CHV1410L vacuum cleaner charger current ratings

Thanks for the explanation!

Yes, it uses 4 18650 Li-on cells (in 4 of 5 slots in battery pack - 1 empty slot) with 16V max and nominal voltage of 14.4V (3.6V * 4), as they're connected in series. The part I'm not sure from above answer is how can the battery controller (BMS), draw different amps from different DC sources with the same voltage. It's not like a type-C USB cable with a e-marker / data interface to negotiate voltage / current with the wall charger / DC power supply. It's just plain DC with 2 cables (red for +, black for -) in the wall charger.

PS: I don't have access to the charger, so I cannot do measurements. I have only DC power supply to charge the vacuum cleaner.

@rishabs it does not allow different amperage it just allows the full charge to the batteries. It is not limited to anything below the current 2A that it is drawing from your power supply. If you would use an adapter that delivers 1A then it would let the battery charge at that amperage :-) Like I mentioned, for as long as your batteries do not heat up, there will be no issues.

The original B&D charger mentions 400 mA, which I guess is the maximum current supported by the charger at 23V (to handle heat issues etc). So, the load (the BMS) in the charging circuit should consume current between 0 - 400 mA at the 23 Volts. I understand that the BMS in the vacuum cleaner supports much higher charging current at 23V and is fine with regulated / lower currents (the original charger), but I guessing there should be good reason for B&D to limit current to 400mA. The label in the battery pack reads (DB144LD / 22Wh / 10-BM-D15).

Unfortunately, my DC power supply (30V / 2A) is much basic. I tried setting it to CC mode at 400mA with 23V, but the voltage drops from 23V to 8V when the CC limit of 400mA is hit. Maybe a better DC power supply would stay close to 23V at 400mA simulating the actual B&D charging characteristics.

@rishabs there is also the possibility that the original charger only supplies 400mAh to be the battery controller ;-) I do not know the mAh of the 18650 for your cells, but I do know that a 3000mAh can be charged safely with 3A and that the typical charging current ranges from 0.5A to 2.0A A lower charger rate (about %50-75% charge amperage) will increase the batteries life span. Using the data provide by you, your battery has 22Wh at 14.4V which would be (Wh*1000/V) (22*1000)/14.4=1500mAh

Keep in mind that the load (in your case the battery), will only consume what it needs. It will not take on more. The power supply only needs to supply the current that the battery requires. Even if the power supply can supply much more, the battery will only use what the battery needs.

How about using something like a 10ohm 20Watt resistor in series to match your power supply more to the original charger? Or even a rheostat if you have access to one. Of course, you could also design a quick circuit around a LM723

Adding resistor to DC power supply output worked great.

1. 5Ω (10 watt) resulted in 660 mA causing 15 watts power dissipation.

2. 10Ω (10 watt) resulted in 440 mA causing 10+ watts power dissipation.

3. 15Ω (10 watt) resulted in 360 mA causing 8.28 watts power dissipation.

15Ω worked perfectly with no resistor heating. With this the drop in current over time was very slow and steady (compared to without resistor when current drop was much faster as the current range was high).

I didn't measure exactly, but after roughly 3 - 4 hours the charging completed (from blinking blue led to solid blue led). Total run time for the vacuum cleaner with full charge is around 10 - 11 mins. Anything above 7 - 8 mins sounds good for me (device being few years old).

Thanks!!