Using a stepdown transformer on a turbine
 

I have a windblue 540 low wind turbine. It does not produce a lot of amps. The most I see out of it is about 1-4 amps but when it is spinning the voltage at open circuit goes up to all 30V easily. It is a 3 phase wind turbine.
This is my theory:
Run the 3 phase through a stepdown transformer. And when it produce voltage like 30VAC for eg. the transformer step it down to about 14VAC while increasing the current at the output so you have a lower voltage but a higher current going to the battery. With this method i would have a higher current going to my battery at all times.
Would my theory work?

Lower voltage/higher current means more losses to resistance, but this isn't a problem if the distance is small. Also, your battery may not be able to take the higher amps, which means that you are either wasting energy (best case scenario) or damaging the battery (worst case).

Maybe you could wire a second battery in parallel to make a 24V system, instead of 12V? This would also eliminate any losses through the transformer.

the distance is short to the battery. I have the rectifier right next to the battery so as the AC is converted to DC it reaches the battery in a 4 feet run. And i dont think the battery will damage by the amp that will be going in it. It's a large deep cycle battery.

if i design a step down transformer that have for the output 15V whenever the turbine passes that amount on the VOC it will be step down to that 15V? So in that case the turbine wont be able to go to a much higher voltage before the step down process begin which would result in higher current???

I think I understand what you're trying to say here.

This will have to be a relayed connection of some sort so it only goes through the transformer when you have excess wind and power. If you're way under current for the battery this would be a better solution.

If your battery fills somewhat quickly, I may instead recommend a digital switch that starts charging a second battery in series when the voltage is that high. You can probably do that for about the same cost as an efficient 3 phase transformer (or 3 single phase transformers) to do the same thing.

Also keep in mind that the added inductance and resistance of the transformer on the AC load side may add some unwanted cogging effects to the turbine.

The trouble is, you have a "wind turbine" that is based off a car alternator that is designed for "low wind", amps times volts gives you watts, there is no way to get your watts higher without putting your "wind turbine" on a taller tower where it will see higher wind speed, so your real problem is that your wind turbine is putting out around 30 to 100 watts and is going to take a long time to store up enough energy to do any work.

Totally missed the output - Ryland is correct... it's going to take a substantial amount of time to charge your batteries with that output.

Creating a step down transformer with relay system will charge the battery twice as fast (ignoring losses) when engaged and if you're in a "because I can" type of mood, then by all means go for it.

It probably won't be cost-effective vs starting a 2nd build or (maybe) a build of a higher tower if that's your priority. I'd like to point out though that a "low wind" turbine may not have the alternator characteristics needed to produce more wattage in general though so a higher tower may result in a more constant upper range of 4 amps, but it may or may not go higher than that without furling or (worse) completely burning out.