We will "slightly" modify the battery and charging of a portable Vacuum Cleaner.
For this we need:
1. Li-Ion 18650 batteries x3 (unprotected cells)
2. TP4056 charging board - http://www.ebay.co.uk/itm/301905672102?_trksid=p20...
3. Some wires, soldering iron, solder
My parts cost was ~13$.
Step 1: Let's Have a Look Inside
We can see the built-in battery - 1500mAh (3 elements, 1.2V each)
Reasons for change:
- Battery is of poor quality - it should give ~8min runtime, but it gives less than 5min
- The sucking power is not good, because of the battery
- The battery is not charged well - all 3 elements are charged in series, and the charger is very simple - a stand with a 5V/300mA adapter, charges the battery through a diode
- No indication for charge end, I doubt that it ends at all.....
Step 2: Battery Replacement
We can put Li-Ion battery because it has almost the same voltage (3,6V - 3,7V), bigger when fully charged (4,2V). And we will put several in parallel to increase capacity. Advantage - we have more capacity in a smaller form factor, and we don't need cells in series to achieve the required voltage.
Cut the original battery terminals, so we can use them again!
Use more wire to solder to the batteries, it should be thick - 1.5mm , 2mm, because high current will flow.
At first I put only 2 batteries, but measured current ~10A which is ~5A per battery, which I think is too much. That is why I put a 3rd battery (now ~3.33A per cell).
Step 3: Charging
For charging the battery pack, we will use one of these boards.
Just solder it on the ends of the battery pack. Break and file the plastic so the usb plug can be reached from outside the body.
After thatt put some hot glue to fix it. Put a lot of it around and under the board. Because the glue is transparent, you will see the red/blue LED through the hole!!
Step 4: Plug It In, and You're Ready!
When the blue light comes ON - it means - charging complete!
Capacity is ~6600mAh on similar volts, compared to 1500mAh from the original battery.
So now I have ~30 min runtime, which is quite enough!! Much better sucking power, because of the stable battery pack power parameters, voltage drop over amps. And of course because of the slightly bigger voltage.
Charging time is ~6-7h with this 1A charger :)
Thanks for reading & enjoy!!!