Home-made battery boxes/packs for portable DVD, DAP, flash device possible?

[adam917]

Is it possible to make a battery pack, where you put in AAA, AA, C, or D batteries, that will allow to portable DAP or DVD player to run longer? If not for the portable DVD player, than at least fot those flash and HDD devices that only use their own special batteries? I've heard of this being done by several MisticRiver users with their iRiver iHP-/H340, so I wondered if it could be expanded upon for portable DVD players and applied for DAPs/PMPs.

Thanks...

 

[RedLeader]

to put it simply.... yes. I actually did this for my old iPaq 3650. The battery was running down quickly, and instead of buying a $60 replacement battery, I bought some rechargable AAs, a little battery pack and a tip that fit the DC in on the unit. Check the voltage/amperage that your charger needs, and see how many batteries of what type you will need. It's not elegant, but it works.

 

[Jazper]

Quote:

Originally Posted by RedLeader to put it simply.... yes. I actually did this for my old iPaq 3650. The battery was running down quickly, and instead of buying a $60 replacement battery, I bought some rechargable AAs, a little battery pack and a tip that fit the DC in on the unit. Check the voltage/amperage that your charger needs, and see how many batteries of what type you will need. It's not elegant, but it works.

just make sure you put a diode on one of the wires, otherwise your DAP or ipaq battery may try to charge the batteries you are trying to use (if you use rechargables)

 

[adam917]

Quote:

Originally Posted by Jazper just make sure you put a diode on one of the wires, otherwise your DAP or ipaq battery may try to charge the batteries you are trying to use (if you use rechargables)

Oh yes, this is exactly something I was wondering about for a while. What is a diode and how do you instal it? How does it work? I certainly would not want one set of batteries trying to 'charge' another set.

 

[ATAT]

Diodes allow one way flow of current but not the other.. so if the potential is higher on one side it blocks but allows on the other.

Just grab one from ratshack and put it inline with your charger in the correct polarization...

NB - Alkaline batteries rated for 1.5 are actually 1.7 so if you have 24 volts in 1.5 you actually get 27 volts or so.. that might be bad so do this
Get a higher voltage i.e. 30 volts if charges at 24 .etc and get a zener, put it in parallel with source, put a diode in series to prevent backflow and plug it in..
Should work pretty well

Tatsu

 

[Jazper]

Quote:

Originally Posted by ATAT Diodes allow one way flow of current but not the other.. so if the potential is higher on one side it blocks but allows on the other. Tatsu

I couldn't have said it better myself

 

[adam917]

Quote:

Originally Posted by Jazper I couldn't have said it better myself

OK. Thanks...

 

[SiBurning]

Great idea. The diode is useful if the voltages work out. Been thinking of asking for better ideas on the DIY section. There are some low voltage drop regulators and dc-to-dc converters, but everything has tradeoffs.

I've rigged up several of these gizmos. My most current (pun intended) job charges my DAP. It's made of 3 parts from ratshack. (1) A holder for 4 AA batteries with a 9V plug, one of their (2) heavy duty 9V plugs & wires, and solder the leads to the right size (3) DC adapter. Also added a piece of shrink wrap tubing to keep the wires from contacting. The DAP takes 5VDC, so 4 rechargeables is just about right.

A diode has two terminals and one end has a line on it. The symbol for a diode is >| where the arrow (which should be a solid triangle) points in the direction of current, from positive toward negative. The line mark on the diode matches the vertical line in the symbol, so that end attaches to the negative or black lead.

 

[firefox360]

I have one that suppose to recharge my iPod, but seems like the mAH of the 9v is too low of a ratio for it, so instead it just acts as part of the battery to the iPod. I connected a 9v battery to an on-off switch which is then connected to a 5v Regulator (Motorola brand, although there are alot of others). From there it's connected to 2 LED's to serve as a diode, then that is connected to a female USB jack. Remember that the maximum specs that USB accepts is 5v.

 

[SiBurning]

Quote:

Originally Posted by firefox360 I have one that suppose to recharge my iPod, but seems like the mAH of the 9v is too low of a ratio for it, so instead it just acts as part of the battery to the iPod. I connected a 9v battery to an on-off switch which is then connected to a 5v Regulator (Motorola brand, although there are alot of others). From there it's connected to 2 LED's to serve as a diode, then that is connected to a female USB jack. Remember that the maximum specs that USB accepts is 5v.

Could be.

There's a limit to how much current you can draw from any cell. I forget and I'm too lazy to spend more than 10 minutes searching. Let's say the limit is between 20% and 80% of the rating. Example: at 40%, a 200mAh cell can push 80 mA maximum current. The wall wart that came with my DAP is rated for 5VDC @ 2A. While I doubt it needs that much, I do plan on rigging something to measure the current coming off the battery when it's charging and playing. Meanwhile, as long as the batteries stay cool, I'm happy.

Two LEDs? Could be a drop as much as 1.4V giving only 3.6V at the usb.

 

[rab10]

There are plenty of resources with step by steps on how to make your own home made battery boxes for portable gear. Just follow the steps and modify the design to fit your portable's specifications. However, becareful with Voltages and polarity.

Here a couple of links:

How-to make a ‘usb battery’
http://portableaudio.hackaday.com/en...4000520028239/

Altoids Battery Pack (Detailed Guide, specific for iRiver iHP-1xx/H3xx mp3 players)
http://www.misticriver.net/showthrea...=battery+packs

Ipod altoids battery pack v2
http://www.hackaday.com/entry/2645310329796286/

IPod - Battery Pack
http://drewperry.co.uk/index.php?cat=1&page=1

DIY Playstation Portable Usb Charger
http://www.angelfire.com/games5/dsre...sb/pspusb.html

DIY USB Power Cable for Sidekick
http://home.earthlink.net/~gregston/sidekick_usb_power/

Instructions on how to make a USB On The Go cable/box, Charger, for the iriver H320 / H340: http://reality.sgi.com/sawson/h320/

LiPoly BatteryPack:
http://www.misticriver.net/showthrea...=battery+packs

Battery Pack Discussions:
http://www.misticriver.net/showthrea...=battery+packs

 

[firefox360]

Quote:

Originally Posted by SiBurning Two LEDs? Could be a drop as much as 1.4V giving only 3.6V at the usb.

Nope The LEDs I have are, I'm guessing (no label on the packaging), rated at 2.5v each. So with one it would burn itself out. Plus the way I have them wired up, I get the full 5v at the USB jack. Here's a simple diagram of how I wired the LED's up:

---- USB ----
+___________-
|___________|
|___________|
- LED +- LED +
|___________|
|___________|
+___________-
----- 5V ----

Not sure if the polarity for the LED's are correct. Just tried and tried 'till they worked.

 

[Phil Ramsay]

Making an external battery pack for iPods can be fairly straight-forward, and can be very useful.

I've got a link to a photo of one I made in my sig.

There have been some good threads on the details of how to do it (try search on external battery).

Most devices should be similarly easy to build for.

 

[ATAT]

Hmm.. thought expriment.. how about extending one of these to be a laptop battery? there's nothing fundamentally different about laptop charging compared to portables and laptop batteries are EXPENSIVE.. perhaps this is an untapped market of sorts?

 

[nph134]

Quote:

Originally Posted by adam917 Is it possible to make a battery pack, where you put in AAA, AA, C, or D batteries, that will allow to portable DAP or DVD player to run longer? If not for the portable DVD player, than at least fot those flash and HDD devices that only use their own special batteries? I've heard of this being done by several MisticRiver users with their iRiver iHP-/H340, so I wondered if it could be expanded upon for portable DVD players and applied for DAPs/PMPs. Thanks...

some players already have that when u buy em, like the sony d-ne20 for example