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Old Oct 07, 2013, 09:56 PM
Quietly Scheming!!!
geekness's Avatar
Australia, WA, Port Hedland
Joined Jan 2013
398 Posts
Question
How do I automatcially switch between 240V mains and battery backup?

Im designing a UAS ground station and want to be able to power the whole setup from 240V mains from this PSU, but then be able to switch to a battery when away from mains power, or be able to plug into a car battery supply.

I was looking at this and this, but they dont meet my power requirements.

Any suggestions will be appreciated.
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Old Oct 08, 2013, 01:29 AM
Stuart
srnet's Avatar
UK, Cardiff
Joined Dec 2008
3,266 Posts
Quote:
Originally Posted by geekness View Post
but they dont meet my power requirements.
Which are ?
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Old Oct 08, 2013, 03:11 AM
Who let the dogs out?
phil_g's Avatar
Pontefract, Yorkshire, UK
Joined Jul 2007
1,082 Posts
Not sure if the requirement is for battery backup (as per title) or for alternative battery/mains (as per description).
The KISS solution is to run the ground station from a lead-acid battery which is on permanent float charge. Depending on your requirements, this could be for example a car battery or leisure battery (typ 80a/h ish) combined with a suitable intelligent charger, or say a ups battery (typ 7ah) with a simple 1A 13.8v regulated supply. Lots of ham radio repeaters have been running for decades on nothing more elaborate than this.
Your own solution will depend on voltage requrement, typical and max current draw, required operational time without power, required recovery time (for recharge), budget, etc...
Cheers
Phil
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Old Oct 08, 2013, 05:59 AM
Quietly Scheming!!!
geekness's Avatar
Australia, WA, Port Hedland
Joined Jan 2013
398 Posts
Quote:
Originally Posted by srnet View Post
which are ?
12v 40a
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Old Oct 08, 2013, 06:33 AM
Quietly Scheming!!!
geekness's Avatar
Australia, WA, Port Hedland
Joined Jan 2013
398 Posts
Quote:
Originally Posted by phil_g View Post
Not sure if the requirement is for battery backup (as per title) or for alternative battery/mains (as per description).
The KISS solution is to run the ground station from a lead-acid battery which is on permanent float charge. Depending on your requirements, this could be for example a car battery or leisure battery (typ 80a/h ish) combined with a suitable intelligent charger, or say a ups battery (typ 7ah) with a simple 1A 13.8v regulated supply. Lots of ham radio repeaters have been running for decades on nothing more elaborate than this.
Your own solution will depend on voltage requrement, typical and max current draw, required operational time without power, required recovery time (for recharge), budget, etc...
Cheers
Phil
I need alternative battery/mains supply.
I have broken my components down to 3 groups
PC: 12V, 16A
Displays: 12V, 16A
Video and telemetry system: 12V & 5V, 5A

My main power supply unit is 12V, 40A
I think I will also use 2 x 12V 20A SLA batteries

For the PC I will use 2 of these in parallel, in series with one of these

I will do the same for the displays.

I will just use one of these for the vid/telem system, then use this to get 5V from it.

As they say, a picture is worth a thousand words, so see the attached.
Now, just so you know, I am not an electrical engineer, I'm a structural Engineer. I haven't read any electrical books to do this, I've just drawn this based on my assumptions only. If you have any suggestions or pointers for me, feel free.
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Old Oct 08, 2013, 11:12 PM
Registered User
Joined Nov 2007
895 Posts
These power converters would generate main voltages from a 12 volt car battery. Just plug in your setup for mains power.

http://www.harborfreight.com/catalog...lt?q=converter

I realize these are for US mains (110V), you would have to get a converter for the crazy mains you have but the idea is the same. You could also run a coffee pot and TV with the same unit. Maybe even a small A/C.
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Old Oct 09, 2013, 01:34 PM
Michael
United States, ME, Wells
Joined May 2008
1,121 Posts
West Mountain Radio

Check out West Mountain Radio "http://www.westmountainradio.com/dc_power.php".

I use their ISOpwr, but you might want their Super PWRGate PG40S. The former I use with my automobile (one leg has power cord connection for auto battery plus alternator and the other leg has a deep discharge sealed gel battery.) The latter is designed to switch between a power supply and a battery. Both will charge your battery.

Both devices utilize Anderson PowerPoles (AKA Sermos) crimp connectors; I also purchased their crimper tool and 15, 30, and 45 amp connectors.

I have no relationship with West Mountain Radio other than as a satisfied customer. I have been using an ISOpwr and a RIGrunner for several years; completely trouble free. I like that everything is protected by automobile fuses.

Michael
Quote:
Originally Posted by geekness View Post
12v 40a
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Old Oct 09, 2013, 07:37 PM
Quietly Scheming!!!
geekness's Avatar
Australia, WA, Port Hedland
Joined Jan 2013
398 Posts
Quote:
Originally Posted by Snowflake6515 View Post
Check out West Mountain Radio "http://www.westmountainradio.com/dc_power.php".

I use their ISOpwr, but you might want their Super PWRGate PG40S. The former I use with my automobile (one leg has power cord connection for auto battery plus alternator and the other leg has a deep discharge sealed gel battery.) The latter is designed to switch between a power supply and a battery. Both will charge your battery.

Both devices utilize Anderson PowerPoles (AKA Sermos) crimp connectors; I also purchased their crimper tool and 15, 30, and 45 amp connectors.

I have no relationship with West Mountain Radio other than as a satisfied customer. I have been using an ISOpwr and a RIGrunner for several years; completely trouble free. I like that everything is protected by automobile fuses.

Michael
Very nice, thanks for the tip.
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Old Oct 12, 2013, 06:26 PM
Registered User
New Zealand, Wellington, Porirua
Joined Jan 2013
96 Posts
I would start my measuring actual current draw of your components first. I find it hard to believe your PC requires 200 watts. Also, take care of what kind of Pico PSU you've got. Some don't regulate the 12V input and pass it straight through to the motherboard. If your battery is fully charged, at 13.8V, that's 15% higher than what the motherboard is rated at.

Same goes for the monitors, just because the controller is rated at 4A, doesn't mean the monitors will consume that much.
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Old Oct 13, 2013, 02:34 AM
Stuart
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UK, Cardiff
Joined Dec 2008
3,266 Posts
Quote:
PC: 12V, 16A
Displays: 12V, 16A
I would agree with Viperdae, that sounds a little high, a total of almost 400W.

The power consumption of the PC and monitor I use here averages around 50W total.

The 19" LCD monitor uses around 25W, and the PC which is fanless,totally silent, runs from 12V, micro ATX machine, uses between 25W and 50W depending on what its doing, 25W at idle.
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Last edited by srnet; Oct 13, 2013 at 03:44 AM. Reason: more info
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Old Oct 13, 2013, 08:48 PM
Quietly Scheming!!!
geekness's Avatar
Australia, WA, Port Hedland
Joined Jan 2013
398 Posts
Quote:
Originally Posted by viperidae View Post
I would start my measuring actual current draw of your components first. I find it hard to believe your PC requires 200 watts. Also, take care of what kind of Pico PSU you've got. Some don't regulate the 12V input and pass it straight through to the motherboard. If your battery is fully charged, at 13.8V, that's 15% higher than what the motherboard is rated at.

Same goes for the monitors, just because the controller is rated at 4A, doesn't mean the monitors will consume that much.

Quote:
Originally Posted by srnet View Post
I would agree with Viperdae, that sounds a little high, a total of almost 400W.

The power consumption of the PC and monitor I use here averages around 50W total.

The 19" LCD monitor uses around 25W, and the PC which is fanless,totally silent, runs from 12V, micro ATX machine, uses between 25W and 50W depending on what its doing, 25W at idle.
That's really helpful info, I'll try and measure the consumption of the equipment, hopefully I can reduce the weight of my battery and also some costs.
I've got a "watts up" meter, so I can do it quite easily.
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