Infini battery capacity setting

[cvzyl]

Does anybody know how the battery capacity setting of the Infini inverters can be changed? My systems shows a capacity of 200Ah, it worked fine for me but I have now increased the bank size to 500Ah. I cannot find where this setting can be adjusted. It seems affects the "tail" current, on a bigger bank the tail current remains much higher than on a small bank. As a result my inverter remains in bulk for too long, it is waiting for the charging amps to drop to indicating the bank is fully charged. I suspect this limit is something like 1-2% of bank capacity but given the size of my bank it is now in the order of 5-10A rather than 2-4A on the current setting.

I have an Infini 3kW+, using SolarPower to make changes to inverter settings.

Will appreciate any assistance.

C

 

Edit: Correction, I cannot actually find the battery capacity anywhere on SolarPower. It indicates 48V and 4 batteries (there are actually 16). Cannot find a way to tell the inverter what the battery bank size is.

[superdiy]

Hi Chris, I cannot remember if I've ever seen such a setting.  I don't think the "4 batteries" thing can be changed either - they assume 12V batteries are used and on a 48V system you would have 4 of them.

I don't think the tail current is bought into account when charging either. The thing is, the 3KW infini can only charge up to 25A, so on a bank of up to 250Ah, that would be the recommended 10% of the Ah rating of the bank and it would take x amount of time in the absorption stage before the charger switches to float. You have now increased your bank to 500Ah and effectively it will only be charged @ 5% of the Ah rating of the bank and therefor, if you start off at the same SOC for both banks, the larger battery bank will take much longer to become fully charged than the time it took the smaller bank to get to 100%.

[Guest]

What a bummer!!!

Yes, I can relate, for I have bought the wrong controllers for the panels mounted and the batts connected, more than once.

[cvzyl]

Thanks superdiy. The idea is the bank capacity is increasing but the amount drawn from it does not so result is lower DoD. Therefore the amount needed to recharge the bank every day remains the same. Only problem is that it reaches bulk at around 13:00 but remains in bulk until around 16:00 when solar drops low enough that there is not enough PV available to maintain bulk voltage.

Cobus

[Coulomb]

I thought that this might be a question that I could answer with my firmware reading skills. Although I don't have an Infini, and they don't seem to have type approval for grid connection in Australia, I did come across one firmware archive (.rar file) in my travels, and had noted that they use the same software, and the same multi-tasking "OS". However, there the similarities seemed to end.

* There are no symbols with the firmware archive that I found. (I don't even know the version number; the files have 20150311 in their names). That makes it hard going, but I could apply some of the symbols from the Axpert firmware reading.

* The serial command handling is very different, and initially I could not even find the command handler code.

* Handling of the LCD display seems quite different. The LCD display itself is different, of course, but I had hoped not vastly so.

* There is a lot of orphan code in there, that doesn't seem to be called from anywhere. So when I tried to find the LCD handling code, I eventually found a reasonable match, only to find that it appears to be uncalled! I've since checked for initialised code pointer arrays (there are two), and that reduced the orphan code proportion, but only slightly. So I still don't know if that code is truly unused, or if I'm missing some important way that a lot of it is called. So far, I'm leaning towards this code as being truly uncalled.

Yesterday I decided to give the Infini code another push. Now I have a better idea of how the commands are handled. I have the RS232 protocol manual, but I can't find a single command that matches the protocol. The commands seem to be separated into three groups; the query ones, the parameter updating ones, and a few miscellaneous ones. All he query commands appear to be two letters, or at least unique to the first two letters. There are 21 of these two character commands, though several of them do nothing. The QP command seemed like it might be similar to the Axpert QPIGS (Query Parameter Inquiry General Status) that is also documented in the RS232 protocol manual. But the reply i totally different; instead of spaces separating the numeric responses, there are the capital letters A, B, C...  V, W, I, J, K. At least one other command is like that. Also, the RS232 document indicates 22 response fields; the QP command has 27, and the Axpert QPIGS command has 17. So that makes it hard to make progress.

I know that several of you are developing monitoring software, some of which include the Infini, so you must know the format for at least a handful of commands. Are you prepared to share this information? Or can you point to a source of documentation that I haven't seen so far? I suppose I could decompile the Voltronic Power Systems monitoring software, but I'd prefer not to have to do that.

On the parameter updating side, the handler appears to be using some sort of hashing, though I haven't found the hashing code. The hash table has 45 entries, but as with any hash table, there are unused and duplicate entries. Most of the real functions pointed to by this table end with a call to a function that emits a different to usual acknowledgement: instead of the usual "(ACK" and checksum,. it sends three binary characters in place of the open parenthesis; the three bytes are 0x01 (ASCII SOH, Start Of Heading), 0x05 (ENQ, ENQuiry), and a byte that varies with the command. It always seems to be the third byte (char?) of the sent command. Does this sound familiar to any of the monitoring software developers?

So unfortunately, so far I've not been able to help with this question. I would note however that the Axpert battery charging software relies entirely on the charge current falling below a threshold for 50 seconds; the main point of the patched firmware was to also include a voltage threshold. However, this would not help in this case. For this case, it would be better to base the charge termination solely on voltage. As it is, the Infini would be leaving the 500 Ah battery in bulk / absorb all day, which would not be good for the battery. The RS232 document suggests that the battery capacity is reported, but it does not mention a way of changing it. The protocol documents I have seen only seem to document about half of the commands that are available, so not all hope is lost.

[Chris Hobson]

On 25/08/2016 at 0:54 AM, Coulomb said:

So unfortunately, so far I've not been able to help with this question. I would note however that the Axpert battery charging software relies entirely on the charge current falling below a threshold for 50 seconds;

Morning @Coulomb

Our resident Axpert/PIP "brains trust" is an Aussie. I should be offended but with our Mickey Mouse government it is nice to know there are some things that they cannot touch. When they have finished levelling this country to the ground you will still be there for us .

Just for interest sake what is this threshold? 

[Guest]

7 hours ago, Coulomb said:

I know that several of you are developing monitoring software, some of which include the Infini, so you must know the format for at least a handful of commands

Looks like all the protocols are different. Axpert 3kv , return string are also different for the 5kva (Qpigs) Now with the Infini 3kva and 5kva, the returns strings differ aswell and the query command

The New Apert Infin , commands is totaly different from all 

 

[Guest]

@Coulomb. Do you know how to force the Axpert into bulk mode ?

[superdiy]

20 hours ago, cvzyl said:

Thanks superdiy. The idea is the bank capacity is increasing but the amount drawn from it does not so result is lower DoD. Therefore the amount needed to recharge the bank every day remains the same. Only problem is that it reaches bulk at around 13:00 but remains in bulk until around 16:00 when solar drops low enough that there is not enough PV available to maintain bulk voltage.

Cobus

Cobus, what do you mean with "it reaches bulk at around 13:00 but remains in bulk until around 16:00"?

Charging always start off with Bulk, being constant current until the set "Bulk" voltage is reached, then it goes into Absorption mode, where a constant voltage is applied and the current gradually drops off. Lastly it goes into Float mode after the current in Absorption mode was below a pre-configured value for a pre-configured amount of time.

I assume you meant that it goes into Absorption mode at around 13:00 and stays in Absorption mode until the sun goes down. What is the current at say 15:00 or 16:00?  Is it quite low, e.g. around 1 A? Mine is configured to go into Float mode after the current in Absorption mode stayed under 0.7A for more than 1 hour. Since you have increased you bank's size quite a bit, you might have to adjust that "go into float current setting" to be a bit higher than what it was before, since the bigger bank will now draw more current in Absorption mode than what was drawn by the smaller bank.

[cvzyl]

superdiy, you are correct, it never goes to float. It remains at 58V from around 13:00 until 16:00. Around 17:00 it is still around 6-7A at 58V which is 1.4% of bank capacity. It never drops down to 54V (float).

Where can I change this setting?

[___]

I don't know exactly how the Infini determines when to go to float (hopefully using tail current), but as I recall, when you go to float your battery is usually only about 85% full, and it actually needs that last bit of extremely inefficient float charging to go all the way. If your batteries spend no time in float (tail current never drops low enough), it's an indication that they don't reach 100% SoC.

It might even make sense to charge them from the grid early in the morning. The reasoning behind this is that when the batteries are at a low SoC, the charging efficiency is high and you get good value for the electricity you buy. Then you switch the charger off as soon as you hit absorb and let the sun finish it off, leaving ample time to float them. This isn't my idea by the way, heard this on a solar training day, something to do if the batteries are a bit low (maybe you had an outage the previous night) to get them back up quick.

Of course the only way to know for sure is to have a battery monitor in there, like the BMV.

[cvzyl]

plonkster, I think it does reach 100% SoC. I have a BMV702 and see that the capacity reaches 100%, normally around 14:00.

[___]

18 minutes ago, cvzyl said:

it does reach 100% SoC

Okay... well then the inverter/charger either has the wrong tail current set/programmed. It thinks the batteries aren't full yet because it still accepts 7 amps of charge... :-) So it's probably directly related to not knowing the size of the bank.

[superdiy]

22 hours ago, cvzyl said:

superdiy, you are correct, it never goes to float. It remains at 58V from around 13:00 until 16:00. Around 17:00 it is still around 6-7A at 58V which is 1.4% of bank capacity. It never drops down to 54V (float).

Where can I change this setting?

Is 58V not too high for your type of batteries, because if the voltage setting is too high the batteries will draw more current in the process of trying to be charged at the higher voltage. Please give us some details about the batteries.

Something else which comes to mind - If I remember correctly you've mentioned something about older batteries and a battery experiment a while ago - maybe I'm confusing you with someone else. If however you have added older batteries to your bank, check all the batteries again, maybe you have 1 or more shorted cells - that would definitely cause the higher current draw.

[cvzyl]

superdiy, you are correct. I added 300Ah Trojan T1275's to my existing bank of 200Ah Vision batteries. One of the batteries feels significantly hotter to the touch than the others. Might be the problem.

I don't think the 58V is too high for the Trojans and also within spec for the Visions. In fact the Trojans require an equalizing voltage higher than I can achieve at this stage.

[superdiy]

On 8/26/2016 at 8:00 PM, cvzyl said:

superdiy, you are correct. I added 300Ah Trojan T1275's to my existing bank of 200Ah Vision batteries. One of the batteries feels significantly hotter to the touch than the others. Might be the problem.

I don't think the 58V is too high for the Trojans and also within spec for the Visions. In fact the Trojans require an equalizing voltage higher than I can achieve at this stage.

Seems like you might have one or more faulty cells. I agree that under normal conditions 58V is not too high for the Trojans, but keep in mind that if you raise the voltage when equalizing batteries, in perfect condition, the current will also be significantly higher during equalizing. By having one or more shorted / damaged cells in one of the strings, might put all the remaining cells in that string into permanent equalizing state @ 58V, which will result in the higher current flow in that string and that might be why your charging current does not want to go below a certain value. I would suggest that you check the batteries sooner than later.