Switched mode power supplies

[purifier]

Can someone help me with the following:

1. What are switch mode power supplies and how are they used ?

2. How can they be used to charge a Lead-Acid Battery? say 12 V , 30 Amp Hours .

3. What are the requirements of the battery?what does the battery need? Is the batteries temperature a factor?

4. What circuits would you use to charge the battery?What current is usual to charge the battery?

5. How would you build a charger for such a battery using a switch mode power supply?

I would be pleased if someone could answer the above questions... Please help...

 

[fredsm]

There are numerous tutorials and explanations available
on the internet on SMPS. Google is your friend.

PWM chargers are becoming more and more popular.

Each battery family and type will have differing charge
curves. Capacity will determine charge rates.

The circuits used are determined by the end usage.
The more intelligent the charger, the more complex
it will be. It can be as simple as a tranformer and
diode, if the transformer is current limited.

There are some examples of analog and switching
chargers on my web site; the site is incomplete, and
there will be additions in the future which will include
modifying a PeeCee 200W supply to charge a lead-
acid battery up to 100 AH.

**broken link removed**

<als>

 

[ing_gcm]

Try to visit https://www.smps.us/, you'll find lot of literature about switched mode power supplies, from power supplies basics to advanced topics.

Rgds
ing_gcm

 

[epp]

4. Battery capacity is dependant of temperatue. Nominal temp in Europe is 20degC, and 25degC in USA. Higher the temperature the lower the capacity and lifetime (10 deg increase of temp -> 50% lifetime reduced). High temperatures could lead to thermal runaway which will destroy the blocks.

Regards.

 

[2borg]

Ok you must check some of book but in a global you must know characteristic of few basic type of converter .. after that you can decide what you need ...

bye!

 

[Apollo13]

A supply has input power and delivers ouput power, I hope thats okay.
Assume you need to generate 50V and 10A from a input supply of 100V. We could use a resistor devider or a linear regulator. You take in 100W and give out 500W. The rest 500W is wasted as heat. The problem is the heat generated. Leads to temperature increase and decreases reliablity of the converter. Also the cooling techonology has not developed as fast as as our community has worked in haet generation. To decrease this heating factor you go for SMPS design. You could theritically hit 100%.

Assume for a cell phone driven by Li-Ion battery (4.2V) driving a processor fabricated in 90nm (0.9v to 1v) better to use SMPS or a buck converter. Save battery power, less heat, better performance of other circuits.

This link is for batteries in portable world
**broken link removed**

Also visit Robert pease sit on national , in his ed design coloums he has an article on battery charging.

 

[omore]

At this time, guess you got the answer to your questions, anyway
at www.powerint.com and www.ti.com you can get a lot of info abt SMPS and also for battery charguers