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Battery Backup System

horseplay

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Aug 19, 2021
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I am new here but have been watching a lot of battery videos. Want to get my hands wet by setting up a small backup system, UPS. But to this day I have not been able to find a design for what I think a simple need. Maybe I am making everything too complicated. I have a reef tank and all the power is coming from one wall plug. So what I need is:

1. Battery I assume LiFePo4. AC to DC charger and DC to AC inverter.
2. Battery is charged from the wall.
3. During a power outage the power is automatically switched to battery.
4. Once the wall power is back up the consumption will automatically switch to wall.

So if I get the AC charger connected to the battery and the whole system connect to the inverter will it work for my purpose?

Thanks in advance!
 
I am new here but have been watching a lot of battery videos. Want to get my hands wet by setting up a small backup system, UPS. But to this day I have not been able to find a design for what I think a simple need. Maybe I am making everything too complicated. I have a reef tank and all the power is coming from one wall plug. So what I need is:

1. Battery I assume LiFePo4. AC to DC charger and DC to AC inverter.
2. Battery is charged from the wall.
3. During a power outage the power is automatically switched to battery.
4. Once the wall power is back up the consumption will automatically switch to wall.

So if I get the AC charger connected to the battery and the whole system connect to the inverter will it work for my purpose?

Thanks in advance!
The all-in-one unit like the GroWatts is simple... (it has UPS mode like how you wanted. It has charger from AC or Solar. Or use Solar energy first or Street power..etc.)
1. Energy audit on how much power the reef tank uses - like a Kill-A-Watt meter
2. Size the battery from the energy audit on how long you want to use the battery as backup for the pump
3. Decide to get solar panels to extend the usage when no street power.

There are many videos from Will on it. or the website on the top "DIY Solar Blueprints" for diagrams and parts.

Thanks.
 
LiFePO4 isn't necessarily the best choice. It could be good for 10 years of daily deep cycling, but since you say "backup" your number of cycles are probably much fewer.
LiFePO4 has some particularly good performance parameters, but also some issues that have to be managed.

AGM or Gel is also popular for backup.

Commercial lithium batteries (LiFePO4 and others) usually cost several times what lead-acid does. DIY LiFePO4 can cost less than lead-acid.

All depends on your application, and how much storage you want.

Reef tank - start with power draw needed for pumps and heaters. Peak and average over a day.
How long a power outage do you need to handle? If more than 12 hours (one night), plan for PV charging.

A small all-in-one/hybrid probably fits the need. Pretty much what Archtype said.

One that has an internal relay for pass-through of AC power. No reason to have it operate as an on-line UPS; likely its inverter is less reliable than the grid.
For greater redundancy, run your tank equipment directly off grid AC, and have a second set of equipment that runs off battery if power goes out. Depends on likelihood of failure and value of the fish.
 
Lots of good points. Thank you.

The reef tank would consume about 60 Watts then the power is out. The lights and heaters will not be running. If I budget for 20 hours of run time then it will take 1200 Watt-Hours.

The growatts is probably too big for me. This will work for me also, right?


This is the all-in-one system.

Also, the pumps for the reef tank natively run 24V and I have a small draw of AC power from the router (so I can monitor remotely). Can I get a 24V system and hook the pumps directly to the battery?
 
Also, the pumps for the reef tank natively run 24V and I have a small draw of AC power from the router (so I can monitor remotely). Can I get a 24V system and hook the pumps directly to the battery?
Yes, easily. I made a simple 12 volt version of what you want to do. It also has the benefit of not having inverter losses, as well as a much lower cost.

You would would either use a 12 volt battery with a 12v to 24v step up regulator for your pumps (your router is also more than likely 12 volts, all you need is a barrel plug, not an inverter), or a 24 volt battery with a 24v to 12v step down for the router. They also have ones that take normally 8-40v and make it a stable 24v or 12v, which is better for sensitive electronics.

Then you would get a charger that could supply a proper float voltage and also enough power to run your loads. If the power went out, all your loads are already connected to the battery, so no transfer switch required.

Mine was like this;

AC mains -- 12v 5 amp "wal wart" dc power supply -- adjustable step up to 13.3v -- 12.8v LiFePO4 (with bms) -- 12 volt regulator -- barrel plug with fuse to routers

The connections are fused where appropriate as well.

If you decide to go this route, I will happily provide the products I used.
 
@A.Justice this is exactly what I need, for this small backup system. I have two pumps 24V, 50W together and the router is 12V 17W running. I will get the 12V version and step up to 24V. Then I would be able to use the same battery in my teardrop camper as well.

Thanks!
 
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