Power specs for the spectrum ST4
Input Voltage: 11.0-24.0 volts.
Current for the ST4 at rest (motors not energized): 0.1A to 0.2A based on back light setting
Current Requirements - 2.0 Amps , 3.5A preferred for high speed moves
Connector: 2.1mm x 5.5mm x 12mm circular barrel connector – center positive.
Powering it from the wall – use the supplied adapter. Just because it fits doesn’t mean it will work ok! If you power it with a recycled supply from your old wifi router that says 12 volts/ 450mA – you aren’t feeding the rig enough current and the motion will suffer. If you plug it the the charger for a another manufacturer’s battery – it will likely harm the ST4.
Studio Speeds - as we tune up the spectrum ST4, powering the rig at 24 volts from a strong supply will allow you to take advantage of the highest speeds and payloads the spectrum can provide.
Amp Hours, Watt Hours, mAH . . .understanding this should take milliHours!
Amp Hours (good for when you know voltage of the pack) - Let’s talk capacity. Batteries are rated with something called Amp-Hours (Ah) or milliamp hours (mAh). Amp hours are valid when you know the voltage for which is was tested. This is important and tricky as most portable lithium power packs are tested at 3.7 volts (what their cells are rated for). A 12 volt 1Amp hour battery theoretically will be able to provide 1 Amp at 12 volts for 1 hour. It would theoretically be able to provide 0.1Amps at 12Volts for 10 hours. For a fixed voltage battery, the math is simple – Capacity/Current=Time.
Watt Hours - A more standard measure of energy is also a great place to start. If a pack is rated for 100Watt Hours, it could put out 1 Watt of energy for 100 hours, or 100 Watts for 1 hour. To convert from to and from Amp Hours, use the following formulas.
- AmpHours x Voltage = Watt Hours
- (mAH/1000) x Voltage = Watt Hours
- Watt Hours / Voltage = Amp Hours
- (Watt Hours / Voltage) *1000= mAH
Here some examples;
|Battery||Watt Hours||Amp Hours at 12 Volts||
ST4 Run Times based on 0.4 amp continuous
|RavPower 23000||85||7 theoretical, 5.5 typical||5.5/0.4= 13.75 hours|
|Tenergy 10Ah LiFePO4 12.8V||10*12.8 =||10 rated, 8 typical||8.0/0.4= 20 Hours|
|Generic from ebay||1 billion promised||who knows||0 - don't use them - they break and ruin your life|
For the money and the warranty, I think one of the best portable pack out there right now for the price is the RavPower 23000mAH pack The pack doesn’t have the full 23000mAH capacity at 12 volts. This capacity is measure at 3.7 volts. so plan for about 4400 mAh at 12 volts. The pack has a hard shell and is well built. For 1.5 lb pack, this will give your 6-14 hour of shooting.