help me

[denatra]

Hi guys....
Would you please help me?
How to make Battery charger circuit
For wireless phone
The output 9V 350 mA
Because where I live the electricity go out frequently
We have only 12V 4Ah (battery) in our market
Do you have any suggestion?

Thank you

 

[rjvh]

hi I don't know where you live but a 4Ah battery is not realy a big power source
(My motorbike battery is bigger)

as it is for a cordless phone I think the batterys are normal rechargeble baterys (nicads)

can you give some more details please

Robert-Jan

 

[Sceadwian]

For a wireless phone 4Ah is huge. But 9 volts? That seems odd, all modern cell phones use a single lithium cell. More details are definitely in order.

 

[blueroomelectronics]

Wouldn't the phone include a charger?

 

[rjvh]

For a wireless phone 4Ah is huge. But 9 volts? That seems odd, all modern cell phones use a single lithium cell. More details are definitely in order.

I dont think its a cell phone but one of those around house phnones with a reach of 200 meter max

i asumed that the poster runs from batery power as the mains drops out and so want to recharge the device batery from a 12Volt power

pretty comon here in cambodia
a lot of people still have there electrics running on car baterys and they are a bit bigger than 4 Ah

Robert-Jan

 

[Sceadwian]

Rules with cordless phones as far as I'm concerned.
If it doesn't use NiMhs throw it out, NiCad cordless phones are based on stupid chargers and short constant recharging of a NiCad will cause the memory effect especially on a cordless phone usage basis (short discharge constant charge). NiMhs with a smart charger are best, and by smart I mean smart user as well, we don't put our NiMh units on the base unless they're 1 bar for the battery. The set we have is going on two years and not the slightest sign of decreased battery life (3-4 days off the charger) 2-4 hours talk time. Every other NiCad handset I've ever used has barely lasted a year before capacity decrease.

 

[Hero999]

You probably don't need a charger, a simple 9V power supply using the LM317 will probably do.

Alternatively, it might even work from 8V so an LM7808 might work.

 

[mountain87]

Hi guys, i'm a new remember. a later time you help me please.OK?

 

[audioguru]

The base station of my cordless home phones don't have a rechargeable battery so they don't work when the power fails.

 

[mountain87]

hi every body! i'm finding about Led Matrix. Can someone help me? Please and thank you very much!

 

[Hero999]

What exactly do you want help with?

 

[denatra]

Hi guys
Dear Robert-Jan
The phone is Panasonic model NO.KX-TC1743B (cordless phone)
it use external adapter the input is 220v 50 Hz
The out put is 9v 350mA so it charges the batteries in hand set but if there is
A failure in power source the phone will not work (receive or send calls)
The base unit will not communicate with hand set
so all I want to do is to make circuit To charge External Battery at the same time to make it work maximum 4 hours

Best regards
Danny

 

[Boncuk]

Alternatively, it might even work from 8V so an LM7808 might work.

... another alternative would be using an LM7809.

 

[rjvh]

Hi guys
Dear Robert-Jan
The phone is Panasonic model NO.KX-TC1743B (cordless phone)
it use external adapter the input is 220v 50 Hz
The out put is 9v 350mA so it charges the batteries in hand set but if there is
A failure in power source the phone will not work (receive or send calls)
The base unit will not communicate with hand set
so all I want to do is to make circuit To charge External Battery at the same time to make it work maximum 4 hours

Best regards
Danny

Hi Danny

your cordles phone is charged in the base set and the base set is powerd only with a external adapter that gives 9 volt

so if the power drops than your base set will be dead (as it have no back up ) and your mobile part is dstill working but it stops at your base set

in that case i think that the batterys that you buy at the market are more than enough to keep it going for 4 hours
the only thing what you have to do is bring the voltage down from the 12volt of the battery to 9 volt

as boncuk wrote it needs only a LM7809 (and surounding parts) to do that

at the suplying side (for the battery) you need a battery charger

in the schematic I post you see a cheap to build and simple charger /conditioner

the gost diode (doted one) is only to adjust the zener voltage as zener diodes do have a high tolerance level

they can differ easy 10% from the printed value on the component
every diode (poarity importand) will ad an 0.6 a 0.7 V on top of the value

of course you can look on the internet for different schematics as they are many out there

sucses building it
Robert-jan

 

[audioguru]

Hi Robert-Jan,
A battery is only partially charged when its voltage reaches a certain level. The battery current and its voltage determines when it is fully charged.

Many products that use a rechargeable battery have the battery being trickle-charged all the time. Then the power supply powers the product and trickle-charges the battery at the same time without switching.

The voltage of your zener diode varies significantly because it does not have enough current in your circuit. Add a resistor from the base of the BC547 to the negative of the battery.

 

[rjvh]

Hi Robert-Jan,
A battery is only partially charged when its voltage reaches a certain level. The battery current and its voltage determines when it is fully charged.

Many products that use a rechargeable battery have the battery being trickle-charged all the time. Then the power supply powers the product and trickle-charges the battery at the same time without switching.

The voltage of your zener diode varies significantly because it does not have enough current in your circuit. Add a resistor from the base of the BC547 to the negative of the battery.

Thanks for your coment I can only agree with you

Robert-Jan