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2 x Shoto SDA10-48100 not discharging evenly

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I have two of these in parallel. Yesterday at the end of the day they were fully charged (all SOC LEDs lit). This morning one of them has 2 SOC LEDs lit and the other is flashing RED in alarm mode which I believe indicates it is flat. Do I have to cascade them to get them to discharge evenly? Tx.

  • Author

I have now had the batteries correctly wired up for 4 days and its better but one still drains considerably faster that the other. If I run things conservatively one battery will be showing 2 or 3 out of 4 state of charge LEDs on in the morning and the other one less. If I am more aggressive then one battery will be on 1 or 2 LEDs and the other flashing alarm. This is after both batteries ended the previous day fully charged.

Is this "normal" or is something wrong? How do I figure out if there is a problem with the battery that goes flat quicker? Tx.

  • Author

Tx. The inverter stops charging them. I hadn't thought that not charging completely might be the issue. I have it setup as follows:

Battery float charge voltage 51.8 V
Battery bulk charge voltage 52.5 V

I found those settings on these forums.

  • 3 weeks later...

If isolating them did the trick, doesn't that mean that the bms's weren't doing their job? Considering that the cable between them is an rs485 cable and that they were communicating with each other. 

  • Author

I am not at all certain that that part of the system is working. I do have them connected with a LAN cable. However I have not managed to get them to communicate with Solar Assistant using an RS485 to USB or RS232 to USB cable. Nothing seems to work.

I believe the cable should be rs485, not lan. I just oredered a set of 3 similar looking batteries, from another manufacturer, and i am curious how they will perform. I am looking for people Who have similar batteries to share their experience.

 

I also saw that this battery has 2 models, a 15s and a 16s. Judging by the charging voltages, i would say that you have the 15s version, right? 

Edited by Nickso

  • Author

Yes I think I have the 15s version. I have an RS485 to USB cable for the connection to the Solar Assistant Raspberry Pi. As far as I am aware the cable between the batteries is simple straight LAN cable (no crossover) which is what I have. 

 

Maybe someone else with more knowledge will enlighten us. I suspect that a special cable is needed, as the ports should follow the rs485 protocol. Also, with different manuals of these batteries, i often saw that the master should be with the address 0000 (all switches in the 0 position), but again, nothing can be taken for granted.

If you get the chance to try cascading the with a rs485 wired cable, let us know how it went.

image.png.f6c8a7e750368c397611031928be0bb9.png

 

on the other hand, according to this, the straight lan cable should work...

image.png.401706067537aba1a3c114555b7142b8.png

So i guess that, with this kind of batteries, all you can do is see what you get and just go from there. As i said in my post, linked above, i also ordered something similar and mine will come with no kind of manual, just plug and play and with no kind of communication even between the batteries. At least that is what the seller is saying, that no CAN means no comms, even if the batteries come with rs232 and 2xrs485 ports.

  • 3 months later...
  • Author

I managed to get RS232 communication working with my batteries but only to one or the other, the cascade using RS485 does not seem to work. I also have software from Shoto that communicates with the batteries and Solar Assistant is also working (to one battery but thats ok as they are now in sync .. see below).

I had more problems with uneven charging. Basically one of the batteries would stop charging at something less than 100% when the other one was full. This got worse every day until one was stopping at only 72% after only a week. Shoto advised me to set the battery bulk charge voltage to 57.6 V which finally sorted this out. That is above what it says on the side of the battery but that assured me that the BMS would protect the battery.

  • 1 month later...
  • 11 months later...

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