Power to my scope.

[cjdawson]

Hi all.

Several years ago, I did a project to distribute power to my telescope, dew heater and Fan for my DSI.  I'm in the middle of changing my telescope setup, and am going to remake that project to suit the new kit that I have.   Over time, this method of power distribution has proven to be great.  Over the years, I've learned a bit about the project in real use and can take the lessons forward.

The original power box project is here. http://astronomy.cjdawson.com/projects/PowerBox.html

The cable that I used transferring the power between the two boxes is actually cable that is used for serial cables.  So, I have no issued with Ampage and voltage drop, it works fine in practice.

On the first version of the power box, I used 7-pin Din plugs and sockets.  This gave enough wires to carry all the power that I needed, without any issues.  The problem with this type of plug is that it's quite flimsy and ended up getting distorted, through abuse (treading on in the dark and stuff like that)

This time around, I'm thinking about using 9 pin D-sub conectors (the type that are used on serial ports)  These ports are rated at 7.5amp per pin, allegedly, so combined with the cable that I used last time (I have plenty available for use)

I have no problems in thinking that the cable and plugs are up to the job. Things will start to get a bit tricky after this.

I'm thinking about assigning the pins, for devices.  So, I have 9 pins to play with, that should be plenty. I want to make sure that I have room for possible expansion if it's practical.  So here's the assignments that I'm thinking of..

1. Ground
2. +12v, for scope and aux sockets
3. +5v, for Synguider
4. Dew Heater Channel 1 +
5. Dew Heater Channel 1 -
6. Dew Heater Channel 2 +
7. Dew Heater Channel 2 -
8. not assigned
9. not assigned

This is the pin outs that I'm thinking about assigning.

The dew heater elements will get their own pins, as these items can draw a large current, 6 amp is the theoretical limit.  At the moment, I have only one dew heater controlled by a vellman k8004, and the element is nichrome wire wrapped in heat shrink and copper tube.

Channel 2 is a possible future expansion with a second k8004, so that I can have a second heater element.

Channel 8 and 9 I'm wanting to keep clear so that I can add something else in future, but  I'm not sure what, and not even sure if I ever will.

Pin 1 ground, will be a common ground between for both the 12v and the 5v rails (Assuming that I am able to do that, will test it out when my 12v to 5v converter arrives)

The 12v pin will carry power for the scope, Electric focussor (btw, it's the 1206 focusser from Meade, the one that plugs into the #909 apm. So I have no worries about this being on the same channel as the scope)  And an Aux socket.

The aux socket will be a 2.5mm DC socket.

There will be two boxes involved in this project, a large box, and a small box.

The small box will be mounted on the side of the telescope, to project the connections. These will be as follows.

2 * 3.5mm mono audio sockets - these will be for the dew heater elements, channel 1 and 2. (I preferred these to RCA, as they provide a firmer connection)

1 * 2.1mm socket - this will be for the 5v supply to the SynGuider.   Deliberatly using 2.1mm so that in the dark, I can't plug this into the wrong socket*

2 * 2.5mm socket - this will be for the Aux sockets.

* There is no problem with the SynGuider being run from 12v, just that the manual says it will convert the other volts to heat, so I want to limit the heat buildup at the scope and ensure better power efficiency in the process)

note: there will be a cable comming out of the box specifically for the 2.5mm plug for the scope.

I'm thinking about trying to work in a PCB with a three fuse holders, one for the scope, and one for each of the aux sockets.

The main control box, is going to be a much larger box, this will have space to accomodate 2 k8004 PWM circuits. a couple of bargraphs to show the amount of power going to each channel of the controller, and a knob for each to control the power.  This box will also have the 5v DC-DC converter, and the cable that connects the whole lot to the battery.

I'll start putting up images, once I have building things. Oh, one last thing, for those people wondering, the battery is a 70Ah caravan battery.    In addition to this lot, I'll be running an EL Panel, and my SkyFi from the same battery.

The power supply for the SkyFi is a 12v to 6v dc-dc converter, which also have a volt meter built in, this is how I will know when the battery is getting low.  When that happens, I can simply switch to my second 12v battery.

[NEM]

Is there any possibility of something with a serial port being accidentally plugged into the 9 pin D connector?  If so you might be better to use pin 5 as GND and leave pins 2 and 3 unassigned.

Noel

[Horwig]

Have you considered something like a 7 pin xlr, physically even stronger, and no danger of confusing it with a serial cable or focuser motor etc

H

[cjdawson]

Is there any possibility of something with a serial port being accidentally plugged into the 9 pin D connector?  If so you might be better to use pin 5 as GND and leave pins 2 and 3 unassigned.

Noel

For me, there is no chance of a serial port be plugged in by accident.  Actually, at the moment, I have the choice of which parts will be male and female.  So, I might just do the opposite of my Autostar serial cable, which is the only one in the setup.  The autostar cable will be plugged into my SkyFi, actually, I'm more likely to leave that permanently attached to the SkyFi, and unplug the Autostar end (easier for storage at the moment)

Something that I had not considered though, was including a 3 wire serial cable into the setup.  Doing that would allow me to keep the SkyFi close to the battery, and have the autostar serial cable comming from the box that will be attached to the scope - closer to the handbox cable.   One thing that would concern me, is that I'd be running power and data through the same cable, not a problem but mixing 12v and 5v does concern me, what would happen if 12v ended up being forced into Autostar?   Don't think I want to risk that. 

Have you considered something like a 7 pin xlr, physically even stronger, and no danger of confusing it with a serial cable or focuser motor etc

H

Yes, I've considered XLR and decided against it.  The problem that I have with XLR is that the connectors and plugs will be bigger than a D-Sub 9.  With a 7 pin, there won't be any room for further expansion, and if it turns out that the 5V can't share ground with with 12v, I'd need pin 8, before we think about it.    Doesn't look like there are 9 pin panel mounts for XLR, so that kinda of rules that option out.   I am considering 3 pin XLR to connect to the battery.

As an alternative to XLR, I'm also considering using these

http://www.maplin.co.uk/p/maplin-8-way-audio-locking-connector-line-socket-fk30h

The 2 way version would be good for the power to the main box, the 8 way version would be able to supply the power to the scope end.  I like the idea of being able to lock them in place, and it has the advantage of not being a serial cable, so no chance of confusion.

[cjdawson]

I've been thinking about whether the D-sub 9 is the best connector to use, and have carefully considered it.  XLR whilst they are extremely strong connectors, I wasn't able to find panel sockets that had more than 7 pins.   Also, the panel mount sockets that I was did look quite big and I think it would not work well in the project box that I'll be attaching to the scope.

The audio connector, looks like a better bet, however it's limited to 8 pins.  This is a possibility, and I'm not going to completely rule that out yet.

I think the answer to whether I go with the audio connector vs the d-sub depends on whether I can have the ground pin shared between the +12 and +5v.   The reasoning here is that if I can share the ground, the two unassigned pins, can be for an 8v line, that could be used to power my DSLR.  If I can't share the ground, then I'll only need 8 pins, so can use the audio connector.

As for the possibility of plugging a serial cable into the project by accident, that's easy to mitigate.  Firstly, I have the choice of whether where to place the male, and female connectors.  The 9 pins serial port plug on my Autostar serial cable is 9-pin female, as is the 9 pin port on my ancient modem (I'm keeping it for sentimental reasons)  so I can bear this in mind when wiring everything up.

There are two project boxes in my setup, I'm planning on using a serial extension cable to run between the two boxes, one end will be male, the other end female.   I'm going to make the female end, the one that supplies the power, this is the big box that contains the dew controllers and the 12v supply.  The small box that plugs onto the scope can have the male pins, if some idiot decides to plug a serial cable into this, it won't hurt anything as there will be no power, and even with the pin outs that I'm looking at above might as well be open circuit, not that it matters as there will be 0 volts in the circuit.

The other thing to think about here is that the only serial cable present in my telescope setup is the serial cable from the Autostar to my new SkyFi.  As I'm not planning on unplugging that from my SkyFi again the issue of connector confusion is even less likely to be an issue in practical use.

[cjdawson]

My female D-Sub 9's arrived today.

The breakout board will make it dead easy for wiring things up.  Looking at the layout and based on some of the feedback, I'm going to change the pin assignments.  Here's the new layout.

1. Reserved

2. Reserved

3. +5v

4. +12v

5. Ground

6. Dew Heater Channel 1 +

7. Dew Heater Channel 1 -

8. Dew Heater Channel 2 +

9. Dew Heater Channel 2 -

What this will mean is that the shorter set of pins towards the top of the image will be for the dew heater, and the lower part will be for the power output.  The two pins closest to the port won't be used initially.  If everything goes according to plan, I could use one of those pins for an 8V supply to run my 70D.  That will be an addition that I'll be thinking of adding at a later date.

So, how's all this going to work?  Let's start with my showing you the project box.

I'm going to cut a hole, so that the connector can poke through, not sure exactly how I'm going to do this yet, will probable end up putting in a piece of metal to mount the port too, like on a pc expansion slot.

In the space to the right I'm going to make a fuse board, for three 20mm fuses.  These will be 2a quick blow fuses, one for the scope, and one for each of the aux sockets that I'm going to add.

Along both long edges I'm going to drill hole for mounting the various items.  The top edge will have 2 * mono 3.5mm sockets for the dew heater elements.   Then the three 2.5mm DC sockets, one for the scope and the others for whatever I want (Fan for my Meade DSI and electric focusser to name a couple of things)

On the other long side will be a single 2.1mm DC socket this will be for the 5v supply to my SynGuider.

The fuseboard is going to be mini project.  What I'm planning to do is etch a PCB.  It's going to have two screw terminals for the input, and four terminals for the output.  I'm going to wire all the grounds into one connector on this version.

Whilst I'm making this PCB, I'm going to make up two fuse board PCB's.  I should be able to etch them both from the same photo sensetive board without any problems.  I'll cut them down so and then I will know for sure how much space I have left in the project box.

I chose making a fuseboard over using panel mount fuses for a couple of reasons.

1. In the 10 years that I've used my scope, I've never needed to change the fuse.  So having it screwed under a panel in the project box isn't an issue.

2. As you can see into the box, it'll look more pleasing to see a PCB, over a spaghetti of wires.

Once the rest of the parts arrive, I'll be able to make this part of the project up fairly quickly.  Once completed, I'll turn my attention to the power delivery part of the project. (The bigger box)

[cjdawson]

Had an idea for how to mount the DB9 port properly.  I'm going to use a DB-9 blanking plate from a PC.  Cut that down to fit into the box, then I'll secure that with a couple of bolts.  The DB9 Breakout board can then attach to that, so that the port itself sticks out through a hole that I'll cut into the plastic.  I'm doing this instead of mounting the socket directly to the plastic as the plastic is a couple of mm thick and this will cut down the amount of connection area.  I feel that mounting directly to the plastic will not give a good enough connection.

[cjdawson]

The 12v to 5v DC to Dc converter arrived today.  Just did a quick test with an ohmeter and have confirmed that the black 0v wire on both sides of the converter are common.  This is great news as it means that I can use the same ground pin for both the 5v and the 12v returns.

This means that the two reserved pins can be used for my DSLR, and if I can pull off the same trick with the return for that then there still one pin left over for something else.

[cjdawson]

I just got hold of one the PC Serial port plate, and found a nice happy little accident that will help me.  The box has four posts to screw the lid on with.  There is a small gap that is big enough for my to slot the plate behind.  Once trimmed down to size that means I can slot the DB9 port holder into place and it won't need to be fixed.  All that I'll need to do is cut a slot into the box so that the port can poke out to allow connection.

[cjdawson]

My bank holiday weekend has been fruit full

I've completed the box that will attach to the scope, here's a look at the inside.

Heres a rundown of the box, starting at the right side.

Female DB9 - This is the input which will come from the other box, that I have yet to make.

notes: the connector is mounted on a PC expansion bracket that I cut to size and epoxied into place.  I'm thinking about adding some bolts, but I'm not sure it's needed.

Blue wires - channel 1 dew controller.  It's a 3.5mm mono socket, I decided against the RCA style that others use, but there's nothing stopping me changing it later.

Orange wires - channel 2 dew controller. Again, 3.5mm mono socket.

Red and black - 5v 2.1mm DC connector.  This will be to power my SynGuider.

PCB - This is my fuse board for each of the 2.5mm DC sockets on the top.  Each fuse is 2A quick blow.

The PCB is stuck down on a couple of layers of foam backed sticky tape.

I'm not expecting the that the fuses will ever blow - they didn't on the V1 power box.   But just in case, I've taped a few spare fused inside the lid of the box.

Decided against using the blue box in the end.  The reason is that I realised that the clearances needed for the various sockets would have been too tight and there was a risk of short circuits.

Next part of the project will be to make the business end that delivers the power, and has the dew controller circuits.

[Stub Mandrel]

7.5A per pin seems bit optimistic. That suggests you could start a car using all nine pins...

This one is rated 5A:

http://cpc.farnell.com/1/1/10598-multicomp-5504f1-09p-02-03-f1-plug-d-pcb-r-a-9-way.html

and my guess is that is a total across all the pins. Even for low power 5V applications it's usual to use 32 or 3 pins for power and earth.

I've used XLR for my stepper drive and that's only 400 mA

<EDit>

Seems I am worrying unnecessarily, rating are per contact and this guy did a test at v35A through one connector: http://electronics.stackexchange.com/questions/84962/how-big-current-i-can-commutate-using-d-sub-connectors

Must admit, I am surprised!

[cjdawson]

5A is still more than I'm going to need.   On the version one power box, I was using something similar to this.

http://cpc.farnell.com/deltron-enclosures/611-0700/7-pin-black-standard-din-plug/dp/CN00056

For the 8 years or so that I was using it, it was one of the parts that worked without problems.  The problem with that type of connector was that it was two half shells which clipped together, there was no strength and it distorted really easily.  Hence changing to DB9 as I feel that it's a much stronger connection type.

[cjdawson]

Now that I've completed the box that will attach to my scope.  (Btw, I'm going to attach some velcro to the back of the box and use that to stick it in place)

My attention is turning to the box that will provide the power and dew controls.

I've not giving this part of the project a huge amount of thought, up until now.  Everything I said previously about this bigger box was just rough ideas.

So, let's get down to the detail.

Here's what the box has to do.

1. Provide an enclosure for both dew heater control circuits.  (These are my Vellman K8004 projects that I mention before)

2. Provide the 12V power for the scope and accessories.

3. Provide the 5V power for the Auto Guider.

4. Have space for adding more things in future - (possibly power my DSLR and maybe my SkyFi as well 8 V and 6V)

5. Have a connector for the battery

6. Have a DB9, so that I can connect the two boxes together.

So, I've selected a large project box that is going to house all of this.

I have a 12v to 5v automotive DC-DC converter.  This is how I'll be getting the 5V.  It's a small package and once I cut down the cables, it'll take up only a little bit of room in the box.

I'm going to have to cut out the box for the DB9 - I'll do the same thing that I did for the small box.  That turned out to work fairly well, even thought the box does look like it's been hacked (which it has)

I've got a two control knobs with 1k potentiometers and 12v illuminated switches on order from CPC.   I'm going to used these so that I can turn each K8004 on and off independently, the control knob is used to set the PWM active ratio.  The LED will provide an indication as to whether the circuit is on or off.

The box is going to get power from an external battery, ultimately ending in a 12v automotive plug.

I was thinking about simply running the cable directly through the side of the box and down to the plug.  But as people have been mentioning XLR, I've been looking around and found an XLR plug and panel socket at CPC which will do the job nicely.  This way I can put a 10A fuse in the cigarette lighter socket, and have protection for everything.  The plug will connect into the large project box - I'm thinking about adding another 10A fuse behind the XLR socket.  (This will be an inline fuse)

The from there, I can split the power off for the two K8004's, the 12v line and the 12v-5v converter.

This is the part of the project that I need to think about some more.  Basically, I want to be able to split the power up, and I love to have a neat solution - much like the little fuse board that I made for the scope end.  If I can get something of the shelf that will do the job, I'll be happy with that, but if I have to make up a custom board, that's fine too.   I'm open to suggestions on this bit.

note: On the V1 power box I had a series of 10 LED's that showed visually what the setting was.   I've made the decision to leave this off for now, but I'm going to leave space on the box, so that I have room to add this on at a later time. (I want to try and use a couple of proper bargraph displays, rather than a series of 10 seperate LED's.  I want to have two of them close to each other, so am going to tackle this part as a separate project later.

[cjdawson]

Just thinking about the power split.  Here' the details of what I need to split

12V pass through

K8004 * 2

5V supply

And two spares.  These are likely to be for a 12V to 8V converter for DSLR power, and one spare for something else.

So in total the 12v positive will need to split 6 ways.  As will the 0v ground wire.

The first thing that I have springing to mind, is the green screw terminals, and etch a board. That board will have to be able to take 10A current.  I don't think that's a problem,as  the small terminal bocks that I used in the fuse board are rated at about 16A.

I'm going to going to have to make sure that the cable from the XLR to the splitter, is cable for higher current than the wire that I was using in the scope side box.

[Lonestar70]

Just thinking about the power split.  Here' the details of what I need to split

12V pass through

K8004 * 2

5V supply

And two spares.  These are likely to be for a 12V to 8V converter for DSLR power, and one spare for something else.

So in total the 12v positive will need to split 6 ways.  As will the 0v ground wire.

The first thing that I have springing to mind, is the green screw terminals, and etch a board. That board will have to be able to take 10A current.  I don't think that's a problem,as  the small terminal bocks that I used in the fuse board are rated at about 16A.

I'm going to going to have to make sure that the cable from the XLR to the splitter, is cable for higher current than the wire that I was using in the scope side box.

Hi,

The screw terminals may be rated for 16A, however you will need to use track a width of at least 7.38mm in 1 oz copper at 10Amp... with a track clearance of 0.66mm.

For 2 oz copper the track width will need to be 3.69mm with the same track clearance.

These figures are based on a max track temperature rise of 10deg C (in Air) and a maximum applied voltage of 14v DC. (A fully charged battery is approx 13.8V).

I hope this helps.

Best regards.

Sandy.

[cjdawson]

I'd be willing to put money on my pcb being 1 oz copper. The track clearance isn't going to be a problem as I like to have at least 1mm between tracks - actually more like 3 or 4.

Was thinking about using something like this...

http://www.maplin.co.uk/p/5-way-tagstrip-fm34m

But, on a closer look, not sure that I'm happy to use that.  Can see myself making another PCB up, basically with 2 power rails, and the terminals interleaving.   I'll mock up a board layout tonight and see if I'm happy with it.

[cjdawson]

Think I'm just going to make a PCB for this job rather than try to find something off the shelf.  From what I've seen, it looks like there isn't really anything.  Oh well.

Here's the PCB design

For size, when printed, both of these boards will fit onto a single PCB that's 100mm by 70mm.  The tracks are 4.5mm diameter.  So I don't think there will be any problems with the load that I'm looking to put through.

I'm going to drill out the 14 holes, then place terminal blocks rated for 16A into the holes.  Whilst the tracks are not 7.5mm, I think they'll be good enough to power the scope and heaters.  Again, I'm going on past experience that I was running my scope and one heater using a fuse board that I made, where the trackes were no where near as wide as these.

[Lonestar70]

Hi,

4.5mm tracks in 1oz copper will handle 7amps continuous with a 10deg C track temp rise...

at 10 amps the track temp rise would be approx 22deg C.

Voltage drop in the track will be 0.02v/inch @7amp... 0.03v/inch@10amp.

Assuming the 10amp usage is at peak loading (short term) then you should be OK.

Good luck with your power pack build.

Best regards.

Sandy

[cjdawson]

Thanks sandy.  Your input has been extremely helpful.   7amp continuous should be plenty.

Thinking about my breakdown...

1.5 amp for the scope (both motors running at top speed)  the 2A fuse on it for it has never blown but should protect the scope of something goes wrong. (In theory)

2.5 amp is the theoretic max for my 8" scope's dew heater element.

2.5 amp for the guidescope header element (which I have yet to make, it's an 80mm scope, rather than a 200mm scope, so shouldn't need anywhere near as much power)

500 mA should be enough for the SkyFi and the SynGuider.  (Although, I'm not planning running the SciFi through this yet - I do have provision to be able to add it later if I want - spare pins ;-))

So with all that running, the theortical max that I'll be pulling is 7amp!   And that's theortical maxiumum.  I'm going to alter it to include a 20mm fuse holder.  This way, I'll be able to put the 10A fuse in place

In Reality, here's the normal running figures.

500ma for the scope (tracking, not slewing)

800ma for the main heater (I tend to run the heating element at about 10-20%.  the 800, is about 30%)

800ma for the guide scope heater (again over egging this to be safe)

200ma for the SynGuider.

So for normal operation I'm likely to be pulling something along the lines of 2.3 amp.

My plan is that the SkyFi will be powered seperately from the battery, as will my ELPanel.  I don't mind adding the SkyFi to this project at a later stage (Have a space reserved for it).  But the ELPanel can remain seperate as it's not really something that needs to be scope side.

The SkyFi, I might end up attaching to the scope, at the moment, I want to power it from the battery directly as the DC-DC adapter that I have for it also has a volt meter built in.  (Nice to see if my battery is getting flat)

I was thinking about the PCB design that I posted above whilst on my way in to work this morning.  I'm going to resdesign the circuit, so that it has a 20mm fuse holder for a 10A fuse.    I'm also thinking about adding an LED to the circuit, to show that the whole system has power.   If so, I'll add a piece to the board, for a resister, and if I can find something suitable a plug and socket for the LED - possible using pins like in a PC case.

[cjdawson]

Yep, I'm going to do the LED thing using this.

http://www.maplin.co.uk/p/maplin-2-way-01-inch-series-straight-pcb-latch-plug-header-rk65v

and 

http://www.maplin.co.uk/p/maplin-2-way-pcb-latch-housing-hb59p

This way, I can detach the LED if/when I take the box apart to upgrade, or change something.

[cjdawson]

Here's the version 2 divider board

 

The tags on the top left will be for a 20mm fuse holder like I used in the scope box's fuse board.

There's pads for a resister, and an the latch plug header.  This will form a circuit for an indicator.

[Epicyclus Dave]

Great project you are working on here , nice detailed documentation  , I still have the xlr power socket mod to do on my neq6 , tho I have had no problems with power issues since I converted a step up power pack to supply 13.8V to my mount a couple of years ago.

Dave.

[cjdawson]

Glad you are finding this to be a useful thread.  As one point, I was starting to worry that it was rambling on.  

The 13.8V thing must be a neq6 specific thing.   The first version of this project came about shortly after buying my scope (over 10 years ago)  I used the internal C cells for my LX90 once.  They were brand new batteries and I had a "Motor unit failure" (or was it Motor unit fault) after about an hour of using the scope.  Then I hit the fledgling internet to find that others had the same issue and solve it using a jumpstarter to power their scope, so I did the same.  After a bit of time, I found that the jump starter wasn't great, and I wanted to make a Dew heater.  I did that using a K8004 kit (actually that circuit I've retrieved from my original Dew Heater so that it can be channel 1 on my latest version) it worked well, but I foiund that I had wires everywhere and there was pressure on the 12v DC socket for the scope - which I really didn't like as I didn't want that to fail.  So, The first version of my power project was born.  It's purpose was to deliver 12v for the scope, a spare 12v line, and power for the dew heater.  On that project, I had 6 * 3.5mm Jacks that I could use for various dew strips, but I never needed to make a second one.   There was also a problem that I broke the Jack plug on the scope a couple of times because it stuck out to the side, which was annoying. So this time, I've made sure that all the cables are out of the side of the box, rather than the top.  This way when on the scope, they'll not poke out to the side.  The project box on the scope is a bit on the large side, but having said that, it's got everything that I want, and room to add a couple more connectors at a later date.

As I said earlier, I'm currently using a 70Ah leasure battery, which admittedly is a bit of overkill.  If I remember to charge the battery, I know that I can have an all night observing session without needing to worry about whether I'm going to get a flat battery.  Once I've completed this project, I'm going to take a breather - to let my wallet recover, or I might just do the third box, and fouth box that I'm thinking about to complete everything for all time.

Box 3 is going to be a battery box.  This will house a 70Ah battery, have an XLR connection so that I can plug into the box that I'm making at the moment, Also I'll have several Automotive 12V sockets, and a few USB sockets.  I'm also thinking about adding a solar charge controller to that box.

Box 4 will be a much simpler box, that will house my second 70Ah battery, and will allow me to plug into box 3 so that the two batteries can pool resources (I've seen youtube videos of things like this, and it seems like a good idea if I can get the connections right)

With Box 3 & 4, I'll be able to run the scope, and other things for a whole weekend, including charging my phone, ipad, and Mifi, oh, and run lighting for a tent as well (not that I've been camping for over 30 years)  Just imaging going to a star party weekend with 140Ah of battery power.  Don't think I'll have any power problems

That's my master plan.

The box that I'm working on at the moment, will ultimately become part of the box that holds my scopes attachments and bits.

[Epicyclus Dave]

I used marine twist lock 12v sockets on my home made 90aH AGM battery box and are still working a treat after 3 years . admittedly, last years astro season nights were a total cloud fest , but I hope we get some good frosty nights this winter

Dave.

[cjdawson]

I've started working on the second box.  Lots of bits all over the place, which I need to bring together.  The main part is that I've etched the PCB's that I need for the second box.  After making a mistake in the PCB layout for the main distribution board, I've redone it.  Also I've take the opportunity to include a facility for an LED to should that the whole box is getting power, the PCB trace also includes space for a resister so that I don't blow the LED.

This set of PCB traces is the complete set of boards that I've made for both boxes.  Using this, you'd be able to make all three PCB's from a single board - unlike me, who did them seperately.  This way will save money for any repeat in the future.