Simple charge circuit for rechargeable battery 6V 4Ah ?

[SphinX]

Salam,

I have small system take it's power from wall dc adaptor .
The system power supply is regulated to 5V DC

I want to use a backup battery ( Reachargeable Battery 6V 4Ah)

I want my system work from the wall dc adaptor and in the same time charge the backup battery.

When the system power (wall dc adaptor) fails, the backup battery work automaticlly to maintain the system working.

Is there any simplest circuit do that ?

Note: My application is Time Attendance Machine using proximity cards.


Thanks very much

 

[Elavionic]

You must be most specific. Each type of batteries requery a different charger (lead, NiCd, NiH,...)- Never the less for charging any kind of battery, at 6 V, you need a supply greater than 6V, your 5V will not work.
The most simple circuit to backup power is a relay (On when power is present and Off for battery power). My advise, and if you have space, is to use a lead battery, just supply a constant voltage at the terminal and its done.

 

[SphinX]

Thanks Elavionic

I use Lead type Battery.
I use wall adaptor (+9 VDC) to supply my system (Regulated to +5V).

Can I charge the Lead Battery with 9VDC ?
I want when the system is fail, the battery automatically maintain the system working.

Do you have simple diagram to do that?

Thanks for your reply

 

[wisely77]

hi,

just to point out some issues, for hot swapping, relay may not function properly.

you see, mechanical is slow, so for the circuit to switching supply from one source to another source may cause suddently power lost.

what i suggest on this is using hot swap ic, like ma4271, max4272 or max4273 depend on your application.

as for the charging circuit, i think you may try here

http://www.myra-simon.com/bike/charger.html

hope this is useful

wisely

 

[fireplus]

hi,

you can search for UPS system (uninterrputal power supply)

go to www.epanorama.net a lot of information there.

bye


Fire in the Wire :sm2: