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Posted

Hi. We are using a Deye Inverter (5kw), and 2 Revov R100 LiFe batteries.

The inverter is Not set to recognize the batteries as Lithium. It's currently dealing with voltages? The batteries have built in BMS capability. Can we solve this with a click of a button? 

By selecting lithium on the inverter (will the BMS auto manage the change?)

Also the single inverter is running as a slave. Should it not be Master as its the only one!?

Not currently a problem as the system is working correctly but doesn't seem correct in my head. 

Please help. 

Thank you. M. G. McDonald

Posted

As a single unit slave is correct.

The LFP batteries should ideally be managed with the BMS talking to the inverter, but I don't know whether your batteries' BMS is supported/recognized by the Deye, I have a Sunsynk and the software is, as I understand it different from the Deye, hopefully there's one of the others that can help you out with the settings needed for the BMS.

Posted

How interesting! Thank you so much. That is really helpful. The installer is coming out tomorrow so I'll keep you posted. The Deye is a hybrid like the Sunsynk. 

Im hoping we just have to select one button on the Deye and Revovs will pick it up. 

Another quick question.

Since both batteries have BMS I would imagine that they'll figure out a way themselves to be Master and Slave so to say? Or will that be largely irrelevant? 

Posted

If its these then I think the one connecting to the inverter would be treated as the master and the 2nd battery, should probably plug its CAN cable into the 1st battery and thus be seen as slave, but you'd better take this with a pinch of salt, since I am not 100% sure on this, I have no LFP batteries yet, still got some old creaky Lead Acids.

Posted

Thanks. Yeah those are the batteries. What you are saying makes sense. 

I'll let you know what the installer says once he has been. 

My primary concern was damage to the batteries, as a result of the inverter detecting them as lead acid. 

I so badly want to push the Lithium setting on the inverter, but I'll wait for the installer to do it. 

Thanks again for the response. The system is working very well, just needed insight into the battery/inverter lithium setting. I would hate for the batteries to be damaged due to something so simple that can be fixed by the push of a button! 

 

Posted

Hello. 

Sorry for the late response. The installer was out, & we ended up just setting the Invertor to read 'Battery as %' & not Lithium.

We have encountered no issue since installation, & system is working normally. 

I think the built-in BMS is able to pick up what the system needs I guess...

If I can ask you, why is the invertor (as the only one) set to be the slave and not the master?

Thanks.

Posted
6 minutes ago, Mixhael Finch said:

The installer was out, & we ended up just setting the Invertor to read 'Battery as %' & not Lithium.

Ideally this should still be changed to use the BMS and use Lithium as battery type, as I understand it, the BMS, if the inverter can talk to it, can give more accurate SOC to the inverter, also tell it what the allowable current draw is and what the allowable charge current is etc.

If the system is not set to Lithium with an interface to the batteries' BMS, then the inverter relies on the voltage to determine the SOC and this is way less than inaccurate, since it presumably assumes Lead Acid cells and their combined voltages for a given SOC would be rather different than the Lithium packs' voltages, I would think. So beware of assuming a given state of charge based on your current setup, it may be underestimating it (which would be, ok) or it could be overestimating it (which would be bad), either way, if the Deye can talk to and understand the Revov R100's then that would still be your best end result.

Note that voltages which fluctuate with temperature, more so for LeadAcid batteries, I think than for Lithium and if the inverter is set to read the temperature of the batteries and they are actually Lithium, but not set as such for the inverter, then SOC assumptions that the inverter is basing on voltage will also be way off.

Posted

Just to add, the BMS lets the inverter know what the capabilities of the battery pack are and what state of charge is. The BMS is also responsible, otherwise to prevent the individual cells from dropping below a pre-set value on discharge (presumably by disconnecting the pack from the load entirely, should this happen) and also preventing individual cells from reaching too high a voltage during charging, this is mostly done by way of balancing the individual cells that may be reaching a upper limits with some lower voltage cells, by swapping a little bit of charge from higher voltage cells to lower voltage cells/charge up a resonant circuit from the cell that has more charge before switching it to the cell that can take the charge, alternatively by burning off some power into resistors from the higher voltage cells until all individual cells are at app. the same level of charge/100% SOC.

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