How To Choose Battery
How to select the correct battery pack (General Knowledge)
- First of all, you must get to know your device:
- What is device's input voltage? ( V)
- What is its power consumption ( Wattage ) ?
- What is Maximum current drain ( A) ?
- What is your expected running time by a battery pack ?
- Decide battery pack voltage you will choose
- Battery pack voltage must be equal or a little higher than your device’s need.
- If you need a exact voltage, which battery pack can not provide, you may consider to use a DC-DC regulator
- Decide Battery pack's Capacity ( mAh or Ah)
- Battery capacity is depended on how long you need to run your device ( hours ), which can be calculated as the follow:
- ( Ah) = Device's Wattage (W) x Time to run ( Hours) / Battery Voltage (V)
- For example, if using a 12V battery pack, and run 10W DC device for 10 hours, you need choose a battery pack with capacity > 8.3Ah, e.g (10x10)/12 = 8.3
- 1000 mAh = Ah, higher mAh will provide longer running time.
- Decide Battery pack’s Max. discharging current
- Before order battery pack, you must pay attention on battery pack’s Max. discharging rating on the specification or description. Please don’t think any battery can take any current drain.
- You shall know your device’s max. discharging current. If you don’t know , you must measure it by a multi-meter.
- The battery pack’s Max. discharging rate of the chosen Battery must be higher than that device requires
- Choose Li-Ion, NiMH or Lead acid battery?
- What type of rechargeable battery will work for you. Question is size and weight. The table below lists the advantages and disadvantages of these batteries for your reference.
|
Chemistry |
Cost |
Weight |
Temp(ºC) |
Cycle Life |
Shelf Life (months) |
Volts / Cell |
|
Lead Acid |
$$ |
Very Heavy |
-65 to 80 |
300 |
12 |
2.0 |
|
Nickel Cadmium |
$$ |
Heavy |
-20 to 65 |
500+ |
6 |
1.2 |
|
Nickel Metal Hydride |
$$$ |
Moderate |
-10 to 65 |
500 |
12 |
1.2 |
|
Lithium Ion |
$$$$ |
Light |
-20 to 60 |
500 |
12 |
3.7 |
|
Lithium Polymer |
$$$$$ |
Light |
-20 to 60 |
500 |
12 |
3.7 |
- Li-Ion batteries has the highest energy density ( mAh/weight), and become more and more popular. However, Li-Ion may explode and cause a fire if it dose not use properly. Please read our safety warning.
- Choose a Battery Charger
- Please always follow our suggestion to choose a smart charger. So called smart charger must has automatic cut-off function when battery is full.
- Never use NiMH/Li-ion battery charger for Li-ion/Nimh battery pack, it will cause battery exploded
- Always charging your battery with attention, and put battery in a fire-proof container box to avoid accident.
- Understand risk to use NiMH and Li-ion battery. Please read our safety warning. before buying a battery.