I need a help on selection of a battery. I have used 12v 2amp smps in my circuit with nema 17, 200step/revo., 1.7amp/phase to drive stepper motor i have used big easy driver(A4988 based).I need a help in light weight rechargeable battery selection with aprox. 8 hr backup capacity battery after fully charged.
can i use 12v 8800ah li ion battery ? will big easy driver capable for this input? what happen if i apply this input to big easy driver? And help me to find out circuit which automatically switch to battery supply when there is no 230v ac supply (There is no output from 12v 2amp smps). Help me to find out proper battery with long backup capability.

 

no such thing as a 12V Li-ion. They come in multiples of the single cell voltage - 3.7V nominal. That means 3.7, 7.4, 11.1, 14.8, ... The big easy uses the A4988 which can take up to 35V (though I'd stay at 24V or less).

What kind of a device are you powering? What are power requirements. Does it need to run continuously? Have you measured the current draw.

I would first look at a UPS before trying to build a battery backup system.

 

no such thing as a 12V Li-ion. They come in multiples of the single cell voltage - 3.7V nominal. That means 3.7, 7.4, 11.1, 14.8, ... The big easy uses the A4988 which can take up to 35V (though I'd stay at 24V or less).

What kind of a device are you powering? What are power requirements. Does it need to run continuously? Have you measured the current draw.

I would first look at a UPS before trying to build a battery backup system.

Thanks for reply. Battery is 11.1v 8800mah li ion.But my question is that is it ok that i will connect this battery to big easy driver with this high amp rated battery?I need to use this battery in syringe pump as a backup supply.I have used nema 17 motor with rating i have mentioned.And i have settled big easy driver for this maximum current ratting of nema 17

 

Amps are pulled by a device, volts are pushed. So, the big easy will only take what it needs. That's not a problem.

syringe - is this a life-safety thing?

 

no such thing as a 12V Li-ion. They come in multiples of the single cell voltage - 3.7V nominal. That means 3.7, 7.4, 11.1, 14.8, ... The big easy uses the A4988 which can take up to 35V (though I'd stay at 24V or less).

What kind of a device are you powering? What are power requirements. Does it need to run continuously? Have you measured the current draw.

I would first look at a UPS before trying to build a battery backup system.

I need to use this battery in syringe pump as a back up supply .current it will draw about 1.2 amp.But my is question is can i use li ion 11.1v 8800mah battery for longer backup?can i connect 8800mah rated battery to big easy driver ? means big easy driver work with 11.1v 8800mah li ion battery?

 

Amps are pulled by a device, volts are pushed. So, the big easy will only take what it needs. That's not a problem.

syringe - is this a life-safety thing?

Thanks for reply.Yes syringe is a life safety thing.And please suggest me what kind of battery with long backup capacity will i use?
supply requirement: V=12v and I= aprox.1.3amp

 

I won't give you recommendations on hacking together something for a life-safety application. That requires super high reliability. There is a lot of engineering and testing that goes into that kind of equipment and I am pretty sure you aren't up to the challenge. No disrespect meant, I just don't want to be a part of it.

Get a professionally designed backup system. There are lots of UPSs available that will give you a far better margin of safety than you can build yourself.