Emergency Battery Backup 2.0 - New and Improved!

Discussion in 'DIY' started by chipmunkofdoom2, Sep 20, 2016.

  1. chipmunkofdoom2

    chipmunkofdoom2 Well-Known Member

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    Hi All!

    So a while ago, I created a post about battery backup for our tanks. The system still works and the concepts still apply, but it's not the most elegant of systems. In the event of an outage, you have to drag out your battery, drag out your inverter and manually attach everything. Not the worst thing if you happen to be home at the time of the outage. Not so great if not. I've gone through several iterations of this system, and while my version was a bit more DIY, what I'm going to recommend is fairly straight forward and anyone with a bit of common sense should be able to do it.

    My system is a bit more complex than it may need to be, but I have certain requirements that the system must meet:

    1. Must be upgradable. If I want to be crazy and buy 7.2kWh of battery power and run my entire system for days in the event of an outage, I wanted to be able to do so.

    2. Every part must be commercially available and off-the-shelf. If I can't search on Ebay or Amazon for it and find 10 different variations of it, it's too specialized and too rare. This also means that functionality must be compartmentalized so that broken parts can be replaced without throwing out the whole system and starting over.

    3. The system must have an automatic changeover, meaning I need to do nothing for the system to start powering my tank. The system must automatically switch back over to AC once power is back up, and the batteries must recharge on their own without any intervention from me.

    There are easier ways to do at least two of those, but it was hard to find all three.


    HOW IT WORKS

    So first, it's probably best to describe how this system works.

    At the end of it all, you will have your load (your aquarium, or whatever devices you'd like to power). I power my Vortech MP10 and my return pump with my system, but I could potentially power more. While a robust system will power many things, it's best to only power the bare minimum (return pump, circulation in DT, dosing pumps/skimmers if necessary). The less power you use, the longer the system will last.

    At the beginning you have your power sources. This means the AC power when your power is on, and a battery power source when it is not. Since batteries are DC and most of the stuff we use in our aquariums is AC, we need something after the battery to turn the DC into AC. Those are called inverters and come in all shapes and sizes. More to come on that later. You'll also need a battery maintainer to keep your battery topped up when your power is on. Again, more to come on that later.

    Finally, we have something in between the power sources and the load (your aquarium). There has to be some sort of device that detects when power fails and switches the load from your wall power to the inverter. The device also needs to see when the power comes back on, and make the switch back to battery power.


    THE EASY WAY OUT

    Before I go into the specifics of this system, there is a device that will do mostly all of this for you. All you need to do is add a battery and you're good to go. It's called an inverter/charger. It works essentially like the system above. You connect a battery to the device, plug the device into the wall, and connect your load (aquarium) to the device. The result is that the inverter/charger charges the battery and keeps it topped off while you have power. When the power goes out, the device switches AC power to the inverter and begins draining the battery you connected. When power comes back on, the inverter switches to AC power and charges the battery back up. Easy as pie, and some like the Tripp Lite to which I linked are very cheap, < $200.

    Personally, I do not like inverter/chargers. The main reason is they combine a LOT of functionality. They charge your battery. They convert DC to AC. They sense AC power failure and switch to battery power. If any single one of these functions fails, your inverter/charger is now worthless. If you're lucky enough to still be under warranty, you may get it fixed, but if not, you have to buy a whole new system. With my setup, if your AC switch fails? Buy another and replace it. Inverter? Same thing, buy a new one and replace the bad one. If your battery carger breaks, buy a new one. I really needed this modularity in my design, as I hate the idea of having to throw out a device because one single piece fails. There are lots of other nuances that I don't particularly care for with these devices, but that'll have to go in a follow-up post.

    If you need the simplicity of a single device, however, an inverter/charger may be for you. Additionally, if you don't have much DIY or electronics experience, I think this is probably the best way to go for you.


    NO TURNING BACK NOW

    Before we get started, be aware, this project messes with 120VAC. This can easily kill you. If you haven't worked with electronics or wiring before, I would recommend you not undertake this project and just go with an inverter/charger. Or, learn a bit more first.

    I'm going to supply a rough parts list below. While all of these will work together, just about any battery, inverter, or charger will do. I encourage you to learn about every single one of these pieces of the system before attempting something like this. You don't have to be an expert, but a bit of knowledge will really help you understand how these things work and your other options.

    Inverter: Standard 1000W MSW inverter - $70

    Just about any inverter will work here. This seems to be a well-reviewed inverter with decent capacity (1000W).

    Battery: 12VDC 35 Ah (about 420 Wh) - $64

    Similar to the inverter, a decently reviewed and priced 12V battery. You can use a larger battery, smaller battery, a bank of batteries wired together... really you can add as much battery power as you want. This is just a decent battery to get you going. Any battery you buy, though.. make sure it's AGM (absorbent glass mat) and/or sealed (SLA or sealed lead acid).

    Battery charger: Black and Decker 12V Charger - $20

    The charger charges the battery (duh!). Since you're getting an AGM battery, make sure your charger is designed for AGM batteries (this one is).

    Transfer switch: Xantrex Auto Transfer Switch - $65

    This switch switches between the wall and battery power. Very important. I haven't been able to find many alternatives to this. Basically, if you want to switch AC and you don't want to wire up a relay (like I did), you need something like this.

    Grounded three prong extension cord: (any will do) $10.

    This should be an extension cord, meaning one end has the three prongs (male), and the one end accepts three prongs (female). I got mine at target and it was < $10.



    So for about $230 (give or take) you can have this whole system up and running. You may want to change out a few parts (I'll discuss some of these in another post), but that will get you a basic system.


    ASSEMBLY

    So the assembly is pretty basic, and may vary based on the parts you get. But, the core concepts remain unchanged.

    1. Attach your battery charger to your battery and plug it in. This should always remain attached to the battery and will always keep it topped off. How you connect your battery to the charger may vary, but most chargers should come with either clips or screw sets to make the connection

    2. Take your 3 prong extension cord. Cut it about in half, although where you cut it doesn't matter. I simply got an 8' three-prong extension cord from Target. You should have a white, black and green wire coming out of the cord where you cut it (you may have to strip off some of the black shielding to expose the individual leads). Here's what mine looks like:

    [​IMG]

    **NOTE** - For the following steps, NOTHING SHOULD BE PLUGGED INTO ANY WALL OUTLETS, ATTACHED TO ANY INVERTERS OR CONNECTED TO ANY BATTERIES.

    3. You'll also notice on the transfer switch that there are three wire bundles coming out. One of these says "From Utility," and it also has a green, white and black wire:

    [​IMG]

    This is where your "wall power," the stuff from the electric company, goes. Take the male end of the extension cord (the one with the prongs sticking out) and attach it to the "From Utility" wires coming out of the transfer switch. Attach green -> green, white -> white and black -> black. For safety, I'd recommend soldering the leads together and wrapping with heatshrink. (note: I don't actually have the Xantrex switch I'm recommending here, which is why I'm using stock photos. I went with a simple relay. However, the connection is pretty straightforward). Since this wire is "From Utility", we'll eventually be plugging it into the wall, but not yet.

    4. Take the female end of the extension cord (the one that accepts the three prongs). We will want to attach this to the "AC Output To Load" cable coming out of the other side of the switch:

    [​IMG]

    Same deal, attach black -> black, white -> white and green -> green. This is where you will plug in the equipment that should run during power failures. You will have to use a surge protector or something along those lines if you need to plug more than one thing into the system.

    5. Plug the "From Utility" cable into one of your wall outlets
    6. Attach the inverter to the battery and turn it on.
    7. Plug the "From Inverter" cable into your inverter.
    8. Plug your aquarium equipment into the "AC Load To Output" cable.

    And presto! You're all done. To test it out, unplug the "From Utility" cable from the wall. Your power source should automatically switch over to the inverter. Plug it back in, and it should automatically switch back to the utility power. To make sure that it is running off of the wall, try unplugging the "From Inverter" input from the inverter.

    I'll follow-up with another post regarding some useful information about inverters, batteries, and capacity. I wish I could have done more pictures of my setup, but I actually wouldn't recommend my setup to anyone who hasn't worked with electronics before, and didn't want to confuse an already long thread.

    Any questions, let me know!
     
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  2. DaveK

    DaveK Well-Known Member

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    A good article on battery backup.

    I will add this. The battery used as an example is 12 volts at 35 amp hours will give you about 420 watt hours to use in the event of a power failure.

    An Eco Tech MP40wQD will draw between 9 and 38 watts per hour, depending upon your speed and mode settings. Remember it takes a lot more power to start a motor than it does to keep it running.

    Splitting the difference, to make the calculation easy, it's about 25 watts. Dividing that into the 420 watt hours, means you'll be able to run the pump for about 16.8 hours. This assumes perfect conversion through your electronics. Typical with losses, expect to get a bit less, maybe 15 hours of use.

    Now why all the calculations?

    As you can see, 15 hours is not going to last you through a major disaster where you don't have power for several days. Also, we haven't even talked about keeping the tank at temp or running the main circulation pump.

    The bottom line, make sure your batteries can get you through a major disaster. You may need a lot more than you think, depending upon what you consider to be critical.
     
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  3. chipmunkofdoom2

    chipmunkofdoom2 Well-Known Member

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    Good points, Dave, thanks for bringing them up. I was planning on a follow-up post on capacity either tonight or tomorrow.

    Interesting note, this battery is actually a pretty good value for your money in terms of watts per dollar, even if the capacity is low. It's second place, though, to a huge 100 Ah battery that costs around $160. If I had to recommend a battery, it would be that $160 1.2kWh beast. But this little 35Ah battery would probably make a good battery bank if you buy 2 or three.

    Anyway, more to come.
     
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  4. chipmunkofdoom2

    chipmunkofdoom2 Well-Known Member

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    Battery capacity

    So as DaveK alluded to a few posts ago, one thing you'll want to do is buy an appropriate battery to meet your needs. There's no sense in not tailoring this system to meet your exact specifications if you're going through all this trouble. In this post I'll discuss how to determine how much capacity you'll need, as well as some of the limitations of a battery-based system, and why I think they're a better solution than generators despite the cost.

    So how do you determine how much power you need?

    Before we get into calculations, let's discuss the batteries you'll likely be using. I recommend AGM (absorbent glass mat) deep cycle batteries because these have a pretty good life expectancy and are a good balance between price and capacity. It's important that you either get AGM or sealed batteries, as standard flooded lead acid batteries release hydrogen gas as they charge. This can easily reach high concentrations if you store your batteries in an enclosed space. Hydrogen is explosive. You don't want that accumulating where sparks can occur. Additionally, traditional flooded batteries are usually damaged pretty severely by discharging them deeply (more than 50%). Just because AGM batteries can be deeply discharged, however, doesn't mean that you should or that it's good for them. If possible, I'd get double the capacity you calculate your system needs. This will allow for various inefficiencies, keep your batteries running longer at normal discharge, and even give you some breathing room if you have a super long outage and need more run time than you expected. We'll discuss this a bit more at the end of the post. So, long story short, buy AGM batteries and get lots more than you need, just to be safe.

    Here are a few good deals on Amazon for AGM batteries. I've listed them by capacity. I've divided the total watt hours by the battery cost to give an idea of the relative value of the batteries. More watts for your dollar = better deal!

    12V 100Ah battery (1,200Wh total): $160. Watts per dollar: 7.50
    12V 35Ah battery (two-pack, 840Wh total): $119. Watts per dollar: 7.05
    12V 35Ah battery (420Wh total): $64. Watts per dollar: 6.56


    Calculations

    So, now down to the math. The first step is to decide what you would like to run with your back up system. I chose to run my return pump and my circulation pump, but you can run almost whatever you'd like off of this backup source. I'd recommend at least running your circulation in tank, as well as potentially your return pump (depending on how large it is). So let's say you'd like to run your return pump and your circulation pump. We can use my tank as an example: I have an MP10 for circulation and a MJ1200 for my return pump. If you have mainstream equipment like this, it will probably be easy to find power usage information online. The Vortech MP10 appears to use between 10 and 20 watts, while the MJ1200 appears to use about 20W. We'll split the difference on the MP10 and call it 15W. So these two together will use about 35 watts.

    So, now we have our wattage draw (35W). As I mentioned before, batteries are typically listed in volts DC (like 12V) and have a capacity (like 35Ah, or amp hours). In order to determine roughly how many watts a battery will provide, you need to multiply the voltage by the capacity. The battery I linked to above is 12V and has a capacity of 35Ah. 12V x 35Ah = 420 watts (more specifically, watt-hours).

    So our equipment needs 35W and our battery provides 420 Wh (watt-hours). So how long can that battery run all my equipment? If we divide 420Wh by 35W, you get 12 hours. Not bad, and this is actually close to my system's actual capacity (I'm currently running a 50Ah battery, about 600Wh total). Let's say, however, that you need (or would like) more time than that. Let's say that you get frequent outages in your area and want to be able to run your system for at least 24 hours. We'll use my tank as an example again. I need 35 watts of power for 24 hours. 35W x 24h = 840Wh. In order to determine how many amps our battery must have to meet this, we can simply divide the 840Wh by 12V to get Ah (remember, our AGM batteries are 12V). 840Wh / 12V = 70Ah. So if I wanted to run my tank for 24 hours, I would have to buy a battery with at least 70Ah capacity. If I wanted to run my tank for 2, 3 or even 4 days? Multiply that number by 2, 3 or 4 (140Ah for 2 days, 210Ah for 3 days, or 280Ah for 4 days).


    What about the temperature?

    So you may have noticed I didn't mention using a heater with this setup. You can use a heater with this type of system. You have to consider power draw very carefully though. If you have a 40g tank and have a 200W heater, that essentially destroys the power budget we laid out above. A heater doesn't run all the time and isn't always drawing its full capacity, so these calculations are tough to do. But let's assume your 200W heater runs for 30 total minutes in an hour. That means your heater will draw 100W per hour. If you have 40W worth of pumps and 100W of heater to power, you'll be using 140 watts every hour. This means a 420Wh battery will only last you 3 hours instead of the 12 hours we estimated above (420Wh / 140W = 3 hours). This estimate may be high or low, depending on how often your heater has to kick on, but it's still a good enough rough calculation. I wouldn't say that you can't or shouldn't run a heater on this type of setup. I would say that a heater is one of the pieces of equipment about which I'd worry the least in the case of an outage. Water movement and gas exchange is much more of a concern in the short term. Water will retain its temperature for a while, especially if the ambient temperature in your home isn't too low. If you are an edge case for whom a heater is an absolute necessity in an outage, be prepared to buy may more batteries. Or consider a generator.


    The costs are adding up...

    So as you look at the cost of a 35Ah battery ($65) and then see you may need 200Ah or more to run your system for a few days.. you may start wondering how much all this battery capacity will cost you. Unfortunately, batteries are not cheap. Amazon has a 100Ah battery for about $160.. but you'll notice to run my tank for 4 days, I'll need at least three of those, almost $500. It's true, it won't be cheap to run your tank for a long period of time on batteries. I'd argue, however, that no solution is perfect. Even though this setup has caveats, so do generators (really, the only other long term viable solution aside from this type of battery system).


    Gas Generators - The battery's only real competitor

    NOTE: While I have researched generators thoroughly, I've only used them. I've never owned one long term. I try to speak very generally about the pros and cons and make observations that anyone could make with a bit of research.. but if you own a generator and disagree or see something that's inaccurate, please speak up!

    Really the only competitor to the system we're discussing is a gas generator. While it's true you could run your tank in perpetuity on a gas generator with enough fuel, the picture isn't all sunshine and roses.

    First thing to consider is the cost of a generator. You'll see no-name Chinese junk with a few thousand watts of capacity at the big box stores for $150 or so. When looking at $160 for a battery alone, you may think this is the way to go. However, if you read reviews of these units, you'll find that many people claim to have reliability or longevity problems with these cheapo units. Additionally, it may be difficult to find service for something with a no-name engine and a limited 1 year warranty. I wouldn't feel confident long term with one of these units. I've considered dropping the money for a quality Honda or Yamaha generator, two brands with great reputations, service and track records.. but these routinely cost $800+. There's a reason a name-brand generator costs about $800 for 1,000W and no-name generators cost $150 for 2,500W. Long story short, if you get a quality generator, you'll probably be paying a good amount of money anyway. Even then, there are still compromises to make with a generator.

    I own an apartment-style condo. I wouldn't feel comfortable putting my generator on my porch because of the potential for carbon monoxide coming into my unit. Additionally, it would be difficult (though not impossible) to get extension cords from the ground to my second story unit (and further inside to my aquarium). If you live on the third story or above of an apartment/condo building, a generator is going to be very difficult to pull off. What's more, if you live in a townhome or a neighborhood with a homeowner's association, you have to ensure there are no bylaws regarding the continual usage of a noisy gas generator. Even the premium Japanese models make some noise, albeit considerably less than the cheap Chinese junk. I don't think my association would permit me to run a gas generator on the property, even in the event of an outage.

    There is also maintenance and upkeep with a generator. If it breaks, obviously you have to get it repaired. You also have to pull out these generators and run them every few months. You also must make sure the gas doesn't go bad and have gas available if the power does go out. If you live in an area that receives heavy snow or severe tropical storms that limit your ability to safely leave your home and you can't get fuel, your generator may not do you much good. You could always stock up on fuel before a storm, but there's no getting around having to maintain the generator and start it every few months to make sure it's working. If you fail to run the generator every few months, you may pull it out in the event of an outage and find it doesn't work. Regardless of how much cheaper it is, if the generator doesn't work, the savings might not be worth it.

    Probably the most important factor me, though, is that outside of expensive natural gas generators tied to your home (a expense that costs thousands of dollars), your generator isn't going to start automatically in the event of an outage. You must get out the generator, set up the wires, and plug your equipment in. If the power goes out for 7 hours during the work day and you don't know about it, the generator won't help. Similarly, consider you go out with friends on a weekend night and don't come home until the next day. Your tank could be alone for 16+ hours without power if the power fails shortly after you leave.

    While a battery backup system isn't perfect, it does not suffer from these issues. First, a battery bank to last your tank 2 or 3 days may cost a few hundred dollars, but it will last 5 to 10 years if you buy quality batteries and don't discharge them heavily very frequently. You don't need to do anything special to your batteries every few months to make sure they're good to go in the event of an outage. Simply buy a good battery maintainer like I discussed in the first post, and your batteries will always be topped off and ready to go. This type of system has no moving parts, except for maybe the transfer switch, which means that the likelihood is much lower that something is going to break sipmly from sitting unused. It's not impossible for things to go bad just from sitting unused. But, it's much less likely that a battery bank will go bad when left alone for 3 years as opposed to a generator left alone for the same amount of time. For those in an apartment or condo building, or those who have similar logistical constraints that prevent generator usage (perhaps a tank in an office), a battery backup is really the only way to go. The big deal for me, however, is the automatic switchover that occurs with this type of battery system. I'd much rather know that my tank is safe in the event of common, relatively short outages (<24 hours) than prepare for long-term outages that occur once or twice a decade. Again, your situation may be different. You'll have to decide what is best given your power reliability and major storm frequency.


    Why can't I have both?

    If your batteries can pick up as soon as the power drops off, that's great. But what if the outage is major and you won't be getting power back for a few days? At that point, if you're able to run a generator, it may be a good idea to do so. Having a generator and a battery backup system is very expensive, however.

    Perhaps a better solution is to plan for a system that can power your tank for a day or two. This will cover outages due to minor storms and utility equipment failure very well. If you have a major storm and power won't be back for a week or so, you will at least have two or three days on battery. This will give you some time to beg, borrow or steal a generator from a family member of friend, or figure out a different solution if running a generator is completely out of the question. This is my plan. I have about 18 hours of system capacity currently and plan to eventually have 2 days of run-time. If a major storm is the cause of my outage, that 24 - 48 hours will give me time to assess and adapt if I know power won't return for a long time.

    Well, that was a rather long post to explain that you multiple the voltage by amperage to get wattage... but I feel like it's all good info if you're looking into a system like this.

    Let me know if you have any questions!
     
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  5. DaveK

    DaveK Well-Known Member

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    One other item that should be pointed out since it's a safety issue.

    It should be obvious, but just in case, batteries and salt water do not like each other. Set up you batteries and electronics as far away from your tank as you reasonably can. You want zero chance of SW getting around them. Putting them around the back of the tank, or in your stand is not the best idea.
     
    #5
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  6. Oliver D

    Oliver D New Member

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    I personally run a 6000 kva ups with pure sine wave output and that system lasts me up to 24hrs running my main pump and my powerheads temperature here is less of a proplem.
     
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  7. chipmunkofdoom2

    chipmunkofdoom2 Well-Known Member

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    That's great. If you have a UPS with a few thousand watts of capacity and a decent inverter, I'd definitely use it. It sounds like a great piece of gear. This, however, is not typical of most consumer UPSs.
     
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  8. Oliver D

    Oliver D New Member

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    This is a industrial UPS that was used as a back up for a server of a bank
     
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  9. nanoreefing4fun

    nanoreefing4fun Well-Known Member
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    Best of luck all RS Florida members ! Prays you all will make it through safe !
     
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