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12V Sodium-Ion Smart BMS for 4S Packs, JK B2A8S20P, 200A, Bluetooth, 2A Active Balance, Pre-Programmed (NFPP or Layered Oxide)

Available to order Ships in 4–6 weeks.

$129.00 USD

Sale Sold out

Cathode NFPP Layered oxide

Programmed and bench-tested in Michigan
Sodium-ion profile set for your cathode
Pre-order: ships in 4-6 weeks

A JK smart BMS set up for sodium-ion before it ships. Most lithium BMS boards ship with LFP or Li-ion limits that cut a sodium pack off early or let it charge past the cell's limit. We program this JK B2A8S20P with a sodium-ion profile for your cells (NFPP or layered oxide), check the cutoffs on our bench, and put a settings card in the box.

Set up for: 4S sodium-ion packs (12V class), including cold-climate builds. Most 12V inverters cut out at 10.0–10.5 V (2.5–2.6 V per cell) before the BMS limit is reached, so the BMS cutoff is your backstop.

What we set for you

Per cell	Charge cutoff / resume	Discharge cutoff / resume	Balance start
NFPP 18650 (our cell)	3.70 / 3.60 V	2.00 / 2.20 V	3.30 V
NFPP 160Ah prismatic	3.45 / 3.35 V	2.00 / 2.20 V	3.30 V
Layered oxide 18650 (our cell)	4.00 / 3.90 V	2.00 / 2.20 V	3.40 V
Layered oxide 32140 10Ah	3.95 / 3.85 V	2.00 / 2.20 V	3.40 V
Layered oxide 210Ah prismatic	3.90 / 3.80 V	2.00 / 2.20 V	3.40 V

Every charge cutoff sits at or below the cell datasheet maximum. We also set the low-temperature charge limit and pack capacity, then lock the settings with a parameter password so a tap on a preset in the app can't overwrite them. Ask us for the password if you want to change them yourself.

Pick your cathode, then tell us the cell. NFPP and layered-oxide cells need different limits, and cells within each cathode differ, so add your cell model in the order note. Other cell? We set it from your datasheet.

The hardware: JK B2A8S20P

This is the JK B2A8S20P from JK BMS (Jikong), the smart BMS most DIY Solar Forum builders now use. We buy it direct from the factory, set it up for your cells, and test it on our bench in Michigan before it ships.

Download the JK B2A8S20P datasheet (PDF)

Specs

200A continuous discharge, 2A active balancing (moves charge from high cells to low cells)
Bluetooth app for iOS and Android: live cell voltages, current, temperature and state of charge
UART and display port standard
Stays powered down to a 7.5 V pack, so it keeps protecting a 4S sodium pack all the way to its low cutoff
Board size 152 × 127 × 16 mm

What's in the box

JK B2A8S20P BMS with P- and B- terminals
Balance lead harness
Temperature sensors (2 external, 1 on the board)
Settings card with every value we set

Other cell counts

This listing is set up for 4S. The same board covers 4S to 8S sodium-ion. Building something less common, like 5S, 6S or 7S? Order this listing, put your cell count and cell model in the order note, and we program it for your pack. Not sure it fits? Ask before you order.