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Battery box

wookie1965

By wookie1965
in DIY Astronomer

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symmetal

symmetal

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Twin and earth is awkward to work with for such a job using many short lengths and will take up quite a bit of room as it isn't flexible. The extra insulation which isn't needed for 12V and the bare earth would be a pain to deal with. I would use 10A stranded twin for connections from your fuse box similar to this. You can get it in various current ratings. The main connection from your battery could use 20 or 25A cable or maybe just connect 2 lengths of the 10A cable in parallel to give 20A capacity. Good luck with your build. :smile:

Alan

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wookie1965

wookie1965

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50 minutes ago, mapstar said:

Just picked up on your build Paul. Hope it's coming on well 

Got battery in on some insulation got most of bits just need someone tell me will 2.5 mm twin and earth without the earth be OK to use or should I but some 6 amp cable. I will put pictures up when I start. 

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wookie1965

wookie1965

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42 minutes ago, symmetal said:

Twin and earth is awkward to work with for such a job using many short lengths and will take up quite a bit of room as it isn't flexible. The extra insulation which isn't needed for 12V and the bare earth would be a pain to deal with. I would use 10A stranded twin for connections from your fuse box similar to this. You can get it in various current ratings. The main connection from your battery could use 20 or 25A cable or maybe just connect 2 lengths of the 10A cable in parallel to give 20A capacity. Good luck with your build. :smile:

Alan

I think I can use the twin and earth then to the fuse board and use the 10 amp you suggested for the rest thanks. 

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symmetal

symmetal

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8 minutes ago, wookie1965 said:

I think I can use the twin and earth then to the fuse board and use the 10 amp you suggested for the rest thanks. 

Yes that sounds fine. For the short length of twin & earth you'll be using you should be able to just pull the earth wire out with a pair of pliers to save it getting in the way.

Alan

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wookie1965

wookie1965

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Just now, symmetal said:

Yes that sounds fine. For the short length of twin & earth you'll be using you should be able to just pull the earth wire out with a pair of pliers to save it getting in the way.

Alan

Cheers Alan much appreciated. 

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cjdawson

cjdawson

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For the switch if you look carefully one of the prongs will be a different colour - normally more of a brass colour than silver.    This is the +ve for the LED, supply 12v to that pin.    The next pin, is the +ve for the switch and the last pin is the -ve for both the switch and the LED.

 

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symmetal

symmetal

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Here's a diagram I found on a car forum which saves drawing one. This shows the 'brass' coloured pin is the negative for the led. The easiest way to check if you have a multimeter in ohms/continuity check mode, is with the switch in one position, you will measure open circuit (high resistance) between all the pins. With the switch in the other position there will be a short (0 ohms) between the centre pin and one of the others. The centre pin takes +12V from your battery (via fuse) and the pin it is shorted to with the switch in one position is the +12V input connection to your distribution board. The pin which is high resistance or open circuit to both other pins with the switch in either position, is the 0V (ground) return for the led and goes to your 0V common bus bar.

led_rocker_switch_diagram.jpg.8f9c3b5bb7208d773ff7ffe71f574487.jpg

This differs from cjdawson's reply though. Having one pin as positive for the switch and another as negative for the switch would short out the battery, unless I've misread the reply. :icon_scratch: Only +12V would be switched and not the 0V so the 0V connection to the switch would only be for the led. There will be a resistor inside the switch (around 10k or so), connected to this terminal to limit the current through the led. 

Alan

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RayD

RayD

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2 minutes ago, symmetal said:

Here's a diagram I found on a car forum which saves drawing one. This shows the 'brass' coloured pin is the negative for the led. The easiest way to check if you have a multimeter in ohms/continuity check mode, is with the switch in one position, you will measure open circuit (high resistance) between all the pins. With the switch in the other position there will be a short (0 ohms) between the centre pin and one of the others. The centre pin takes +12V from your battery (via fuse) and the pin it is shorted to with the switch in one position is the +12V input connection to your distribution board. The pin which is high resistance or open circuit to both other pins with the switch in either position, is the 0V (ground) return for the led and goes to your 0V common bus bar.

I read @cjdawson reply as switching low, which I would never do on a power circuit.  I deleted my posts as I didn't want to add to confusion by detailing 2 different methods.

Switching low means there will be +ve on the outlets at all times, which isn't ideal.

Below is a simple diagram of how I see these switches working, and as such I have connected mine in a method akin to your diagram (I appreciate there is a resistor in there as well, this is indicative).

20171101_170723.thumb.jpg.88c04e644168cc27a077233895ffd645.jpg

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RayD

RayD

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11 minutes ago, symmetal said:

I agree with you Ray. Linking your diagram to mine, T1 = Power, T2 = Acc, T3 = Ground. Being pedantic, your diode needs an arrow coming out of it to turn it into a led. :wink2::grin:

Alan

Well being even more pedantic 2 actually, so it was a double omission lol.

I've seen these switches with different terminal designations, perhaps ones from China, so I just check the switch pin outs before connecting.

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RayD

RayD

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10 minutes ago, wookie1965 said:

I used this drawing as a guide the only thing different was the led on/off switch, I think I have blown it wiring it up wrong well the led part as it switches everything off and on.

 

You should be fine ditching the LED side and just using the switch.  You'll be surprised how bright and annoying the LED's are when you're imaging anyway, so you may not even want it.

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RayD

RayD

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1 minute ago, wookie1965 said:

I am a bit dubious about the cable i got for the auxiliary's I got this it is working but seems a bit thin.

  http://www.ebay.co.uk/itm/AUTOMOTIVE-12V-24V-2-CORE-TWIN-THINWALL-RED-BLACK-AUTO-CABLE-WIRE-WIRING-LOOM/201950989367?ssPageName=STRK%3AMEBIDX%3AIT&var=501958593606&_trksid=p2057872.m2749.l2649

Which one did you get?

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RayD

RayD

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1 minute ago, wookie1965 said:

The 11 amp one I hope I have not bought wrong. The cable from the battery is 32 amps with the 20 amp fuse.

 

11A will be fine.  You're fused at 10A, but you could cut that down to 7.5 as you probably won't be using much which will be using anywhere near 10A.

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symmetal

symmetal

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You would need to reverse the connections you've wired to the switch wookie to get the led to work properly. The battery +ve via fuse should go to the centre pin. At the moment if you connect the unconnected terminal to battery 0V your led would be permanently on with the switch in either position. If you don't need the led then it doesn't matter.

As Ray says the 11A will be OK for your installation. It's all looking good.:smile:

Alan

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