Backyard Aquaponics
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Only that 12 v pumps are terribly unreliable. There are inverter charger combos with automatic transfer switches. That means that while there is grid power, the batteries charge and the outlets run off of said power, then when the power fails, it automatically kicks on the inverter and powers the outlets itself.

I was looking at a number of 12v pumps and was told that they are not continuously rated. If you run them continuously they die pretty quick apparently.

Thats what I'm doing at the moment - Pump has been running for about 7 weeks to date so will see how it goes. Its a brushless type - pulling water from mid tank via one of the big black sponge filters to try and stop solids blocking the pump.

Hi guys, thanks for enlightening me with all this info. But i still have couple of questions. First, i did not notice mentioning anywhere how to attach 2 devices on one battery via relay, that is 12V water pump (something like this: http://www.ebay.com/itm/NEW-12V-DC-Micr ... 5404223306) and 12V airpump (something like this: http://www.ebay.com/itm/DC-12V-70L-Min- ... 43b3ea7682).

I am asking, because i would like to have backup system which will replace the "on-grid"-one 100%. If power goes off, i dont want to just switch to the airpump...i need the water pump to continuously pumping to GBs as well, just like nothing happened. Is this even possible with 1 relay or you need 2 of them?
I have four 6V 180Ah wet cell batteries (deep cycle). I connected them in parallel (2) and in series (2) to get 12V and 360Ah.

The second concern relates to the bateries and smart charger that i have. Do you think i have to charge them all separately or can i do it all at once, considering that automatic smart charger will do his job?

Brushless 12v pumps are very reliable, it's the cheap bilge style pumps that are rubbish.

You can just connect the two devices in parallel if you want them both to operate at the same time.

My first brushlesss pump lasted abuot 4 months - still worked though something must have gone wrong with the electronics as it was drawing twice the power and producing half the flow. It did run at low voltage at one point in time so that may have upset it. Its replacement has been going for about 3 months now.

I'm using a old laptop power supply through a $3 dc/dc converter to float charge a battery. From the battery I have a low voltage cut out relay connected to a timer which supplies the pump, so the pump will not pull the battery too low.

I second Torcz's question. Why would we need a 100 amp relay to run a pump pulling less than 10 amps? Wouldn't a 30 amp automotive relay do the job just as well for far less dollars?

Great thread, by the way. Good to get the heads up on some dodgy work being sold for big bucks and most input is really constructive.

I have one of those 38 Lpm air pumps I am going to set up on a battery backup system. I also have some brushless 12v water pumps I will muck around with using a venturi for aeration. Should be interesting.

Does anyone know a discussion which covers required water flows for venturi aeration? The search function is not working for me.

I think i will rather go with UPS who can charge batteries at the same time (float or full charge). Output is pure sine wave, so no need to plug any inverters or dealing with DC pumps. As long as there is electricity from main grid, AC pumps runs normally. When power goes off, power from batteries kicks in and supply the pumps with AC current. Brilliant!

I bought it online for 110 EUR, which i found very cheap, if you compare it with all the costs you have when you go with new DC pump, inverter, relay...And it is not so complicated with all the wires and stuff...

I could post you link to the page where i bought it, but its in slovenian language, so it will not help you a lot, so i am giving you the link of the Alibaba page, just to get the picture:
http://staba.en.alibaba.com/product/142 ... utput.html

Anyway, I will post pictures of the backup system soon.

My biggest concern with UPS's stems back from computer tinkering days (a while ago...) when UPS failed neither battery backup nor mains power got through so you may think power was restored but in reality you have just performed mass euthanasia. Could also be something else went catastrophically wrong in my UPS too!


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Greetings,
I was watching a youtube video and saw a comment from you about a Chinese Venturi you use.
Do you have any videos or information on this?

Thanks,
Scotte

Hi guys,

Just wondering if it is possible to charge 2 batteries from a solar panel via a controller? Are the cheap ebay ones only intended to be connected to 1 battery or is it just a matter of how many amps the y can pump out?
Like this:
http://www.ebay.com.au/itm/30A-MPPT-Sol ... 04a&_uhb=1

I currently have my 12v backup system running on a 12v 120ah battery, but that is only enough for about 17hrs according to the online calculator I used… so I would like to add another 120 ah… I figure a large solar panel like 200 W would also extend my range a little.

I will also be running a 12v water pump on the backup via a timer so that some water gets circulated to plants as well and hopefully be able to survive 2-3 days without power.

Any suggestions?

If the batteries are identical and aged the same you can charge them in parallel, though if they have different characteristics one will take more of the charge than the other.

Also if one develops a faulty cell it will 'steal' charge from the other healthy battery when running on backup.

Are you pulling an average of 3.5Amps eg 42Watts on backup (based on max battery depth of discharge of 50%)? Thats a fair draw, is that just for an air pump?

How long do you want your backup system to run for? If you want to extend range much more you'll need to factor in the likelihood of cloudy days.

People regularly parallel batteries on boats to get more amp hour capacity. By paralleling we mean connecting the positive terminals together and the negative terminals together, as opposed to cereal when the positive from one battery connects to the negative to another, doubling the voltage. Like Mattyoga said, you need to use batteries of the same type, size, and age, or you are asking for trouble. People often think that they can just slap another battery in parallel whenever their budget allows them to purchase one, but the older batteries will rapidly degrade the new battery to their level of degradation. It goes without saying that you can not mix AGM, gel cell, and standard flooded batteries. Their charge windows are rather different, and you will likely destroy the more expensive limited electrolyte batteries.

Ron is spot on, other than suggesting that rolled oats or mueseli are related to batteries
Series connection makes for fewer problems long term. If you are paralleling 2 * 12V batteries, make sure you take your neg from one and positive from the other, to ensure an even rate and depth of charge and discharge, otherwise one battery will get a very different workout to the other. This page has lots of useful info about how to connect Lead-acid batteries: http://www.smartgauge.co.uk/batt_con.html

In electrical substations they will often series 55 batteries, and with not one cornflake involved.