Making A Battery Pack..help Needed...

[daveyfontan]

Hi Guys.
I want to design a battery pack with a high capacity Mah Rating.
Making the battery box to go on the back of the GP32 is no problem.
I know i need a 3 volt input.
What i need to know is this:

If i was to conect more than 2 NIMH batteries but in SERIES , so that the voltage is STILL 3 VOLT , but the MAH is higher , does it just mean my GP32 will run for much longer or will the extra MAH or Amp Hour rating effect the voltage or GP32 in any way.
I really dont want to blow the BLU but am keen to make a large clipon battery pack for trips etc.
I can get batteries in SERIES to have an OUTPUT of 3 VOLTS ...BUT will the Mah rating of say 96 Mah or 9.6 Ah cause any damage to the GP32.
I don,t think it will as the voltage is still only 3 volts.
My understanding is that the Mah ONLY relates to how long the battery will last between charges.
Can anyone tell me if i,m right...???

I,m working on a 6 - 10 cell thesis with a charged life of up to 18 > 30 hours BETWEEN charges...Will be good if it works.
PLUS it will just clip in place of the battery cover...
If CraigX or any of you tech guys can advise me , it would be appreciated.
If i can do this then i will publish the results and share it with the community.
If it comes to it , i,ll use my FLU as the Guinea Pig..
Thanks Everyone.
Davey Fontan.
Original Mystic Ninja. h34r:

 

[0-bake]

hm, i'm not sure, if i remember correctly, but i think you have to add the batteries in parallel way, to keep the voltage at 3V and raise power. in series, the voltage will raise and the power will stay constant.
but i'm not sure, if i remeber it correctly....and btw, it's called mAh (milli Ampere hours), just looks a bit confusing

but my question is: how do you carry a 10 batteries pack? it's quiet a lot and a bit heavy. or do you carry it in your pocket and just have a wire to the gp?

 

[NiN^_^NiN]

PARALLEL gives u more Mah series gives u higher volts

go here http://www.doomportables.org/batteries.html

part of the site im with we make handheld snes nes etc.

have a check it will give u diagrams on how to put batteries in series and parallel

h34r:

 

[Vimacs]

dont put rechargeables in paralel, they will kill each other

 

[echidna]

that just my opinion, but i think that you cannot make your battery pack without making an electronic schematic to protect the GP32. Because It's not designed to take a lot more than 3V - 100mA.

Think about it.

 

[NiN^_^NiN]

It's not designed to take a lot more than 3V - 100mA.

Where did u ever hear that from :blink:

The gp32 uses 3v 300mA standard

i use a wall adapter at 500mA

some people use it at 1000mA / 1amp

but your getting your wires crossed

A wall adapter outputs so a set mA

but batteries dont output 2000mA if thats what you have the device will get the mA it needs.

say he has 3v at 4000mA the batteries wont put 4000mA into the gp32 the gp32 will suck 400mA or so out of the batteries depending how much it wants.

unlike wall adapters it only provides how much the device ask from the batteries.

hope this clears it up

h34r:

 

[spongebue]

here's something that goes with Nin's site that will go on once Abbibi (the owner) updates his site: http://benheck.com/ipw-web/bulletin/bb/viewtopic.php?t=90

It should be the 8th post down

 

[daveyfontan]

Thanks for the info Guys.
I meant PARALLEL and not series.
Ok....
I don't see how more than 100 ma would harm a GP32 when i use 500ma Power Supply and have done for ages on the FLU...
Surely the GP32 will only take what it needs.
And i would think the GP32 has its own electronics to deal with amperage going in.
Don't think i need any extra electronics on the battery pack.
I have no problems running my Zodiac on a very high wattage power supply...Usually used to drive heaters and hairdryers even though its suggested using only up to 50 watts.
No problem there then.
Just look at the 2 x 2300 mah rechargables i,m using at the moment.

The thing i don't understand is WHY can't i connect rechargables in PARALLEL.
Why is that?? Will they kill each other...Its not a real problem but i would prefer to use rechargables.
Thanks...
Davey Fontan...
Original Mystical Ninja... h34r:

 

[daveyfontan]

I also Understand that AMP are DRAWN and not pushed so if thats the case then higher amperages would not cause any kind of damage as the device will only TAKE what it wants.
Makes sense when i think of the power supplys i have run my gameboys , gamegears etc etc on and they never seemed to suffer any damage due to the output of the power supply as long as the voltage and polarity were spot on.
Davey Fontan...
Original Mystical Ninja... h34r:

 

[Tristan]

Ok, let me just clear this up with some boring electronics formula's, and explanation. The formula you want is U = I * R. Which means voltage equals amperage times resistance. Let's change this formula. I = U / R, this means amperage equals voltage divided by resistance. Seeing as the voltage is always the same (3v), the only things that change are the resistance and the amperage. When a system needs more power to do stuff, the resistance will drop. And when the resistance drops, the I (or amperage) rises. That's why when you plug a 50W lightbulb in your wallsocket it doesn't shine as bright as a 200W lightbulb, even though they have the same power at their disposal.

So, long story short: It doesn't matter how much mAh you have.

The thing you want to be worrying about is the fact that the rechargables need to be charged EXACTLY the same, because else they will be discharging into each other.

 

[chris_r]

Why not just carry an extra pair of batteries round with you? I bought 4 NiMH and I charge 2 of them while Im using the other 2.

 

[daveyfontan]

Thanks for the info Tristan regarding the maths and rechargeables problem.
I guess with normal Duracells etc its not a problem as it would be with rechargables.
As for carry the spare set of batteries Chris , i do that but i sometimes spend days in hospital and i can,t always take / use the charger so a longer lasting battery pack would be great.
I spend hours on my GP32 when in hosp as its so boring etc so after about 6 hours i need a fresh set.
I,m hoping to join 10 in parallel and they should last for at least 30 hours...(I think)

Davey Fontan...
Original Mystical Ninja... h34r: