PIP-4048MS and PIP-5048MS inverters

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curasun
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Re: PIP-4048MS inverter

Post by curasun » Fri, 30 Mar 2018, 07:32

Hello guys,
I'm also having problems with charging my batteries fully. I've set the absorb time to 120min. It doesn't stay for 2 hours in absorb.
planning to buy a PCM60X from MPPsolar. Is this charge controller better?
Is their someone on this forum using this charge controller who can comment on this?

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Re: PIP-4048MS inverter

Post by weber » Fri, 30 Mar 2018, 07:39

curasun. What main firmware version is your inverter running?
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Re: PIP-4048MS inverter

Post by coulomb » Fri, 30 Mar 2018, 08:38

curasun wrote:
Fri, 30 Mar 2018, 07:32
I'm also having problems with charging my batteries fully. I've set the absorb time to 120min. It doesn't stay for 2 hours in absorb.
I note that even with timed absorb, absorb mode will be exited if the charge current falls to a particular value. That value is the number of active paralleled machines multiplied by two.

As an extreme example, suppose you had three paralleled machines (or a 3-phase setup with one machine per phase). Let's say you only have PV connected to one of them, and the battery voltage is near the absorb setting. The two machines with no PV connected still count towards the minimum absorb current of 3 * 2 = 6 A. The current will be non-adjusted currents, so about one amp more than the actual current. So if the charge current falls to 5 A or less, then as long as the battery voltage is close enough to the absorb voltage setting for 30 seconds without exception, then the charger will exit absorb stage regardless of the time spent in absorb.

[ Edit: actually because of the ~1 A difference between measured charging current and actual charging current, the effective threshold for the 3 machine example would be more like 3 A. So the current would have to fall to 2 A or less before this early exit from timed absorb would kick in. ]

NOTE: in the official firmware, the 30 second figure mentioned above was 10 minutes. Weber and I judged that this change was a misguided attempt by Voltronic Power to make it seem that they fixed their charge bug, so we changed this 10 minute figure to 30 seconds, as it was in earlier firmware versions such as 72.40. [ Edit: this change affects all absorb to float transitions, whether timed or not. ] That could make it seem that our patched software has regressed. But really, the original firmware would have exited early, but you'll always get 9.5 minutes more absorbing from the original firmware. This still could be an hour short of what you asked for.

I'm guessing that Voltronic Power consider 2 A per paralleled machine such a ridiculously low value that they're doing us a favour by cancelling absorb at this point, because the battery is "obviously" full. It would only take a single instruction patch to change this so that the threshold in timed absorb is zero, so the charge current could never be strictly less than the threshold (since nothing is strictly unsigned less than zero). So when in timed absorb mode, absorb mode would never be exited early, and would continue until the absorb timer ran out.

This is a moderately significant change to the way the charger would operate. Perhaps some owners who set their absorb times too high will overcharge their batteries if we made this change. However, it seems to be that this is a "you asked for it, you got it" feature, rather than a "I know better then thou, I'll do what I think is right" annoyance (and an undocumented annoyance at that).

What's the feeling amongst timed absorb users? Would anyone be inconvenienced if we patched the firmware to work more like it says it does?
The other question is, does a battery do any real absorbing if the charge current is low, less than 2 A per paralleled machine?

[ Edit: if the current -> if the charge current ]
[ Edit: paralleled machines that are switched on -> active paralleled machines ]
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Re: PIP-4048MS inverter

Post by sinux » Sat, 31 Mar 2018, 03:09

coulomb wrote:
Fri, 30 Mar 2018, 08:38
What's the feeling amongst timed absorb users?
That would be a very welcome change for me!
I've got 4 100ah gel batteries in series.
I've read somewhere that "Gelled cells should be charged at no more than the C/20 rate, or 5% of their amp-hour capacity." (http://www.electrovehicles.co.za/unders ... y-charging)
For me that would mean charging at 5 Amps. Sadly this setting doesn't exist (would it be possible to add it? ), so I'm charging at 2 amps.

A suggestion could be to check if setting 32 is set to anything different from auto before allowing a charging current less than 2 volts for absorb. In this case, the user most certainly would want the absorb timer to be taken into account.
coulomb wrote:
Fri, 30 Mar 2018, 08:38
The other question is, does a battery do any real absorbing if the charge current is low, less than 2 A per paralleled machine?
It would probably depend quite a lot on the size of the battery bank. I've recently bought a 12V battery charger (https://www.midas.co.za/pebble.asp?relid=1741&t=75). It has a slow mode that limits the current output to 2amps (as opposed to 8amps on fast mode). The manual says 2 amps is the standard way of charging the battery... I measured it absorb at less than 1amp for a couple of hours on a SLA 80ah 12v battery.

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Re: PIP-4048MS inverter

Post by curasun » Sat, 31 Mar 2018, 04:50

Hello,
Coulomb Firmware 73, it is a December 2017 model.

Thats the factory installed firmware.

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Re: PIP-4048MS inverter

Post by weber » Sat, 31 Mar 2018, 07:45

sinux wrote:
Sat, 31 Mar 2018, 03:09
I've got 4 100ah gel batteries in series.
I've read somewhere that "Gelled cells should be charged at no more than the C/20 rate, or 5% of their amp-hour capacity." (http://www.electrovehicles.co.za/unders ... y-charging)
For me that would mean charging at 5 Amps. Sadly this setting doesn't exist (would it be possible to add it? ), so I'm charging at 2 amps.
Sinux, It is more difficult than you might think, to add new values for a setting. In any case, C/20 is a very low current. When I google "gel battery maximum charge current" I find 0.2C or C/5 commonly mentioned. That would be 20 A in your case, so I'm sure 10 A would be just fine. It's all about whether the battery temperature rises significantly during charge. You could measure this. It should not rise more than about 5 °C above ambient.

Clearly you are only using a single PIP/Axpert inverter, so Coulomb's extreme example does not apply. In fact the standard code has been saving your battery. If a nominally 48 V 100 Ah gel battery is being held at 57.6 V and the charge current has fallen to 1 amp (0.01C) then it is definitely full! That one amp is doing nothing but electrolysing water and generating heat.
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Re: PIP-4048MS inverter

Post by coulomb » Sat, 31 Mar 2018, 18:26

curasun wrote:
Sat, 31 Mar 2018, 04:50
Hello,
Coulomb Firmware 73, it is a December 2017 model.

Thats the factory installed firmware.
Ah. So the early absorb termination could well be the long standing factory firmware bug, described here.

[ Edit: described the wrong charging bug; added link. ]
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Re: PIP-4048MS inverter

Post by coulomb » Sat, 31 Mar 2018, 19:02

Error 90 — Attention firmware updaters!

Weber and I have updated the patched firmware, both LC and LF versions, from 73.00a to 73.00b. This fixes a problem whereby on older hardware, the inverter would end up with an error 90 (fault code 90), after 60 days of running time. There has already been one machine stop working with this error; this was with factory 73.00, so this affects factory as well as patched firmware. So to users who have re-flashed their machines that came with an earlier version, be aware that you have a ticking time bomb, which could "go off" in a few days! Either roll back to a pre 73.00 version, or update to patched firmware 73.00b or later. There is no such problem with machines that came with factory firmware 73.00 or later.

See the Firmware section of the index post to find the latest patched firmware files.

[ Edit: minor changes to make it easier to find "error 90" or "fault code 90". ]
[ Edit: "no problem" -> "no such problem"; 73.00 still has the same charge bugs. ]
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Re: PIP-4048MS inverter

Post by frnandu » Tue, 03 Apr 2018, 17:17

Hello guys, first of all, thank you for all your effort into making the firmware and sharing your knowledge here.

I want to be able to remotely turn the PIP on/off completely, so I'm thinking about connecting the on/off switch cables into some relay controlled by a raspberry.
Does anyone know what kind of voltages/amperages are being used on those on/off switch cables?
What kind of relay (or other electric mechanism) could be safely used there? I'm kind of ignorant on such matters, so any help would be much appreciated.
Thanks
Last edited by frnandu on Tue, 03 Apr 2018, 21:36, edited 1 time in total.

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Re: PIP-4048MS inverter

Post by coulomb » Tue, 03 Apr 2018, 18:16

"Coulomb's partial schematic trace of the main power supply circuit" is available from the index.

The AC start switch carries battery voltage, so you need to be careful with fault currents. A ~1 A 60+VDC fuse would be wise, on the pin 1 side. The switching current is quite low, however. Hence, many small relays would be suitable, perhaps even a printed circuit mounting type, but to be safe its contacts should be rated at 60 VDC. Any current rating would be suitable. Many cheap relays' contacts are rated for 240 VAC, which sounds plenty, but their DC rating might be as low as 28 V, making them unsuitable. Merely wire the normally open contacts across the start switch. The start switch needs to be off for the raspberry to control the PIP, obviously.
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Re: PIP-4048MS inverter

Post by frnandu » Tue, 03 Apr 2018, 18:59

Thanks, any idea where to get a relay with contacts rated for 60VDC?
Would a SSR be ok to use?

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Re: PIP-4048MS inverter

Post by coulomb » Wed, 04 Apr 2018, 13:57

frnandu wrote:
Tue, 03 Apr 2018, 18:59
Thanks, any idea where to get a relay with contacts rated for 60VDC?
The usual electronics stores: Jaycar, RS Components, element14, mouser, etc.
Would a SSR be ok to use?
I'd guess so, but higher current models might have too much leakage (i.e. they might not turn off "hard enough").
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Re: PIP-4048MS inverter

Post by xenonhost » Wed, 04 Apr 2018, 15:00

I have bought 11 months ago 48 pcs Winston LifePO4 for a friend. They worked well, but 2 weeks ago 18 pcs got swollen and they are all shortcircuited. I need a BMS, something for remaining 16 pcs connected to PIP.

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Re: PIP-4048MS inverter

Post by weber » Sat, 07 Apr 2018, 12:28

Hi @sinux. Coulomb and I recognised that we hadn't fully investigated your earlier bug report. We finally got a chance to do so, spending many hours on it yesterday.

We note that we have already determined that your second problem—the exit from an otherwise timed absorb stage when the charge current falls to 1 amp—is not caused by any of our patches, and is not a bug, as it has the potential to prevent damage to batteries held at absorb voltage for too long.
sinux wrote:
Tue, 20 Mar 2018, 18:39
I'd like to report a bug/regression :
From version 72.70c beta, you've "improved the accuracy of the battery charge and discharge current readings, particularly for low currents, as displayed on the LCD, and as given in response to the QPIGS and QPGS serial commands"

It looks like you've reduced the amount of amps reported by the inverter for battery charging current by 1 amp?
Yes, and whenever the charging current was already zero (and so could not be reduced), we've increased the discharge current by 1 amp.

So, if you were to write some code in your Raspberry Pi to reverse this operation, i.e. if the discharge current (as reported by versions 72.70c, 73.00a or 73.00b) is greater than zero, subtract 1 amp from it, otherwise add 1 amp to the charge current, then your coulomb counter should work just as it did with the unpatched or earlier patched versions of the firmware.
At first glance it seems reasonable to do that because the new figure becomes finally the real battery current, in most cases (see below).

The previous battery current reported (before the upgrade) was actually "battery charge or discharge current" + "self consumption".
This is why the inverter would always report 1 amp even when the battery was in float and full.

I don't know exactly why, but there's an exception to this case, when in bypass mode and charging with AC.
In this state, the battery charging current doesn't include self consumption (or maybe more logically the self consumption is much less than the average 50W in solar charging mode with inverter on).
It turns out that your second "more logical" guess is correct. The self consumption when AC charging (and hence in bypass/line mode and not inverting) is only about 14 watts, whereas it is about 65 watts when inverting. Our patches mistakenly assumed about 50 watts in both cases. And so, while we improved the accuracy of discharge current readings and solar charge current readings, we made AC charge current readings less accurate.

Thank you so much sinux, for bringing this problem to our attention. We are now working on a 73.00c that will not only take these different losses into account, but will also round to the nearest amp instead of rounding down like previous versions. And this time, we will attempt to use these changes not only to give more accurate current readings, but also to give actual charge currents that are closer to the requested current.

73.00c will also fix some bugs in the original firmware, that cause minor problems when changing parameter settings via the LCD and buttons, as described by OomD here. Coulomb produced successful patches for these yesterday.
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Re: PIP-4048MS inverter

Post by sinux » Sat, 07 Apr 2018, 21:22

Hi Weber,
Thank you and Coulomb for taking the time to investigate this bug!
weber wrote:
Sat, 07 Apr 2018, 12:28
We note that we have already determined that your second problem—the exit from an otherwise timed absorb stage when the charge current falls to 1 amp—is not caused by any of our patches, and is not a bug, as it has the potential to prevent damage to batteries held at absorb voltage for too long.
Yes, duly noted.
weber wrote:
Sat, 07 Apr 2018, 12:28
So, if you were to write some code in your Raspberry Pi to reverse this operation, i.e. if the discharge current (as reported by versions 72.70c, 73.00a or 73.00b) is greater than zero, subtract 1 amp from it, otherwise add 1 amp to the charge current, then your coulomb counter should work just as it did with the unpatched or earlier patched versions of the firmware.
Thanks for the tip, will do that.
weber wrote:
Sat, 07 Apr 2018, 12:28
We are now working on a 73.00c that will not only take these different losses into account, but will also round to the nearest amp instead of rounding down like previous versions. And this time, we will attempt to use these changes not only to give more accurate current readings, but also to give actual charge currents that are closer to the requested current
Whoa great news! Really looking forward to that.
Again thanks very much for all your work on the firmware!

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Re: PIP-4048MS inverter

Post by mohfamous » Sun, 08 Apr 2018, 14:36

coulomb wrote:
Tue, 17 Jan 2017, 20:02

Image

thanks coulomb for your hard effort
could you explain the circuit
thanks

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Re: PIP-4048MS inverter

Post by coulomb » Sun, 08 Apr 2018, 17:21

This circuit, present on only some models (before the fuse protection "feature") merely disconnects the battery negative strap from the rest of the inverter if the processor doesn't cause the opto-coupler (OP2) to be lit, which will turn on the four paralleled MOSFETs (only 1 shown). The circuit makes more sense when the integral reverse diode is shown (I've changed the original to suit now):
Reverse protection sch.png
Reverse protection sch.png (5.81 KiB) Viewed 1854 times
If the battery connection is reversed, the terminal marked BATT- will actually be positive with respect to what I've drawn as earth in the diagram. As a result, the integral diodes will be reversed biased, the power supplies that runs off the battery to power the processor won't operate, and the processor won't turn on the opto-coupler, so the MOSFETs will stay off. This will cause approximately a 0.6 V drop across the integral diode, which is not good for efficiency. But as soon as the processor is running, the opto-coupler will turn on, which will apply some 15 V to the gates, and the MOSFETs will turn on hard. These will reduce the 0.6 V drop to that of a low valued resistor.

So the idea is that if you accidentally connect the battery in reverse, nothing blows up, and there is no great splat. In later models, they must have a large diode connected across the battery after a fuse (which is a piece of plated metal with a narrow neck). In these models, if you connect the battery in reverse, the diode conducts, and nearly the whole battery voltage appears across the fuse. There would be an enormous surge of current, a mighty clap of noise and flash of light as the fuse blows. After your sight and hearing recovers, and you change your underwear, you rewire the battery cables, use the spare fuse provided, and check your work really carefully before turning on again :-O

[ Edit: added "the integral diodes will be reversed biased". ]
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Re: PIP-4048MS inverter

Post by paulvk » Sun, 08 Apr 2018, 20:04

In building my remote control unit I decided I needed to test for parallel units with QPGSn so I set up a little routine to go through QPGS1-5
QPGS1 returned
(1 77777777777777 B 00 240.1 49.94 229.2 49.87 0412 0381 009 50.0 000 078 000.0
000 00802 00746 009 00000010 1 3 060 120 20 00 008
returns what is expected

QPGS2 returned
(1 77777777777777 B 00 240.1 49.94 229.2 49.87 0412 0381 009 50.0 000 078 000.0
000 00802 00746 009 00000010 1 3 060 120 20 00 008" (0 00000000000000 P 00 0
00.0 00.00 000.0 00.00 0000 0000 000 00.0 000 000 000.0 000 00848 00784 009 0000
0000 0 0 010 110 0
As can be seen two lots of data

QPGS3 returned
00 000CrLf
not much something wrong here maybe that is it up there in QPGS2

QPGS4 returned
(0 00000000000000 P 00 000.0 00.00 000.0 00.00 0000 0000 000 00.0 000 000 000.0
000 00848 00672 008 00000000 0 0 010 110 02 00 000
the first 0 says not exist so ok

QPGS5 returned
(0 00000000000000 P 00 000.0 00.00 000.0 00.00 0000 0000 000 00.0 000 000 000.0
000 00804 00729 009 00000000 0 0 010 110 02 00 000
the first 0 says not exist so ok

Note I am checking for a valid CRC

I will have to see which unit I am plugged into master or slave did not look when I plugged the cables in.
I would be interested to know what is returned for others with two or more inverters.

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Re: PIP-4048MS inverter

Post by paulvk » Sun, 08 Apr 2018, 20:09

coulomb wrote:
Sun, 08 Apr 2018, 17:21
So the idea is that if you accidentally connect the battery in reverse, nothing blows up, and there is no great splat. In later models, they must have a large diode connected across the battery
Or maybe a fet and diode

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Re: PIP-4048MS inverter

Post by simat » Sun, 08 Apr 2018, 23:17

About a week ago I got a 2p15s LFP battery connected up to a new PIP4048MS using this BMS as a frontend to my BMS software running on a Raspberry Pi. I am not using the battery disconnect function of the BMS until I have upgraded the MOSFETs to higher spec ones.

The first day I tried to charge the battery the dreaded "preamature float" bug raised its head so I downloaded and installed the 73.00b patched firmware (thank you Coulomb and Weber!).

I really like the "Aussie view" feature. I think the "Dynamic Current Control" would be more useful if you could get the SCC to shut the current off completely. I have opted to decrease the bulk/absorb voltage to shut off the current if any individual cell voltages go too high.

With the patched firmware I am not sure why the PIP is switching to float under apparently different conditions. Here is the data from my BMS log of the battery voltage and current when the PIP switched to float on two separate occasions, there was no cloud on the first occasion and some on the second occasion. I have the maximum charging current set to 30A and bulk/absorb charge voltage set to 51.8V.
   Date/Time   Voltage  Current
20180406134424	51.75	-5.3
20180406134434	51.76	-5.2
20180406134444	51.76	-5.1
20180406134454	51.76	-5
20180406134504	51.76	-4.9
20180406134514	51.76	-4.8
20180406134524	51.76	-4.7
20180406134534	51.76	-4.6
20180406134544	51.77	-4.5
20180406134554	51.76	-4.4
20180406134604	51.77	-4.3
20180406134614	51.77	-4.2
20180406134624	51.77	-4.1
20180406134634	51.77	-4.1
20180406134644	51.77	-4
20180406134654	51.77	-4
20180406134704	51.77	-3.9
20180406134714	51.66	-1.8
20180406134724	51.54	2.2
20180406134734	51.49	3.6
20180406134744	51.44	4
20180406134754	51.41	4.2

   Date/Time    Voltage  Current
20180408142759	51.6	-12.5
20180408142809	51.64	-12.9
20180408142819	51.66	-13.4
20180408142829	51.68	-13.3
20180408142839	51.67   -12.6
20180408142849	51.7    -12.6
20180408142859	51.7    -12.4
20180408142909	51.7    -12.4
20180408142919	51.6    -10.6
20180408142929	51.54   -5.5
20180408142939	51.47	-2.8
20180408142949	51.44	-1.9
20180408142959	51.34	0.5
20180408143009	51.28	2.5
20180408143019	51.24	3.2
Thanks,
Simon
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32x90Ah Winston cells 4p8s (24V), 4kW Latronics Inverter, 1160W of Solar Panels
Homemade MPPT controller, BMS https://github.com/simat/BatteryMonitor

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Re: PIP-4048MS inverter

Post by andys » Mon, 09 Apr 2018, 12:44

Quick tip re power up with battery: There are cheap 48V switch mode PSUs available on ebay, I have used one successfully on the battery terminals to fire up a PIP-4048 for quick testing etc.

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Re: PIP-4048MS inverter

Post by coulomb » Mon, 09 Apr 2018, 14:06

simat wrote:
Sun, 08 Apr 2018, 23:17
The first day I tried to charge the battery the dreaded "preamature float" bug raised its head so I downloaded and installed the 73.00b patched firmware...
Yes, it seems inconceivable that the charge bugs still exist, until you see one in action.
With the patched firmware I am not sure why the PIP is switching to float under apparently different conditions. Here is the data from my BMS log of the battery voltage and current when the PIP switched to float on two separate occasions, there was no cloud on the first occasion and some on the second occasion. I have the maximum charging current set to 30A and bulk/absorb charge voltage set to 51.8V.
I note that the currents have a resolution of 0.1 A, so these must be your BMS currents.
Are the voltages from the BMS or from the QPIGS command of the PIP?

Since your maximum charge current is 30 A, the threshold current would be int(30/12) with a floor of 5 A, so it would be 5 A. As Weber posted here, the effective current threshold is 2 A less than this, so 3 A. There has to be no exceptions to this for 30 seconds. The PIP is measuring every second, so it may see exceptions that your BMS does not. [ Edit: perhaps your BMS sees the data more often than that; we may not see exceptions in the data as sensibly reported in your post every 10 seconds. ]

So your first example looks good; the three BMS measurements of 4.0, 4.0, and 3.9 A could be read by the PIP as meeting this criterion; that's the 30 seconds. The voltage falls steadily after that, so presumably the PIP has gone to float.

The second example looks rather different, I'll grant you. Maybe the qualification time should be longer than 30 seconds, but less than 10 minutes. But it's hard to tell what's going on without seeing the currents as reported by the PIP in the QPIGS command, and preferably also the charge stage in the undocumented Q1 command, field QQ (to tell when it really went to float). How hard would it be to provide that data?
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Re: PIP-4048MS inverter

Post by coulomb » Mon, 09 Apr 2018, 14:43

paulvk wrote:
Sun, 08 Apr 2018, 20:04
QPGS2 returned
(1 77777777777777 B 00 240.1 49.94 229.2 49.87 0412 0381 009 50.0 000 078 000.0
000 00802 00746 009 00000010 1 3 060 120 20 00 008" (0 00000000000000 P 00 0
00.0 00.00 000.0 00.00 0000 0000 000 00.0 000 000 000.0 000 00848 00784 009 0000
0000 0 0 010 110 0
As can be seen two lots of data

QPGS3 returned
00 000CrLf
not much something wrong here maybe that is it up there in QPGS2...
Note I am checking for a valid CRC
The command handling code only has one output buffer, and it takes non-trivial time to send the response for a large command, so if you send the second request too soon, you can get buffer merging as you see here. During debugging, we've seen the CRCs correct when data is bad; it's to do with the timing of the CRC calculation. What you read from the serial port isn't necessarily what was in the present buffer; some of it might have been from an earlier command before data was overwritten.

The first machine is index zero, not 1. So what we see here (ignoring the buffer overruns) is consistent with 3 machines.

My guess is that the split between the QPGS2 and QPGS3, which happens at 256 characters, is because one of your 256-byte buffers had overflowed. (It might be an internal Linux or device driver buffer). Note that the character after the double quote is a tab, not one or more spaces.

All this will likely go away by increasing the delay between QPGS commands; it looks like a small increase will do it.
Learning how to patch and repair PIP-4048 inverter-chargers and Elcon chargers.

paulvk
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Real Name: Paul
Location: Sydney

Re: PIP-4048MS inverter

Post by paulvk » Mon, 09 Apr 2018, 16:57

No its not windows or linux its all written by me its a 64k AVR and it just sends what it gets on serial one to serial two which puts it onto the terminal on my PC and I have given it a 256 byte buffer so I increase that too see.
It also does the CRC and will print crcbad to the lcd so I know.
I gave it 3 seconds between requests so that should be long enough.
I did not know it was zero numbered
Anyhow I will keep ploding along with the information requests and once that works ok I will move to settings change menus

Also note I only have two PIPs running.
Last edited by paulvk on Mon, 09 Apr 2018, 21:38, edited 1 time in total.

simat
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Real Name: Simon Matthews

Re: PIP-4048MS inverter

Post by simat » Mon, 09 Apr 2018, 19:41

coulomb wrote:
Mon, 09 Apr 2018, 14:06
I note that the currents have a resolution of 0.1 A, so these must be your BMS currents.
Are the voltages from the BMS or from the QPIGS command of the PIP?
The current is detected by current sense resistors on the Chinese BMS board. These boards use the TI BQ76940 chip to do the cell voltage and current measurements. Checking against my multimeter I would say that the current readings from the BMS are accurate.

The voltage is also taken from the Chinese BMS board. This is the voltage at the battery terminals.
[ Edit: perhaps your BMS sees the data more often than that; we may not see exceptions in the data as sensibly reported in your post every 10 seconds. ]
In this case my software is configured to takes one sample every 2 seconds and average the result over 5 samples.
So your first example looks good; the three BMS measurements of 4.0, 4.0, and 3.9 A could be read by the PIP as meeting this criterion; that's the 30 seconds. The voltage falls steadily after that, so presumably the PIP has gone to float.
I agree with your analysis and like you say this is what one would expect.
The second example looks rather different, I'll grant you. Maybe the qualification time should be longer than 30 seconds, but less than 10 minutes. But it's hard to tell what's going on without seeing the currents as reported by the PIP in the QPIGS command, and preferably also the charge stage in the undocumented Q1 command, field QQ (to tell when it really went to float). How hard would it be to provide that data?
Currently my BMS is only set up to get data from one source. I will look at adding the data from the PIP. I assume that the PIP uses the "KKK Battery Charging Current" when making it decision as to when to go to float.

Thanks for the Information on the Q1 command. I will investigate further.

Simon
Off-Grid with LFP (LiFePO4) battery, battery Installed April 2013
32x90Ah Winston cells 4p8s (24V), 4kW Latronics Inverter, 1160W of Solar Panels
Homemade MPPT controller, BMS https://github.com/simat/BatteryMonitor

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