Wednesday, May 29, 2024

Batteries... the 24 volt Lead Acid replaced by LiFePO4.

24V EVE 230Ah 5.89kWh LiFePO4 Battery Pack Kit with Smart BMS

https://lifepo4oz.com/

is installed and Running.

Step-by-Step Guide: Setting Up Your Daly BMS with LiFePO4 Oz

 Fault : I had a flood which shut down the BMS. After it was dried out it worked again ..  I blew up the 24 to 12 volt module probably by having 12 volt on the line but zero on the 24.   Not fail safe - Beware.

The BMS also "forgets" the SOC and thinks it is 100 percent once it comes back up.

Recalibration is :          Cell Characteristics > SCO Set to 50 percent. 

Charge till 28 volts. (Not 28.6 - too high can be set         Protection parameters >sum volt high protect).

SCO Set to 100Percent.  

BMS Software           Can run on Wine (wouldnt using Synaptic) or on Google / Apps Linux

Stack Compression?   No One thinks this is necessary.

 Some assert the pile should be restrained with threaded Rod or springs .. the kits supplier thinks it is unnecessary.  If it were i would expect to see a spec in the Operating section.  The Compression Spec is in the destructive batch testing section.

The construction of the battery pack will need to be researched. There needs to be some rigidity / compression in the pack because according to some,  failing this the battery packs will swell during charge and this deformation will damage them. 

https://lifepo4oz.com/collections/lifepo4-battery-kits/products/24v-eve-280ah-lifepo4-7-17-kwh-battery-pack-kit-with-smart-bms

Compression Testing Spec  

Ref Page 19

https://batteryfinds.com/wp-content/uploads/2023/09/EVE-LF280K-280Ah-3.2V-LiFePO4-Prismatic-Battery-Cell-SpecificationDatasheet.pdf

Gives the dimensions of a test rig and then specifies the maximum pressure (swelling) the cell should exert to pass the test.  I doesnt seem to refer to the design of a working battery pack. 

 

 

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