Arduino Forum

Using Arduino => Motors, Mechanics, Power and CNC => Topic started by: vj01 on Nov 18, 2014, 08:49 am

Title: L298n Motor Shield Voltage acceptance
Post by: vj01 on Nov 18, 2014, 08:49 am
Hi

i wanted to know if my shield can accept these volts and amps as i don't want to blow the board the voltage and amps for the battery are 7.2v and 800mah, i believe it will be ok but i wanted to double check

thank you
Title: Re: L298n Motor Shield Voltage acceptance
Post by: JimboZA on Nov 18, 2014, 11:03 am
Well mAh isn't an amp rating, it's a battery capacity, more a measure of energy than of power (if we take amps as an analog for power at fixed voltage, and ditto Ah as a measure of energy).

The real question I think you should ask is, can the battery supply enough current for your motors, which depends on the motors not the shield, and which you didn't mention.

You also need to consider the fact that a 298 drops a minimum of 2V, and that becomes almost 5V at higher currents, so is there enough left of your 7.2 to turn your motors?

That all said, the attached shot from the 298 datasheet tells you its maximum voltage and current.
Title: Re: L298n Motor Shield Voltage acceptance
Post by: Cactusface on Nov 18, 2014, 04:42 pm
Hi,
     800mA is not a lot to drive 2 motors, even simple motors can take 1A if stalled. Having said that My current bot runs on 2 x AA(14500) Li-ion cells giving me 7.4v at 1200mA and I get plenty of use out of them.

But I am using micro-motors that seem to be very effective with good speed. I have used the L293/298 a few times but the SN754410 is better, but both lose power in the output transistors, a FET based driver like the DRV8833/35 gives you that extra as almost nothing is lost acroos the FET.

Let us know how it goes. See my bots here: www.melsaunders.co.uk

Regards

Mel.