Can a non-LiFePO4 CC + a BMS cover all parameters?

[MTBioGuy]

Greetings – my existing system consists of an Epever model 5415AN 50A CC feeding a bank of six 6-volt Interstate flooded lead / acid batteries. It works great but I’m in the process of upgrading to DIY 3.2v LiFePO4 (280 Ah) cell packs (8 cells total). Unfortunately I apparently purchased the 5415AN CC about 6 months too early as the next model released was upgraded to include a LiFePO4 profile. Go figure...

I’ve been trying to determine if I can avoid having to buy the upgraded CC model by instead buying a full function “Overkill” BMS as well as setting my Epever CC LiFePO4 parameters using the “USER” profile via RS485-150U PC software & the MT50 remote display instead. The question is… which settings should be managed by the CC and which by the BMS? The Seller cautions about "automatic protection" and "automatic activation" of the cells but offers no explanation. Thanks.

 

[snoobler]

Welcome to the forum. LFP is essentially a drop-in replacement for lead-acid.

There is absolutely no reason to change your CC. Almost all lead-only CC can be made to work with LFP. IMHO, a properly configured USER program is better than any "canned" LFP program I've seen.

All loads and chargers should be configured to maintain the normal range of operation. The BMS should be configured to protect the battery outside of the normal operating range.

If you have questions about specific settings, please include links to manuals.

 

[MisterSandals]

Have you contacted EPEver to see if you can update the firmware to a version that has an LiFePO4 charge profile? That would be optimal. Otherwise i would think you could use a user profile to accomplish everything you need. Even with an LiFePO4 profile you would likely want to customize a setting or three.

And remember, the BMS is a safety mechanism with limits and disconnect functionality.

And what snubber just posted as i was finishing this up...

 

[MTBioGuy]

I’m quoting advice paragraphs (below) from the older Epever Seller. I’ve tried to smooth out a few of the rougher edges in the original translation but I’m still seeing a few areas that puzzle me. Perhaps you can help me fill in the “prior knowledge assumed” areas? I intend to use 280Ah Eve or Lishen 3.2v DIY cells and an “Overkill” BMS. I suspect that, throughout these suggestions, the Seller is referring to full factory-made batteries rather than DIY battery packs (sold without any factory installed SOC monitoring boards). Will the Seller’s statements also apply to DIY cell packs?

Everything you see below came from the Seller. My own questions / comments are contained between square brackets: [ xxxx ]
-----------------------

Seller’s Advice: The old 5415AN controller does not have the activation function of the lithium battery. Only the Lithium model (new 5415AN) has the lithium battery activation function.
(“Li” will be written in the barcode on the side of the newer 5415AN CC)

You can set the parameters of the lithium battery through the “User”, but you must pay attention to:
1) The charging limit voltage on the controller must be set 0.3V lower than that of the BMS, and …
2) the low-voltage disconnection voltage is set 0.3V higher than that of the BMS.

You can also charge a lithium battery with the old 5415AN controller, as long as the lithium battery is prevented from starting automatic protection.

When an over-charge, over-discharge or short circuit occurs, the lithium battery will protect itself. After self-protection, it will stop charging and discharging. It can only be charged and discharged normally after the lithium battery is reactivated. [ But DIY packs will NOT do this on their own? ]

The CC lithium battery parameters set by “User” cannot activate the protection function of the lithium battery. You can buy a BMS with lithium battery activation function.

[ Will the Overkill BMS provide both this “protection function” and “Activation” function… that the old CC model apparently can’t provide? ]

Thank!!

 

[snoobler]

Welcome to the forum. LFP is essentially a drop-in replacement for lead-acid.

There is absolutely no reason to change your CC. Almost all lead-only CC can be made to work with LFP. IMHO, a properly configured USER program is better than any "canned" LFP program I've seen.

All loads and chargers should be configured to maintain the normal range of operation. The BMS should be configured to protect the battery outside of the normal operating range.

If you have questions about specific settings, please include links to manuals.

Please refer to the above.

[ Will the Overkill BMS provide both this “protection function” and “Activation” function… that the old CC model apparently can’t provide? ]

Thank!!

All BMS do.

 

[JeepDaddy]

All loads and chargers should be configured to maintain the normal range of operation. The BMS should be configured to protect the battery outside of the normal operating range.

++ This^^^^

Think of a BMS as a very sophisticated fuse. It should only kick in for protection when something goes wrong. A properly designed and used system won't activate any BMS protections under normal circumstances.