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Topic: 24h power consuption and regulation --> 10W stepper (Read 158 times) previous topic - next topic

arnix

Hi to all.

I am using alum battery for last 2 years and am very pleased how this works.
There are bunch of infos on internet but shortly, this type of rechargeable battery
acts like super capacitor with much lower discharge rate.

OK.
I have 300W solar panel hooked up to 55Ah alum battery ( former lead acid car starter ) and with half sunny day, i can store enough power to run 30W load for the rest of the day ( night ). Of course, charging depends on bunch of situations but the main thing is that this battery type charges much quicker then standard lead acid one and i have test it mostly on cloudy weather. Btw. if necessary i can add another one.

Question:
I want to power my stepper motor electronics from this battery but the main thing is that i want to run it 24/7 so i need to have some regulator which will provide constant output for stepper motor driver and arduino. Let's say some battery management system. As you can guess, i would like to have constant stepper movement, without drops, until there is enough power. After power drops to lets say 9V, system should make automatic shutdown. When the power is restored everything starts from beginning. At 9V, there is enough power to run 30W for next hour or more.

The motor that am planning to use is a geared stepper 1.8 deg, 3A.
What would be the best solution for this ?

Arnix

knut_ny

Stepper driver (eg TB6600) can reduce current to minimum needed (depends on motor load). Reduce holding current to min.
A voltage divider (100k/33k, with a 1uF over the 33k) can be used for voltage monitoring.
To further save energi, use a stepdown (buck) converter for arduinos 4..5V supply (bypass the onboard regulator)
Ny

arnix

Hi !

Stepper driver:
- it looks we are on the same track :-). I have one stepper driver ready (9-40V).

Buck converter :
- ok, great idea.

I know its off topic but if you have some idea how to avoid standard pulse battery charger, that would be great. The problem with the one i have is that this one monitors the state of the battery ( as it it was lead acid one ) on the way that :

- if the battery is fully discharged or under 50%, charger start to charge with very low voltage ( around 3,5V ) and then it start to add voltage as the battery gets charged.

For alum battery this is not needed, because it can "accept" direct charge even if its fully discharged ( i have test it with 200W ) and there was no damage, whatsoever. So, in this case, this is lost time and of course, charging time is slower...

Anyways, if the load is connected all the time, there is no way that battery gets overcharged. But if it does, some simple cut off system can be added..


PaulRB

Why do you need a stepper motor? What is the motor driving?

Stepper motors are not efficient and waste a lot of power. If you can use a DC motor with gearbox, this is more efficient. You can still control direction and speed, and use an encoder to monitor speed and angle turned.

MarkT

Question:
I want to power my stepper motor electronics from this battery but the main thing is that i want to run it 24/7 so i need to have some regulator which will provide constant output for stepper motor driver and arduino.
Stepper motor drivers don't need constant output, they are inherently switch-mode.

The Arduino will need a buck converter or linear regulator (less efficient, less noisy).
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

arnix

HI guys.

Now that you mentioned, servo dc motor would be a better choice.
Do you have some suggestion for some 10W motor ?

A.

PaulRB

Now that you mentioned, servo dc motor would be a better choice.
I didn't mention servo. I mentioned a DC motor. They are not the same. I don't think you understand the differences between motor types and their advantages and disadvantages. I don't think you know what a "better choice" would be. We could help, but when I asked what the motor is for, you didn't reply.

arnix

Motor positioning is based on input from two external sensors.
Based on sensor triggering, motor will turn cca 40 degrees from last state.
This movement can is quite fast ( around 0,5 sec at 300 grams load ).

I need geared system and i need to know position of motor/gear shaft whole time.
So it must be some closed loop system. This is why i wrote that servo motor would be good choice.

A.
   

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