I have seen many 3.6V and 4.8V batteries but never 5.5V I think this is a super capacitor. They are common in short- term RAM backup applications.
Here is an example: http://www.solarbotics.com/pimg/5/image_large1/id808/jpg/CAP-CP047F001.jpg If your "battery" is marked with a XXXXX uF or X.XX F marking, you know its a super capacitor. If it can snap out, it is probably really a real battery. If its a supercap, its probably not faulty, it just can't hold charge for too many days, by design. Try reading the voltage of the supercap immediately after turning off the unit. It should be near 5.0v. The supercap is charged (probably through a limiting resistor) while the phone system is on. I suggest getting a 4-AA holder. Wire two silicon diodes in series with the + lead, to drop the 6.0V down to 4.8V and to protect against reverse current. You dont't want to hit the RAM with more than 5.0V. In fact, it might be a 3.3V RAM. If you measure 3.3V across the supercap while it is on, then you should just use 3 AA cells. Then wire that in parallel with the supercap. The AA cells will keep the supercap charged while the system is off, and the memory should stay up. You can probably even change the cells with no memory loss, because the supercap will be charged. Insert the AA cells while the system is ON to prevent an inrush of current into the supercap. I suspect fresh alkaline AA cells will last over a year here. I DON'T suggest using NiCd or NiMH cells, as they self-discharge too fast, and are only 1.2V each, and there is no charging circuit to charge them in the phone system (if it uses a supercap). Let me know what you think Joe Koberg joe at osoft dot us Support wrote: > I found the problem about my KX-T 616's previous issue with the > dialing out problem. > It is due to the PBX is reset after there's no electrical power for more than > 2 days. > > All of the programmed stuffs lost after there's no power for more than a day. > > So, I opened up the PBX and checked the battery soldered on the mainboard. > > It is written as 5.5V on the battery but when checked, it showed only 2.6~2.9 > mV on the display. > > Hence, I assume it is the battery problem and due to that case all of the > programmed stuffs are lost after there's no AC power for a couple of days. > > I was trying to find the replacement battery for that one but I cannot find > any similar one here. > > However I've got the 4.8V rechargeable battery but which is slightly larger > (about the double in size) than the original battery. > > Before replacing with that new battery, I want to get the suggestions and the > comments about replacing the builtin 5.5V battery on the KX-T 616 PBX. > > Kindly let me know whether it is OK to replace the 5.5V (not working) battery > with the 4.8V battery or should I connect that two in parallel due one is not > properly working and another one is less than it's needed volts. > > Another idea is I could use the AA or AAA size rechargeable 1.5V > batteries and put them in the new external battry socket. However it > would be just 4.5V with 3 batteries or 6V with 4 batteries. > So, I'm afraid of it could damage the system if over voltage or the system > won't funciton if with less voltage. > > I am living in Myanmar (Burma) where spare parts are hard to get > unless it is the common equipments. > Oversea orders are also very hard to take place unless somebody go out to at > least Bangkok or Singapore and get it. > > So, it is left with using the single 4.8 Volt battery or using of (3 > or 4) 1.5V AA/AAA size batteries. > And whether it should be used with the new battries alone or parallel with > that 5.5 volt builtin battery which is not working properly. > > Will be very much appreciate upon any suggestions and ideas. > > > > _________________________________________________________________ > KX-T Mailing list --- http://kxthelp.com/ > Subscription changes: http://kxthelp.com/mailman/listinfo/kxt > > > _________________________________________________________________ KX-T Mailing list --- http://kxthelp.com/ Subscription changes: http://kxthelp.com/mailman/listinfo/kxt
