question

howard42 avatar image
howard42 asked

Is it possible to recover a pylontech battery from less than 44.5V (approx 40)

I have a new install of Multiplus II 3000 with 2 x Pylontech US2000 batteries. One battery is fine but the other is on continuous alarm. I have tried to charge this separately using 52V and 53.2V absorption/float over the past 2 days but it won't move from 40V - Any suggestions?

PS the voltage reading is taken from multiplus II with charging turned off. I also have 100/30 MPPT connected with solar control and this confirms low battery voltage as well.

Thanks in advance

battery chargingPylontech
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2 Answers
Paul B avatar image
Paul B answered ·

You would need to contact pylontech about getting that advice. I would suspect that the Pylontech BMS is stopping the charge for a reason and they should be able to help you I would think

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howard42 avatar image howard42 commented ·

Hi Paul B,

I bought the batteries along with solar panels, and inverter from ITS technologies but I'm beginning to think he's not a main dealer for Pylontech or Victron so support may be an issue. As you say, I may have to deal with Pylontech directly. Do you have any contact details of where I can get some advice? - The only address I have is where to send off the warranty card :-)

Thanks in advance


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trip-tracks avatar image
trip-tracks answered ·

@howard42, have you resolved this issue?

What lights are showing on the alarmed battery?

Have you taken the cables off the battery and measured the battery voltage?


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howard42 avatar image howard42 commented ·

Hi Trip-Tracks, unfortunately I haven't been able to resolve the issue yet.

When I turn the unit on the green led under the switch is illuminated. If I then press SW all the lights illuminate initially but then all the green SOC lights go out leaving just the red alarm led. After about 30s this also goes out leaving just the green on led under the switch.

In the description I mistakenly said that the battery voltage was 40V (reading from the Udc on the inverter). However, I think this must be some default value from the Victron unit as reading straight from the battery the voltage is actually zero. But.... When I turn the battery on the voltage is 0 but by pressing SW it momentarily jumps up before falling to zero again. It is so fast that I cannot get an actual voltage reading. This is straight from the battery terminals - no cables.

As I purchased two batteries I am able to test the installation with the other battery and found no issues - cables, inverter, mppt, solar panels, breakers etc all work fine. As yet I haven't put any load on the inverter as still in process of working on this side of the project - hopefully do that today (camper van conversion)

Thanks for your reply


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trip-tracks avatar image trip-tracks howard42 commented ·

As I understand it, these are new batteries, correct?

If so, I suggest you contact your Pylontech dealer. You may have a faulty module. They should not be delivered empty - mine are usually delivered around 50% SOC.

You sound like you have tried to charge using a 48V supply. Did you do this with the communications cables and the links between the modules disconnected, ie in full isolation?


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howard42 avatar image howard42 trip-tracks commented ·

The batteries are new but as in my reply to Paul B I got the batteries from ITS Technologies and not so sure he is a Pylontech dealer - I may be wrong. Communication has been slow and everything he suggested I had tried already.

As I wasn't bothered about communicating remotely from my phone I haven't gone down the GX route. My batteries are connected to a Victron Multiplus II and through usb/mk3 VE bus I am using VE configure 3 to change charging profile. I have tried different charge voltages 52V and 53.2V (both absorption and float), different currents (10A and 20A), and different absorption times. I have also tried battery to battery and using solar through smart solar mppt 48V 100/30 with control. :-) .

I have tried charging the module; totally isolated, together with other module with/without link and faulty module as the master and as slave.

I have been on this for about 2 weeks now so any BMS equalisation should have happened by now - surely. :-)

As an aside - I can't remember in what combination I had batteries and what absorption/float voltages but the good battery went into alarm mode as well to which I shouted a loud NOOO :-) . It is okay now thankfully but it was a bit of a wake-up call - Maybe it was overcharge alarm as it was already at 50.5V.


Thanks again for your response





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trip-tracks avatar image trip-tracks howard42 commented ·

I think you will find you need a GX device (CCGX, Venus or Cerbo) to manage these modules as they are can bus controlled.

I don't believe they will communicate with each other properly without the canbus control and they also need the canbus to control the Multiplus and the MPPT, both for charging and charge control while balancing cells.

We always setup DVCC to control the charging and it works really sweet.

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howard42 avatar image howard42 trip-tracks commented ·

Thanks Trip-Tracks, yes, looks like I may have to go down that route. I wish I could verify the state of the "faulty" module beforehand though.

I just want it to work, I am not really bothered about collecting data on the state of the modules nor on any historical data of charge/discharge from the solar panels to loads either.

As I said, I know my system does work using my "good" battery but if needs must. - At least I can report more data to chew over :-)

Thanks for the input though.

When you said "mine are delivered around 50% SOC" You are not a supplier per chance and in the UK?

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trip-tracks avatar image trip-tracks howard42 commented ·

Yes, we supply and install these batteries, but in Australia. Sorry.

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howard42 avatar image howard42 trip-tracks commented ·

Ah well, but thanks for your help

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