what hbridge will work

I doubt it would fail due to under powering also but thought it could be a possibility!

How many amps will a 12 vdc wiper motor draw? does any body know. Is there a way that I can measure the amperage with a multi meter? And could not having my ground isolated cause my monster board to go bad?
Terry W.

To measure your current while feeded with PWM, you need a "true rms" multimeter.
Best has got "max" and "mean" values!

Has I haven't such a device, I don't know the answer...

I found with wipers they car draw a lot of power. I used wipers from larger cars in the beginning and I had set my max current in the JRK at 23 amps, but the motors could have been pushed a lot harder.
Normally we run the motors at stall current, which is usually 2.5 - 3 times the rated current. But they can drain more if worked hard enough.
To actually measure a draw of current in motion, you could put a shunt across the power line and get an average reading from a multimeter.

Hi Terry
My one motor from nissan micra drain 6 - 7 amps . Overall per four motors i have 20 - 28 amps in very hard moments . So it's not so much .I would say that wiper motors can drain something from 6 to 10 amps . I using cheap power supply from PC 750 w . It's enough to keep my sim in running. So ,you can count how much power you need for your needs . Take maximum of power 10 amps . if you have four motors it's 40 amps on 12 volts . 480 watts of power supply ,But its theoretical only ! allways take more 30 - 50 % so , should be 600-900w power supply for 40 amps.
If you gonna use motors on metal frame you have to isolate motors ground ,if will not ,it can cause motor drive damage , but if frame is wooden you can leave how it is .

Hello Auryza, Thanks for the information. I will purchase a PS that will give me that power.
Terry W.

if you only need a rough approximation:
take not less than 47A @12V for 2 smolka motors
it's fine but the limit is close!