Powering the Spectrum ST4 - Understanding Batteries

For those who are primarily shooting video, we highly recommend using VMount packs or Gold Mount Packs to power your spectrum.  Getting rid of an extra battery cord makes a huge difference for cable management.  If you really want to streamline, you can optionally put a large pack on the spectrum and the DTAP power to your compatible camera. 

For those with no batteries who want to shoot timelapse, for the money and the warranty, we have changed our tune since the spectrum system was launched.  We no longer recommend picking up stand alone backup packs (power banks). There are a lot of good and good enough Vmount packs on amazon where it makes sense to invest in a compact portable, long term battery.  Go out to amazon and pick almost any 95 to 150 Wh pack and go.  

Things to consider:

1) Flying with them pacs - up to 100 WH packs - you can fly with, but must be in your carry on baggage.  100 to 160Wh packs also seem to be possible, but require airline approval. Check the FAA and your airline for details. 

2) How long do you need to shoot? - 150's are bigger than 98's   150's will go almost all day for.  100Wh packs will get you about 6 hours of shooting, or overnight with most TL shoots.

3) Weight - bigger is heavier.  don't get more than you need as it adds weight to your setup.

4) Are your getting more than one? What are you going to charge it with?  Many packs from off brand vendors include cables to just plug it in to AC power to charge. Great if you don't have a VMount pack, but since the charging equipment is on the battery - usually adds some bulk.

5) What else do you want to power?  Do you want external DTAP/PTAP ports - how about USB power to support your camera.  Check it out as most packs offer more than just the battery.  If you do power other things like a camera from the battery, you will need additional capacity of course!

6) Do you want to purchase name brand, or go offbrands?  Most name brand batteries use higher quality cells and will last longer.  Off brands that are inexpensive work, but will likely need replacment sooner.

All batteries are consumable and shooting times go down after proper and especially improper use.  It used to be that buying into a battery system was $500 plus as you needed a charger and only name brands had any quality control.  Now, experimenting with lower cost batteries from Amazon is less risky as you typically have time to test and send back batteries with issues.   Whatever you pick up, make sure you test it well before your next big shoot!

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 or VMount

Powering it from the wall 12V – use the 12V supplied adapter.  This comes with basic kits at is speced at 2.0 Amps 12.0 volts 100-240V 50/60Hz.  

Powering it from VMount - In Mid 2017 we started offering VMount plates on our spectrum.  The packs are typically outstanding in performance and power to weight ratios.  90% of the units we sell are outfitted with these plates.  The great thing about these packs is they have no step/up or step/down converters in them that have 10-25% loss right out of the gate.  These packs are efficient and rent-able in most parts of the world.  Getting into this type of battery system can be expensive.

Powering it from Gold Mount- In August 2018  we started offering Gold Mount plates on our spectrums.  The packs are typically outstanding in performance and power to weight ratios.  Just like with Vmount, the great thing about these packs is they have no step/up or step/down converters in them that have 10-25% loss right out of the gate.  These packs are efficient and rent-able in most parts of the world.  Getting into this type of battery system can be expensive.

For our mounts , we use either IDX P-V2, or Dynacore VMount Plates.
For Gold Mount plates we use Dynacore.  

Powering it from the wall 12V any old adapter that looks like it might work because, why not, what is the worst thing that could happen?  Just because it fits doesn’t mean it will work.   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.   Worse yet if you plug in AC power or reverse polarity power, it will harm the ST4.  While we try to make the power handling robust and prevent permanent damage, damage from power problems is easily identified and not covered under warranty.  

Powering it from the wall 24V – pick up the optional  24V AC adapter from eMotimo.  It is speced at 3.75 Amps 24.0 volts 100-240V 50/60Hz.  It is great for powering turbo modes or long term in-studio work.  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 a few 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 1.0 Amp-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 (AH) /Current (A)=Time (H).

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;