - don't see how they can claim to have ceased trading AND need outstanding balance paid before they do something? Maybe last resort, but do you have the equivalent of our small-claims-court up there in bonny scotland?
 
SeaGal, the installer claims he is still trading, but not doing anything, if that makes sense. He hasn't shut the company down officially with Companies House, but I doubt he can keep it going for long as he has no real staffing or ability to do anything, and if the size of hole he's currently digging himself on a facebook page is anything to go by, no-one with any brain cells will go within a mile of any company with his name associated!
He keeps banging on about outstanding payment for materials, when the contract issued by his company clearly states 50% deposit, 50% balance due on completion. He refuses to accept that completion means commissioned, working correctly and demonstrated as such to the customer! He has tried three times now to force me to pay the remaining 50% and I have dug my heels in and refused to pay until he sorts out the mess. Oh, and his default response when backed into a corner is to accuse me of lying about the faults, haha. I've taken screenshots of it all, to present to trading standards or court, wherever this ends up!

The RAI charger/inverter has no solar connection, so it absolutely needs battery power to boot up. Solis attempted to do some firmware update, I'm not sure if the update failed because of the charger fault(s) or the charger failed because of the update, but either way the control panel won't respond to buttons and I can't do anything. Solis are sending a firmware update on a stick, how I am supposed to install it when the buttons don't work is anyone's guess..... I have attached a screenshot of the display, prior to turning it all off to conserve what little is presently in the battery.......
 

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Solis are sending a firmware update on a stick, how I am supposed to install it when the buttons don't work is anyone's guess.....
Hopefully they will give you instructions. A certain key sequence will trigger the update even if the screen is not responding. I can't recall what it is off the top of my head, but I have seen it mentioned.
 
He keeps banging on about outstanding payment for materials, when the contract issued by his company clearly states 50% deposit, 50% balance due on completion. He refuses to accept that completion means commissioned, working correctly and demonstrated as such to the customer! He has tried three times now to force me to pay the remaining 50% and I have dug my heels in and refused to pay until he sorts out the mess. Oh, and his default response when backed into a corner is to accuse me of lying about the faults, haha. I've taken screenshots of it all, to present to trading standards or court, wherever this ends up!
Sorry to hear it has come to this, but good you're keeping firm and got the evidence.

Good luck with the Solis 'un-bricking stick'. Fingers crossed it will work - maybe the Solis BIOS triggers a 'boot from flash memory' if a bootable stick is plugged in? Hope so. Keep us updated.
 
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