Building a 16 kWh Home Battery Pack

Steps

1. 1

   Step 1: Choosing cells and case for the 16 kWh build

   I am starting a live build of a 16 kWh home battery pack running at 48V using a kit ordered from AliExpress. The kit includes a protective case and a JKBMS along with all necessary components. For the chemistry, I am using EVE MB31 cells.

   What I used

   Item	Amount	Notes
   AliExpress case	1	Enclosure for the battery pack
   EVE MB31 cells	16	Lithium iron phosphate cells

2. 2

   Step 2: Modifying the case for double stud cells

   The battery case was originally designed for single stud cells with a single screw on top, which are currently cheaper and sold out everywhere. I am using the EVE double stud cells instead because they have two screws and are slightly better. Since they do not fit the housing completely, I need to make a small modification to make them fit.

   What I used

   Item	Amount	Notes
   EVE double stud cells	16	Cells requiring a small case modification

3. 3

   Step 3: Discussing payback time and home battery economics

   A viewer asks if a home battery costing around 7,000 euros can ever be earned back. I explain that it is hard to predict political changes, world events, and energy prices over the next 10 years. A home battery is not a direct moneymaking model, but rather a tool to save costs and reduce reliance on changing energy markets.

4. 4

   Step 4: Managing solar energy storage and net metering changes

   We are expanding our solar panel array from 30 to 51 panels. With net metering disappearing, feeding solar power back to the grid during the day gives little return, while buying power back at night for the electric car is expensive. The home battery stores excess solar power during the day so we can use it in the house, keeping our net grid usage at zero.

   What I used

   Item	Amount	Notes
   Solar panels	30	Expanding to 51 panels

5. 5

   Step 5: How home batteries and solar inverters work separately

   Many people mistakenly view solar panels and home batteries as a single unit. Solar panels and their inverter convert PV power into grid voltage. The home battery uses a sensor to detect whether power is being pulled from or pushed to the grid, adjusting its charge or discharge to keep net load at zero.

6. 6

   Step 6: Battery cell orientation and safety venting

   Laying battery cells on their side is functional, but I advise against it. The electrolyte settles to one side, which shortens the lifespan of the cells. Furthermore, a vent is located at the top of the cell to release pressure safely, and laying the cell flat could block this vent.

   • Cells are functional on their side or upside down

   • Electrolyte sagging shortens lifespan

   • Blocked vents pose a safety risk during high pressure

   Warning

   Keep cells upright as prescribed by the manufacturer to avoid shortening their lifespan and blocking safety vents.

7. 7

   Step 7: Sourcing parts and European availability

   There is a massive run on individual battery cells and parts in Europe, and components like 314Ah cells are frequently sold out. I often order parts from Ncom, a company in Nuenen in the Netherlands, which offers competitive pricing on Victron gear and lithium cells. There are no European manufacturers of lithium iron phosphate cells, so all power cells come from factories in China, though European warehouses in Germany and Poland often handle fulfillment for AliExpress orders.

   What I used

   Item	Amount	Notes
   Ncom	1	Supplier in Nuenen for Victron and lithium cells

8. 8

   Step 8: Understanding cell capacities and marketing numbers

   320 Ah cells do not actually exist; they are the exact same as 340 Ah cells. Some sellers advertise nominal capacity while others advertise maximum capacity based on slight variations between individual cells. This is similar to power tool marketing where Makita 18V drills and Action 20V drills use the exact same internal voltage, but one markets the fully charged peak voltage of 20V.

   What I used

   Item	Amount	Notes
   Makita drill	1	Advertised with nominal 18V rating
   Action drill	1	Advertised with peak 20V rating using identical internal voltage

9. 9

   Step 9: Connecting the battery to inverters using JKBMS

   Any inverter that supports a 48V battery can work with this build as long as the battery has a built-in BMS for protection and balancing. This build uses a JKBMS version 19, which features a communication board. It can be configured to speak different inverter protocols such as Pilon, Growatt, or Victron.

   What I used

   Item	Amount	Notes
   JKBMS V19	1	Battery management system with communication board

10. 10

    Step 10: Takeaways

    • A home battery helps store solar energy to avoid low feed-in tariffs after net metering ends.

    • Double stud cells offer better connections than single stud cells but may require enclosure modifications.

    • Always keep battery cells upright to protect lifespan and keep safety vents unblocked.

    • European suppliers and Chinese marketplaces often source cells from the exact same factories.

    • Cell capacities and tool voltages often use marketing terms for peak versus nominal ratings.

    • The JKBMS V19 supports communication protocols for various inverter brands like Victron, Growatt, and Pilon.