Hello Members

Your assistance would be appreciated.

I have a Deye 5kw inverter with a 5kw LBSA lithium battery and 6 X550w solar panels.

For the past few months each time I switch on an appliance like a microwave or kettle even for less than a minute the battery drops from fully charged to around 6% instantly. This happens when there is no load shedding, very little other loads apart from a few LED lights.

If not switching on an appliance like a kettle, the battery works as it should and discharges correctly as the house usually is drawing around 400w all the time. When we have outages the battery keeps going all night without any issues.

The issue only arises when a kettle or microwave or hair dryer is turned on for a few moments.

I have had this system for 3.5 years and only in the past few months this has started happening.

Your advice would be greatly appreciated.

Regards,

Giulio

1 hour ago, GBF said:

I have had this system for 3.5 years and only in the past few months this has started happening.

You'll need to expand on the story...

Are you connected to the grid? In other words, when you switch on the kettle or other larger consumer, does the grid then pick up the slack? and are you doing this after dark or are the panels, helping out as well, as soon as the MPPT catches up?

Does the Inverter and Battery communicate via RS485 or CANbus, or is the battery handled as a Voltage based device from the Inverters perspective?

If its Voltage based, I'd suggest rechecking *all* the battery cable connections and retighten them, you may find this solves the issue...

Additionally, once the battery or inverter claims 5%, how long until the battery is back up to 100%?

Edited April 24, 20251 yr by Kalahari Meerkat
Additionally...

2 hours ago, GBF said:

Hello Members

Your assistance would be appreciated.

I have a Deye 5kw inverter with a 5kw LBSA lithium battery and 6 X550w solar panels.

For the past few months each time I switch on an appliance like a microwave or kettle even for less than a minute the battery drops from fully charged to around 6% instantly. This happens when there is no load shedding, very little other loads apart from a few LED lights.

If not switching on an appliance like a kettle, the battery works as it should and discharges correctly as the house usually is drawing around 400w all the time. When we have outages the battery keeps going all night without any issues.

The issue only arises when a kettle or microwave or hair dryer is turned on for a few moments.

I have had this system for 3.5 years and only in the past few months this has started happening.

Your advice would be greatly appreciated.

Regards,

Giulio

I presume this happens when you don't have the timer active so that grid can be used when the battery drops to this low level. I make sure I have a timer switched on when using my kitchen equipment. As these high draw items can cause this if the battery is not in 100% shape.

The drop should not happen even if your comms is not working and the inverter uses voltage based. You can however just do a check by selecting voltage for charging even if just when you switch on the kettle with timer active.

I have a 51.8V level with timer on during the 17h to 21h period to prevent battery to be discharged real fast. Check on the screen if grid use does increase when the kettle is on.

1 hour ago, Kalahari Meerkat said:

You'll need to expand on the story...

Are you connected to the grid? In other words, when you switch on the kettle or other larger consumer, does the grid then pick up the slack? and are you doing this after dark or are the panels, helping out as well, as soon as the MPPT catches up?

Does the Inverter and Battery communicate via RS485 or CANbus, or is the battery handled as a Voltage based device from the Inverters perspective?

If its Voltage based, I'd suggest rechecking *all* the battery cable connections and retighten them, you may find this solves the issue...

Additionally, once the battery or inverter claims 5%, how long until the battery is back up to 100%?

@Kalahari Meerkat Thank for your reply.

• I am connected to the Grid

• This rapid discharge when using the kettle etc happens during sunny days and at night.

• Once the battery rapidly discharges itself to around 6% the grid / solar does charge it up again. It charges up to around 30% then next thing its back at 100%.

• I have no idea if its RS485 or CANbus

• I have never changed any setting on the inverter or battery apart from some TOU times and %s. This issue started a few months ago randomly and now it happens every time I use a kettle/microwave

Thank you

1 hour ago, Kalahari Meerkat said:

You'll need to expand on the story...

Are you connected to the grid? In other words, when you switch on the kettle or other larger consumer, does the grid then pick up the slack? and are you doing this after dark or are the panels, helping out as well, as soon as the MPPT catches up?

Does the Inverter and Battery communicate via RS485 or CANbus, or is the battery handled as a Voltage based device from the Inverters perspective?

If its Voltage based, I'd suggest rechecking *all* the battery cable connections and retighten them, you may find this solves the issue...

Additionally, once the battery or inverter claims 5%, how long until the battery is back up to 100%?

@Kalahari Meerkat Thank for your reply.

• I am connected to the Grid

• This rapid discharge when using the kettle etc happens during sunny days and at night.

• Once the battery rapidly discharges itself to around 6% the grid / solar does charge it up again. It charges up to around 30% then next thing its back at 100%.

• I have no idea if its RS485 or CANbus

• I have never changed any setting on the inverter or battery apart from some TOU times and %s. This issue started a few months ago randomly and now it happens every time I use a kettle/microwave

Thank you

20 minutes ago, GBF said:

This rapid discharge when using the kettle etc happens during sunny days and at night.

Ok, ideally one would need to see what happens to the actual cells in your battery, but the 30% rapidly up to 100% is a worrying trend... however, since the battery does keep things tricking over, overnight, when you have power outages, I'd say there may be a connection problem, on the DC side between the battery or even between some of the cells in the battery pack, or between the battery and the inverter, hence my suggestion checking all the DC side connections between battery and inverter and possibly re-torquing them, since if they are slightly loose at 10A/500W its probably not so critical, but at 40+A/2+kW, things will warm up some and thus with more resistance, the Voltage will seem off/lower... but the %age should not show bum numbers if the BMS & Inverter are talking and the inverter is taking the SoC from the BMS.

I don't know the LBSA battery and don't know what BMS it uses, ideally you'd want to get near real time information from the BMS, for cell voltages, there should be 16 of those and that should probably be most of what you'd need to determine whether there is a problem internal to the battery or whether you have a problem external to the battery...

Either way, if you can re-tighten the battery cable connections... be very careful, if doing this whilst the inverter and battery are on, best would be to shut down the inverter and isolate the battery, it should have a switch turning off its DC connection and then re-tighten the 4 connections... positive and negative on the battery end and the same two connections on the inverter end...

Also check any fuses on the DC side (maybe replace them). To rule out issues with the cells you will need access to cell data.

During a normal evening where the load is low, to what SOC level does the battery discharge overnight?

Does it ever discharge to 0% instantly (as opposed to 6% in the OP) this would hint to a cell issue.

Edited April 25, 20251 yr by I84RiS

On 2025/04/24 at 2:52 PM, GBF said:

@Kalahari Meerkat Thank for your reply.

• I am connected to the Grid

• This rapid discharge when using the kettle etc happens during sunny days and at night.

• Once the battery rapidly discharges itself to around 6% the grid / solar does charge it up again. It charges up to around 30% then next thing its back at 100%.

• I have no idea if its RS485 or CANbus

• I have never changed any setting on the inverter or battery apart from some TOU times and %s. This issue started a few months ago randomly and now it happens every time I use a kettle/microwave

Thank you

@Kalahari Meerkat Thank for your reply.

• I am connected to the Grid

• This rapid discharge when using the kettle etc happens during sunny days and at night.

• Once the battery rapidly discharges itself to around 6% the grid / solar does charge it up again. It charges up to around 30% then next thing its back at 100%.

• I have no idea if its RS485 or CANbus

• I have never changed any setting on the inverter or battery apart from some TOU times and %s. This issue started a few months ago randomly and now it happens every time I use a kettle/microwave

Thank you

Sounds to me like your battery cells are out of balance due to not being full absorbed to the top. Or you have a weak cell or 2. Best would be to get someone to check all the individual cells for you.

1 hour ago, WannabeSolarSparky said:

Sounds to me like your battery cells are out of balance due to not being full absorbed to the top. Or you have a weak cell or 2. Best would be to get someone to check all the individual cells for you.

I am busy upgrading my battery banks and can show you an example of a weak cell that could possibly explain what is happening your side too.

See Cell 8 below, voltage is lower than the rest of the cells.
This is during discharging, if I now put a heavy load onto the battery (e.g. kettle) then cell 8 would drop very quickly which will then bring the total SOC down rapidly with it.
The opposite happens when charging, that weak cell voltage goes up a lot quicker than the healthy cells, falsely/incorrectly pushing up the SOC as it prematurely hits its over voltage limit, resulting in the rest of the cells also not charging up fully. Sp your battery SOC ends up being totally out of wack.
See second image below showing visually what happens.

See on the left while charging the weak cell voltage rises quicker than the rest, and then on the right while discharging the weak cell voltage drops a lot faster then the rest.
No amount of top balancing can fix this, I have tried every method out there and none of it fixes the weak cell. Only solution is to replace the weak cell to bring the whole battery back to a good working condition.

LBSA uses Seplos bms. You can download the bms monotoring software to interrogate using windows computer. Below link to the Seplos download kiosk.

https://www.seplos.com/download.html

Edited April 26, 20251 yr by TaliaB

On 2025/04/25 at 7:54 PM, WannabeSolarSparky said:

I am busy upgrading my battery banks and can show you an example of a weak cell that could possibly explain what is happening your side too.

See Cell 8 below, voltage is lower than the rest of the cells.
This is during discharging, if I now put a heavy load onto the battery (e.g. kettle) then cell 8 would drop very quickly which will then bring the total SOC down rapidly with it.
The opposite happens when charging, that weak cell voltage goes up a lot quicker than the healthy cells, falsely/incorrectly pushing up the SOC as it prematurely hits its over voltage limit, resulting in the rest of the cells also not charging up fully. Sp your battery SOC ends up being totally out of wack.
See second image below showing visually what happens.

See on the left while charging the weak cell voltage rises quicker than the rest, and then on the right while discharging the weak cell voltage drops a lot faster then the rest.
No amount of top balancing can fix this, I have tried every method out there and none of it fixes the weak cell. Only solution is to replace the weak cell to bring the whole battery back to a good working condition.

Yes, this is spot on

If the passive dissipative balancer with small resistors built into most of bms we see is not enough to keep up with the balancing of low current cycling often seeb in home PV systems then you likely have unmatched or defective cells.

Using active balancers will only mask the problem, it wont fix it. If the cells are not highly matched in capacity then you will always run into either top OV or bottom UV issues no matter how often the cells are balanced.

The only solution here is to use the batteries, by example in the 20% to 90% SOC range, and just accept that you have less capacity. Hitting cell OV and UV frequently is not good to the health of the specific cell and will likely lead to premature battery failures once the cycle count gets high (this forum is full of such posts)

7 hours ago, I84RiS said:

Yes, this is spot on

If the passive dissipative balancer with small resistors built into most of bms we see is not enough to keep up with the balancing of low current cycling often seeb in home PV systems then you likely have unmatched or defective cells.

Using active balancers will only mask the problem, it wont fix it. If the cells are not highly matched in capacity then you will always run into either top OV or bottom UV issues no matter how often the cells are balanced.

The only solution here is to use the batteries, by example in the 20% to 90% SOC range, and just accept that you have less capacity. Hitting cell OV and UV frequently is not good to the health of the specific cell and will likely lead to premature battery failures once the cycle count gets high (this forum is full of such posts)

This remains an interesting point. As you indicated you can mask the problem until a new cell is bought. Now I have been one that like the balancing from a low level. Yes we know most clever people would say only start balancing when cells start shooting the lights out at around 3.35-3.45V.

My own observation has been the weak cell as pointed out will remain weak. The thing is if you start balancing say at 3.1V with an active balancer there is a good chance that 15min after using the high load this cell will have been charged during balancing. This better prepares this cell to at least provide power during the next high load before it drpos again. If the balancing starts only at 3.4V+ this weak cell will drop instantly and trigger the under voltage again. Such a weak cell can have a delta of around 200mV but will balance to a lower level like 5-10mV until loaded again.

We must also take a clue from those BMSes that do a permanent active balancing from any level and surely although not ideal the designers did think it's a good way. For the above reason I prefer the active balancer vs the passive.

Just my own view and could be flawed.

Thank you all for your detailed and kind words of wisdom.

The original installer is coming next week to do a full service of the system and to check for any problems that could be causing this issue.

I will provide an update once he has been round.

Thank you

16 hours ago, GBF said:

Thank you all for your detailed and kind words of wisdom.

The original installer is coming next week to do a full service of the system and to check for any problems that could be causing this issue.

I will provide an update once he has been round.

Thank you

Hello,

Nive here from Lithium Batteries SA (LBSA).

I am available for assistance to you and your installer in diagnosing the issue with your battery.

Please feel free to contact me directly at 061 476 4824.

To address some of the points previously mentioned:

• Deye inverters establish a connection with LBSA batteries via CANbus, and it is necessary to select BMS mode 00.

• Furthermore, LBSA batteries do utilize Seplos BMS units, which can be accessed using the monitor cable supplied by LBSA. The driver and software are detailed in the product description

  (link below).

https://lithiumbatteriessa.co.za/collections/frontpage/products/built-unit-battery-monitor-cable-2m

• A drop in the state of charge could potentially be attributed to a slow-responding cell or a loose connection.

Morning All,

I had an issue with two LBSA units a few years ago where the one unit was showing almost double cycles per day compared to the older one.

I contacted LBSA and after buying their cable as posted in the reply above, I connected via Teamviewer with them. Their technical assistant remotely check the system and we came up with the simple fix that the firmware for the batteries were not the same. A quick download of the latest firmware was done remotely and the problem of cycles was fixed. Now both batteries are tracking the same in terms of cycles per day.

So, get hold of the cable and install the software and let LBSA connect remotely. I am sure they will sort your issue.

MdF

*******UPDATE*******

Nive from Lithium Batteries South Africa (LBSA) made contact with me on this forum and offered to look into the matter.

She had the battery collected from my house. The battery then received a full service and they found a loose terminal to be the cause of the issue. My battery was returned to my house same day and is now working perfectly.

I cant tell you how impressed I am with LBSA after sales service. Their excellent reviews on Google reviews back this claim up.

Do yourselves a favour and check out LBSA products and support a local business with excellent products and after sales service.

On 2025/04/30 at 7:12 AM, Nive-LBSA said:

Hello,

Nive here from Lithium Batteries SA (LBSA).

I am available for assistance to you and your installer in diagnosing the issue with your battery.

Please feel free to contact me directly at 061 476 4824.

To address some of the points previously mentioned:

• Deye inverters establish a connection with LBSA batteries via CANbus, and it is necessary to select BMS mode 00.

• Furthermore, LBSA batteries do utilize Seplos BMS units, which can be accessed using the monitor cable supplied by LBSA. The driver and software are detailed in the product description

  (link below).

https://lithiumbatteriessa.co.za/collections/frontpage/products/built-unit-battery-monitor-cable-2m

• A drop in the state of charge could potentially be attributed to a slow-responding cell or a loose connection.

Hello Nive,

look at dashboards bellow

I have one LBSA 5 Kw for close to 4 years now.

I have my own monitoring system using Modbus protocol.

I can see every single parameter from the seplos BMS.

No complains except from day one, of the cells cell's (cell number two never reaches full charge).

Bain knows about, as I've informed BMS technical people, they offer to repair it, but I would have to take the battery to your workshop.

I decided to live with it and so far, it has performed well.

Up to date I got almost 3 MW/h out of it, good value for the money.

Good morning, Antonio.

I see what you mean.

Have you tried charging the battery up slightly past its Bulk and Float Voltages to see if it will boost that one cell?
Set the inverter to User-Defined and set the Bulk and Float voltages to 56.8V.

This might be a long shot but it might be worth a try.

If you ever need anything, let us know.

1 hour ago, Nive-LBSA said:

Good morning, Antonio.

I see what you mean.

Have you tried charging the battery up slightly past its Bulk and Float Voltages to see if it will boost that one cell?
Set the inverter to User-Defined and set the Bulk and Float voltages to 56.8V.

This might be a long shot but it might be worth a try.

If you ever need anything, let us know.

Hello Nive,

I have been your best test bench for about 3 1/2 years and I have the archive data to prove it.

Normal runing conditions during load shedding.

I've been running my battery on use define since day one.

Charging current set to 20 Amps, very seldom may change it to 30 Amps, depending on weather conditions.

I will try set the Bulk charging to 56.8 V and float at let's say 56.6 V, I don't know if the Seplos BMS will allow it, it may stop charging and change to equalizing mode once cells reach 3.51 V

Wii let you know the results soon. I should a full battery by about 11:00 Am.

Thanks for the prompt reply.

Cheers.

Edited May 6, 20251 yr by Antonio de Sa

On 2025/05/05 at 9:13 AM, GBF said:

*******UPDATE*******

Nive from Lithium Batteries South Africa (LBSA) made contact with me on this forum and offered to look into the matter.

She had the battery collected from my house. The battery then received a full service and they found a loose terminal to be the cause of the issue. My battery was returned to my house same day and is now working perfectly.

I cant tell you how impressed I am with LBSA after sales service. Their excellent reviews on Google reviews back this claim up.

Do yourselves a favour and check out LBSA products and support a local business with excellent products and after sales service.

That has inspired me. I had a similar issue with my newest purchased Leoch 48100-S pack. From the beginning cell 15 showed significantly higher voltage at charge and lower at discharge. However it couldn't go flat like yours because it's parallel connected with 5 other packs. This being a brand-new pack I contacted the official importer and seller, Averge, with a guarantee claim. But they didn't want to do anything about it. After having red your post I copied it in an email to them and asked to allow me to open the pack without voiding the guarantee to check the cells connections. They wrote me the permission and so I did. I tightened all M4 hexagon bolts of the cell bridges with a socket wrench. Some allowed up to a half turn. After reassembly and re-connection the issue with cell 15 no longer persists. It looks like all cells run the same voltage within a few mV. This proves to me that all cells are in good health. Below pictures taken of the opened pack.

The cell bridges consist of a plate with 2 M4 bolts for each cell terminal. To the left the negative leads to the BMS. Also visible the BMS voltage connections on each bridge.

I think it might be a good idea to do such service after a number of years and expiration of guarantee.

Edited May 10, 20251 yr by Beat