How to make an external battery pack?
- Thread starter TrailsofLife
- Start date
- Status
eawtan said:
What eawtan means is this 7805 regulator chip in the pic below. You need a 8 battery pack to provide about 9.6V to the chip and it will provide a regulated output of 5V.
From http://www.tkk.fi/Misc/Electronics/circuits/psu_5v.html
Do remember to add 2 capacitors to prevent voltage spikes.
Alternatively you can get a variable voltage regulator circuit like this.....
http://www.futurekit.com/detail.php?id=118
Its available in the yellow packs of circuits at the shops at Sim Lim tower or SLS basement. You need to solder it though.
EngHong
O.T.
eawtan, are u an elect engineer?
So I just get this thing from SIm Lim TOwer, solder them together and input with 8 pcs of 1.2V AA batteries(Sanyo) and the output will be 5V?
Ok...if my X-drive last 2.5hrs with its built-in battery, how long will this thing of your works?
Ok...if my X-drive last 2.5hrs with its built-in battery, how long will this thing of your works?
That depends on your device and your batteries. The circuit only regulates the voltage. It takes some current but not alot. Its your x-drive(load) which sucks the current from your batteries and when your current on your batts runs low, your device stops working.
So you have to compare with the mAh of battery of your x-drive and that of your rechargable AAs.
So you have to compare with the mAh of battery of your x-drive and that of your rechargable AAs.
wah cheem again...
How much A does 8 Sanyo2300nimh batteries have?
the x drive battery says 3.7v 1800mah. but the input hole says 5v 2.5A?
?????
How much A does 8 Sanyo2300nimh batteries have?
the x drive battery says 3.7v 1800mah. but the input hole says 5v 2.5A?
?????
actually, do you add up the total of the batteries'mAH? I mean, 1 2300nimh battery is min 1.2V 2100mAh according to the battery, if I put 8 together, is it 9.6V 16800mAh?
Max 2.8 said:
The input hole is for your AC adaptor which should give a 5V 2.5A output to your x-drive. But your battery is a 3.7v 1800mAh battery.
Cannot count like that cos your AA batteries is in series so its still 2100mAH.
Its counted using power. power(W) = current(I) x voltage(v) so for 8sanyo batteries = 9.6v x 2100mAh = 20.16W
For your x-drive battery, its 3.7v x 1800mAH = 6.66 W
Meaning theoratically your battery pack should last at least 3 times your x-drive battery. But this is only simple maths. In reality, there are many more factors comming in which results in you getting less, so take it that at least 2x longer. Best way to know, try it out.
EngHong
So its quite alright...meaning I get almost 10 hrs more lah....
Am I right to say I get that board you show me, attach a 8X battery case to the input...It should give me 8-10hrs of battery supply?
This is interesting....where you buy the board and those little stuff? How much?
Am I right to say I get that board you show me, attach a 8X battery case to the input...It should give me 8-10hrs of battery supply?
This is interesting....where you buy the board and those little stuff? How much?
OT a bit. Sorry to hijack. :sweat:
BTW is there a way to protect wires? eg a earphone wire. Something like a cable sleeve? How do i go about doing it? Any idea?
BTW is there a way to protect wires? eg a earphone wire. Something like a cable sleeve? How do i go about doing it? Any idea?
afbug said:
Not sure why you want to do this but you can buy cable sleeves in Sim Lim tower I think. If I remember you thread your wires through them (they look like black rubebr tubes and come in different diameters) and when heated (previously used soldering iron for this), they shrink and wrap their contents.
The thing is you must be able to pass the wires through them in the first place. With the earphone buds on one side and jack on the other it may/may not be possible.
Or use electrical tape lor
Hi Eng Hong
Just wondering the futurekit thing can provide variable V with 3A which is better than the one you show me that is only 5V with 1A?
If I need 2.5A that means the board you have is not enough, right? It will not power up my device that need 2.5A, right?
Just wondering the futurekit thing can provide variable V with 3A which is better than the one you show me that is only 5V with 1A?
If I need 2.5A that means the board you have is not enough, right? It will not power up my device that need 2.5A, right?
Max 2.8 said:
Its actually for an antenna. The diameter is approx the size of a earphone wire.
wantunn said:Not sure why you want to do this but you can buy cable sleeves in Sim Lim tower I think. If I remember you thread your wires through them (they look like black rubebr tubes and come in different diameters) and when heated (previously used soldering iron for this), they shrink and wrap their contents.
The thing is you must be able to pass the wires through them in the first place. With the earphone buds on one side and jack on the other it may/may not be possible.
Or use electrical tape lor
Must i use a soldering iron? I never use one before. :embrass: Hair dryer ok?
Max 2.8 said:
Erm did i show you one with 5V 1A?
Max 2.8 said:
Not necessary, it may powerup but it may die real fast. These circuits are built with latency of sometimes up to 25% so depending on the components.
Just read the 7805's datasheet. Its max output current only 0.5A so maybe you need to buy a readymade circuit, thses circuits make use of OP-Amps to amplify the current output. The circuit diagrams can actually be found online but its a headache to read.
If you are still not sure, you can go to some of the shops at Sim Lim tower. Some of the shop owners do do circuits for people, just let them know whta you need and bring along what you have.
Eng Hong
enghong17 said:Erm did i show you one with 5V 1A?
Not necessary, it may powerup but it may die real fast. These circuits are built with latency of sometimes up to 25% so depending on the components.
Just read the 7805's datasheet. Its max output current only 0.5A so maybe you need to buy a readymade circuit, thses circuits make use of OP-Amps to amplify the current output. The circuit diagrams can actually be found online but its a headache to read.
If you are still not sure, you can go to some of the shops at Sim Lim tower. Some of the shop owners do do circuits for people, just let them know whta you need and bring along what you have.
Eng Hong
7805 has many variants, the standard is 1A, 78M05 is 0.5A, there is also a 78H05 that can supply 5A and a 78T05 for 3A.
- Status
Similar threads
