PERUN II – Astrophotography Power Bank & Counterweight

PekDar — Sun, 15 Sep 2024 13:30:01 +0000

You can find many different power banks on the market. Unfortunately, none of them met my personal expectations in terms of Astrophotography Power Bank with available power, mobility and small size for mobile Astrophotography and Astronomy. Especially in the context of the possibility to take the power bank on board plane and to be comply with restrictions, requirements and rules present with airlines and security gates regulations.

PERUN II – 3D model

To cover defined above requirements and needs the „PERUN II”, was created, which is improved version of discontinued PERUN first version.

Why “Perun” name? It is the god of thunder and lightning of the ancient Slavic religion. The name reflects the nature of this project and a large amount of energy that has been accumulated in a really small volume of Perun.

While using the first version of PERUN, I carefully noted all its shortcomings and user suggestions, which became very valuable later.

After 2 years of work since first PERUN was released, the first beta version of PERUN II was created. The first prototype was very successful and quickly passed with several field tests. Soon after the second version of prototype was created and it was very close to final version – this version was so successful, that I decided to make it available to a few people who were awaiting with improved version… The third and last version of prototype which has already become the final version containing most of the improvements, based on the collected notes and valuable suggestions from users.

PERUN II arised

Compared to the first version of PERUN, I have added new functionalities reported by users and others based on my own needs, which as it turned out later, were also appreciated by users. This is how a new list of requirements was created, containing changes and improvements, constituting the new goal of the project.

Project goals – more important points

Power source for astronomy / astrophotography devices in the field, without access to a permanent power source.
Possibility to take PERUN II on board the plane, based on present (Feb. 2024) requirements and safety rules during travel with power banks.
Using a Perun as a counterweight to assembly on a rod counterbalance mount. Especially for mounts NEQ6 and iOptron.
Double amount of available power and the number of available power ports for devices by connecting two pcs of PERUN to each other.
Possibility to quickly charge a set of batteries, without removing them from the PERUN body.

Technical specification for Astrophotography Power Bank

PERUN II can use up to 6 pcs of batteries, model: NP-F950/960/970 or compatible, f.e.:

NP-F970 – battery – bottom view

They can be purchased in most stores offering photographic and film equipment.

NP-F970 – battery – top view

Battery technical specifications for model NP-F970. You must buy it separately by your self:

Lithium-ion battery.
7.2 VDC voltage.
8600mAh capacity.
Equipped with a chip, compatible with InfoLithium.
Standard warranty – 12 months.
Free from memory effect.
The max. of the power of six pcs of batteries: 371,5 Wh

To charge batteriesin 100% full you need to buy separately by your self NP-F standard charger or compatible.

Vendor charger – model: NP-F970

Optional – Dedicated fast battery charger for batteries model NPF-970 or compatible.

PERUN C970 – fast battery charger for batteries model NPF-970 or compatible

Approximately 9-10 hours of continuous shooting for the configuration:

CEM25P mount,
MGen II guider,
AITK HORIZON RGB CMOS camera

The body hole diameter fits the iOptron rod counterweight. After using a dedicated reduction, it also fits on the NEQ6Pro counterweight rod and compatible.

Tested and proven devices in cooperation with PERUN II:

Lacerta MGen2 + CCD (guider) camera,
Omegon Pro CCD (guider camera),
CMOS ATIK Horizon RGB camera,
ASI 2600MC Pro camera,
RaspBerry PI4 (Astroberry),
AsiAir (with maximum power requirements 5A),
AsiAir Plus (with maximum power requirements 5A),
Parallactic mount CEM25p,
Parallactic mount CEM26,
Parallactic mount HEQ5,
Parallactic mount NEQ6Pro,
Parallactic mount NYX-101,
2x USB heater,
Power source for mobile phone,
Power source for other mobile power banks charged with USB port

Body housing dimensions – without batteries, battery locks, switches, charging port cover and body locking screws.

PERUN II – Housing dimensions without external items

X → 124 [mm] +- 1 [mm]

Y → 134 [mm] +- 1 [mm]

Z → 56 [mm] +- 1 [mm]

Total dimensions of the body, including batteries (NPF-970 model) and elements protruding beyond the main outline of the body case:

PERUN II – Total body dimension including external items

X → 129 [mm] +- 1 [mm]

Y → 142 [mm] +- 1 [mm]

Z → 162 [mm] +- 1 [mm]

Functional specification for Astrophotography Power Bank

Input current filtering.
Output current filtering.
Over-voltage protection on power ports (12 VDC).
Over-voltage and over-current protection on input power converters.
Filtering out electromagnetic interference on power ports.
Filtering out electrical noise on power ports.
Two PWR converters working in parallel – in case of one PWR converter became failed*, PERUN II will continuous operational with half of the available power of 4 [A].
Main power switch (red).
Dedicated power switch for each power port.
Dedicated LED signaling of the power status of each port.
LED battery level indicator.
Dedicated port for fast charging batteries and connecting PERUN II (twice more available energy).
Possibility to take on board the plane.
Very high energy-to-weight ratio transported on board the aircraft.
Perun itself is a counterweight to the devices suspended on the mount. The more batteries used with Perun, the more counterbalanced it is. At the same time offering more energy at your disposal.
Batteries HOT-SWAP during operational.

* – depends on the nature of the converter failure.

Characteristics of PERUN II

The power source are batteries with a voltage of 7.2 VDC each. Connected in parallel.

During operation, the voltage level automatically decreases in according to the battery discharge state.

PERUN II – full load with 6 pcs of batteries, model: NP-F970

Summary of the currents of all connected devices in one time, must not exceed 8 [A].
Two PWR converters working in parallel – in case of one PWR converter became failed*, PERUN II will continuous operational with half ( 4 [A] ) of the available power.
Without load, PERUN II generates no heat. It heats up slightly during load, therefore does not require active cooling.
Has three 12VDC power ports. Each power port has a current protection of 5 [A]. The set includes one spare 5 [A] fuse.

PERUN II is able to handle momentary currents greater than the nominal operating current 8 [A]. However the connected devices, must be protected against damage.
Voltage range on the power ports has been set in between: 12.2 – 12.9 VDC,
LED battery level indicator,

PERUN II – LED battery level indicator and charging socket

Two USB 5VDC ports – power or charge any device connected to USB-A ports, f.e.:
- heater,
- mobile phone,
- another power bank.

USB ports can be load with a current of 3 [A], you can power or charge any device powered by a USB port in an accelerated mode if they recognize correctly the fast charging protocol.
The same charging port is also used to join PERUN II in a “chain” – doubling the available energy – look to the chapter “Joining PERUN II – twice as much available energy“

PERUN II – dedicated charging / joining port with batteries model NP-F970

Battery HOT-SWAP

If you have more than 6 pcs of batteries, you can replace the currently used ones, which are already discharged or close to running out of energy, with new, fully charged ones during the photo session.

You must remember that the batteries used with PERUN II are not perfect identical/equal (although they are the same model and product) and they discharge each other unequally. To avoid a situation, during battery replacement that, there is suddenly no energy to power the connected devices, replace the batteries one at a time.

The procedure for battery replacing during a astrophotography session is described in the user manual.

PERUN Charger 970 - Optional

Optionally, you can purchase a dedicated fast charger (PERUN C970) for NP-F970 or compatible batteries.

The PERUN C970 charger supports only batteries of the NP-F970 model or PERUN II compatible batteries. Using the charger with another battery model may damage the battery, charger and PERUN II, for which the author and the manufacturer are not responsible.

PERUN C970 charges the NP-F970 model battery to a maximum of approximately 80% +-5% of its capacity. The percentages given are indicative.

Specification - PERUN C970

External dimensions of the housing:

PERUN C970 – housing dimension

X → 205 [mm] +- 1 [mm]

Y → 56 [mm] +- 1[mm]

Z → 95 [mm] +- 1 [mm]

Total dimensions (including elements stick out beyond the main outline of the housing):

PERUN C970 – total dimensions – including elements stick out beyond the main outline of the housing

X → 208 [mm] +- 1 [mm]

Y → 61 [mm] +- 1 [mm]

Z → 95 [mm] +- 1 [mm]

The charger’s AC power socket is a standard, compatible with power sockets on PC power supplies.

There is a current protection device between the AC power socket and the main switch. Standard glass fuse 10 [A].

PERUN C970 – AC power socket with power switch

The charging process information display, represents information like:

Temperature inside the charger, right next to the power converters. The safe operating temperature range is 0 – 85 [C].
Value of current during battery charging process.
Value of voltage during battery charging process.

PERUN C970 – Charging process information display

Active cooling – PWM fan.

PERUN C970 – View of the fan

PERUN II and PERUN C970 – battery charging process

Joining PERUN II – twice as much available energy

If you have two pcs of PERUN II, you can connect / join them to get double amount of available energy and extend in double the operating time of your astrophotography set.

To connect / join PERUN II together, you will need a dedicated PERUN II charging / joining cable included with PERUN II set or included with PERUN C970.

The description how to connect PERUN II is described in the user manual.

PERUN II – stacked

Connecting / joining both PERUN II showed as example on the Figure provides discharge process in balance of both PERUN II and you can power up to 6 pcs devices! At the same time and each will receive as much energy as needed – with limit to max 5 [A] / power socket / device and max 8 [A] / one pcs of PERUN II.

Included

Body – six ports for a battery model: NP-F950 / 960/970, (batteries with a charger must be purchased separately),
PERUN II – Body
Two locks securing the batteries against uncontrolled sliding out of the port – in the case of reverse mounting on the counterweight rod,
PERUN – battery locks
Spare fuse,
PERUN / PRUN II – 5 Amps spare fuse
A set of three power cables, including one with a ferrite filter,
PERUN II – Power cable for devices
Two locking screws for the body to lock it on the counterweight rod,
PERUN II – locking screws for the body
Counterweight rod diameter reducer for mounts equipped with a counterweight rod with a diameter less than 19.9 mm, e.g. mounts: EQ, HEQ, NEQ.
PERUN II – Counterweight rod diameter adapter
PERUN / PERUN II – Adapter in use
Set of 6 pcs battery covers, model: NP-F970,

Comparison to other solutions

The comparison I will provide below is almost the same as in the publication regarding PERUN.

I’ve only updated the cost, based on the final price of the new version, which includes more electronics and additional devices.

Alternative solution, no longer available (checked 22/1/2024) with non valid price: https://www.ioptron.com/product-p/8128.htm

– PowerWeight^TM CW Battery – iOptron – has a maximum power of 96Wh with the price of 158 USD (old price from 2020, customs and vat tax excluded), which can be taken on board the plane.

In order to get the amount of required power comparable to what offer us a Perun, you need to purchase 4 pcs. PowerWeight^TM CW Battery, which gives us cost:

Astrophotography setup with NEQ6Pro mount, 2x PERUN II stacked, CMOS camera, 6 inch Telescope and Astroberry driver with own designed case box + some additional

4x96W = 384Wh –> cost 4×158 USD = 632 USD Gross, price 1Wh = 1,65 USD Gross

4 pcs of PowerWeight^TM CW Battery you can’t put as counterweight on the rod. Even if I use the counterbalance rod extension, we can fit a maximum of 2 pcs on it.

It only gives me half of the power I need to run my astrophotography setup, during the entire night (8 hours average of collecting lights).

– PERUN II – has maximum power 371.5Wh with price (199 EUR body + 132 EUR for 6 pcs battery pack = 331 EUR) – Total cost is 1Wh = 0,89 EUR.

Depend of the destination country… If we add customs duties and tax fees to the PowerWeightTM CW Battery, the difference will be even greater against of PERUN II. After this article, besides the price, I don’t think I need to mention the functional advantage of PERUN II.

PERUN volume shape, it takes less space than 1 pcs of PowerWeight^TM CW Battery !

Therefore, it is possible to add one more PERUN-s as a counterweight on a rod, which will provide total of 743Wh of power! If you could fit 3 pcs of Perun, you would have to change the Watt unit to kW! of power, on a piece of iron rod as a counterweight to my assembly.

PERUN is an uncompromising and unrivaled solution that guarantees me a power reserve for use in the field without access to a permanent power source.

If you are interested in to buy PERUN, please contact me. The e-mail address you can found in the footer of the page or you can full fill contact form. You can also contact me via Messenger / WhatsApp / Signal.

ATTENTION! – the prices given are indicative (with high accuracy). The final price valuation may differ slightly due to the inflation increase in the prices of components needed to build PERUN and their availability or availability of replacements and local TAX applicable.

Mobile Power Bank – PekDar – Astrophotography Engineering