Proper process for balancing two Dyness batteries

wingnut771 said:
What are we arguing about here?
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Are we arguing?

I was saying the two BMS/Batteries are aware of each other since they are connected.

In fact going by the master/slave configuration I would think some part of the Master BMS controls all of the batteries in the bank if not the entire thing.
 
SauRoNZA said:
Other way round really. In AGM it goes into dumb mode and just does what it’s told without caring.

In Lithium mode they fight with each other and the BMW wins.

I’ve never tried to run it completely dead in AGM mode so chances are there is a secondary BMS protection, but I could definitely run it was lower in AGM than on Lithium mode.
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In layman's terms, what is the difference between "dumb" mode and lithium mode? Give a practical example.

IMHO, the only difference is one looks at soc percentage and the other looks at voltage. The percentage one can be wrong because of reasons but the voltage one can never be wrong. This would explain why you can get more in AGM mode. Doesn't mean you are going too low on DoD.
 
SauRoNZA said:
Are we arguing?

I was saying the two BMS/Batteries are aware of each other since they are connected.

In fact going by the master/slave configuration I would think some part of the Master BMS controls all of the batteries in the bank if not the entire thing.
Click to expand...
All it does is add up the capacities and soc percentages imho for the lithium mode.
 
wingnut771 said:
In layman's terms, what is the difference between "dumb" mode and lithium mode? Give a practical example.

IMHO, the only difference is one looks at soc percentage and the other looks at voltage. The percentage one can be wrong because of reasons but the voltage one can never be wrong. This would explain why you can get more in AGM mode. Doesn't mean you are going too low on DoD.
Click to expand...

Fair point and makes sense.

I only ever ran mine in AGM for a very short time when first getting it and didn’t try to drain it entirely just trying to find the cut off threshold.

So what you are saying makes perfect sense, I just can’t remember exactly where that cut off was or if it was there at all in AGM but I do know it certainly went much lower than the Lithium configuration and I want to say that was down to at least 5%.
 
SauRoNZA said:
Fair point and makes sense.

I only ever ran mine in AGM for a very short time when first getting it and didn’t try to drain it entirely just trying to find the cut off threshold.

So what you are saying makes perfect sense, I just can’t remember exactly where that cut off was or if it was there at all in AGM but I do know it certainly went much lower than the Lithium configuration and I want to say that was down to at least 5%.
Click to expand...
AGM mode you generally set the cut offs yourself
 
I’ve actually just remember something and that was a sort of bug with the Sunsynk at the time, not sure if still relevant.

But it was the fact you needed to switch it to AGM mode and set your minimums there which would match your SOC in Lithium mode and then switch it back.

If you didn’t do this and the Lithium values were lower than the AGM ones it would still trigger at the AGM values even if not using that mode.

Referring to Shutdown/Restart etc.

It was why I had so much trouble in my first couple of weeks to get it to listen to me, it wasn’t the BMS cut off I was hitting but a stupid problem with the Sunsynk itself.
 
Lupus said:
AGM mode you generally set the cut offs yourself
Click to expand...

The question was rather whenever the internal battery BMS would still turn itself off or if the AGM values would be adhered to and you can drain it to 100% which you can’t on Lithium more.
 
SauRoNZA said:
Fair point and makes sense.

I only ever ran mine in AGM for a very short time when first getting it and didn’t try to drain it entirely just trying to find the cut off threshold.

So what you are saying makes perfect sense, I just can’t remember exactly where that cut off was or if it was there at all in AGM but I do know it certainly went much lower than the Lithium configuration and I want to say that was down to at least 5%.
Click to expand...
When I was on holiday in CoCT, my mates had a 16kWh sunsynk and 16kW sunsynk, in lithium mode, the lowest I could so was 10%. At 9% it would do a forced recharge @ 5kW from the grid and we dont want that (winter credits on the meter were super low and we trying to stretch it for a few days till month end). At 10%, voltage was 51V, and we all know 51V aint 10%, so I switched to AGM mode and it carried on until 49V where it started blending grid to maintain 49V (no forced recharge). The BMS did this (what witchcraft is this without any comms?), not the inverter, as the inverter AGM setting was set to 47V.

I then set it back to lithium for warranty purposes happy confirming my thoughts that lithium mode is crap.
 
wingnut771 said:
When I was on holiday in CoCT, my mates had a 16kWh sunsynk and 16kW sunsynk, in lithium mode, the lowest I could so was 10%. At 9% it would do a forced recharge @ 5kW from the grid and we dont want that (winter credits on the meter were super low and we trying to stretch it for a few days till month end). At 10%, voltage was 51V, and we all know 51V aint 10%, so I switched to AGM mode and it carried on until 49V where it started blending grid to maintain 49V (no forced recharge). The BMS did this (what witchcraft is this without any comms?), not the inverter, as the inverter AGM setting was set to 47V.

I then set it back to lithium for warranty purposes happy confirming my thoughts that lithium mode is crap.
Click to expand...

Sounds very much like the bug or “trick” I described above in my last post was in play there as well.

But yeah no having used other batteries I don’t know if it’s a Sunsynk/Deye thing or just a Dyness thing.

I remember spotting it by pure accident on YouTube when Sunsynk’s CEO did all those videos and said you need to configure AGM first and then switch to Lithium.
 
SauRoNZA said:
Sounds very much like the bug or “trick” I described above in my last post was in play there as well.

But yeah no having used other batteries I don’t know if it’s a Sunsynk/Deye thing or just a Dyness thing.

I remember spotting it by pure accident on YouTube when Sunsynk’s CEO did all those videos and said you need to configure AGM first and then switch to Lithium.
Click to expand...
Yes, thats the video I was thinking about, let me try find it.
 
SauRoNZA said:
I’ve actually just remember something and that was a sort of bug with the Sunsynk at the time, not sure if still relevant.

But it was the fact you needed to switch it to AGM mode and set your minimums there which would match your SOC in Lithium mode and then switch it back.

If you didn’t do this and the Lithium values were lower than the AGM ones it would still trigger at the AGM values even if not using that mode.

Referring to Shutdown/Restart etc.

It was why I had so much trouble in my first couple of weeks to get it to listen to me, it wasn’t the BMS cut off I was hitting but a stupid problem with the Sunsynk itself.
Click to expand...
Was this the 14% or whatever shutdown no matter what value you set?

Because I have the same crap on a Deye...
 
Mike Hoxbig said:
Was this the 14% or whatever shutdown no matter what value you set?

Because I have the same crap on a Deye...
Click to expand...
I assume its the battery BMS doing its thing. Different batteries will do different things. Thats why I want a DIY one with no welded terminals and a BMS i can set up on my phone.
 
SauRoNZA said:
Sounds very much like the bug or “trick” I described above in my last post was in play there as well.

But yeah no having used other batteries I don’t know if it’s a Sunsynk/Deye thing or just a Dyness thing.

I remember spotting it by pure accident on YouTube when Sunsynk’s CEO did all those videos and said you need to configure AGM first and then switch to Lithium.
Click to expand...
 
Mike Hoxbig said:
Was this the 14% or whatever shutdown no matter what value you set?

Because I have the same crap on a Deye...
Click to expand...

Yeah it was something like that, this was years ago by now so I’ve forgotten the exact details.

Load shedding also buggered off so Shutdown values became somewhat irrelevant.

When load shedding happens I just have it all set to 20% and have enough overhead down to 15%.
 
SauRoNZA said:
Yeah it was something like that, this was years ago by now so I’ve forgotten the exact details.

Load shedding also buggered off so Shutdown values became somewhat irrelevant.

When load shedding happens I just have it all set to 20% and have enough overhead down to 15%.
Click to expand...
Ah to live in a well run municipality.
 
I have a bank of two Dyness batteries on my Sunsynk inverter which I installed 3 years ago. The two batteries are different distances from the inverter and they were installed 6 months apart
In all the time I have had them, they have always been in perfect balance.
What is happening at the OP is not normal. Get the installer to take the weaker battery to the supplier for replacement. There is no other option regardless of the opinions expressed in this thread
 
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