To resolve significant voltage drops to my Pegasus UPB PowerBox (12V dropping to between 11V & 10.5V), it was necessary to replace regular (thin wired) 12v extension cable (2.5mm male to 2.5mm female) sourced online in UK with heavier duty 16 AWG cable.  At the time I was unable to find a supplier of suitable 16 AWG extension cable in Europe and the only suitable product I could find was 16 AWG Y9 Extension Cable with 2.5mm male plug from BixPower ( https://www.bixpower.com/CAB525M9-p/cab-y9.htm  ). However I was unable to find a supplier of the BixPower products in Europe and the BixPower Website in USA wouldn't allow the shipping of the product to the UK, and I went with the option of buying the BixPower cable from BixPower website and had it sent to a relative in the Florida, which I subsequently picked up during a holiday visit to the States in April.

16 AWG DC Power Extension Cable from BixPower (USA) https://www.bixpower.com/CAB525M9-p/cab-y9.htm

(Although not advertised on their website, I eventually learnt that Pegasus Astro will apparently produce an heavy duty extension cable to a custom made length but it was too difficult to obtain in this instance and I went with the BixPower cable from the USA)

When it came to installing the 16 AWG extension cable I found that I couldn’t get a good solder connection between the wire ends of the 16 AWG Cable to a 5.5x2.5mm female adapter that I had bought for the job (at least not without melting the plastic bits in the adapter). So in the end I had to cut the male adapter off the end of the 12V cable from the Pegasus Astro 12V 10A power supply and directly connect its wires to the wires in the extension cable to provide a secure and reliable connection.

I can now operate power from the UPB Box to the LX200 Telescope and focusers and still see an input voltage of 12.0 or 11.9V to the powerbox even with the dew heater on full power.

Background
Since moving over to using the Pegasus UPB for driving dew heaters on the 12" LX200 main scope and 80mm APO guidescope problems have been encountered with voltage drops to the UPB, with voltage dropping from 12.0 V to as low as10.5 V if the dew heaters are turned up to the max.    This is probably bad for the LX200 scope and Focusers and restrict the addition of any new equipment powered via the UPB.     

After enountering initial power supply issues to my Pegasus UPB I bought the Pegasus Astro 12V 10A power supply with the expectation that it would resolve my power issues . (i.e nice stable noise-free voltage supply with plenty of Amps for now and spare capacity for any future equipment). However after connecting my LX200 Scope to the UPB 12 V output the supply issues got worse.

In my first observing session since having my LX200 connected to the UPB Power Output, I happened to turn my dew heaters (12” & 5” bands) from ~50% level up to maximum and I get a red warning symbol and the message "A short circuit (SC) detected or input voltage is out of limits". On the panel the Input Voltage is 10.7V, Current is 2.1A, Total Power is 22W. Total Output Current 1.9A (LX200 + Dew Heaters). [ With no scope and 2 x 12” dew heater bands the voltage drops to 10.5v, Current 2.4A, Total Power is 25W, Total Output Current is 2.2A)

I’m was using a fairly regular 3.0m extension cable. It probably has wires that are too thin but seems little different from all the other ones I see on online shops (None specify the gauge of their wires). I tried two alternate cables , one had a male plug that didn’t fit tightly enough into the UPB Power-In port causing power disconnect issues when moved, whilst the the other cable is too short (only 1.8m) and although it didn’t produce a red warning symbol it showed evidence of a large voltage drop, and low amperage to the Dew Heaters.

When I created a temporary setup and power the UPB directly from the 12V 10A supply I saw the full supply voltage when I have 2 x 12” dew heaters fully on. (Voltage 12.1V, Current 2.7A, Total Power 32W. Total Output Current 2.4A.). However I can’t use this arrangement in the real world. The Power Supply’s output cable is only 1.5m long, but I need to place the Power Supply itself in the bottom of my observatory bay, and run the 12V power a distance of 1.2m to the pier and then up to the UPB mounted on the LX200’s fork arm at a height which is 1.7m off the floor and with a enough extra to allowing for cable routing and allow the fork arm to rotate +/-180 deg when it is operating. Hence a 2.0m+ extension cable requirement.

I didn’t get the out of voltage warnings when I used my original 12V 2.5A supply with cigaratte adapter and extension cables.

(If I positioned the UPB in a conventional position (attached to my guidescope’s dovetails) the UPB would be at height of 2.2m off the floor)

Calculations suggest that to loose no more than 3% voltage over a 3m extension with 12V supply and 10A current draw I would seem to need cable with 3.0mm^2 wires (ie 12 AWG)  (or 2.00 mm^2 , 14 AWG for a 2m extension) https://www.12voltplanet.co.uk/cable-sizing-selection.html

To not loose more than 3% voltage over 3m with 12V supply and 4A current draw I would seem to need cable with 1.5mm^2 wire (ie 15 AWG)
(or 1.00 mm^2 wire, ~17 AWG for a 2m extension).

Ii is noted that the UPB manual mentions needing at least 18 AWG wire for custom power cables and to not exceed 3m. 18 AWG (0.82 mm^2) wire would produce over 4% drop in voltage for 4A current draw and a lot more drop for 10A current draw.

See detailed account with screen shots of the UPB panel from my session and subsequent daytime tests

[ It was a bit of struggle sourcing a suitable power link between the UPB and my LX200 . I eventually used a 1m Pegasus 2.1mm cable (2.1mm male to 2.1mm male), to a short (0.15m) adapter cable (2.1m female to 2.5mm male ) to a 1 or 1.5m extension cable (2.5mm female to 2.5mm male) that plugs into the LX200 Mount. ]

After a computer crash at around 00:23, the AstroProtect service successfully operated to close down the Observatory as soon as the computer automatically restarted at 00:24.  This included closing the shutter, parking the dome and parking the telescope.   The log file recording the automated shutdown is shown below.

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2019-04-23 00:24:23 | PROGRAM AstroProtect 1.3

2019-04-23 00:24:23 | RESTART 2019-04-23 00:24
2019-04-23 00:24:23 | Critical Computer may have unexpectedly restarted
2019-04-23 00:24:23 | Action The Observatory will be checked and made safe

2019-04-23 00:24:23 | SHUTTER
2019-04-23 00:24:23 | Info Finding hardware for POTH.Dome
2019-04-23 00:24:27 | Info Dome name is Pulsar Observatories Dome
2019-04-23 00:24:27 | Ok Retrieving Profile for ASCOM.Pulsar_Observatories_Dome.Dome
2019-04-23 00:24:27 | Ok Setting COM Port To COM9
2019-04-23 00:24:29 | Ok Connected to POTH->Pulsar Observatories Dome
2019-04-23 00:24:29 | Critical Shutter is open
2019-04-23 00:24:29 | Action Closing Shutter...
2019-04-23 00:25:15 | Ok Shutter is closed
2019-04-23 00:25:15 | Ok SHUTTER IS CLOSED (Close Time: 46s)

2019-04-23 00:25:15 | DOME
2019-04-23 00:25:15 | Info Dome is positioned at Az: 80.7 degs
2019-04-23 00:25:15 | Critical Dome is not parked
2019-04-23 00:25:15 | Action Parking Dome...
2019-04-23 00:25:23 | Ok Dome is positioned at Az: 90.0 deg
2019-04-23 00:25:23 | Ok DOME IS PARKED (Park Time: 8s)

2019-04-23 00:25:23 | SCOPE
2019-04-23 00:25:23 | Info Finding hardware for POTH.Telescope
2019-04-23 00:25:23 | Info Scope name is LX200GPS/R
2019-04-23 00:25:23 | Ok Retrieving Profile for MeadeLX200GPS.Telescope
2019-04-23 00:25:23 | Ok COM Port already set to 7
2019-04-23 00:25:29 | Ok Connected to POTH->LX200GPS/R
2019-04-23 00:25:29 | Info Telescope is positioned at Az: 79.9, Alt: 25.9 degs
2019-04-23 00:25:29 | Critical Telescope is not parked
2019-04-23 00:25:29 | Action Parking Telescope...
2019-04-23 00:25:38 | Ok Telescope is positioned at Az: 180.0, Alt: 0.0 degs
2019-04-23 00:25:38 | Ok TELESCOPE IS PARKED (Park Time: 9s)

2019-04-23 00:25:43 | Ok Closing program

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