Some ideas to switch to that wireless receiver

[jackson6612]

Hi

Please don't give me another warning for posting in a wrong forum. Seriously, in my view this belong here in "General Discussion" forum.

Where I'm placed these days here we have electricity blackouts several times a day, sometimes for as long as 3 hours at one time. My laptop could run on battery power for almost 4 hours. The problem is with wireless internet receiver which needs separate power source. It has written on its charger: Input:100-240V, ~50-60Hz, 0.7A; Output: 12V, 1.6A.

Someone was suggesting me that I buy a dry 6V battery and an inverter, and then can power the receiver using power from it.

What would you suggest me? Does that someone's suggestion have some merit? Usually, I don't see current rating as in case of that wireless receiver written in Input field. What does 0.7A input current mean here?

Could you please give some ideas to solve that issue? It is really affecting me.

 

[NobodySpecial]

A 12V car battery will run the wireless for days
Either leave a trickle charger permanently connected to the battery (it will output just over 12V which the wireless unit will easily cope with) or wire the battery in parallel with the PSU and charge the battery occasionally if it's used

 

[jackson6612]

Thanks, NBS.

I don't really get it. The wireless receiver's charger needs 100-240V as input. So, don't you think I would need to use an inverter? Please let me know.

 

[NobodySpecial]

Yes you 2 choices
Take 12V DC from the battery, convert it to 110V AC using an inverter and then convert this back to 12V DC using the power supply.

Or take 12V DC from the battery and put it straight into the wifi hub

 

[Borek]

Charger converts 110-240 AC to 12 V DC. If you have 12 V DC you don't need charger.

 

[jackson6612]

Input:100-240V, ~50-60Hz, 0.7A; Output: 12V, 1.6A

Thanks, NBS, Borek.

But the receiver needs no more than 1.6A as the input. What if the battery is delivering 3A instead.

Can I also use 6V battery with an inverter? Actually 12V is a little heavy to carry around. I would buy a dry battery which doesn't leak so I can put it in a bag.

Please let me know your suggestions. Thanks.

 

[JaredJames]

The problem is current.

Can the 6V battery supply the required current?

The car battery could with ease.

The inverter would also shorten the life of the battery, so I wouldn't see it as a 'long term' solution.

Have you looked at UPS systems? Under small load it could potentially give you what you need.

 

[NobodySpecial]

A device pulls current - so as long as the supply can give more current than the device needs you are OK.

An inverter converts DC from a battery into AC - as if from a power outlet, you can't use it to convert 6V DC to 12V DC directly, there are devices that do this but you probably don't need one.

If you just want to make your wifi hub portable the easiest way is probably a 12V nicad battery pack for a remote control car - or 2x 6V packs in series. These would supply enough power to run the wifi for several hours, are cheap, easy to get and safe.

If you live somewhere that the power is unreliable then you use a UPS (uninterruptable power supply) this is basically a car battery in a box with an inverter which gives you 110v (or 230v) when the poweris out

 

[Borek]

But the receiver needs no more than 1.6A as the input. What if the battery is delivering 3A instead.

Have you ever heard about Ohm law?

If battery gives correct voltage, receiver will draw exactly as much as it needs. Current specification is there only to tell you whether charger is able to supply enough current. For example if some device needs 12V and 2A, and the charger is certified for 1A only it will probably blow sooner or later. But if your charger gives 12V and is capable of giving more current than the device needs, there is no problem.

 

[jackson6612]

Thanks a lot, everyone.

I believe 12V NiCad battery pack is the best choice for me. I this is the same pack used in cordless phones. But I think the problem would be to find a stand alone charger for it.

By the way, does a battery's voltage go down while being used?

 

[Borek]

By the way, does a battery's voltage go down while being used?

Slightly.

 

[jackson6612]

NoBodySpecial said:

An inverter converts DC from a battery into AC - as if from a power outlet , you can ' t use it to convert 6V DC to 12V DC directly...

Doesn't an inverter covert a DC input into some standard AC source such as 120V or 240V? If that's correct, then an inverter could convert 6V battery supply into 240V source?

That receiver also has a built in wifi antenna which can be turned on or off. That would mean when the antenna is in off mode, the receiver would consume less power?

 

[JaredJames]

Doesn't an inverter covert a DC input into some standard AC source such as 120V or 240V? If that's correct, then an inverter could convert 6V battery supply into 240V source?

It does, but at the cost of available output. A 6V battery won't give you much in the way of 'run time' if you try to draw 240V from it with an inverter. You couldn't stick an inverter onto a 6V battery and run your computer for very long.

You don't need an inverter. You want a step up transformer to go from 6V to 12V. But even that will reduce the life of the battery.

That receiver also has a built in wifi antenna which can be turned on or off. That would mean when the antenna is in off mode, the receiver would consume less power?

If you turn the antenna off, it won't be able to send / receive any signals. If it is the antenna picking up the internet signal it means no internet. If it is simply so you can connect wireless with a computer, it means you would need to be hard wired to it.

 

[jackson6612]

It does, but at the cost of available output. A 6V battery won't give you much in the way of 'run time'. You couldn't stick an inverter onto a 6V battery and run your computer for very long.

If you turn the antenna off, it won't be able to send / receive any signals. If it is the antenna picking up the internet signal it means no internet. If it is simply so you can connect wireless with a computer, it means you would need to be hard wired to it.

But that 6V battery could turn on the receiver which needs no more than 20W. I'm not sure about how long for.

Yes, I have to be wired to the internet receiver but it's okay if that could prolong the battery run time.

 

[JaredJames]

But that 6V battery could turn on the receiver which needs no more than 20W. I'm not sure about how long for.

Power = Voltage * Current

So we'll go with the max (20W and 12V based on receiver specs):

20W = 12V * I

20/12 = I = 1.67A (Which agrees with the specification of the receiver)

That is one hell of a current draw and would take a major battery to provide that (we really are talking car battery).

Yes, I have to be wired to the internet receiver but it's okay if that could prolong the battery run time.

Turning the wifi adapter off would save power, but not that much.

 

[jackson6612]

So, that's the choice between a 12V car battery or 12V NiCd battery.

Input:100-240V, ~50-60Hz, 0.7A; Output: 12V, 1.6A

I can understand the reason for mentioning the output current which would mean that the charger could easily handle up to 1.6A of current. But what's the reason for the mention of input current, 0.7A? Perhaps, it says that the charger draws at the most 0.7A.

 

[JaredJames]

So, that's the choice between a 12V car battery or 12V NiCd battery.

You need a battery which can supply 12V and the current requirement of 1.6A. But, you need to check the available Ah (amp hour) rating for the battery. If you have a battery that is shown at 12V and 1A for 50 Ah (50 hours of use at one amp), using it at 12V and 1.6A will reduce the available time to around 30 hours. (You would get 30 hours of use out of it.)
You need to ensure the battery is capable of supplying 1.6A as well.

I can understand the reason for mentioning the output current which would mean that the charger could easily handle up to 1.6A of current. But what's the reason for the mention of input current, 0.7A? Perhaps, it says that the charger draws at the most 0.7A.

It doesn't mean the charger can handle 1.6A of current, it means that when you supply the input of "100-240V, ~50-60Hz, 0.7A", you get "12V, 1.6A" out of it. So when the antenna draws 1.6A from the charger, the draw from the charger on the mains is 0.7A.

 

[jackson6612]

It doesn't mean the charger can handle 1.6A of current, it means that when you supply the input of "100-240V, ~50-60Hz, 0.7A", you get "12V, 1.6A" out of it. So when the antenna draws 1.6A, the draw from the charger is 0.7A.

I think it's going to get complicated for me but I would venture to ask.

"100-240V, ~50-60Hz, 0.7A" - I take it as: You could connect the charger to any voltage source between 100-240 with frequency 50-60Hz, and whatever that source is there should be at least 0.7A available. Do I make any sense?

Ampere is the flow of charge i.e. electrons. How could one have less electrons at the entrance and more at the exit? The charger takes in 0.7A and output 1.6A. I think this kind of principle is also used in transformers.

 

[JaredJames]

"100-240V, ~50-60Hz, 0.7A" - I take it as: You could connect the charger to any voltage source between 100-240 with frequency 50-60Hz, and whatever that source is there should be at least 0.7A available. Do I make any sense?

It means that you can connect it to anything "between 100-240 with frequency 50-60Hz", and get 12V DC out of it. The current is based on what is available from the power supply and what the device draws from it. If the supply cannot give 0.7A, it won't be able to draw it. But, for correct operation, it requires at least 0.7A be available to it.

Ampere is the flow of charge i.e. electrons. How could one have less electrons at the entrance and more at the exit? The charger takes in 0.7A and output 1.6A. I think this kind of principle is also used in transformers.

The 'charger' you keep referring to is a transformer of sorts.

It steps down the voltage from 120-240V AC to 12V DC.

We are getting far too off-topic here. You have been given the solution to your problem.

 

[jackson6612]

We are getting far too off-topic here. You have been given the solution to your problem.

Yes. I offer my thanks to everyone for helping me in such a good way. I think I will go for NiCd battery if I could get a stand alone recharger for it. Oh, one last question: Is 12V NiCd capable of delivering 1.6A? I hope this is going to be a last question.

Thanks.

 

[JaredJames]

Is 12V NiCd capable of delivering 1.6A? I hope this is going to be a last question.

Not necessarily.

This is something you would have to check on the battery itself. It will have ratings on it, specifying Voltage, Max Current and Amp Hour rating.

You need a battery capable of supply at 1.6A, but at the same time it must be able to do this for a sustained period.

So you would be looking for something like 12V, Max 2A, 30Ah. This would give you around 18 hours of use. (These figures are for demonstration only.)

 

[jackson6612]

Thanks a lot for the information, Jared.

 

[NobodySpecial]

Is 12V NiCd capable of delivering 1.6A?

Yes for about 1.5hours, a typical small NiCad pack is around 2.5Amp-hours

But the wifi almost certainly doesn't use 1.6A, my guess would be 0.3-0.5A max - so the battery would run it for 4-5hours.

The 1.6A is the maximum output rating of the power supply, remember it's probably sold to power all sorts of different devices.

 

[JaredJames]

But the wifi almost certainly doesn't use 1.6A, my guess would be 0.3-0.5A max - so the battery would run it for 4-5hours.

The 1.6A is the maximum output rating of the power supply, remember it's probably sold to power all sorts of different devices.

True, but I'd work to the maximums as you don't know what the actual requirements are. If he's in a poor signal area he may require a higher than normal draw.

If the OP gets a battery which can sustain, let's say 1.5A for around 3 hours I'd say that would be perfect as it would give an excellent supply if the draw is less than that.

 

[jackson6612]

Hi again

10mAhr means current of 10mA for one hour

10Whr means power of 10W for one hour? Please confirm this.

Thanks.

 

[JaredJames]

10mAhr means current of 10mA for one hour

10Whr means power of 10W for one hour? Please confirm this.

Correct

EDIT: Sorry, that's just going to confuse things.

 

[jackson6612]

No problem. Perhaps, it belongs in the General Physics forum.

 

[Borek]

No problem. Perhaps, it belongs in the General Physics forum.

95% of your questions in the thread does, it is electricity ABC.

 

[jackson6612]

95% of your questions in the thread does, it is electricity ABC.

But now I fear those warnings! Actually I realized it just now that the thread has been moved to "Computing and Technology" forum. I believe I originally posted it in General Discussion forum.

Best wishes
Jackson