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Lead acid charging circuit for photovoltaic system

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Newbie level 4
Jan 21, 2006
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lead acid charger circuit

I'm going to make a charger for lead acid with PV panel as supply.
My panel is about 50 W, max 21 V and max 2.5 A.

I need regulator or DC/DC converter. I think using adjustable regulator IC would be easier than using PWM buck converter IC. Is this true?

If I use PWM buck converter IC, I still need mosfet for switching right?
I've seen some mosfet, but its power consumption is quite high. Is there any low power mosfet?

I'been surveid the component I need for adjustable I can use LM350. If I use adjusable voltage regulator IC, do I still need current regulator?

My problem right now is searching for the component. I need IC/component that are commonly used and easy to find either for ADJUSTABLE REGULATOR and for PWM BUCK converter IC and mosfet. Could anyone help me to tell some?
I'm going to purchase these components soo.


Yes LM350 is fine, yes you need current regulation..

It's been done by in this site.

**broken link removed**

Thank you,

at this point I've been using LM350 to make a 7,4 V regulator for 6V VRLA battery. I use constant voltage charging method. But I don't how to limit the current while I also want to regulate the voltage at the same time.


Most lead-acid batteries can be charged with a constant voltage. For a 12V the best way is the standby method, or between 13.5 and 13.8 volts, for average room temperatue of 68°F. Depending on the size current limiting may be necessary. I would put a diode between the charger and the battery, this prevents the battery from feeding current back into the regulator when the solar charger is not producing voltage.

My experiance of photovoltaic panels are they very realy able to produce there maximum output specs. Half of that current would be more lickly. Also the quolity of the panel must be considered. They either fail compleatly or give very little output. ( Make sure you check your guaranty).

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