Chainsaw's Simple 12V DIY Backup System

BnBob

chainsaw wrote:

Hi BB, I have 6 stones running off it, one in each tank 5 are IBC's and a 5000 Ltr round tank. I have since made a second one using different relay and power supply. The original still works fine.

Thanks Chainsaw...
Just looking as a 1000L set up so that size should be fine me thinks...

Off to Ebay & Jay car tomorrow...

ccBear

What model Ctek smart charger is recommended

Charlie

something like this bear

http://www.amazon.com/CTEK-Multi-7002-B ... B000FRLO9Y

helomech

I have this charger for my battery banks. It will do 3 seperate battery banks, and works with solar. It also runs as a converter to power 12 volt items. I have the 40 amp one, but you can also get a 24 volt one. It works great, completely automatic.

http://www.xantrex.com/power-products/b ... e-2-2.aspx

Charlie

whats it worth Helomech

helomech

I paid 300 for it. But I needed one that would charge 3 batteries, and would work with solar and only a couple fit that description. This one had great reviews, and I am very happy with it. I don't have any solar panels yet, so this is running all of my 12 volt pumps.

vk3laj

Just grab a solar panel, solar regulator and a deep cycle battery - then your batteries are constantly charged and ready to go with no mains draw

tcshad

Is it possible to have an AC pump running all the time and then when power fails have it switch over to a battery + inverter?

I can't figure out how you'd wire something like that up.

I'd like to get extra air in and also have it be a backup without having to buy 2 pumps.

werdna

Connect the air pump to a UPS

tcshad

I looked into the UPS stuff but you get maybe 1-2 hours runtime out of them whereas just running off a 12v car battery you can easily get 5+

werdna

Get a maintenance free car battery, take out the existing 7ah battery and replace with your new 80ah battery.

tcshad

It gets more complicated than that unfortunately because the UPS's are "smart" nowadays and get a bit confused when you swap out a battery like that. Also not sure if it would be able to charge a large battery like that effectively.

At least from what I was reading about getting extra power out of a UPS by switching out the battery on other forums.

I'd love some information/instructions to the contrary though.

werdna

I have done it before, however it was a few years ago now.
You do need to add cooling fans though, they arent really designed for long use.
But an air pump should be low draw.
Just buy a cheap ups off gumtree an try it, if it doesnt work, sell the ups again!

You can buy ups's with external battery pack inputs.

The other option is to run 12v from a plugpack into an inverter and have it connected to a relay so when power cuts the relay flicks the battery on, similar to the setup in this thread.
But you would want to use a power supply made to supply much more current than your expected draw. Inverters do not like ripple on the DC supply.
You could charge the 12v battery from the power supply with a current limiting circuit if you wanted as well. I could draw up a circuit if you are interested.

swittmann

Hmmm either the site was reloaded from a backup when it was down the other night or a bunch of messages got deleted.

My post was something like this.

I have the following parts and would like to connect them up somehow for use as a backup.
2x 10ah(20hr) 12v dry cell batteries
300w power inverter
6w air pump.

I don't really want to buy a dedicated 12v air pump how. How can i wire this up so it will switch between ac and dc when the power goes off?

LowCarbTNPer

You'll need a DPDT relay to switch between power from the wall and power from the inverter. Hook the NC side to the inverter and the NO side to mains power and the common terminals to your air pump.
You may want a 2nd relay as well to turn the inverter on/off depending on how much power it draws when there's no load. You could run both of them off the same wall wart if it has enough current to run them both.

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