Axpert DOD setting up

[djacobs]

Our friends ledsolarworld.

[Guest]

Here they are: http://powerforum.co.za/topic/446-all-about-batteries/

You need to connect the inverter at opposite ends of the bank, I presume yours are?

[viper_za]

A quick look through the settings and they all seem to be okay.

The only thing is it looks like they have it setup to charge from Eskom when solar is not available

As TTT said battery balancing with your 3 banks is very important

41 minutes ago, djacobs said:

Hi Guys, I am lost with all these calculations. I am not as qualified and only dependant what was installed, but my gut tells me the settings are wrong. Please assist.

01 Sol Output source priority Solarfirst, here most of us use SbU

02 60A  (Max. charging current = utility charging current +  solar charging current)

03 apl Most of us use UPS here

04 sds Power saving mode - Disabled

05 use Battery type User-Defined

06 lte Auto restart when overload occurs - Enabled

07 lte Auto restart when over temperature occurs - Enabled

09 50hz Output frequency

11 30amp Maxiaxim utility charging current

12 46V Voltage point back to Utility

13 54V Voltage point back to Battery mode

16 cso Charger source priority - Solar first, utility only when solar is not available

18 bon Alarm control - on

19 tep Auto return to default display screen

20 lon Backlight control

22 aon Beeps while primary source is interrupt - on

23 byd Overload bypass - Off

25 fds Record Fault code

26 58.4V Bulk charging voltage (Highest you can go will have to do)

27 52.8V Floating charging voltage (This matches the datasheet)

28 sig dont see this in the manual

29 42V Low DC cut-off voltage (This is our problem with the Axpert, If you change this setting the SOC calculations go all wrong, 42V is way too low for us. This is why we install the Victron BMV to get a accurate reading)

30 one dont see this in the manual

31 41V According to the manual this should be Solar power balance: Sbe = Max. input solar power = battery charging power + Connected load power

I have 12 x 250w panels, 12 x 105amp/h dixons, 1 x 5kw axpert. There 4 x batteries connected together. Please guys, help a man inneed.

0827600417

Daniel

 

[Guest]

Suggestion on how to connect the 12 x 105ah, with battery balansers as per what the experts on that would advise.

Note: Cable length from batt - to inverter - and batt + to inverter + should be same length, as short as possible.

 

[viceroy]

I still prefer the use of a bus bar rather than the "opposite connect" method when using parallel strings.

[Guest]

I agreed wholeheartedly Viceroy. DJacobs has been suggested that option also.

The guys who installed it all for him (facepalm). 

[Coulomb]

On 22/02/2016 at 3:38 AM, viper_za said:

The Max the Axpert can do is 58.4V.

Will go through your settings now

Actually, there is a model that will go to 61 V, and handle up to 63 V without exploding. It's an "OEM" model, but I don't really know what that means. It is also an "economy" model, so it may be missing some features. I have not had time to check, and I need to run right now or I'd post a link.

[SilverNodashi]

10 hours ago, Coulomb said:

Actually, there is a model that will go to 61 V, and handle up to 63 V without exploding. It's an "OEM" model, but I don't really know what that means. It is also an "economy" model, so it may be missing some features. I have not had time to check, and I need to run right now or I'd post a link.

OEM means it's open for companies to re-brand, i.e. like how Mustek rebrands them as MECER models. 

[Coulomb]

4 hours ago, SilverNodashi said:

OEM means it's open for companies to re-brand, i.e. like how Mustek rebrands them as MECER models. 

Yes, but I thought they all were.

[Gman007]

On 2015/09/10 at 12:26 AM, Alex said:

Hi alistair, I had the same issue with my Axpert 3KVA. The battery capacity % is directly linked to your battery cut-off voltage setting (21V by default, calculated 10.5V x 2). The software assumes that at 21V your batteries are at 100% DOD so when you change the cut-off voltage to say 23V the software thinks your batteries are empty at 23V which they are not. The Axpert doesn't calculate SOC accurately the % will change quickly depending on load. Unless you have a battery monitor like the Victron BMV 700/702 you're driving a car without a fuel gauge but that's okay if you're willing to do a few calculations.

 

There is nothing is wrong with your batteries or charger don't try to trick it by reducing the bulk charge voltage you will under charge your batteries, the charger doesn't look at your % reading but at voltages so if you're on AC and the battery is at 100% your batteries are actually full. The battery cut-off voltage setting when changed from default (21V) is calculated incorrectly when you switch to battery mode thus giving you the 60% SOC.

 

I have 2x 12V 150Ah C/10 batteries connected in series:

 

How I calculate DOD in it's simplest form.

----------------------------------------------

Formula: Volts x Amps/H = Watts/H

----------------------------------------------

In my case this is 24V x 150Ah = 3600 Watts/Hour

so if I pull a average 600W load that will give me 3600W / 600W = 6 Hours

but I only want to use 50% DOD so 6 H / 2 = 3 Hours

with this calculation I then run a test to see what my voltage is after 3 Hours under an average 600W load.

These calculations assume the inverter runs at 100% efficiency which it doesn't so I always take off 10Ah from my calculation to compensate for energy loss to be safe.

 

Another way would be to look at the average amps/hour, the Axpert 3KVA will give you a reading eg. 25Ah @ 600W you divide this by your capacity.

So if I want to use 50% DOD that will be 150Ah / 2 = 75Ah.

75Ah / 25Ah = 3 Hours @ 600W. 

 

You can also use this online calculator which takes Puekert

Hi Alex. So if you have a BMV how do you allow it to switch off your inverter at 50% battery SOC?

[Coulomb]

1 hour ago, Gman007 said:

if you have a BMV how do you allow it to switch off your inverter at 50%

What most saffers do is they buy the ICC monitoring software, which polls the BMV regularly, and when it reaches 50% (or whatever the setting is), the Pi running ICC sends a command or two to the inverter to switch it to line / bypass mode. So then the battery is no longer being discharged, and depending on solar availability and settings, may start getting charged.

[Gman007]

4 hours ago, Coulomb said:

What most saffers do is they buy the ICC monitoring software, which polls the BMV regularly, and when it reaches 50% (or whatever the setting is), the Pi running ICC sends a command or two to the inverter to switch it to line / bypass mode. So then the battery is no longer being discharged, and depending on solar availability and settings, may start getting charged.

Is there something else that I can use instead of the ICC monitoring software?

[___]

35 minutes ago, Gman007 said:

Is there something else that I can use instead of the ICC monitoring software?

There used to be several people making their own versions of this some years ago. On github I also see a script or two. From the beginning I thought there is room for something open source, and some years ago we used to debate this furiously. Sadly the intersection between computer programmers and axpert owners seems to be an empty set.

[Coulomb]

11 hours ago, Gman007 said:

something else that I can use instead of the ICC

There was SolarMon software, and a thing called Lucibus. I just copied those from the index of the PIP-4048MS and PIP-5048MS AEVA topic. I have no idea of those are still active, or if they will do what you want.

[Gman007]

Thank you appreciate it.

[Gman007]

Now I have to buy a whole software and rapberry PI to do relaying to cut off inverter when batteries reach 50% SOC

[Coulomb]

4 hours ago, Gman007 said:

Now I have to buy a whole software and rapberry PI

If you want to stop the inverter at very close to 50% SOC, yes.

But if you don't care too much how close it is, there are other ways.

For example, use settings 12 and 13 on the Axpert to stop the inverter from discharging past a certain battery voltage, which corresponds roughly with 50% SOC with your typical loads.

The BMV may have a facility for driving a relay at a certain SOC, or if not, some battery monitoring device similar to it.

[Gman007]

Hello thank you, yes I tried that cut off setting but then the inverter cuts off way too early its not capable of seeing the capacity and how much is drawn. Is there somewhere instructions how to setup the ICC software to cut off the inverter using the BMV? Yes my BMV have a relay funtion its the BMV 712

[Nonlinear]

@Coulomb I was wondering if your 73.00e firmware will also help with respect to DOD on older batteries specifically with the "KettleComp". It should prevent unnecessary switching when DOD is not as deep as the Axpert thinks. I think though that the 73.00e is not applicable to these smaller inverters.

[Coulomb]

1 hour ago, Nonlinear said:

I was wondering if your 73.00e firmware will also help with respect to DOD on older batteries specifically with the "KettleComp".

Yes, KettleKomp™ would help, if it was available.

Quote

I think though that the 73.00e is not applicable to these smaller inverters.

Yes, KettleKomp™ has not been "ported" to smaller inverter firmwares, indeed only to two firmwares. There are something like 150 individual patches, some involving new code, for a full patch set like 73.00e or 72.20e.

[Nonlinear]

Thanks @Coulomb. To be honest I've been pondering switching to the 73.00e from my current 72.70c now that my batteries are getting older and especially I have actually seen the kettle cause exactly this kind of trouble where the system switches even though the real DOD is not as poor as the Axpert thinks. I'm a little nervous though, the 72.70c firmware has served my two Axperts (in parallel) really well. Is it worth it?

[Coulomb]

23 minutes ago, Nonlinear said:

Is it worth it?

It could be said that I'm not the most unbiased person to make this decision 

There is little additional risk to this (since you are already running patched firmware), and it doesn't take much effort to flash two inverters once you've done it before (so you know you have the right equipment, and what to expect).

The newer firmware won't eliminate all switches due to heavy loads, but it certainly seems to help. So in my biased opinion, yes, it's worth it.

[Nonlinear]

Thank you. I think I'll give it a go.