Friday, January 18, 2008

Kokam batteries on ebay


Kokam batteries are available on eBay. These are used in aero modelling and hence have good power.. they can be and have been tried on palm(see brighthand)

Seller: wwworadicalrcocom
This one costs- $34.95 (for 3!!)
Capacity: 2500mah Voltage: 3.7V nominal
Continuous Discharge Rate: 3C (2.5A)
Max Discharge Rate: 17.5C (17.5A)(Burst)
Dimension: 3 1/2" x 2 1/2" x 1/8"
Weight: 50.6g (1.8oz.) (each)
Combination: 3 single cells with solder tabs.
These batteries are good for any size motor up to S-400.

This punter is using Nokia batteries in Palm!

If they are li-ions then they already are the same type, regardless of brand or capacity. There is no problem using batteries of different brands or sizes. On one of my early mods I used the original palm battery internally and 3 nokia li-ions externally, and had no problems at all. Eventually I discarded the palm battery (because it was past useful life) and placed another nokia inside.

((Brighthand- Tungsten T3 - 7200 mAh battery modification... MONSTER POWER!!! ))


Brighthand.com Smartphone and PDA Discussion Forums > Device Suppliers > Palm > Retired Palm Units (click to view devices) > Tungsten T series
Tungsten T3 - 7200 mAh battery modification... MONSTER POWER!!!

Nokia battery will work in Palm!

If the external and internal batteries are connected in parallel, then the palm will "see" the whole pack as a single battery, and there is no reason why the internal battery should be discharged first, or why the voltage should drop and recover so dramatically, unless something is not working properly. You can expect some voltage variation after allowing the batteries to rest. For example, my 4-battery pack may gain about 0.03V to 0.06V (depending on usage) after powering off my T3 for a few minutes, but if the readings go from low voltage warning all the way to 4.1V then something is wrong with your mod.The fact that the voltage is dropping and then recovering at such levels may be due to several reasons, but there are two particular issues I have encountered during my battery mods, and you may want to look into them:- The internal battery may be past its useful life. If so, then it will present a higher resistance and higher self-discharge than the new ones, so the new ones will continuosly discharge into the old one, in an effort to keep the voltage at the proper level. This is potentially dangerous because nothing is controlling the rate at which the internal battery is being charged by the external ones, so there's no control over voltage or current. In this case you should discard the internal battery.- The connection between the batteries may be faulty.This happened to me in my first mod, the wires and connectors between the internal and external batteries had a high resistance due to faulty soldering and wrong choice of wire. In this case the battery pack would dissipate power across the connecting wires, and this would also lead to fluctuating voltage readings. In my mod the external batteries would charge and discharge at a different rate than the internal because the wires and connectors acted as a resistance connected across the terminals of the batteries. I had to replace connectors and do a better job at wiring to solve this.I recommend you to measure voltage across the connecting wires. Voltage drop should be zero during charge and use, anything above means the wires or connectors are faulty.