diferent batteries connected in parallel

[snake21]

hi friends,i have a question concerning batteries.i have a small ametek 38vdc turbine which i am am using to charge a 100a/h 12v deepcycle battery.i was given a 200a/h 12v car battery which is in good working condition.

my question is,can i connect these 2 batteries in parallel to my wind turbine?

thanks

[joestue]

As long as the batteries are from the same family (lead-antimony plates, flooded and vented, 1.265 spc gravity = your typical car battery) then there is no problem. A gross generalization: the only difference between deep cycle and normal is the plate thickness.

[dnix71]

200 AH car battery? Automobile starting batteries are not rated in amp-hours. Reserve minutes or cranking amps maybe, but not AH.

Can you give us the make of car battery?

If it's a regular starting battery it won't last long unless you keep the voltage from going below 12.4. The plates are thin and sulfation that forms can't be shed without destroying the plates because they are thin.

Real deep cycle traction batteries also have more open space at the bottom for flakes and sludge so it doesn't short out the cell.

Of course in your case, free is free.

[Rover]

Short answer, yes you can do it
Long answer .. you may not want to

The battery differnces , even with Identical batteries (assumming fllooded, agm or gel) , based on age ififference s enough to be worrisome, your older ones will try to over charge and your newer ones will be undercharged. At some point you will rediuce the efficeincy and longevity of the entire bank.

Now.. with different capacity batterires and an age diference ... hmmm , without some mighty fine electronics in betwen to adjust charge/discharge rates (probably more costly than the battery) ...ok... but really not feasible

[snake21]

oki,thanks

[wooferhound]

I was under the impression that a car battery is 30-35 amphours ?