How to Automatically Switch 12V 6A Fan Between Power Supply and Battery Backup?

33 6

#1 21672271 04 Sep 2014 17:56

Piotr Marciszewski Piotr Marciszewski

Anonymous

Post #1
21672271 04 Sep 2014 17:56

Hi everyone,

I apologize for the basic nature of this question. I am trying to create the following circuit, I was hoping someone on this site would be able to help draw it out.

I want to run a 12V (6.0 amp) fan with a 12V power source, with the option to run it off of a battery. So when the power source is plugged in, the battery is not used, but when you unplug it it automatically draws from the battery and vice versa.

Thanks in advance!

-Peter
ADVERTISEMENT
#2 21672272 04 Sep 2014 18:16

John Schmitz John Schmitz

Anonymous

Post #2
21672272 04 Sep 2014 18:16

What type of battery is it?
Could the power source be used to charge the battery?
ADVERTISEMENT
#3 21672273 04 Sep 2014 18:21

Piotr Marciszewski Piotr Marciszewski

Anonymous

Post #3
21672273 04 Sep 2014 18:21

I don't know what type of battery yet to be honest. I was thinking two 9v with some resistors to bring it down to 12, but ideally some form of rechargeable that yes can be recharged while plugged into the power source.

though i guess that adds another level of complexity as there would have to be something that controls the recharge rate and sever the charge when battery is at capacity??
ADVERTISEMENT
#4 21672274 04 Sep 2014 19:11

John Schmitz John Schmitz

Anonymous

Post #4
21672274 04 Sep 2014 19:11

A 12v lead acid battery ( like a car battery ) would be simplest. Buy a 10 amp smart charger/ maintainer and leave it on the battery. Then you don't need to switch power sources when the charger is unplugged. A smart charger will protect the battery from over charging.

A charger like this and a wet or gel cell lead acid battery should work

"Charger()":http://www.marinco.com/en/~/media/inriver/311103-6344.pdf
#5 21672275 04 Sep 2014 19:38

Piotr Marciszewski Piotr Marciszewski

Anonymous

Post #5
21672275 04 Sep 2014 19:38

ok - can you help me draw out the circuit? basically this whole circuit with the fan must be portable and the main power source will be 12v motorcycle battery (which will be hardwired from battery). With battery backup has to be small 9V the biggest.
ADVERTISEMENT
#6 21672276 05 Sep 2014 06:11

John Schmitz John Schmitz

Anonymous

Post #6
21672276 05 Sep 2014 06:11

Your request is confusing, draw out a circuit for what you have and maybe I can help.
#7 21672277 10 Sep 2014 23:49

Blake Kopachena Blake Kopachena

Anonymous

Post #7
21672277 10 Sep 2014 23:49

You could have a relay used as a disconnect so that when current flows from power source through a coil allowing a normally closed contact to open prohibiting current from flowing from the battery. You may however have two sources for a few milliseconds during the switching.
Create an account, log in here. You will receive points by participating in discussions.
Join this discussion.

Install Elektroda application

Didn't find an answer? Ask Artificial Intelligence

*I agree to send the question to OpenAI, Anthropic PBC, Perplexity AI, Inc., Kagi Inc., Google LLC - owners of language models in order to prepare the best response. The companies may monitor and log information entered into the form.

*I agree to publicly display my question and answer. The question and answer will be publicly available to everyone. The process may take a few minutes. Upon completion, you will be redirected to the page with the answer.

Wait...(2min)

Topic summary

The discussion addresses designing a circuit to power a 12V, 6A fan from a primary 12V power source with an automatic switch to a battery backup when the main power is disconnected. The user considers using two 9V batteries with resistors to achieve 12V but acknowledges the complexity of charging and regulating rechargeable batteries. A simpler solution proposed is using a 12V lead acid battery with a 10A smart charger/maintainer to allow continuous charging and prevent overcharging without manual switching. For automatic switching, a relay can be employed to disconnect the battery when the main power is present, though brief overlap of power sources during switching may occur. The main power source is intended to be a 12V motorcycle battery, and the backup battery should be compact, ideally a 9V rechargeable. The circuit must be portable and capable of managing charging and power source selection effectively.
Summary generated by the language model.

How to Automatically Switch 12V 6A Fan Between Power Supply and Battery Backup?

Didn't find an answer? Ask Artificial Intelligence

Topic summary