4 classic 250's 4 si6048 1 mnsmacomm & 240 lifepo4

[The Ugly One]

So I am doing a project that I am not exactly sure how it will work out .. so my question is if I have my 4 classic 250 (standard. Not carpoffs) connected with the sma comm box. How will the classic 250s know to vamp down the power supplying the lifepo4 once they are charged? Will the command come from the sma sunny island? Or will it be an external command from the bms. I believe I will be using the rec bms modules. I don't want to drop $10k+ to find out that it was an expensive learning experience. Anyone with insight to the internal working I am most thankful for the advise!
And I am not using eve 280a lifepo4. But the same battery just not from Alibaba. But from the actual manufacture company with it being ul 9540a certified. I don't trust the certs on Alibaba. Expecially on $30k+ worth of batteries.

[boB]

Hello Ugly.

The vamp comes down naturally, usually, as the battery gets charged. The battery just takes less current to keep it at whatever voltage it is sitting at.   That is unless you have extra DC loads across the battery taking more power/current than the battery needs at that time.

Assuming no extra DC loads and just the battery, you will need to know what "charged" means for those batteries.

Do they simply reach a voltage and want to stay at that voltage for a while (Absorb) so that their BMS can do their balancing thing for 1/2 hour or so ?   

Or are they supposed to stop charging immediately  after they reach this stopping voltage ?

Using the SMA Sunny Islands to control those 4  Classics, the S.I. itself would contain the parameters that the Classics require.

I think that is the answer to your question unless I have missed something.

boB

[The Ugly One]

That was part of what I was wondering. It answered a good amount of it. So as long as the sunny island is configured properly for the lifepo4. Then the midnites will listen to the sunny island.
My question I am still wondering then is how does the external bms contribute to the operations an charging of said batteries ? I will have to get them on the phone then.

[boB]

The BMS  "should" be basically invisible except that the battery company should be able to tell you, either by phone or by manual, the requirements for how you should set the Sunny Island for charging the battery.

Good luck.   I you can, let us know how that goes and what you are supposed to do.

We might just learn something.

boB

[FNG]

You may want to talk to Tech support, I recall something about SMA removing the support for the SI Comm adapter when they added support for Lithium.

[The Ugly One]

You may want to talk to Tech support, I recall something about SMA removing the support for the SI Comm adapter when they added support for Lithium.

Thank you for that information. I will be talking with their tech support.

[Wizbandit]

Kind of a mute point. Midnite discontinued production on the SMA Comm Adapter...