DIY Universal Battery Backup For Your Reef

[chipmunkofdoom2]

A few days ago (3/2/2018) I lost power in the recent Nor'easter. I had a battery backup system in place, and thankfully it functioned fairly well. However, I had upgraded my aquarium since I had originally planned out the battery backup and the system did not last nearly as long as I wanted it to. The battery took frequent recharges from my car to keep going. I've since re-evaluated my system and in the process, decided to write a post about general-purpose battery backup designed for reefs.

Read the full article here...

 

[wcharon]

Excellent detailed information. Thanks for sharing...

 

[Oleshp]

Exactly what I was looking for to buy me some time to get the generator going! Thanks for the write up!

 

[chipmunkofdoom2]

Thanks very much @wcharon and @Oleshp. I was worried that this might be too much detail, or that it might be too general. But I hope that it will at least get reefers thinking and get a discussion started on power failures and backups.

 

[wcharon]

At the moment I am using a Belkin Battery backup for a Jebao RW-15 that last around 6 hours but for sure I will be moving to this approach as I will prefer to run the return pump RODC-5500 and a Gyre-230.

Actually I already put the items in my Amazon cart so I don't forget. Really appreciated.

 

[Ruben's Reef]

Great write-up. I was working with a friend on a Solar Panel connected to a battery to power at least my two wave maker in case of a power outage but I think your setup is a lot easier and practical. Thanks a lot for sharing. This should be on the DIY page as an sticky.

 

[chipmunkofdoom2]

Great write-up. I was working with a friend on a Solar Panel connected to a battery to power at least my two wave maker in case of a power outage but I think your setup is a lot easier and practical. Thanks a lot for sharing. This should be on the DIY page as an sticky.

Thanks, I'm really glad you found it useful. Charging batteries with a solar panel is not a bad way to go if you have the space and you get adequate sun. Having said that, battery maintainers take up almost no space and are super simple. Just hook them up to the battery and plug them in. The Black and Decker I featured in the post is really cheap too, only $15.

 

[wcharon]

I read in a post before in another thread that a 4 stage battery charger / maintainer is better. Can you please comment on this option?

 

[Oleshp]

Say I have my tank on its on circuit, could I install the transfer switch directly In the circuit instead of messing with cords? And do they make those transfer switches in 20 amp? I hate putting a 15a accessory into a 20a circuit even if it never draws anywhere near that

 

[chipmunkofdoom2]

I read in a post before in another thread that a 4 stage battery charger / maintainer is better. Can you please comment on this option?

I haven't used 4-stage chargers before, so I don't know a ton about them. It appears that in some cases, the charger attempts to discern if any batteries are undercharged (this can happen sometimes with battery banks), and it attempts to charge them to the level of other batteries. Some other 4-stage chargers appear to equalize/desulfate on the 4th stage. So it appears to be a case-by-case thing. Battery bank charging is not necessarily a bad thing, but only useful if you have a battery bank. Equalization/desulfation is not necessarily a bad thing either, just make sure the charger supports AGM batteries (or whatever type of battery you have). Different batteries have different requirements in terms of equalization/desulfation voltages.

 

[chipmunkofdoom2]

Say I have my tank on its on circuit, could I install the transfer switch directly In the circuit instead of messing with cords? And do they make those transfer switches in 20 amp? I hate putting a 15a accessory into a 20a circuit even if it never draws anywhere near that

This transfer switch from Go Power! is supposed to be 30A. Ignoring the issue of wiring up the circuit itself to the transfer switch, this should handle a 20A load. I'm not sure about the specifics of wiring the transfer switch directly into the circuit though. You might need an electrician for that part.

How much power do you estimate your tank uses? Running your entire tank on an inverter and battery is likely going to be a substantial load. How long would you want your tank to run on battery power?

 

[Oleshp]

According to my apex, it's about 6a with everything (including heater) on. The wiring doesn't scare me, there's a lot of electricians in my family who will help if needed and I am no stranger to electricity or wiring (I'm an auto tech). FWIW I put in the circuit that the tank is on now. I am thinking of putting 4 to 6 deep cycle marine batteries. I would really at the most need it to last for 6 hours as we rarely travel and even more rarely go more than a few hours away.

 

[kecked]

Really nice build. I tried the off the shelf stuff and it laughed at me after a few hours. Thinking to add a generator on a bicycle to charge the batteries! trick charge and work out all in one. The inverter route stinks and is inefficient. Having direct DC pumps is much better. My biggest problem is warmth and hot water bottle helped that a lot.

 

[chipmunkofdoom2]

According to my apex, it's about 6a with everything (including heater) on. The wiring doesn't scare me, there's a lot of electricians in my family who will help if needed and I am no stranger to electricity or wiring (I'm an auto tech). FWIW I put in the circuit that the tank is on now. I am thinking of putting 4 to 6 deep cycle marine batteries. I would really at the most need it to last for 6 hours as we rarely travel and even more rarely go more than a few hours away.

Ah okay, sounds like you have a pretty good handle on this stuff. Yeah I'm sure you'd be able to hook it up to the circuit. That 30A box will probably be the best bet.

So 6A at 120VAC is around 720W. Any inverter of 1,000W or higher would probably work just fine. A 2,000W inverter might be best to give you some wiggle room in case you upgrade your aquarium in the future. The big challenge will be the battery capacity. At 12VDC, 720W requires 60Ah of battery. The faster you discharge a battery the lower the real-world capacity is going to be. I have a 100Ah battery, but according to the manufacturer, at a 60Ah draw, the battery will only last for one hour and provide a total of 60Ah, not the 100Ah for which it's rated.

If we account for battery depth of discharge of 80% and add a 10% buffer for inefficiency, your system would need around 82Ah to run ((60Ah / 0.80) * 1.1 = 82.5). If you got five of the 100Ah batteries I linked to above, then the current draw from each battery would be around 16.4Ah (82 / 5), provided the batteries are wired correctly and discharged evenly. The manual says that those batteries will last for 5 hours at a discharge rate of 17Ah, so five of those batteries would last you around 5 hours. You might be able to get 6 hours total out of them, but you might be discharging the batteries below 80%, which could cause premature wear.

Any equipment you could have your Apex shut off in the event of an outage would reduce the battery requirement. Aside from being a little expensive though, it's totally doable to run your entire tank for a few hours on power failure.

 

[chipmunkofdoom2]

Really nice build. I tried the off the shelf stuff and it laughed at me after a few hours. Thinking to add a generator on a bicycle to charge the batteries! trick charge and work out all in one. The inverter route stinks and is inefficient. Having direct DC pumps is much better. My biggest problem is warmth and hot water bottle helped that a lot.

Yep that's definitely true. On the proposed setup above, you're going from a DC battery to AC back to DC again (in the case of DC pumps). Not very efficient. If you could wire the battery to your pump's battery backup port (provided it had one) that would be ideal and would save a whole lot of inefficiency. Plus, most DC pumps throttle back when on battery backup, which would save you even more energy.

 

[Oleshp]

I appreciate you actually doing the math for me lol. I was guessing at 4 to 6 batteries. Good call with having the apex kill unnecessary items. Thanks again for the info!

 

[tgp4274]

could you put up a wireing diagram for the way you wired the relay??
pleeeeeeeze

 

[chipmunkofdoom2]

could you put up a wireing diagram for the way you wired the relay??
pleeeeeeeze

Yep, sure

Here's a picture of a pretty standard DPDT relay:

In DPDT (double pole, double throw) relays, like the one pictured above, common is the "output." Normally open and normally closed are the inputs. Coil is the electromagnetic coil that makes the connections. In the case of this relay, there are two states of operation. When the relay has power applied to the coil, one connection is made (Normally Open to Common). When power is not applied to the relay, another connection is made (Normally Closed to Common). Here's a crude diagram of how you would wire this. In my diagram, the live wires are red and the neutral wires are grey, but in real life the live wires will likely be black and the white will be neutral:

To make this work for our aquarium, we connect power from the utility to the Coil and to the Normally Open (NO) terminals. Connect the inverter output to the Normally Closed (NC) terminals. Finally, connect the output to the Common terminals. In my case the "from utility" and "from inverter" were the male ends (the ones with the prongs) of grounded extension cords. The "output" was the female end (the plug part) of a grounded extension cord.

Please keep in mind that all the live and neutral wires must be hooked up tot he same poles. In AC-coil relays, it doesn't really matter which side you choose. Just make sure all the live wires and neutral wires are on the same sides. Also, be sure to tie the ground wire from all three sources (the output, the utility and the inverter) together.

 

[tgp4274]

awesome thanks

so if i understand corectly....
the inverter is on constently??

 

[chipmunkofdoom2]

awesome thanks

so if i understand corectly....
the inverter is on constently??

You're welcome

Correct, the inverter would need to be always switched on. I've wanted to put a relay between the battery and the inverter, and only have power flow when the utility fails. But, I haven't thought of anything good yet. The problem is that because the battery supplies 12VDC, the current flow can get pretty high from the battery to the inverter, even at relatively low wattages. I haven't found a relay with a high enough capacity to put between the battery and the inverter. Not one that I would feel comfortable enough with.

To make sure the inverter is working, I do a system test once a month or so. I unplug the utility cable and make sure the switch goes to battery backup and that the inverter is working properly.