12V LiFePO4 Smart BMS for 4S LFP Packs, JK B2A8S20P, 200A, Bluetooth, 2A Active Balance

A JK smart BMS for LiFePO4, set up and checked before it ships. Active balancing, a Bluetooth app and LFP limits set and verified on our bench, so it is ready to wire into your pack.

Set up for: 4S LiFePO4 packs (12V class).

What we set for you

We set the pack capacity and check every cutoff on our bench. Want different limits (90% charge for longer life, a higher low cutoff)? Add a note at checkout.

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 LFP, 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
• Runs from a 7.5 V pack and up
• 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 3S to 8S LFP or NMC. 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.

Build the rest of the pack

12V LiFePO4 ChargerProgrammed to matchBattery Pack Hardware Kit, 4SPlates, busbars, dividers, coversClass T Fuse, 250AAlways fuse the pack

How it ships

• Pre-order: ships in 4–6 weeks. Our first batch is on the way. Every unit is set up and checked on our bench in Michigan before it ships.