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spudgun avatar image
spudgun asked

Pylontech Charge Current Limit

I have 3 Pylontech US2000 Plus connected in parallel with a MultiPlus 48/3000/35 and a MPPT 150/45.

The CCL is set at 30A by the battery, is this because the MultiPlus can only charge with 35A and the battery knows this? I haven't connected the PV panels yet but when I do should I see this value raise to 75A as the MPPT can provide an extra 45A?

The DCL is set to 75A so I'm assuming that all 3 batteries are being detected and everything in the setup is fine. Any comments welcome please and thank you.

Pylontechcurrent limit
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5 Answers
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

It is most likely due to a cold temperature condition. Make sure the batteries are above 15 degrees C (as displayed in the CCGX), and it should increase.

I do not have the Temperature / Charge Current derating table for these batteries. Perhaps you could request it from your Pylontech supplier and post it here?

Those parameters are supplied by the batteries BMS and are not influenced by which Victron equipment is connected.

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spudgun avatar image spudgun commented ·

Thanks for your answer Guy. Yes, the temperature was at 11 degrees C so it limited the charge current. All good now.

I had no luck finding the Temp/Charge Current table but I'll post it if I do get my hands on it.

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alaskannoob avatar image alaskannoob commented ·

Here is what my Pylontech dealer sent me as far as temperature effect on charge/discharge of the US5000.derating-curve.png

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derating-curve.png (38.6 KiB)
digima avatar image
digima answered ·

These values are like the max CCL/DCL for one unit.

If you link correctly the 3 US2000. (B?) with the master unit having the Canbus to venusgx, the device entry should display a 150Ah capacity system. Did you check this 150Ah value?

The nominal charging value for one unit is 0.5C being 25A, and 75A for the 3

As the Pylontech is monitored by itself, it will shut down if a voltage, current or temperature condition is met, out of limit.

But I did not notice a change of displayed values on my 3 pylontech system linked to a derating.

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gary-c avatar image gary-c commented ·

Can someone tell me. For a 5 Kva multiplus the min recommended battery cable thickness is 50 mmsq. As per the manual. Does this only apply when using lead acid batteries. I see that the Pylontech batteries come with std 25mm sq main battery leads. Also if you now parrallel stack say 6 pylontech US 3500 batteries. Each capable of 37 amps at C2. Surely a much higher cable spec is required. Is the total bank limited to the current output rating of of one...

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Phil Gavin avatar image Phil Gavin gary-c commented ·

I have seen this discussed elsewhere. The consensus was for a maximum stack of 4 fed as a ring from the top and bottom battery, thereby doubling up on the 25mm2 cable.

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gary-c avatar image gary-c Phil Gavin commented ·

Thanks for the feedback. Sorry still not fully understanding your explanation. Could you please give more detail of refer me to the conversation on the topic

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Phil Gavin avatar image Phil Gavin gary-c commented ·

There are four terminals on each battery so they can paralleled.

(2 Pos + 2Neg)

Considering a group of 4 batteries:

The first battery in the string is connected to the DC busbars and onto the second battery, the third battery is connected from the second battery and onto the fourth battery.

The fourth battery is connected from third battery and then back to the DC busbars,

So the string is only four batteries in parallel and connected with a pair of 25mm2 cables at either ends to the DC busbars.

Keep the cables to the DC busbars the same length.

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gary-c avatar image gary-c Phil Gavin commented ·

Thanks understood

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rossmuller1 avatar image
rossmuller1 answered ·

I am having a similar issue, I have a 3kVA Multiplus II 48V with 2 x US2000 Pylon. CCL on Battery Parameter is only 20A where as the data sheet says 25A recommended. Surely as i have two in parallel I can expect 50A. Main issue is we are exporting to the grid via the inverter which is DC coupled by MPPT. 150/60.

Any ideas?

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Murray van Graan avatar image Murray van Graan commented ·

Hi @rossmuller1. First, make sure that the GX sees both pylontech batteries, and not just one. Second, the charge current limit is dynamic, which means that somewhere between 95 and 100% SOC the battery will reduce the charge current limit. This is normal.

If you enable DVCC, disable SVS and STS, and enable current limit then you should not have to see a reduction from your MPPT. In other words, you can have 60A coming from the MPPT and only 20A going to the battery with the balance being exported.

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karel avatar image karel Murray van Graan commented ·

Hi Murray, I came across your reply above. I have been struggling with the same problem of my feed in power comming from PV reducing at around 10h00 every morning due to something happening in my system (Multiplus II, 1 pylontech US2000, 4455W PV , Smart Solar MPPT 150/70, venus GX, ESS and DVCC). It is clear from trends that once my MMPT charge voltage raises above 52.xx V that the MPPT is throttled by some pylontech command. I tried your DVCC settings above but with no effect. I did however notice on trends that my pylontech CCL drops from 10A to 5A at the same time the MPPT output is reduced/throttled. Bty temp ranges between 21C and 24C over a 24hr period so not that and also no alarms. I have been told that my problem was having only 1 pylontech Bty but from the original post it is obviously not that. I am also aware that on a 5kVA Easy solar system with 1 pylontech bty this problem does not occur. Any other ideas would be welcome.

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lucode avatar image
lucode answered ·

Having experienced a similar issue after upgrading from lead batteries to Pylontech. In my case the cause was likely the Limit Charge Current param from DVCC. It was set for Lead batteries to 25 A but then disabled. But somehows the 25 A limit was still active until I did restart the GX device. Then it was strangely suddenly enabled again.


2020-10-22-11-29-39-remote-console-dvcc.png (58.6 KiB)
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alaskannoob avatar image
alaskannoob answered ·

Having just purchased 8 x US5000 batteries (not yet delivered) and having sized my SCCs (2 x 450/200 smart solar) and my PV (22KW) and our inverters (2 x MPII 8000VA) to account for the Pylontech stated max charge/discharge current of 100A per battery.....and after jumping through hoops to overcome the 100A cable rating in order to get 200A to each set of four batteries, and given that I live very off-grid in Alaska in an area where the hottest summer temp we see is in the 70s, I am going to try to keep this post as non-emotional as possible and hope that somebody informs me that this PylonTech BMS has been updated.

I have just now read from this Victron page, that the PylonTech BMS restricts charging current to 25% of what it can actually take to extend the battery life for warranty coverage. And that it starts to restrict charge current below 64F? And that it "severely" restricts charge current below 50F!?

Can somebody please tell me I didn't just waste a MASSIVE amount of money on these batteries because I expected them to perform according to advertised specs?

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nickdb avatar image nickdb ♦♦ commented ·
Do you mean UP5000? Pylons have a common problem of low continuous discharge current, so larger systems need a lot of them to work.

Ignore Max discharge ratings as these are transient only and of little use to anyone.

On paper the 5000 is great but it, at release, had a poor warranty period (5 years) and its recommended discharge is 50A, which is rubbish.

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alaskannoob avatar image alaskannoob nickdb ♦♦ commented ·

US5000. Here is a chart my Pylontech dealer gave me regarding temperature effect on charge/discharge of the US5000 if it's helpful.derating-curve.png

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derating-curve.png (38.6 KiB)

Related Resources

Victron Pylontech battery compatibility guide

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