Hello everyone,

First time posting here and need some help with my inverter please.

I have a Mecer SOL-I-AX-5M4 (Axpert) inverter, paired up with Solar Assistant and for some reason, although the Battery absorption charge voltage is set to 56.4v, the battery will only charging at 54v.

Here is a pic of my current settings (Pulled off another thread on here) for my Shoto battery - SDC10-Box 5 (5.12kwh)

This is the current charging of the battery at the moment (On 75%, charging to 95% - It never reaches 100% for some reason and just stops at 95% - That's another issue I need to fix sometime)

 

Anybody able to assist with why it's not charging at the 56.4v that's setup in Solar Assistant - I've checked the WatchPower app and the bulk charge it reflecting the same voltage.

 

58 minutes ago, Gonduir said:

my Shoto battery - SDC10-Box 5 (5.12kwh)

I assume that's a 16S LFP battery. LFP cells have a very flat voltage versus SoC curve; at 1 kW it will take about 4 hours to take the battery from 20% Soc to 100% SoC. Until you get to about 95% SoC, the battery voltage will be quite flat (with a slight change at about 75% SoC). Maybe you just haven't been charging enough, or have enough solar for your loads plus battery charging?

35 minutes ago, Coulomb said:

I assume that's a 16S LFP battery. LFP cells have a very flat voltage versus SoC curve; at 1 kW it will take about 4 hours to take the battery from 20% Soc to 100% SoC. Until you get to about 95% SoC, the battery voltage will be quite flat (with a slight change at about 75% SoC). Maybe you just haven't been charging enough, or have enough solar for your loads plus battery charging?

Thanks for your reply Coulomb, appreciate it.

At the moment, my battery is only being charged using grid power, my solar is being installed this weekend but wanted to understand if there was something wrong with my current setup.

Since posting for help, my battery started charging at 55.6v once it reached 95% and stopped charging at 98%, it's gone back to the float voltage of 54v.

What I understand from your advise, everything seems fine with the current setup and battery, will just have to see once my solar is installed. 

Wanted to ask another question regarding updating the firmware of the inverter.

I've read the forum post here but it's very confusing to me if my firmware can be updated.

Is someone able to assist me with understanding how to tell if my inverter can be updated to a newer firmware version?

The current firmware version is 52.00.

16 hours ago, Gonduir said:

I've read the forum post here but it's very confusing to me if my firmware can be updated.

That post was from early 2019, and is very 5 kVA specific. Now there are 5.6 kW models like yours, and 7.2, 8, 10, and 11 kW models. As well as the smaller power models.

And yes, it is confusing.

I don't have any 52.xx firmware to confirm, but I'd be 95% sure that 52.xx firmware is the equivalent of 74.xx firmware (for the Axpert MKS IV, there are overlaps with other models' version numbers), except for the '28066 chipset.

So if you have a specific problem you want addressed, you could ask your supplier for a firmware update, or watch the forums for an update.

20 hours ago, Gonduir said:

although the Battery absorption charge voltage is set to 56.4v, the battery will only charging at 54v.

I assume your setting 01 is SbU. With setting "Back to battery mode" at 54V the inverter will go back to that mode at 54V and stops charging from grid. Since you did not have any PVs there was no further charging.

On 2023/11/03 at 2:13 PM, Gonduir said:

Since posting for help, my battery started charging at 55.6v once it reached 95% and stopped charging at 98%, it's gone back to the float voltage of 54v.

Try increasing your bulk charge time to 120mins, so the battery has time to balance before the inverter goes to float. When balancing, the battery will switch on and off and the current drops to zero and the inverter will think the battery is full and switches to float.

1 hour ago, jumper said:

Try increasing your bulk charge time to 120mins, so the battery has time to balance before the inverter goes to float. When balancing, the battery will switch on and off and the current drops to zero and the inverter will think the battery is full and switches to float.

Generally it sounds OK. There is the problem if cells are not very well balanced at the top end and after a number of charge/discharges that in this 120min while waiting for balancing that 1 or more cells could reach the upper level of 3.65V and give a fully charged signal to the inverter to stop bulk charging. 

@WannabeSolarSparky

Showed us how quick balancing can be with balanced cells. 

On 2023/11/04 at 6:29 AM, Coulomb said:

That post was from early 2019, and is very 5 kVA specific. Now there are 5.6 kW models like yours, and 7.2, 8, 10, and 11 kW models. As well as the smaller power models.

And yes, it is confusing.

I don't have any 52.xx firmware to confirm, but I'd be 95% sure that 52.xx firmware is the equivalent of 74.xx firmware (for the Axpert MKS IV, there are overlaps with other models' version numbers), except for the '28066 chipset.

So if you have a specific problem you want addressed, you could ask your supplier for a firmware update, or watch the forums for an update.

Thanks! There isnt a specific problem I would like to fix, being in the IT industry I like to keep my devices on the latest firmware  I'll keep and eye out of the forums for a version that would work with my inverter. 

6 hours ago, jumper said:

Try increasing your bulk charge time to 120mins, so the battery has time to balance before the inverter goes to float. When balancing, the battery will switch on and off and the current drops to zero and the inverter will think the battery is full and switches to float.

Thanks Jumper, I've tried to set the setting for balancing charging and the charge time - The ability to active Balance Charging work but when setting the timeout for it to 120 seconds, it doesn't seem to accept the value I input and when I query it, it looks like the value has been removed.

Do you have any idea why this might happen?

 

Your battery probably is going into over voltage protection on one of the cells that's not balanced...on a new battery there can easily be a 200mv inbalance between cells. If just one cell reaches 3.65v over voltage protection kicks in.

Thanks Froggy - Is this something I need to worry about or change something in the settings to stop it from going into voltage protection?

The BMS will balance the battery over time....no idea what BMS is In the Shoto battery,or if there's a active balancer. It can take many weeks for a passive BMS with low balance current to get the cells even. Most batteries stert balancing at 3.45v per cell.

Set absorption change to 55.2v...and float to 55v.

At 3.45v per cell battery will change to about 99% full. And it gives the opportunity for cells that are at a higher voltage to balance.

Also set change current lower...50A or less ... preferably 30A

Interesting video on the quality of the Shoto Bms.

 

18 minutes ago, TaliaB said:

Interesting video on the quality of the Shoto Bms.

 

retrofit with JK BMS 🥰 problem solved 🙃

14 hours ago, Gonduir said:

The ability to active Balance Charging work but when setting the timeout for it to 120 seconds, it doesn't seem to accept the value I input and when I query it, it looks like the value has been removed.

Equalisation and timed absorb are different things. The timed absorb and equalisation time settings are in minutes: 120 means 120 minutes, or two hours.

21 hours ago, Scorp007 said:

Generally it sounds OK. There is the problem if cells are not very well balanced at the top end and after a number of charge/discharges that in this 120min while waiting for balancing that 1 or more cells could reach the upper level of 3.65V and give a fully charged signal to the inverter to stop bulk charging. 

@WannabeSolarSparky

Showed us how quick balancing can be with balanced cells. 

Unfortunately the seplos BMS doesn't balance as quick as an active balancer like @WannabeSolarSparky has installed. When it goes into balancing at +95% it does a few different things... it limits the current to 10A, but it also does what is called 'intermittent charging' where the battery actually switches between charging, discharging and standby constantly every few seconds while it burns off charge in the highest cells, so it takes much longer to balance. This behavior also drops the current to zero every time the battery goes into standby which the inverter can mistake as the end of the charge cycle. Balancing might be quicker than 120mins, I just use that to be sure in case of bad weather (I'm off grid) because once the battery reaches 100% it disconnects the cells from the DC bus anyway and the cells will settle, so they won't sit at bulk voltage the whole time.

 

10 hours ago, TaliaB said:

Interesting video on the quality of the Shoto Bms.

There was a known batch of batteries which had a bad diode installed due to the covid shortages (I think in the BMS), but afaik they were being fixed under warranty without any questions.

16 hours ago, Gonduir said:

Thanks Jumper, I've tried to set the setting for balancing charging and the charge time - The ability to active Balance Charging work but when setting the timeout for it to 120 seconds, it doesn't seem to accept the value I input and when I query it, it looks like the value has been removed.

Do you have any idea why this might happen?

As @Coulombmentioned above this is the equalization setting, you need to change the 'timed absorb' to 120mins (you can change this later once you've seen how long it actually takes to balance your battery)

13 hours ago, Froggy said:

At 3.45v per cell battery will change to about 99% full. And it gives the opportunity for cells that are at a higher voltage to balance.

The seplos BMS will only start balancing cells above 3.5V, so some cells need to get that high. Also, if you don't charge to 100% fairly regularly you can start to get SOC drift.

Thanks Jumper, really appreciate the assistance  I'll play around with the settings to get the equalization working on the inverter to the battery.

The manufacturing date of my battery says it from 30/09/2022, hope that is outside the Covid issues that were seen in previous batteries.

At the moment there are no issues with the battery or inverter that I can see, it just worries me that it stays on 95%.

9 hours ago, Coulomb said:

Equalisation and timed absorb are different things. The timed absorb and equalisation time settings are in minutes: 120 means 120 minutes, or two hours.

Thanks, I'll play around with it and try have watch power accept the settings like you suggested  

17 hours ago, Gonduir said:

I'll play around with the settings to get the equalization working on the inverter to the battery.

If you don't have timed absorb (bulk charging time) on your inverter (should be setting 32) you can use the equalization function. I run equalization on my shoto at 57V every 5 days aswell just to make sure it gets a full charge in case the weather has been bad. If you had comms between the inverter and battery it would be automatically charging to 57.8V to set it to 100%SOC, but that means an overvoltage protection on every charge, which I don't like, I get to 100% with 56.4V, it just might take a little longer.

17 hours ago, Gonduir said:

The manufacturing date of my battery says it from 30/09/2022, hope that is outside the Covid issues that were seen in previous batteries.

It shouldn't be a problem with your battery, it was the older SDA48100 model which I have that had this issue, the SDC10-Box5 came out after that so I wouldn't worry about it.