Mecer/Axpert Inverter Settings

[Jesse]

Thanks Coulomb

[Jesse]

Hi Guys

I just got two more panels in order to maximize my system to accommodate an added intermittent load of a small cabin, so I will now have a total of 8-300W 72 cell panels hooked up 2S4P [changing from 3S2P as per Coulomb's suggestion].

Some research I've come across recently seems to point to Lithium-Ion batteries not liking to have a full charge, and with the added panels they will be fully charged even more than usual, especially since the added load is intermittent.

With this in mind, or for any other reason, are there any changes in the settings that are needed/suggested?

My current Off-The-Grid system:

• Mecer SOL-I-AX-3MPlus48 Inverter/Charger [installed 2016 with three panels]
• 8-300W 72 cell Enersol &/or Renewsys panels [hooked up 2S4P, oriented to the NE and tilted at 45 degrees]
• 2-US3000 Pylontech Batteries [installed Feb 2020 & have not gone below two bars]
• Yamaha EF5500FW Generator [not needed since I went to 6 panels and the Pylontechs Feb 2020]

Current settings:

01, U?I [Utility first]

02, 20A [Maximum charging current]

03, UPS [AC input voltage range]

04, SDS [Power saving mode disabled]

05, USE [Battery type]

06, L?E [Restart enable]

07, ??E [Restart enable]

09, 50Hz [Output frequency]

11, 15A [Maximum utility charging current]

12, 48 [Irrelevant, since I have selected U?I in Program 01]

13, 54 [Irrelevant, since I have selected U?I in Program 01]

16, CU? [Charger source priority]

18, BOF [Alarm control]

19, ?EP [Auto return to default display screen]

20, LOF [Backlight control]

22, AON [Beeps while primary source is interrupted]

23, BYE [Overload bypass]

25, FEN [Record fault code]

26, 53.2 [Bulk charging voltage] - Swellendam, Western Cape

27, 50.5 [Floating charging voltage]

29, 46 [Low DC cut-off voltage]

 

[Coulomb]

4 hours ago, Jesse said:

16, CUt [Charger source priority]

I'd be tempted to change this to SNU (Solar aNd Utility charging). May as well make use of whatever solar is there, enen though you'd only be using utility (generator) when solar is poor.

4 hours ago, Jesse said:

26, 53.2 [Bulk charging voltage] - Swellendam, Western Cape

27, 50.5 [Floating charging voltage]

Especially with extra panels, the likelihood of overshoot means that you should change setting 26 to 52.5 V. The Pylontech BMS cuts off at 54.0 V, which is uncomfortably close to 53.2 V.

Generally, 51.8 V is used for the float setting (when not using 53.2 V), but 50.5 is fine (closer to what I run myself).

[Jesse]

Thanks Coulomb!

[nmb100]

Hi. I am very new to the inverter world, but saw this post and think it relates to my queries. I have the 3kV Axpert inverter with 24V (2 x 12V) AGM batteries linked and no solar, simply charging the batteries from a plugpoint, not directly onto the DB board.

1. I cannot get the Watchpower software to work with a PC (I had to find one with a serial COM port). The software installs fine, but it is not communicating with the inverter. The PC I am using is Windows XP. Any thoughts? I have changed the baud rate to be the same on the PC com port and Watchpower. I thought about trying to make a RJ45 to RJ45 network cable, which would then alleviate issues of distance a lot, but am not sure which Rx/Tx/GND wires to use.
2. From what I can tell, using settings 26, 27 and 29 enables me to turn off the inverter when say we have a major power outage and the batteries are depleted to a specified level. Am I able to set the batteries to continue discharging, even if the Utility power returns, until almost the depleted setting? I was informed by my battery guy that discharging the battery to only 80% remaining, uses a full battery cycle, whereas running it to around 20% remaining, then switching back to the mains, will lengthen the battery life as the cycle will not be used.

Thanks. If anyone could be of assistance, I would be greatly appreciative.

[Coulomb]

14 hours ago, nmb100 said:

Hi. I am very new to the inverter world,

Welcome.

1. Quote

   I cannot get the Watchpower software to work with a PC (I had to find one with a serial COM port).

You don't need one with a serial port; most of us use a USB to serial adapter.

 

Quote

The software installs fine, but it is not communicating with the inverter.

Does your model have an RS-232 port (using an 8-pin RJ-45 connector)? Or just a USB-B connector, as you'd find on a printer?

If it has the RJ-45 connector, did it come with an RJ-45 to D9 cable? If so, are you using that cable?

You need to use that cable to convert the non-standard RJ-45 connector to standard D9 connector.

 

Quote

The PC I am using is Windows XP. Any thoughts?

That should be fine.

Quote

I have changed the baud rate to be the same on the PC com port and Watchpower.

You don't have to do that; Watchpower changes the bit rate etc automatically.

Quote

I thought about trying to make a RJ45 to RJ45 network cable...

? RS-232 is very different to networking. They are totally different protocols.

Quote

From what I can tell, using settings 26, 27 and 29 enables me to turn off the inverter when say we have a major power outage and the batteries are depleted to a specified level.

It's actually only setting 29. 27 and 27 are for charging, not discharging.

Quote

Am I able to set the batteries to continue discharging, even if the Utility power returns, until almost the depleted setting?

You could, but it's a bad idea.

Quote

I was informed by my battery guy that discharging the battery to only 80% remaining, uses a full battery cycle, whereas running it to around 20% remaining, then switching back to the mains, will lengthen the battery life as the cycle will not be used.

Sorry, your battery guy is misinformed. The lower the discharge of any lead acid battery, the longer its life. Since you are using this for regular load shedding (I presume), you should change setting 29 to cut off the inverter at a higher voltage that the default. The default value is set assuming that losing utility is a rare thing, and you want the longest run time when that rare thing happens. But with regular load shedding, that will kill a lead acid battery in a matter of months. Try to get the inverter to shut down at around 50% SOC (still harsh for the battery, but nowhere near as bad as defaults), which is often about 24.0 V battery voltage (depending on loads). 24.0 V is probably the highest you can make that setting (the low DC/battery cut-off voltage, setting 29). Yes, this will shorten run-time during a blackout, but it's the only way to have the battery last.

[Ismail]

Hi all

 

First post... here goes  

 

I have solar power system installed at my house for just over a year now and my issue is that I am not maximising my solar production since my battery almost never drops below 80% and is fully charged before 12am on most days (attached images refer). The system uses grid power to charge the battery once it goes below 80%

 

Unfortunately my installer has passed away so I now need to change the setup myself and I'm hoping to get some assistance from the solar gurus on this forum.

 

My system details are as follows

1 * Axpert Type MKII 5kVA

1 * Narada Lithium Iron 4.8kW 100ah battery

4 * 330W Polycrystalline Panels connected in 1 string

1 * Raspberry pi monitoring software

 

 

My inverter settings are as follows

01, SBU [SBU Priority]

02, 40A [Maximum charging current]

03, APL [Appliances (Default)]

04, SDS [Power saving mode disabled (Default)]

05, USE [Battery type]

06, LTE [ Restart when overload - Enable]

07, LTD [Restart when over temperature- disable (Default) ]

09, 50Hz [Output frequency]

11, 40A [Maximum utility charging current]

12, 46 [Back to utility setting]

13, 49 [Back to battery mode setting]

16, SNU [Charger source priority - Solar and Utility]

18, BON [Alarm control - ON]

19, ESP [Auto return to default display screen]

20, LON [Backlight control]

22, AON [Beeps while primary source is interrupted]

23, BYE [Overload bypass- Enable]

25, FDS [Record fault code - Disable]

26, 51.6 [Bulk charging voltage]

27, 51.5 [Floating charging voltage]

29, 44 [Low DC cut-off voltage]

31, SBE [Solar Power Balance - Enable (Default)]

33, EDS [Battery equalization - Disable (Default)]

34, EV [Battery Equalization Voltage - 58.4 (Default)]

35, 35 [Battery Equalized Time - 60 (Default)]

36, 36 [Battery Equalized Timeout - 120 (Default)]

37,  37 [Equalization Interval - 30d (Default)]

39, AdS [Equalization activated immediately (Default)]

 

These settings correspond to the Narada recommended settings which I also found on this forum (see attached image)

 

I looked at a friends installation (done by the same installer) and the settings on his inverter are identical to mine but his batteries drop to 60% and this was setup by the installer remotely. What software do I need to do the changes remotely and what values will I need to change?

Further, do my settings look fine? are there any changes that could be made on the inverter itself that will get me more solar power production?

 

 

Edited March 24, 2021 by Ismail

[Coulomb]

14 hours ago, Ismail said:

The system uses grid power to charge the battery once it goes below 80%

Is that according to the battery or the inverter? Because the inverter will make a wild guess assuming a lead acid battery. Does whatever creates those graphs get its information from the battery BMS via a cable?

14 hours ago, Ismail said:

my battery almost never drops below 80%

That's pretty weird considering setting 12 (46 V), which would be about 1% SOC for a 15S LFP battery (I'm guessing that's what the Nerada is inside). Hopefully I'm wrong about that.

Can you post a graph of battery voltage?

14 hours ago, Ismail said:

do my settings look fine?

They agree with the manufacturer's setting as shown in the photo above, but those are some weird settings (especially settings 12 and 13). Perhaps Nerada make several 100 Ah 48 V batteries: are you sure yours is an 48NPFC100?

I've just had a quick search on the 'net, and can't decide whether it's 15S or 16S. I see one datasheet recommends 54.0 ± 0.5 V charging (doesn't say whether that's absorb or float). That's rather different to the 51.6 V that you are using, and corresponds to 3.60 VPC (usually absolute max never-exceed for LFP).

I wonder if you're actually not charging your battery properly, despite following the manufacturer's suggested settings. And this is somehow confusing the BMS, thinking it's at 100% when it's actually well below.

 

 

Edited March 25, 2021 by Coulomb

[Ismail]

37 minutes ago, Coulomb said:

Is that according to the battery or the inverter? Because the inverter will make a wild guess assuming a lead acid battery. Does whatever creates those graphs get its information from the battery BMS via a cable?

As far as I understand it is according to the battery. There is an RS485 that is connected from the battery to the Raspberry Pi.

37 minutes ago, Coulomb said:

That's pretty weird considering setting 12 (46 V), which would be about 1% SOC for a 15S LFP battery (I'm guessing that's what the Nerada is inside). Hopefully I'm wrong about that.

Looking at the spec sheet attached, it shows that the discharge end voltage is 40.5V. Would this correspond to a fully depleted battery and does this mean that the Narada just runs at a much lower voltage?

 

37 minutes ago, Coulomb said:

Can you post a graph of battery voltage?

Sure, this todays graph. The 80% corresponds to 49.5V. Today was a gloomy day in JHB and we only got good sunshine in the afternoon 

37 minutes ago, Coulomb said:

They agree with the manufacturer's setting as shown in the photo above, but those are some weird settings (especially settings 12 and 13). Perhaps Nerada make several 100 Ah 48 V batteries: are you sure yours is an 48NPFC100?

100% as it's on the manual and cover of the battery

37 minutes ago, Coulomb said:

I've just had a quick search on the 'net, and can't decide whether it's 15S or 16S. I see one datasheet recommends 54.0 ± 0.5 V charging (doesn't say whether that's absorb or float). That's rather different to the 51.6 V that you are using, and corresponds to 3.60 VPC (usually absolute max never-exceed for LFP).

I wonder if you're actually not charging your battery properly, despite following the manufacturer's suggested settings. And this is somehow confusing the BMS, thinking it's at 100% when it's actually well below.

Thanks, I will try and find the local battery supplier find out if the battery is being charged properly. I do however think the battery is actually full since I have never run out of battery power and I use power liberally even if there is no grid feed for over 4 hours at night.

48NPFC100.pdf

[Coulomb]

7 hours ago, Ismail said:

Sure, this todays graph.

Those roughly 2-hourly spikes in the battery voltage graph make me think you are switching between line and battery modes many times at night. That's not ideal, cycling the battery unnecessary.

Or perhaps you have a load that cycles like that. The battery voltage sag seems high to me if that's the cause.

[Ismail]

4 hours ago, Coulomb said:

Those roughly 2-hourly spikes in the battery voltage graph make me think you are switching between line and battery modes many times at night. That's not ideal, cycling the battery unnecessary.

You are correct. Each time the battery goes to the 80% the utility takes over to feed the house and the battery is charged. My battery is set to charge at 40A, It seems like I don't really need to charge the battery this fast. Would reducing this current to 30A or 20A for example increase the life span of my battery? This will also result in a lower number of cycles because the battery will be charging for longer instead of continuously charging and discharging  

4 hours ago, Coulomb said:

Or perhaps you have a load that cycles like that. The battery voltage sag seems high to me if that's the cause.

Thank you. I will investigate this further 

[Coulomb]

3 hours ago, Ismail said:

My battery is set to charge at 40A, It seems like I don't really need to charge the battery this fast.

You could leave the maximum charge current at 40 A, and set the maximum utility charging lower, 30/20/10 A. That way if you happen to have a short period of intense sun, you can make the most of it, while still preventing most of the cycles at night. Those cycles are hard on the relays as well as on the battery.

It still should not be cycling at night, though. I can't see what's causing that.

 

[Ismail]

4 hours ago, Coulomb said:

You could leave the maximum charge current at 40 A, and set the maximum utility charging lower, 30/20/10 A. That way if you happen to have a short period of intense sun, you can make the most of it, while still preventing most of the cycles at night. Those cycles are hard on the relays as well as on the battery.

It still should not be cycling at night, though. I can't see what's causing that.

 

Thanks Coulomb. I will change accordingly. I will work continue looking for a solution and post once found

[Ismail]

On 2021/03/26 at 3:29 PM, Ismail said:

Thanks Coulomb. I will change accordingly. I will work continue looking for a solution and post once found

Hi Coulomb,

 

I've managed to resolve the issue. It's a simple setting on the ICC software. The user selects "Back to Grid" percentage and "Back to Solar" percentage. This has nothing to do with the settings programmed on the inverter.

 The setting only works if you have the Narada communication cable that reads the actual battery SOC and not just the estimate in terms of the voltage  

[Rowansear]

Hi guys, please can you help me, i have a Mercer 8kva inverter, when i connect the 3.6kwh 48v 70Ah lithium ion phosphate battery, when i put the inverter under load, there is a clicking noise inside the inverter and the lights switch on and off with the clicking of the inverter

 

[Coulomb]

7 hours ago, Rowansear said:

i have a Mercer 8kva inverter, when i connect the 3.6kwh 48v 70Ah lithium ion phosphate battery,

That's a very small battery for a quite large inverter.

Most LFP batteries are rated at 0.5C continuous; that means that a 3.6 kWh battery can only supply 1.8 kW (at the battery terminals; less at the load) before it eventually cuts off. 1.8 kW is only 22% loading for the 8 kW inverter. The BMS might allow 1C for a short time, but that's sill only 3.6 kW. The manual recommends a minimum of a 250 Ah* battery; that would be for a lead acid battery, you could probably get away with half that in LFP. But that's still about twice what you have.

What sort of loads were you running when the problem occurred?

* That's for a 7.2 kW model; an 8 kW model may require 275 Ah.

Edited October 16, 2021 by Coulomb

[ShaneR]

Hi all, 

 

Super new to all this, Im no electrical engineer, but I think Im just not getting the best out of my inverter setup at all..
after 2 hour loadshedding the battery voltage is at 22.8 and they do not last a full 4 hour loadshed.

surely this setup should for the load I have on it sustain?

The batteries are new, had them for around 2 months, I have had them loadtested, results were perfect?

I have a:
Mecer SOL-I-AX-3VP inverter

with 4x 120AH TOYO gel batteries connected to it in Series

Its a simple setup I know, but its all I could afford.

The system is connected to a Sub DB which is connected to my main DB to 2 wall plugs (my home office and lounge for TV and fiber) and 1 breaker of lights (Home office and Lounge)

I do not have any solar connected to my system (yet) so I rely on Utility to charge the batteries between load shedding.

I just use it to power my home office for my wife and I, the average Load is around 400W and max up to 600W if we are using the lights or watching tv.

The settings of my inverter I think are a mess, I have tried to read all I can but I just need some advice please.

I have for battery type (05) FLd set as I thought that means Flooded batteries which Gel are?

 

I have no idea what's going on

I had this installed by a qualified elec and I have a coc so the connections are all good, but the settings he said are up to me... 

 

HELP!

[ShaneR]

well I just came across something it seems i was following the "stand by" battery voltages and not the cyclic battery voltages 
I didn't want to throw heaps of power at the batteries in thinking they would last longer, it seems i may have been doing them an injustice...

 

I have now, increased the voltages to the cyclic recommendations on the side of the batteries, 

hopefully this makes a difference, 

still any settings advice would be greatly appreciated 
 

[jumper]

11 hours ago, ShaneR said:

well I just came across something it seems i was following the "stand by" battery voltages and not the cyclic battery voltages 

This was most likely the issue and you were undercharging. I use the cyclic voltages for bulk charge and the standby voltages for float and use the range for different temps. I use the higher voltage in the ranges in winter and the lower in summer.

The FLD setting is for flooded batteries where you can replace the water, the AGM setting would be better, but USE mode with manual voltages to suit your battery and temps is much better.

Also make sure your batteries are charging fully between load sheds, you might have to push up the amps if possible or your batteries will deteriorate much quicker.

[ShaneR]

@jumper - Thank you so much for the response!

Yeah, these 120ah batteries say they can be charged at 38amps I am currently charging them at 20A

perhaps pushing it up to 30A during winter might be better, they are in the garage on a wooden rack, but it is freezing in there in winter, so temps should be ok for them.

 

I am using the USE mode for battery type

Bulk charge is now set to 29.2V
Floating Charge is set to 28.6V
the inverter has a "battery equalization" which is on, and set to 30V

Do these look ok to you?

I have 4x 120ah bats, cyclic use says charge at 14.4V to 15V Ive kept it in that range without going to the MAX, but any other suggestions will help!

 

thank you !!

 

 

 

[jumper]

12 hours ago, ShaneR said:

@jumper - Thank you so much for the response!

Yeah, these 120ah batteries say they can be charged at 38amps I am currently charging them at 20A

perhaps pushing it up to 30A during winter might be better, they are in the garage on a wooden rack, but it is freezing in there in winter, so temps should be ok for them.

 

I am using the USE mode for battery type

Bulk charge is now set to 29.2V
Floating Charge is set to 28.6V
the inverter has a "battery equalization" which is on, and set to 30V

Do these look ok to you?

I have 4x 120ah bats, cyclic use says charge at 14.4V to 15V Ive kept it in that range without going to the MAX, but any other suggestions will help!

 

thank you !!

No problem, your settings look good, you can maybe lower the float a little, I use 27.6V as my bats settle to just over 13V.

I would set the equalization to run for 30mins only and can probably run once a week. Good idea not to charge to max voltage, the equalization will take care of that.

If 20A works for you then I would leave it, but if it's not enough to charge between load shedding then push it up to 30A. I'm sure temps will be fine, these aren't very high charge currents.

Hopefully that keeps things running smoothly.

[Hilton B]

On 2018/09/18 at 3:57 PM, Chris Hobson said:

1. With  900W of Enersol panels the inverter is not going to manage to even charge at 20A so that setting is fine.
2. I would be happier with 54V especially since you have hot summers.
3. I would prefer to get the solar to charge the batteries rather than grid. I would go with 54V may be 55V
4. Good idea
5. The Axpert SOC setting are notoriously poor. I would tend to ignore those settings. I would get hold of a Victron BMV so that you can monitor your batteries. Using the Axpert SOC settings is like driving a car without a fuel guage. You are going to come up short somewhere along the line.

Those Vision batteries are VRLA (Valve Regulated Lead Acid) batteries and it is not recommended to equalise them better to get an HA02 or Victron battery balancer.

If you want you can post you inverter settings and with your input  we can optimise your settings.

Hi All, I'm also running VRLA Gel batteries. I read somewhere on this forum setting float at 13.6v as recommended by the battery manufacturer Allgrand, equalize can also be 13.6v., thus eliminating any further costs for a battery balancer.

Edited June 19, 2023 by Hilton B
Added comment.

[Arrio van der Westhuizen]

Good day

I have a 5600w Mecer inverter with 3 x 51.2v100ah lifepo4 batteries. When I switvh it over it barely lasts 2hours. Can someone please assist with the correct settings for the inverter?

[jumper]

On 2024/02/23 at 8:00 PM, Arrio van der Westhuizen said:

Good day

I have a 5600w Mecer inverter with 3 x 51.2v100ah lifepo4 batteries. When I switvh it over it barely lasts 2hours. Can someone please assist with the correct settings for the inverter?

Are your batteries charging to 100%? If so then it is probably your cutoff voltage that needs to be dropped. What is it set to?

[Coulomb]

When a battery is advertised as being 51.2 V nominal, that usually means it's 16S (51.2 / 16 = 3.20 VPC). A 48 V nominal battery is usually 15S (48.0 / 15 = 3.20).

Most suggested LFP battery voltages are for Pylontechs, which are 15S. So your bulk charge voltage should be up around 55.2 - 56.0 V (3.45 - 3.50 VPC average).