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12V bike battery(with/without battery charger) to regulated 12v 2A circuit for mini computer ? Answered

I want to make a UPS type of device for my tv box which takes 12V-2A power can anyone suggest how to build one I am not able to find any DIY to work with it and I would like to use that TV box as my little NAS device since it runs on windows. and to make it running even in power outages I need some type of UPS for it. regular UPS would convert 12-v to 230v and then 12v that seems a lot of power wastage.
if anyone can suggest a better way to do it it would be a great help

Thanks in advance..



Best Answer 1 year ago

Here is a simple inverter circuit and another that shows how to get more current.

If you think about it, the oscillator is close to a square wave and that means C1 does no need to be very large because after rectifying there is only a narrow dip unlike a sine wave rectified with huge dips that need lots of capacitor.



Thanks for the reply..

got a help in right direction..
can you please update the values of capacitor and resistors they does not seems to have voltage n capacitance value in pictures. also can I directly connect battery to the capacitor next to rectifier without 12v to 12v isolation center transformer.

I also searched for rectifier use and found some projects like that in http://www.eleccircuit.com/regulator-5v6v9v12v-1a-...

which I found similar to it so in that but with 6v output there is one circuit as attached image in that page is values in that image does the job?

thanks for reply



First ) Yes you can but then as the battery runs down so will your 12 Volts.

While the inverter generates 24 Volts that gets regulated down to 12v and until your battery gets down to 7v your output will remain at a steady 12v..

Next ) When you find a transformer and measure its impedance and optimum frequency of the iron, then I can specify R1, R2, Q1, Q2...

The DC Bridge should be 50v 4A...

C1 = 400 uF @ 50v.

C2 = 47uF @ 50v..

You will also need to mount a heatsink for the TO-220 regulator..

FYI: I wanted to build something like I have tried to drow in image..

bear with my for low drawing skills. :P please open image for better understnading.



Kudos on the block diagram..

Very few people can do this today...


No I would not worried about battery getting down to 7v since my small computer will not take much power and here at my location power cuts are rare it is just for the protection just in case when power cut is there my portable hdds that is attached to this will not cut off instant. or if I am running internet through this and doing any internet transaction it will not be intercepted in between.

I will hook up a bike battery charger with over charge protection with it so it would not harm battery and my computer(small NAS) can be running 24*7

I just got the idea that might help you as it looks like you still need to hone your skills.
A device like this will do what you need.
Of course you should consider a decent filter circuit on the output to make sure the TV won't get interference.
If you need to charge while the converter is connected, like a UPS, than you also need a filter on the input side to prevent the ripple from the charger damaging the converter.
As an alternative you can also use a big headphone jack for the connection and use it to disconnect the battery from the TV.
This however would require a higher input voltage so you can feed the battery charger from it and power the converter at the same time.


Thanks for the reply I tried googling all the links and since I do not have much knowledge about the circuits and electronics I am not able to get what I want through that projects. so I asked for the help if someone have the needful knowlege that can help me with it.



Then the issue becomes can you build this from remote instructions safely.

Unfortunately when working with mains electricity knowledge and experience are what keep you alive.

No one will be able to cover all possible issues and if it can something will go wrong.

I would start with many simpler circuits and projects until your skill level is enough to be able to understand the circuits you can google and build from them with confidence.

I know this isn't the answer people want here, but it takes several years to train as an electrical or electronic engineer - for a reason - there is a lot to learn.


Yes I can build it remotely I have knowledge of soldering and electronics and stuff but not much wider knowledge that I can come up with some circuit on my own due to insufficient knowledge and unavailability of tools it is hard for me to come up with one and test it before hooking it up with my computer(TV Box) so asked for help thanks for the reply appriciated..


1 year ago

Sine Vs Square wave filtering.

Be sure to click the pic ti view the entire image.


There are car PC systems available, including power supplies for 12V.
Might be a good option to do some online searching for these ;)

hellow i think electricals appliences works on a.c power sources and your u.p,s takes 12 v d.c then convert it into the 220 v a.c then your t.v take 220v ac nd convert it into 12 v d.c by a step down transformer and rectifier circuit

if u want to operate ur t.v on 12 v

1st step remove that transformer from ur t.v

2nd step connect a 15-24v battery with 7812 voltage regulator (or other 12 v regulator)

final step connect the output of that regulator with ur tv input

thanks nd be careful


That is what I said that it is a loss of energy since changing it from 12v to 230 and then changing it back to 12v 2A since if you step up or step down voltage some of the energy is lost during this process. so it is not efficient way to do it so asked is there any way we can just have 12v battery and regulate that high power to a low 2A power

Thanks for the try..

hey bro there is some kind of loss like copper loss or eddy current loss and it is negligible so there is no losses due to step up step down nd this is the only one efficient way rather than u directly connect the 12 v d.c with t.v

But If u want to do that then first thing open ur t.v set nd check the voltage produce by ur t.v transform nd then remove it nd connect it with bettery...

There is no need of circuit or resistance becz it also raise the losses in heat form or some other form thanks

It is a TV box bro powered by a charger type of adapter.

it's like a small computer not a TV. adapter voltage is 12v2A here is the link for the product if you wanna see.


More details would be

I would want to build a circuit or some device that will run on bike's 12v battery with or without battery charging adapter

what would that device do is it will take power from 12v battery and give me constant 12v 2A output.

So that in case if I keep that battery on charger and lights go out. it will still be running and taking power from battery so I can get continuous power even if power cuts are there.