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Old Oct 15, 2004, 4:54 AM   #1
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Greetings,

I'm considering building a 6 AA cell pack to plug into the DC-in of a portable CD burner to operate it in the field. Can i do this without risk to the unit or would it require special circuitry?

I'm hoping to find a Solar AA battery charger that will work to charge the Maha powerex 2300's up. I realize the smaller solar chargers will take a couple (few?) days, if they work at all, but it's my best option. Has anybody had success with them?

I talked to someone knowledgable about batteries and he shared that the NiMh batteries peak at abut 1.4V, so conservatively 6AA would be 8.4V. or, as they weaken...7.2V. The unit's rechargeable LiIon is rated for 7.4V. The AC adapter is rated for 9V. and the amps are less than the 2.3 A of the NiMh.

It seems like i'm in the range of workability, but i don't know that the units battery technology doesn't warn it of low power and avoid mid-burn crashes and such. I also don't know that the unit may need the internal battery to charge up in order to run off AC. In other words, it could be that i plug in the AA's to the DC-in and have the internal battery run them down, but not have enough power to function the unit.

Icould trial and error for the answer to that one. My main concern is the unit's well being.

Thanks,

Shawn







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Old Oct 15, 2004, 5:44 AM   #2
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Yes you can do it and your voltage is about right the only other thing is to get the polarity of the plug right. However, without battery charge level indication you may indeed run into a mid burn crash due to loss of power
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Old Oct 15, 2004, 9:09 AM   #3
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Well, I've made a couple of battery packs before and I've always aimed for the indicated voltage.

If you have a car, get a dc voltage adaptor. BUT MAKE SURE IT PROVIDES THE CORRECT AMOUNT OF CURRENT. Some adaptors provide varying currents, some as low as 200mAh. You need to read the adaptor instructions carefully. Also find out what the current and voltage rating is on the supplied / recommended dc adaptor.

Since it's 9 volts as you indicated, I'd go to 8 cells (9.6v). This pack will last much longer than 6 packs. If your squimish about the silght over-voltage, grab the recommended adaptor. Take a voltage reading and you'll find it slightly higher that 9 volts. I found this true to almost all of my equipment that uses power adaptors. The voltage drops when under load.

I just tested my scanner adaptor. It's rated at 24 volts 800mAh DC. The voltage I get is tested at 25.3 volts. Test out some of your equipment at home if you need to be absolutely sure.

You need to be absolute sure your dc voltage adpator is set to the right voltage and polarity. I fried a little cassette recorder when I forgot to check the voltage setting. It was rate for 3 volts and the adaptor was set at 12 volts.

You should read the instruction manual for the cd burner. It will tell you whether it cuts the power from the internal battery or not.

As for making one yourself, you can buy pre-made ones and an AC charger as well. These are packs made for RC cars and other toys. These are usually 9.6 volt packs. The only thing you will need to do it make a plug adaptor to go from your pack to your burner. The parts are availble and cheap (well, at RadioShack). The AC charger requires the original plug to charge the pack.

No matter the case, double and triple and quadruple check to make sure your voltage and polarity are correct. Then check a couple of more times.


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Old Oct 15, 2004, 9:15 AM   #4
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With memory cards dropping all the time, buy a (another)512 MB card. It'll be easier and faster and a heck of a lot more portable than carrying a cd burner and battery pack.

I talked to a friend who was taking a day long hiking trip. He described everyone taking digital cameras and laptops. The laptops were there to download pictures from the cameras when they reached capacity. This was just before prices dropped for memory cards. I purchased a 512 Mb SD card for 110$ Can. A month later I bought a 512 MB SD ultra II card for 99$. So think about just buying another card or two.
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Old Oct 23, 2004, 2:48 PM   #5
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Thanks,

Very helpful advice.

I ended up just buying the 6 and 8 pack battery holders with 9v style snap connectors. Looks like they'll work.
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