Question regarding charging a lead acid battery

[arunbhaskar]

I've built a wind turbine using 3ph permanent magnet alternator. For the wind speeds I get near the installed turbine, the voltage range is from about 10 to 50V (DC voltage after rectification). I've purchased a 12V lead acid battery. So I'm really confused as to what method of charging I have to incorporate.

Can someone suggest the best method for charging the battery for the given conditions..??

Also, I need to know what are the range of DC voltages that can be directly applied across the battery without any current limiting resistor for a 12 V lead acid battery.

 

[smd_lover]

If you want high efficiency this is not simple.

For most Lead acid batteries maximum charging voltage is about 14V.
See the factory specs of the battery for precise info.

If you want to keep it simple you can build a 14V voltage regulator with a blocking diode behind it.

Have you got a brake system on the windturbine?

 

[arunbhaskar]

I don't have a braking system on the turbine.
Is it not possible to have a constant current charging using a high value inductance in series with the battery?

Can anyone please explain what methodology of charging will perfectly fit the given constraints?

 

[smd_lover]

A perfectly fit is a SMPS-buckregulator in combination with a MPPT algorithm to always get the maximum power out of the generator.
This is usually done with a microcontroller.
For 'braking' purposes you can add a dummyload to the system.

 

[srizbf]

nowadays there are "charge controllers" available for such application.

you may get one specifying your voltage and AH.

 

[pauloynski]

I don't have a braking system on the turbine.
Is it not possible to have a constant current charging using a high value inductance in series with the battery?

Can anyone please explain what methodology of charging will perfectly fit the given constraints?

If you have a large room to place the inductor it would be possible..... but stupid. Charging a battery is not only a matter of supplying a constant current. You need to sense when they enter the floating voltage region and stop it. Furthermore, you need to decrease the current when they approach this limit.
The best way to solve your problem is using a SEPIC (like the LT3724, google for more) switched mode power supply. Whit it you can buck/boost the voltage to keep it always inside your needs.
There is no simple solution: or you go complex or you´ll have to waste lots of energy.
Regards

 

[arunbhaskar]

Thank you all for the suggestions. I'll look into each of it and choose what best suits my requirements...