suggestions for a temporary "clean" 12v feed at home

Refueler

Refueler

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CliveF said:
You wont be needind much power to run that. Get a model aircraft power lipo from the likes of Hobby king.

some 12v 2200mAh batteries are on sale at the moment for about £6 - 7
Click to expand...

I use ex flight LiPo's for many things that have low demand ... but I would not suggest a LiPo for OP's use ....

I take it you are a user who is aware of LiPo characteristics ... storage charge - do not discharge lower than 3v / cell ... puffing .... etc etc ...

He would need to pay the x quid for the battery ... then xx quid for a charger to service the LiPo ... discharging when not in use to storage ... charging up for use ... discharging after back to storage etc.

mmmmm not such a great idea ??

If a battery - then as another says - a SLA 12v battery ... commonly used for House Alarm systems ... a trickle charger for such can be had for a fiver ...
 
wonkywinch

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rogerthebodger

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wonkywinch said:
Would you suggest a resistor in series with the capacitor to limit the inrush current when first powered up that would appear as a short circuit to the PSU? How about a pico value capacitor also in parallel to remove RF noise from the supply as well?
Click to expand...

A disc ceramic may b useful as a RF filter never found it necessary to have a resister in series as the output impedance would limit inrush
 
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Minerva said:
This winter, one of my pet projects is building a Raspberry Pi with open plotter to replace my aging Windows tablet on the boat.

I've got it mostly there, but one item I can't yet get set up is the Weatherfax; the mains to 12v dc adaptor I have is too "noisy" for the weather fax.

I don't have spare leisure battery at home and as my set up is in my pottering shed at the back of the garden, it's too far to run some hot-wires from the car battery. Any suggestions, short of buying a new leisure 12v battery or taking one from the boat (6 hour round trip)?

It's a Nasa Target SSB so very low demand with power consumption 300mA @12v

The obvious answer is to leave it 'til the spring and set it up on the boat, but then time demands will be on Antifouling and recommissioning, not playing with gadgets... It's been quite fun getting an Arduino heading sensor, a spare NMEA mast head wind instrument wired in and the AIS info, and remote display to multiple devices all working nicely so far next to the heater in my shed.

I'm almost tempted to buy a Radar scanner to add in too! :D
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OP wants to receive HF weather fax signals. In my experience any form of switch mode power supply including computer will wipe out any HF reception with noise.
So battery or linear regulated power supply is only option. The 12v supply he has is not likely to be able to charge an SLA battery. If OP uses 18650 lithium cells in flashlight etc and has a charger for same then 3 in series could provide 12v for a time. Or 10 0ld NiMh batteries or even 8 1.5 volt dry cells. Celll holders are quite cheap and available on ebay. ol'will
 
greeny

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Burglar alarm, motor bike or lawn mower battery using the charger he already has. Maybe 12 to 25 quid ish if you shop around. Depending what size you chose and where from.
 
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Refueler

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Best as I and others suggested ... House Alarm SLA battery and a cheapo mains adaptor charger ... package deal would be cheap enough.

Or go buy a Emergency Car starter pack - one of the older SLA versions - not the LiPo ones they now fob off to people.... unless willing to pay that price.
 
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Refueler said:
59 quid for a regulated 240 - 12v PSU ?????? and only 5A ????

I have a bank of regulated 240 - 12v 10A PSU's for my Lithium chargers ... I can buy two for the price of that chandlers version .. and the 12v is clean.
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Fair point. Didn’t check the amps on that to be fair. Mine is a higher rating for sure. I got mine with the weaco fridge years ago.
No doubt there are cheaper. I can only testify to the quality of the one I have similar
 
wonkywinch

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QBhoy said:
Fair point. Didn’t check the amps on that to be fair. Mine is a higher rating for sure. I got mine with the weaco fridge years ago.
No doubt there are cheaper. I can only testify to the quality of the one I have similar
Click to expand...
Your device and the OPs requirement for a noise free DC supply are likely not mutually compatible. An item made to power a fridge via a cigarette lighter socket may not have the smoothing and filters necessary for a sensitive computer/weatherfax receiver project.
 
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wonkywinch said:
Your device and the OPs requirement for a noise free DC supply are likely not mutually compatible. An item made to power a fridge via a cigarette lighter socket may not have the smoothing and filters necessary for a sensitive computer/weatherfax receiver project.
Click to expand...

True - but its not like 10 .. 20yrs ago ... today there are very 'smooth' regulated PSU's that do the job OP wants for budget money ..

If not wanting to check out such - then as I and others have suggested ... SLA battery ... easy peasy.
 
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wonkywinch said:
Your device and the OPs requirement for a noise free DC supply are likely not mutually compatible. An item made to power a fridge via a cigarette lighter socket may not have the smoothing and filters necessary for a sensitive computer/weatherfax receiver project.
Click to expand...
Not relevant. It doesn’t make a noise at all 😂.
But seriously though, I was having a look for the one I have. Can find similar but not exact. It’s rectified and designed for compressor cooling systems and items of a sensitive nature, requiring a clean wave.
But no doubt…everyone else knows better than the next guy on here !
 
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wonkywinch

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I'm puzzled why so many posters are suggesting a battery to the OP when his request was for a power supply? The battery suggestions and their prices don't take into account the need for a charger. How much ripple will the charger put on the line when charging needs to be taken into account else the OP can't test or operate his project whilst the battery is under charge if the charger is cheap and cheerful.
 
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rogerthebodger

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wonkywinch said:
I'm puzzled why so many posters are suggesting a battery to the OP when his request was for a power supply? The battery suggestions and their prices don't take into account the need for a charger. How much ripple will the charger put on the line when charging needs to be taken into account else the OP can't test or operate his project whilst the battery is under charge if the charger is cheap and cheerful.
Click to expand...

The OP also says he has a mains 12 Vdc power supply but is electrically noisy.

A set of capacities' smooth rectified power supply so to me would be a cost effective first stage and if it doesn't work look for a different solution
 
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