Power backup for aquarium

[madsalts]

Hi,

This isn't a solar thread per se, but it deals with many of the same issues. The questions I have are beyond the knowledge of post aquarium enthusiasts, and I have no idea where else to post. If anyone can help me out, it would be great.

Hi,

I need a backup power supply for an aquarium. I’m leaning toward using a UPS, though a generator is also an option. The advantage of a generator is running costs over a long period of time. I live in an area that has mini brownouts on a regular basis (the power flickers for a second or two at least once a week) and sees an outage at least once a year. In the past, there have been outages lasting days. The local grid has been upgraded to some degree after power was down for a week several years back. To gamble that an outage will last less than a day is a chance that I might be willing to take, considering some of the advantages that UPS systems have over generators.

The advantages of a generator:
-I wonder how safe it is to have an AGM battery on trickle charge in the house.
-Some generators can run for days straight.
-I wouldn’t be gambling that the power would only be out for a short period.
-Quiet

Disadvantages:
-Many generators can only run a few hours before being overtaxed.
-Noise.
-Right now, I’m in a situation where I can have a generator outside. Depending on how my living arrangements change in the years to come, I might not be able to do this. This isn’t an immediate concern, however.
-I’d need to get a generator with, or buy an aftermarket product that allows, automatic start-up
-I’d need to perform engine maintenance on the generator.

Regarding the UPS, I have poked around at other threads on this forum and it seems that a special UPS would be needed to run for an extended period of time. I don’t even know if “UPS” is technically what I’d even want. I need something that will automatically start when there is a loss of AC power, trickle charge batteries when needed, be able to run for quite a while, and use AGM marine batteries, and ideally not come with redundant internal batteries. Is it worth using Gel batteries instead? Maybe I simply need some sort of inverter. I don’t know. Loraine Technology was mentioned on this forum as being appropriate for this. I have my doubts as to whether they are, though. Their products seem to be huge. I’m guessing that they’re for industrial applications. I checked out Magnum Dimensions. If nothing else fits the bill, I might get something from this company. Their products are small (about 30 lbs), are held in high regard on this forum, and do what I need them to do. The disadvantage is the cost, which reflects extra features that I don’t need. For instance, I don’t need to access the device from the internet. Can anyone recommend brands that can do what I will need them to without all of the bells and whistles?

Also, I wonder how long I can expect a battery to run. I have seen the formula (to give a rough estimate): (10 x Ah)/Watts of used appliance = run time of appliance. Is this somewhat accurate? Does this take into account conversion losses?

Finally, to what degree should a UPS be over-speced? I realize that starting current is often greater than running current for appliances. If I have a UPS that can handle 1000 Watts, an appliance runs on 600 Watts, and starts has a start-up current (listed) of 970 watts, would using a 1000 Watt-rated UPS be cutting things too close?

Also, what is the effect of using multiple appliances? If I have a 1000 watt UPS that is expected to start an appliance with a starting current of 600 amps, but I already have another device drawing 400 amps, am I right to think that this will be a problem?

Thanks. The answers to these questions will help me a lot.

[lkruper]

Before you buy anything, you will need to understand your loads. An inexpensive device called a Kill-o-watt meter can be used to accurately measure the actual watts consumed which will be different that the manufacturer nameplate.

To answer your question regarding UPS-like capability, you should consider inverter/chargers used frequently in the RV industry. They are like UPS but don't have internal batteries. They power from your grid power and charge the batteries but cut over with a transfer switch when power fails.

You will need to decide on an inverter that is pure sine wave or modified sine wave. It is possible that if you limit your application to just what it takes to keep your fish tank operational (lights, heater, pump, aerator, etc) that you can save by not paying the high premium for the pure sine wave inverter/charger. But be careful because some devices don't work well without it.

Most inverters will handle a surge when appliances start up, many times 2X the rated wattage. I am not sure why you are asking about appliances when your request is for a fish tank. If you have a broader need for energy backup, then you will probably need to define and share the complete list of what you have in mind in order to get good advice on equipment.

[madsalts]

Thanks for the reply. I'll check out "inverter/chargers". By "appliances", I did not mean things like dishwashers, refrigerators, etc. I meant equipment within the tank (pumps, heaters, etc.). Also, is it safe to buy a used inverter/charger, or might I be risking a fire by doing so?

[lkruper]

Thanks for the reply. I'll check out "inverter/chargers". By "appliances", I did not mean things like dishwashers, refrigerators, etc. I meant equipment within the tank (pumps, heaters, etc.). Also, is it safe to buy a used inverter/charger, or might I be risking a fire by doing so?

I probably would not be concerned about a used inverter/charger so long as the price was right and it was working. If you are concerned about safety, you may want to look for a UL listing on the device.

[Sunking]

I can help you out here a bit and help narrow down your options and dispel some myths you have brought up.

First let's discuss generator and Inverter (Run Times). Generators Both genny and inverterts, you get what you pay for. They come in three grades of quality.

1. Consumer or Light Duty. Build quality and price is all over the place. Run time is not determined by be over taxed in the manner which I think you meant. As long as it is not over loaded electrically. They can run for days or weeks before the seize up from the valves, pistons, or other moving parts just plain wear out coupled with the oil breaking down. They are designed to be cheap and sold to consumers and use Gasoline as a fuel source which is the last thing you really want if it is mission critical.

2. I wil lump commercial and industrial together because there is a fine line between them. They are simply designed for Heavy Duty extended period of times. Everything in them is designed for abuse and long life. They use LPG and Diesel fuels. They also do not come with fuel tanks unless they are on a Trailer for portable field ops. If a portable is going to used for long period of times like a communication facility, you park a fuel truck next to them. Pad mount genny's use large fuel tanks that may be above or below ground. Large facilities use two tanks. Once called a Day tank that can run the genny for days. Th eother tank is a very large tank and pumps are used to fill the Day tank. Just about all large gennys larger than 40 Kw use Diesel Fuel. Gasoline would never be considered. Too expensive and cannot be stored for any long periods of time.

Inverters you are way off base. Sure inexpensive box store and mobile Inverters are not designed for continuations use. Even inexpensive hard wired Inverters used for solar and battery can run continuously. Any small biz up to mega sized businesses use what is called a Dual Conversion UPS. That means Rectifier (charger) > Battery > Inverter. Their data and communications equipment run full time on the UPS Inverter. The rectifier changes AC power to DC power to charge the bateries and run the load equipment off the Inverter. If it is really mission critical the UPS will be powered from a generator when commercial power fails.

OK let's get to your application. First not a Solar Application, so let's not go there. You have a few options. If everything you intend to power requires AC power you can either buy a Dual Conversion UPS which will be expensive, or build your own McGuiver aka James Bond UPS. Real simplee you buy a Rectifier sized to both run the Inverter and charge the batteries.

So here we go. By your own admission you stated you have brief Brown-Outs and maybe an extended outage once a year. That means you have to decide which outage you want to cover. For short outages and Brownouts is cheap, but will not carry you through a long outage without a genny. Or you can make a system with batteries to carry you a day or few days. It is expensive due to the much larger battery and Rectifier.

So here is how pros do it and I have designed hundreds of them both large and small. I already gave it away. You use a Rectifier that can power the Inverter and charge the batteries quickly, but th ebatteries are only sized to carry you through say 30 miinute to an hour to allow you to get the generator on-line.

You canno tdo this until you specify the requirement. To go this route you have to use special AGM batteries made for a UPS because the Rectifier will charge the batteries ver fast plus enough to run the equipment at the same time. The batteries are required to be discharge at very high rates of 1C to 4C. Very few batteries can do that. It takes a special expensive UPS AGM battery.

To your last question there is no special equipment required to keep AGM batteries inside confined spaces. AGM's were developed for air and space craft in very tight confined spaces. So there i sno issue having them inside. Commercial UPS have them crammed into a cabinet with little or no ventilation.

OK back to you. Define the requirements and how deep are your pockets? It gets real expensive real fast.

[madsalts]

great information, thanks. I'll let you know exactly what my requirements are. It will take a few days, as I'm looking to make some equipment upgrades. Once I figure out what I'm going to be running, I'll know what my power requirements will be.

[lkruper]

great information, thanks. I'll let you know exactly what my requirements are. It will take a few days, as I'm looking to make some equipment upgrades. Once I figure out what I'm going to be running, I'll know what my power requirements will be.

How expensive are your fish? I used to have salt water tanks and the fish are pricey.

[madsalts]

Well, at long last, I'm posting an update. I cut a finger earlier, so I'll keep the typing to a minimum. This is mainly asked of "Sunking", but anyone can answer. I have not yet measured anything with the kill-a-watt. I need to provide backup to a fridge/freezer, heater (for an aquarium), and a few aquarium pumps. An online source says that a fridge/freezer will draw about 130 watts, max, at any one time. The heater will draw 25 watts at any time. The pumps will certainly draw less than 50 watts total, at any one time. So, I'm looking at about 200 watts. Of course, there are issues of startup draw, etc. As a ballpark estimate, a dual-conversion UPS rated at 3000 VA, 2100 Watts (link at end of post) seems like more than enough. I'm asking this now, because if the linked UPS is a good deal relative to the route involving the inverter and rectifier that Sunking mentioned, I'll get it before it slips away. Otherwise, I'll take actual measurements. (I have not taken measurements yet since I have not yet replaced the fridge/freeezer, which I plan to do soon.)

However, if this UPS seems to be wildly more expensive than what I'd pay for a sufficient inverter/rectifier setup, please let me know. I've also linked to a GE "refrigerator inverter board", which is probably similar to what I'd be paying for an inverter. I have no idea how much a rectifier would cost.

Importantly, I'm a novice when it comes to electronics. Another $100-$200 on the UPS would be worth the price of not having to spend weeks figuring out how to safely implement the McGyver method. So, what route seems appropriate in my case? I'm very appreciative of the help so far.

UPS:

http://www.ebay.com/itm/Minuteman-CPE3000-Dual-Conversion-Online-UPS-Tower-3000VA-2100W-120V-/301987248265?hash=item464fd7b889:g:syoAAOSwmtJXYqrG

refrigerator inverter board:
https://www.amazon.com/General-Elect...ds=ge+inverter

[Mike90250]

First - some more data for the fridge. 130w is about right when running. Add another 400w for the defrost 15 min cycle. Starting motor surge generally needs a 1Kw inverter to start. A good energy star fridge is about 1Kwh daily usage.
Just buying a fridge inverter repair board, will not convert a standard fridge to an inverter fridge, it needs a new compressor with different coolant, You buy an inverter fridge, you can't convert one.

So, UPS. How many hours do you need backup for ? 8 hours ? 16? 24? 48? That sets the size of the battery pack.
the link to the UPS Minuteman CPE3000 VA should do the trick. Just need to figure the battery voltage and calculate the pack size for your desires.

[foo1bar]

the link to the UPS Minuteman CPE3000 VA should do the trick.

That says it requires a 30A plug ("L5-30P input plug")

If it were me, I'd be looking at a smaller UPS (or 2 UPSes) and a generator.
It sounds like 75W for the aquarium and 130-500W for the fridge/freezer.
I'd probably not do anything with the fridge/freezer, and buy a UPS for the aquarium - probably something for ~$150 that has 1500VA/865W. And should run for 13min at ~430W, so probably >25 min at load you'd have on it.
Then buy a nice quiet honda 2000W generator for ~$1000.

A fridge/freezer can last >1 hour without power with no problem (just keep the door closed). So I'd probably not do a UPS on it.

[SunEagle]

That says it requires a 30A plug ("L5-30P input plug")

If it were me, I'd be looking at a smaller UPS (or 2 UPSes) and a generator.
It sounds like 75W for the aquarium and 130-500W for the fridge/freezer.
I'd probably not do anything with the fridge/freezer, and buy a UPS for the aquarium - probably something for ~$150 that has 1500VA/865W. And should run for 13min at ~430W, so probably >25 min at load you'd have on it.
Then buy a nice quiet honda 2000W generator for ~$1000.

A fridge/freezer can last >1 hour without power with no problem (just keep the door closed). So I'd probably not do a UPS on it.

I agree with your plan. It seems to me to be the lowest cost solution for critical power backup of the aquarium and fridge.

Even my small dorm room sized fridge uses about 500wh a day. That can require a few hundred watts of panels and about a 200Ah 12v battery system. Which is not cheap.

[madsalts]

Well, a few thoughts:

First off, I have a 2,000 watt generator. If my understanding is that I will need to have a battery array that can charge quickly using special "UPS AGM" batteries, not just standard "AGM" batteries.

I'm guessing that by hooking the generator to the UPS, I will be powering the "devices" at the same time that the batteries are charging. When the generator is turned off, I will then feed off of the batteries until I connect the generator again. Is this correct?

As for my needs, after doing some reading, it seems that a freezer can keep things frozen for up to 48 hrs if it is full. If this is correct, and if I fill dead space with ice, it seems that I can get by indefinitely just by buying ice. As for the fridge section, allowing food stored in it to be a loss seems like a reasonable price to pay for not having to buy backup for the fridge/freezer. Besides, every once in a while I can hook the generator to the fridge/freezer to keep it cool. Considering that with the aquarium I'd only be drawing 50 watts an hour, it seems that building a system for at least 24 hour battery backup wouldn't be that expensive. I think that this is the way that I'll go.

Since I won't be using this system for computers, but only for pumps and a heater, I'd like to go with a "line interactive UPS" rather than a "double conversion" UPS, just because of cost. It seems that considering my energy needs, I can get such a thing for under $200 new. Are there any brands that I should be looking at? Any that I should avoid (besides the no-name made-in-China knockoffs)?

Thanks.

Edit: It was mentioned earlier that I should avoid the type of UPS sold in "box stores". How would I know if I'm looking at something that's even in the same ballpark as what I'm looking for as far as continuous run time? Is the ability to connect an external battery a good indicator?

[inetdog]

One very important factor is that most UPS units are designed to be used only a few days per year (except the always-on dual conversion types). The batteries and charging system supplied for this usage will quickly destroy the batteries if instead you rely on the UPS every day to allow for short generator run times.

You may need to look instead at a system designed from scratch for the use pattern you are planning for.

[madsalts]

I only intend to use this a few days per year. Considering the wear on these devices, would a used double conversion UPS be a wise choice?