DALY BMS 7S 24V 20A for Lithium Ion Battery

Description

What we know

• This BMS is specified for a 7-cell in series (7S) Li-ion/NMC pack (nominal ~25.9 V, full charge ~29.4 V) according to the listing.

• Continuous current rating stated as 20 A in the listing.

• It offers major protections: over-charge, over-discharge, overcurrent, short circuit, temperature (as per listing features).

• It supports passive balancing of cells to maintain pack uniformity.

• The vendor in India shows a price around ₹719 (incl. GST) and stock.

⚠️ What to verify / caveats

Before you integrate this BMS into your battery pack/project, there are a few things you absolutely should check:

1. Series and Chemistry match

   • This board is for 7S NMC (Li-ion) packs. If your pack is a different series count (for example 8S, 10S etc) it will not align with correct voltage cut-offs.

   • If your cells are a different chemistry (e.g., LFP) the BMS may not be suitable because voltages differ. For instance, one Reddit post warns:

     “They are not interchangeable. … You need to pick up a new one for LiFePo4.”

2. Check real continuous vs surge current

   • It says 20 A continuous, but in real-life applications loads can surge beyond that (motors, controllers, etc).

   • One spec page shows “Discharge Current: 10 continuous, for 10sec: 30 max”. So make sure you review the full spec sheet for your specific unit because there may be discrepancies.

3. Wiring / balance lead / install layout

   • For a 7S pack you will have a balance connector with 8 leads (B-, B1+, B2+, … B7+). Ensure you wire exactly as per the BMS datasheet.

   • Make sure high current wires, correct gauge, good soldering or welding, proper thermal considerations.

4. Charge criteria & cut-offs

   • The listing shows an over-charge protect at ~29.4 V (which corresponds to ~4.2 V per cell) and over-discharge protect at ~21 V (~3.0 V per cell) in one spec sheet.

   • Verify cell manufacturer’s voltage spec for your cells. If your cells are rated for different max/min voltages you may want a BMS that matches those exactly.

5. Thermal & environment conditions

   • At 20A continuous, there will be heat generated in the MOSFETs and paths. Ensure proper ventilation, mounting on insulating yet thermally safe backing.

   • Consider ambient temperature. If the system will see hot/harsh conditions (e.g., in EV under seat or outdoors), check the board’s allowed ambient temperature range.

6. Warranty & vendor authenticity

   • The listing shows in one case only 15 days warranty. For a critical application (EV, etc) you might prefer longer warranty/support.

   • Ensure you buy from a trusted vendor; verify you are getting the correct model (7S 20A NMC) and not a mislabeled variant.

🎯 Suitability for your use case

Given your earlier mentions of EV / battery-pack use, here’s how I’d evaluate it for your specific scenario:

• If you are building a 7S (~25.9 V nominal) NMC pack, and your expected continuous load is up to ~20A (and surges not much higher) this BMS can be a good fit.

• If your load is higher (say 30-40A continuous or big surge currents) then this board may be the bottleneck; you might want a higher-current version (30-40A or more) or dual parallel BMS boards (but that adds complexity).

• If your pack is not 7S (for example you need 8S, 10S, 12S, etc), then this is not suitable and you will need to pick a BMS with matching series count.

• If your application is an EV (with motor, high start current, frequent high loads) I’d lean toward a BMS rated for significantly above your peak load (so you have margin) and perhaps with “smart” monitoring features if you want telemetry.

• For static ESS (energy storage) or moderate loads (e-bike, light scooter) this board could be quite cost-effective.