back up power supplies

Privatteer

I'm not sure of the legalities of using the higher voltage in US.

Efficiency depends as much on the product to the voltage. You could get a cheap 230v pump that uses twice as much power as a 115v.

Internally I expect the sweetwater pump will be identical. The only difference is likely to be the arrangement of the coils.
That could be done internally or at the connection box.

At 230v the current will be lower, which means there would be a slight reduction in power loss due to resistance. Would be more important if you had a long cable run to the pump.

If you can legally use 230v, I would be inclined at option 2. Especially since its only short term until you fire up the genset.

Burnsy

Simo wrote:

Invest in an expensive smart battery charger that turns off when the battery is full, constantly float charging a battery with an ordinary "dumb" charger will severly damage your battery life and capacity.

Good luck

Or you could stick a small solar panel on to keep the batteries constanty charged, they are now cheaper than smart chargers such as CTEK.

Try
www.solarsteve1950.com

Look who the WA agent is, he is nice guyu who will give you a discount if you mention BYAP :wave1:

Privatteer

Simo wrote:

constantly float charging a battery with an ordinary "dumb" charger will severly damage your battery life and capacity.

Not 100% right. Float charging a battery at its designed float voltage, normally 13.8v can be done permanently. Best method when you also will have a device powered off it as the device power draw can confuse smart chargers into thinking battery is flat.

The "dumb" chargers you refer to are fast charging at 14-14.5v.

Be warned that some solar panel "charger" kits are even worse. No charging regulation at all I just tested a 10w one and had 17v going into a car battery.... Started to boil after about 5 mins.
The solar kit linked to however looks like it includes a regulator.

Burnsy

Privatteer wrote:

Be warned that some solar panel "charger" kits are even worse. No charging regulation at all I just tested a 10w one and had 17v going into a car battery.... Started to boil after about 5 mins.
The solar kit linked to however looks like it includes a regulator.

Yep that is an important point for all to note, solar panels generally put out around 17-19 volts so you must have a solar regulator in between the panel and the battery. The solar controller/regulator not only reduces the voltage but is like a smart charger and monitors the voltage in the battery and will switch to float mode once the battery is at capacity.

Burnsy

Just a heads up to turn your power off routinely to check your fallover switches are still doing their job. Ours had given up the ghost when I checked it yesterday, when you shake it is rattles so something has gone bunk. Got a replacement half an hour ago and plugged it in only to find it is not switching, just switches continuously and everything runs at once, guess I am off back to Jaycar on the way home :evil:

arbe

Bugger.

At least you tested it and got a replacement quickly.

Jamey

Burnsy wrote:

Just a heads up to turn your power off routinely to check your fallover switches are still doing their job. Ours had given up the ghost when I checked it yesterday, when you shake it is rattles so something has gone bunk. Got a replacement half an hour ago and plugged it in only to find it is not switching, just switches continuously and everything runs at once, guess I am off back to Jaycar on the way home :evil:

This is why i paid through the A R S E for commercial components for mine. at least i know it will stick upto the job. One main problem is that Relay Coils die, and having them ON for 100% of the time to work as a fail over device when the power go's out which is like hardly ever is a real issue.

Iv been speaking to a sparky about designing a device that works without a relay.... it can be done...

SnowT

Hiya Jamey..
As you said you have your contact on 100% of the time..

To make sure that the relay doesn't stick you need to bit a maintenance..

the bit that stuff up the most that you can repair is the part that operates the Solenoid..
Your sparky should know what I'm trying to say.. Over time they get a bit corroded and tend to stick..
A few cleans with a piece of sandpaper will get them nice and smooth again..

Replacement Coils for the relays are not expensive and are easy to replace..

Juergen

stimson

Simo wrote:

I am going to make a failover switch using this 240 volt Relay

Attachment:

240 Volt relay.jpg

http://www.jaycar.com.au/productView.as ... BCATID=754

and a junction box, GPO and three prong plugs I have lying around, for ~ $20 I will get the same sytem you can pay $125 for. Used together with a 600W inverter and my three stage charger and a large deepcycle battery I think I will have a cheap and versitile emergency back up system to run my air pump and maybe even a small sump pump aswell.

I know all of this has been mentioned earier in the topic but I think this system has distinct advantages over a UPS designed for a computer:

- Variable battery size to suit different systems
- Inverter can be used for different functions such as running an air pump in your car to get your fish home alive
- Separate charger is always useful to have
- I can use the battery for other functions such as running the kids electric ride on car.

i visited jaycar and picked myself up one of these relays, can you show us a pic of what wire goes where?

Dave Donley

Ok, so I have a 12v relay, a marine battery, an inverter, and an air pump. I understand how to connect the relay so that the air pump is run by the battery through the inverter when the power is out, by using a 12v "wall wart" transformer to power the relay coil.

I'd like the same air pump to be powered by the wall outlet when the power is working too, rather than the pump only working when the power is out. Could the wire from the battery to the inverter go through the relay for this, so that the air pump is not driven by the inverter when the power is on?

Privatteer

Simplest would be to source a 13.8v dc power supply either current limited or sized to handle the max draw from the battery when flat. The run the airpump off the inverter 24/7.

Other methods are going to require break before make relays or a timer interposed between 2 relays to prevent 2 sources of AC being fed into the airpump and probably blowing your inverter.

Dave Donley

Ok, thanks for the info Priv, I think I'll go ahead and get another two outlet air pump for the backup like the one I was going to use. I am wondering if I can use check valves to route both to the same air stones.

ccBear

I would love to see how to wire up the Jaycar relay mention 4 post's back. Can it be wire to a air stone and a 12v pump at the same time.

240v motors and appliances are being sold in the states and used legally. They refere to them as heavy duty not sure but believe it is because they last longer.

ccBear

I would love to see how to wire up the Jaycar relay mention 4 post's back. Can it be wire to a air stone and a 12v pump at the same time.

240v motors and appliances are being sold in the states and used legally. They refere to them as heavy duty not sure but believe it is because they last longer.

chainsaw

Hi ccBear, Welcome and Have a read of this link viewtopic.php?f=8&t=9805

if you have any problems PM me I live at Palmwoods.

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