Could I charge my 12v 2.5A bike battery and car battery 12v 44A by just...

[Broz]

...connecting with a 12v 6A transformer.? Could I charge my 12v 2.5A bike battery and car battery 12v 44A by just connecting with a 12v 6A transformer of 12v 6Amp or I have to buy a specified charger?

Also,

I have a bicycle operated with battery of 24v, how can i charge this battery?
What if i use rectifier with my transformer to convert AC voltage into DC then would it be fine to charge my battery with this circuit?

 

[adaviel]

transformers use AC batteries use DC you will destroy the batteries. or maybe the transformer, with the car battery.

get a proper charger. there are good cheap smart chargers now. make sure it works for lead-acid (I presume the bike is also lead-acid)

for the bicycle, I guess you need a 24V charger. most lead-acid ones are 12V with maybe a switch for 6V. again, make sure it's for the right type of battery (NiMh, lead-acid, whatever)

 

[Billy]

Is the transformer like an electric train transformer. Is it12 volt dc? it will probably charge the 12 volt batteries, but probably not the 24 volt.