Transformer for 12V to 24V DC?

This is likely an electrical question more than anything else - sorry about that.
I have a 400W 12V Wind Turbine that I’d like to couple up to a small 24V solar off grid system I have on the property. The turbine manufacturer wants a fortune to rewind the unit so that option is a non starter. I had considered a DC to DC converter from Victron, not sure how to size the thing and would it even work just connected between the turbine and the battery?
I also have a bunch of old, but working, step up step down transformers, 110v to 240v. Could I use one of those to simply step up the voltage? I assume they “do” DC as well as AC? Or would it just short circuit?? I think i have one that’s 2000w. Any ideas? Thanks.

A Victron DC to DC converter would be the best option. Transformers need an alternating current (AC) to generate the magnetic field, they do not work with DC.

The conversion is pretty simple - 400W/12V = 33A. So you would need two of these in parallel - Victron Orion-Tr 12/24-15A (360W) Isolated DC-DC converter.

Although, in my experience, a 400W wind turbine will rarely, if ever generate close to 400W. You will be lucky to get 200W out of it.

Thanks Jason.
Agreed on the power output, not sure I’ve ever seen more than 15A / 180W max output.
I will try just one DC to DC unit, protect it with a 15A breaker, to cover that hurricane force day.
Cheers, appreciate the info.

There is no dc xformer to step up 12V DC to 24V DC, but only possible with AC Voltage. What you can do with your 400W 12V DC wind turbine to generate 24V DC is to get another same 400W 12V DC and connect both in series.
Total power= 800W
Total Voltage=V1+V2= 24V
From P=VI
then I=P/V=800/24= 33.3A