Transformer Design

Go to your nearest automotive parts store and just buy a common 12 volt one.

You will be time and money ahead guaranteed.

Cannot really give you a GA for this as a 150Ah battery is likely going to be a sealed lead acid type rather than a lead acid car battery (which has a lower Ah rating) and I have not seen an automotive store that sells smart (SLA) battery chargers for this chemistry and battery size (normally they only sell ones that will charge up to say 25Ah sealed lead acid).

A solar distributor would be a better bet.

It sounds like you want a battery charger for charging a large (sealed lead acid perhaps) battery.

You can either buy a complete battery charger suitable for charging 150Ah batteries at a local supplier (for example at a solar equipment supplier may have something this large), or alternatively if you want to build your own (possibly to save money) then just buy a transformer off the shelf at your local electrical supplier.

It is not advisable to wind your own transformers without a good electrical knowledge and a suitable transformer kitset (which can be purchased) as there are serious safety concerns along with the fact that unless you build it correctly your transformer won't produce a suitable output for your battery charger.

Do you have a design (or off-the-shelf product) for your battery charger circuit as the transformer will need to be suitable to match it?

Dear friend

Please Purchase 220 V/12 V- 2A Branded make Transformer and used