Help a newbie build a battery box

[MonkeysAteMe]

I'm new to circuit board engineering, and I would like to make an external battery pack for my consumer electronics.

I would like to have a battery pack that runs on AA's that I can use to charge multiple devices(mp3 player,cell phone, portable DVD player, etc..).

I can use both a dc plug(the kind that plugs into a car) or an ac plug. (would prefer that it used ac if possible).

I would seperately charge the AA's.

Can I just hook up a dc outlet directly to the batteries, because the dc plugs have transformers built in, or do I need to do more?

Are there any links to sites that would help or can you guys tell me what to do?

Thanks.

 

[Thunderchild]

what exactly do you want to do ?
I hope you intend those to be rechargeble AA batteries (more environmentally friendly) and I would suggest using a dry led acid battery like a car battery they are probably more competitive as far as cost per Watt.
if your going to power multiple devices you will need it to have a voltage regulator, charging NiMH battries is also more tricky than a led acid battery, to charge the lead acid battery you just need a DC power supply that is a couple of volts more than the battery, assuming it has diodes in it like the rectifier of a wall transformer you won't have to worry about putting a diode between the battery and power supply, you will need a resistor of a value equal to (DCin-battery volts)/amps to charge.

i do though recommend using the dedicated adapters for stuff mainly because what you propose is such a wasteful method:
you will charge batterys, this in itself is probably only 50 efficient (for every W charged 2 watts will be consumed as battery heat and charger overhead), you will then do the same thing again having to possibly drop the voltage with a regulator loosing more efficienzy to charge yet more batteries, you will end up using ten time the power you get in the end, ok I know we are talking small power here but remember this becomes an important issue as power consumption rises,

your best bet is to make a backup for each devise and where possible use standard batteries like AA and AAA these you can easily charge, for example I have 6 AAA batteries and 16 AA batteries and so I know where ever I go i am ok for 24-72 hours for power before I get to a wall socket that I can charge them up on.

perhaps if you supply more details we can help better your request is a bit too generic

 

[MonkeysAteMe]

My plan is to make a DC battery charger. The outlet will be a car lighter, and the plug will be whatever car adaptor my device uses.

I believe that the car adaptors have their own regulators so I wouldn't need to make any.

I do hope to use some kind of rechargeable batteries. I need about 9 volts of energy.

I would take out the batteries to charge them.

I hope this is enough information.

I was messing around with some stuff I bought earlier and I melted the battery holder. I had 8 AA's hooked up to a battery holder with a 9v plug on top. I did not connect the 9v plug to anything so I don't believe the circuit was connected. It began smoking and it melted the plastic a little.

HOw am I to prevent this? I hadn't connected the circuit yet the batteries kept running. Do I need to get a switch?


Thanks for the help.

 

[Thunderchild]

if the circuit was not connected probably there was a short on the battery wiring, the problem is how will you charge the MiMH batteries you will need to remove them from the holder each time, I suggest a 12 Volt 2-4 amp dry led/acid battery, on the output you wil need a regulator such as the LM317 but you need to specify what current you want the battery pack to output

 

[MonkeysAteMe]

I was going to use the electronic devices car chargers to regulate voltage.

I'm not sure what current I want (but I think the charger will regulate that).

Are there any sources for people beginning electronics? (DC Circuit board stuff would be my focus)

 

[chemelec]

I was going to use the electronic devices car chargers to regulate voltage.

I'm not sure what current I want (but I think the charger will regulate that).

Are there any sources for people beginning electronics? (DC Circuit board stuff would be my focus)

WHAT "electronic devices car chargers"?
I have No Idea What you mean by this?

 

[MonkeysAteMe]

I probably should have said car adaptor. I plan on using a car adaptor **broken link removed**

to plug into a car lighter **broken link removed**

and the car lighter is plugged into a battery pack.

I hope this makes things clearer.

 

[Thunderchild]

then the solution is simple just get a 12 volt led/acid battery of 2-4 amps and charge it with a car charger (220volts / 12 volts) and connect the cigarette lighter socket to the battery. this is more of a mechanical project than electrical as you will need to spend more time thinking of how to box it

 

[MonkeysAteMe]

Ok thank you.

Does anyone know of any sources where I could learn more about basic electronics?

 

[JTECH]

Basic Electronics Lessons

Ok thank you.

Does anyone know of any sources where I could learn more about basic electronics?[/QUOTE


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