Recommendation of H-bridge

Community General Discussions
1

Hi awesome robotics enthusiatic people 

I'm in the need for a good reliable H-bridge for two projects, however I always like to buy something with the posibility of using it for an upgraded project, therefore I am interested in knowing if I can use a 25A conteniously Dual H-bridge when 
the motors I use only draw 5A each. or would I be better of picking a H-bridge with can support 5 or 10A?

I'll use an arduino Mega as microcontroller.

For project one; Will I be using two linear Actuators from Linak which runs on 24V and draws 5A each. 

The second project; Will be two 100W Motors for a robotic platform, both running at 24V and draws 5A each as well.

I bought a H-bridge on Ebay and used it with the actuators, which resultet in one of the transistors becomming so hot it melted the solder and the transistor fall off..

This was the model I bought:
http://www.ebay.co.uk/itm/3-36V-Dual-15A-H-Bridge-DC-Motor-Driver-30A-for-Robot-Arduino-Compatible-new-/121133655610?pt=LH_DefaultDomain_3&hash=item1c3420e63a


Now I am looking for a more reliable H - bridge, some of the one I've been looking at is:

https://www.robotshop.com/en/devantech-md22-24v-5a-dual-h-bridge.html

https://www.robotshop.com/en/dimension-engineering-sabertooth-2x25.html

https://www.robotshop.com/en/sabertooth-dual-regenerative-motor-driver.html

http://www.ebay.co.uk/itm/111008002913?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

http://www.ebay.co.uk/itm/121061024615?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

http://www.ebay.co.uk/itm/121061024617?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Any of these you can recommend me to buy or if you can direct me to a product you believe is better for me feel free, I'll highly appreciate it.

Also I need to buy a battery and was looking at this:
http://www.ebay.co.uk/itm/271841298368?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

However it says in the description:
Output current : 1 - 2.4A

Does this mean that the battery will not make it possible for the motors to draw 5A each? or will the battery be destroyed or will it just only provide less than half of the current the motors needs resulting in the motors only turning less efficiently?

Thank you, best regards

HitecPrimate 

2

Go for the highest you can

Go for the highest you can afford, an higher rated motor driver will be cooler, more reliable and less noisy. If it’s an overkill you can then try to scale down with cheaper drivers if necessary, but if you buy the lower rated first and burn them, you must buy a higher rated one:-) 

Get LiPo or NiMh for motors. Dumb batteries just burn or go flat under heavy load, batteries with protection circuitry like LiPo packs will shut off from overheating or over current. Check always the original description of the manifacturer, on e-bay often they are resellers.

3

Voltage
For H-Bridges, if you’re using a 24v battery, it depends on the battery chemistry to determine is’t maximum charge.

A freshly charged battery will always have a higher voltage than it says it does.

Sometimes a device (such as an h-bridge) will list a voltage as an “absolute maximum”. For example, the Sabertooth has 30v listed as an absolute maximum. I’m planning on using this on a robot with a 24v LiFePo4 chemistry. I have to do some testing to make sure I don’t melt the H-Bridge (they’re rather expensive). I’m not sure that 24v is enough for my intended use.

Good luck!

4

You might build up one, if

You might build up one, if you can etch smd boards.

you can use allegro a3941 or a similar chip to drive 4 mosfets. One allegro and 4 mosfets are going to drive one motor (or multiple motors connected in series or parallel) bidirectionally , so calculate the estimated price. That way, you determine the max. Current of your h bridge by changing the mosfets accordingly. There are some ready designs in different websites. 

And for batteries, LiPo is the best option I think. Be careful with them, though.

5

…

Thank you everyone, this have been helpful! :slight_smile:

I’ll later this weekend look for what I’ll buy of battery, charger and H-bridge and post it.

How do I pick the right charger? I’m thinking about buying one from E-bay - you can never get enough from ebay :slight_smile: