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"Floating" Pylontechs?


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2 hours ago, Ironman said:

Mine was set to Multiplus - and somehow the multiplus has a completely different SOC level.

The Multi does its own measurement of charge going into and out of the battery. In VE.Configure you will see there is also a charge efficiency figure that you can set for your batteries (and the default 0.85 is a bit too pessimistic, even lead-acid users should move it up to 0.88 or 0.9, and LFP should move it to 0.95 even).

Now the Multi only knows about its own charge current, it does not (normally) know what the solar chargers are doing. Except that in an ESS system we TELL the Multi what the solar chargers are doing (we periodically take the current reading from the solar chargers and tell the Multi how much extra current is being charged with externally). This means that the Multi CAN do SOC determination on its own. BUT... and this is where a whole lot of caveats come in: You must properly configure the charge efficiency in VE.Configure, an even then, you must remember that the solar-charger-to-Multi-sync is only every 3 seconds. Additionally, the Multi estimates its DC current from the AC values (so it could be off by 1-2A), so this SOC determination essentially does newtonian integration over a value that is affected by a lot of...uhm... factors.

So in essence, the SOC determination of the Multi isn't perfect, but to be fair, SOC determination is never perfect, it is always an estimate. It's just that in DC-tied systems, the Multi is usually less accurate than the battery monitor, and it drifts quite a bit more.

That is why the default battery selection (Auto) in the GX device will always favour a battery service (BMV or BMS) over the Multi.

Additionally, if you use the battery's SOC figure, the GX device will write that across to the Multi so that the Multi uses the external SOC measurement for decisions (in assistants for example), but if the Multi is itself selected as the SOC monitor, it won't do that because writing from yourself to yourself is obviously not the right thing to do.

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44 minutes ago, Gerlach said:

Just spoke the guys at Bluenova. There batteries floating charge is 55v and get it fully charge after using it is 56.2v 

Victron SmarthLithiums are the same. You charge them to 14.2V per battery, and then "float" at 13.5V.

To be clear though, while it is a good idea to lower the voltage a bit after the battery is fully charged, the terminology still hails from lead-acid days. With a lead acid battery you have bulk, absorb, and float. With a lithium battery you really only have "bulk" and "charged". The Multi still retains the old state names and they display on the GX device, so people get confused because they don't understand why it sometimes says Absorption and sometimes Float. When you have a managed battery (eg the Pylontech), do not worry about what state the Multi thinks it is in. The battery calls the shots anyway.

Edited by plonkster
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Majority of the LFP batteries are built as 16S cells for a 48V pack or 4S for a 12V pack. Therefore 56.2V or 14.2V setting. And this setup works great, since it fits into a range of most solar chargers.

For a shame, Pylontech opted for a non-standard 15S architecture of the pack and now we have to deal with it:

  • It's a bit harder to finetune the charger for 15S.
  • By removing that 1 cell from the 16S pack, manufacturer also removed a bit of voltage margin between fullycharged and overcharged states.
  • You can't paralel 15S pack with a standard 16S pack. So, you are locked forever to buy from that same manufacturer.

But that's the life :)

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  • 4 months later...

Hi all,

I would like to bring up this thread again. I had a Victron MPPT installed yesterday and have moved my panels off the Axpert onto the Victron. My installer has configured the Victron for my Pylontechs - but I am not 100% of his settings. So I am hoping for a bit of help from you guys please 🙂

On the Axpert, I had the following charge settings (which seemed to work quite well for me):

  • Bulk: 52.2V
  • Float: 52.0V

My installer has now programmed the following values:

  • Absorption: 52.0V
  • Float: 51.0V
  • Equalization voltage: 0.00V
  • Re-bulk voltage offset: 0.40V
  • Absorption duration: Fixed
  • Absorption time: 1h 0m
  • Tail current: Disabled
  • Equalization current percentage: 0%
  • Automatic equalization: Disabled
  • Equalization stop mode: Fixed time
  • Equalization duration: 2h 0m
  • Temperature compensation: Disabled
  • Low temperature cut-off: 5 deg Celsius

In ICC I can see that the Pylon gets charged to 52V and then hovers for a while around that value (I assume that this is Absorption) - with SOC at 97%. Then it drops to just under 51V and stays around that value (I assume that this is Float) - with SOC at 96%.

So I guess my questions are:

  1. Are the settings above made by my installer generally correct? Or is there anything that I need to change?
  2. What would you recommend I'd use for Absorption and Float? 52.2V/52.0V as I previously had it or 52.0V/51.0V as it is now? What are upsides/downsides and risks of each?

Thanks in advance for your help 🙂

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6 hours ago, wolfandy said:

Are the settings above made by my installer generally correct? Or is there anything that I need to change?

Yes they perfectly correct and recommended by victron for Pylontech setup. No change

 

6 hours ago, wolfandy said:

What would you recommend I'd use for Absorption and Float? 52.2V/52.0V as I previously had it or 52.0V/51.0V as it is now? What are upsides/downsides and risks of each?

No change. As installer set.Check this https://www.victronenergy.com/live/battery_compatibility:pylontech_phantom?_ga=2.146844279.1545381250.1584818150-1826497651.1580643129 read disqus all the way down

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I would do this.

Absorption voltage is 52.5V (There is no such thing as Bulk voltage. Bulk is the stage where the voltage has not yet reached the absorption level and we're throwing maximum current at it).

Float at 51.8V.

Reason: To properly balance, you need to be at or above 3.48V per cell, plus a small offset just to give the battery something to work with. But above 3.45V per cell little extra energy is stored, hence 51.8V (~ 15 * 3.45) is a good charge voltage.

51V is 3.4V per cell, which is also fine. But I would definitely raise the absorption voltage a tad. You will then see the SOC go to 100% too.

Edited by plonkster
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Tagging along here as my Pylon bank is also tripping the master on odd occasion - moved it the other day to 52.5 + 52.0 & got it happen 24 hours later again so will now try what your suggesting there Plonkster & see if it will stop.

Edited by 2una
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  • 1 month later...
On 2020/03/22 at 2:22 PM, 2una said:

Tagging along here as my Pylon bank is also tripping the master on odd occasion - moved it the other day to 52.5 + 52.0 & got it happen 24 hours later again so will now try what your suggesting there Plonkster & see if it will stop.

 

 

 

So been set at 52.5/51.8 since i guess march 22nd

 

 

 

spacer.png

 

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Multi II 5000 - Firmware is 469

3 x 3000B Pylontechs

Used only as backup - no solar

Was doing the same on a Multi II 3000

 

Any further ideas to try?

 

Edited by 2una
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5 hours ago, 2una said:

Any further ideas to try?

Internal error usually means cell imbalance. Which is weird if it has been kept charged all the time. Only thing I've tried in the past that seemed to have worked was to discharge the batteries a bit and recharge them and see if the error clears.

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On 2020/05/09 at 5:53 PM, plonkster said:

Internal error usually means cell imbalance. Which is weird if it has been kept charged all the time. Only thing I've tried in the past that seemed to have worked was to discharge the batteries a bit and recharge them and see if the error clears.

Turning the master off/on sorts it out till next time it appears again. It would also do it amongst load shedding times when it was getting discharge use so that also don't seem to rectify the problem.

 

@wolfandy Is yours still doing this or you find a fix ?

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3 hours ago, wolfandy said:

Am using 52.2V and 51.8V - and my system is running without any problems. But I am also cycling my Pylons every night

Only slight oddity that I see every now and then is that the Pylon BMS reports 101% SOC 

Ok thanks

 

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  • 2 weeks later...

Interesting response to Pylontech alarm from company rep. in the Victron community forum

https://community.victronenergy.com/answers/50455/view.html

The cause of this alarm message:Our battery has a kind of BMS logic:When the battery is not charged or discharged for 3 days,always in idle state. The battery will automatically shut down and go to sleep mode.Only when the battery is charged or discharged again, by then the battery will automatically activate.

So when there is a battery to sleep mode and shut down, our Master battery will light up red light and send message to the inverter show there is an internal alarm. (You can check the first three days of the alarm record, the battery will be used once.)

 

What I want to highlight fist is that. This is a normal BMS logic of our battery, to reduce unnecessary self discharge consumption loss of the system.it will not affect the normal use of the whole system or cause damage to the system. So don’t worry.

 

This situation usually occurs when the inverter sets the battery to the backup power supply, or UPS mode. The battery is not used as often, and it is usually left unused after being charged to 100%.

The solution:

1.Determine the working mode of on-site situation. If the customer does not want to use the back-up mode, please set the battery has priority over the public-grid to power the load.

 

2. If the customer only wants to use the battery as a backup power source, The customer can limit the inverter to charge the battery only up to 90% not 100%, so that the battery will not enter the standby state.

 

Hope these information will help. Please let me know if you have more questions.

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14 hours ago, RETNEV said:

Interesting response to Pylontech alarm from company rep. in the Victron community forum

https://community.victronenergy.com/answers/50455/view.html

The cause of this alarm message:Our battery has a kind of BMS logic:When the battery is not charged or discharged for 3 days,always in idle state. The battery will automatically shut down and go to sleep mode.Only when the battery is charged or discharged again, by then the battery will automatically activate.

So when there is a battery to sleep mode and shut down, our Master battery will light up red light and send message to the inverter show there is an internal alarm. (You can check the first three days of the alarm record, the battery will be used once.)

 

What I want to highlight fist is that. This is a normal BMS logic of our battery, to reduce unnecessary self discharge consumption loss of the system.it will not affect the normal use of the whole system or cause damage to the system. So don’t worry.

 

This situation usually occurs when the inverter sets the battery to the backup power supply, or UPS mode. The battery is not used as often, and it is usually left unused after being charged to 100%.

The solution:

1.Determine the working mode of on-site situation. If the customer does not want to use the back-up mode, please set the battery has priority over the public-grid to power the load.

 

2. If the customer only wants to use the battery as a backup power source, The customer can limit the inverter to charge the battery only up to 90% not 100%, so that the battery will not enter the standby state.

 

Hope these information will help. Please let me know if you have more questions.

 

What i'm seeing seems to support that & I'm still getting the alarm even set at 52.2/51.8 - i gave it load on the 21st to have the alarm go off again this am 24th.

 

 

14th i set it to 52.2/51.8

49929153466_efba561977_c.jpg

 

@plonkster - Cheif any idea a setting to put it at 90% to try?

 

Edited by 2una
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Also just seen this comment - would this be a possible usable approach to use remembering that i'm backup/UPS only?

Quote

Thanks for the explanation @Ned Yu (Pylontech). I noticed that the error would always appear exactly 3 days after the end of the last discharge/charge cycle. There is another way to prevent the error and keep the batteries charged at 100%. If the ESS assistant is loaded onto the Victron Multiplus, the system will draw small amounts of power from the battery and return it shortly afterwards. See battery voltage vs. current below:

This prevents the battery from going into idle mode and generating the internal error alarm.

 

https://community.victronenergy.com/comments/50458/view.html

Edited by 2una
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The idea of "holding" the SOC is in my opinion a flawed one, because SOC tracking is always an estimation of a chemical process. At the edges we can be fairly accurate, because we know the voltage rises as the cells fill up, but lower down LFP cells has a flat curve and you can easily end up slowly discharging a battery while you think you're holding the SOC constant.

The only solution would be to keep them at a lower voltage, say 51V (3.4V per cell). Usually in a Victron system there is enough back and forth going on that it should not be  problem, but if it is, there's three things I can think of.

1. If you're running "Keep Batteries Charged", you can (in VE.Configure) enable Dynamic current limiting for that AC input. This is actually meant for generators. What it does is when a larger load starts on the output, it uses the Multi to "cushion" the blow, so that the generator gets more of a gradual load increase. By using this you make the batteries do something every now and then.

2. Instead of using "Keep Batteries Charged", put the system into optimised mode, and then enable Scheduled charging. Set a charge schedule that runs evey day from midnight for 23 hours and 55 minutes. The effect would be that every day just before midnight it will discharge the batteries for 5 minutes, also avoiding the "error".

3. Ignore the error...

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1 hour ago, plonkster said:

The idea of "holding" the SOC is in my opinion a flawed one, because SOC tracking is always an estimation of a chemical process. At the edges we can be fairly accurate, because we know the voltage rises as the cells fill up, but lower down LFP cells has a flat curve and you can easily end up slowly discharging a battery while you think you're holding the SOC constant.

The only solution would be to keep them at a lower voltage, say 51V (3.4V per cell). Usually in a Victron system there is enough back and forth going on that it should not be  problem, but if it is, there's three things I can think of.

1. If you're running "Keep Batteries Charged", you can (in VE.Configure) enable Dynamic current limiting for that AC input. This is actually meant for generators. What it does is when a larger load starts on the output, it uses the Multi to "cushion" the blow, so that the generator gets more of a gradual load increase. By using this you make the batteries do something every now and then.

2. Instead of using "Keep Batteries Charged", put the system into optimised mode, and then enable Scheduled charging. Set a charge schedule that runs evey day from midnight for 23 hours and 55 minutes. The effect would be that every day just before midnight it will discharge the batteries for 5 minutes, also avoiding the "error".

3. Ignore the error...

Ok thanks Plonkster - For Option 3 I need to check but i have it in my head if mains fail whilst the master is in that alarm state that it fails to deliver battery power but maybe i'm wrong, will check next time it throws it.

I'm not currently on ESS setup at all but thanks for those 2 options to think about moving to. 

I watched all of the ESS vid & there was nothing i saw that really jumped out to use.

Edited by 2una
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1 hour ago, 2una said:

Ok thanks Plonkster - For Option 3 I need to check but i have it in my head if mains fail whilst the master is in that alarm state that it fails to deliver battery power but maybe i'm wrong, will check next time it throws it.

I'm not currently on ESS setup at all but thanks for those 2 options to think about moving to. 

I watched all of the ESS vid & there was nothing i saw that really jumped out to use.

Hi @2una - I have actually checked and for me it works. The BMS activates immediately after power failure and all 3 of my Pylontechs operate through the master. Red alarm led comes on after 3 days again.

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