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I just recently realized that the reason that my robot is slower than calculated, could be the voltage loss in the l298n.
Is there any way to get rid of the voltage loss, is there a better h-bridge chip, or are they all pretty much the same?
The LMD18200 H-bridge is what you are looking for. It uses MOSFETs so it doesn't get really hot like the L298 (which uses bi-polar transistors and provides a significant voltage drop to the motor). It also has built in flyback diodes, so you don't need external diodes like with the L298. The disadvantage is that there is only 1 H-bridge per package, whereas the L298 has 2 (a dual H-bridge). This makes the L298 cheaper to use. Also 1V do you actually thank that will make a difference. Did your calculations take into account weight, fraction and that the rated RPM of your motors is for no load , so under load they will drop a considerably amount like 20-30%.
Hi,Quote from: Jak24 on October 30, 2010, 05:33:32 AMI just recently realized that the reason that my robot is slower than calculated, could be the voltage loss in the l298n.Easy to test - wire one of the motors around the L298 (i.e. let it get full speed) and compare.
However... Calculating the exact top speed of a vehicle is next to impossible unless ALL factors are known.
Quote from: Jak24 on October 30, 2010, 05:33:32 AMIs there any way to get rid of the voltage loss, is there a better h-bridge chip, or are they all pretty much the same?There are lots of better bridges, but did you consider a relay and a single power MOSFET per motor?
I tested it like that, i got about 15% more speed
Quote from: Soeren on October 31, 2010, 03:17:22 PMThere are lots of better bridges, but did you consider a relay and a single power MOSFET per motor?wouldn't that only allow the motor to turn in one direction?
There are lots of better bridges, but did you consider a relay and a single power MOSFET per motor?