Using a lead acid 24/7

We get a lot of power failures and I would like to keep my TV and satellite working during this time.
But as the decoder takes a lot of time to reboot/rescan I would like to permanently let it work of a lead acid and a inverter, even if the city power is on. The battery will be permanently connected to an intelligent charger. What is wrong with what I want? Will I drastically reduce the life of either the lead acid, charger or inverter by leaving them on 24/7?

Easiest and cheapest will be to buy a manufactured solution like one of these:

It's called a UPS, which is an acronym for "Uninterruptable Power Supply". They have a small inverter, small charger, and small sealed lead-acid battery built in. Most quality ones also provide surge protection. You can usually find them in retail electronics stores, as well as large office supply stores.
They are available in a variety of wattage outputs / runtimes. Made by a variety of manufacturers:
APC (A Schneider Company)
Cyberpower
Tripp-Lite
I'm sure there are other manufacturers as well, but those are the ones I'm familiar with.

APC has a wealth of resources on their website, as well as free giveaways(note multiple companies such as Staples, Office Max, etc sell them)-I am not advocating one company so I hope this stays within CPF rules. I have used several variations, from a $29 one to protect a PC up to large capacity to protect networks, phone systems and copiers. Simple to use, software included to monitor your power on line, and in the event of a massive disaster it allows you to power off equipment in the proper sequence to save data in the event of a scenario where power could be off for several weeks. In addition, the lead acid batteries are replaceable and some units include USB out of 5 volts so you can charge your flashlights, flashlight batteries and phone...

I think the questions needed to be asked is how long is the shorter power outages that a UPS can reasonably handle and the total load of all items needing to be powered. There is two levels of power for each item and that would be full on and off/standby. I had a small ups on my dvr and 5 dvd player to remember settings and programming at one time I had a larger one that was on my tv set too but it is an old tube type that takes a lot of power which cut into total backup time so I went to just having the items I needed on it instead on a smaller one that could run for about 15-20 minutes.
We used to have outages lasting several hours often here till a huge ice storm tore things up and they redid things and the outages are almost non existance now mostly a blink or so. I recommend at least 10-15 minutes runtime and I recommend that your outage average you calculate about double runtime on your battery/inverter (UPS etc) combo. I think if you are draining it often more than 75% it may reduce the battery life than keeping it below 50%.

Indeed, if required runtimes are on the longer side, that would need to be factored into the decision of which one to get. Fortunately, most manufacturers will have a reference chart of loading vs runtime for each model, as they do vary in battery capacity.

Get a good charger, good true sine wave inverter, and a good battery. Make sure the charger keeps the voltages (at the battery terminals) within the battery manufacturers specifications at all times. Essentially what you are building is a UPS like those used in datacenters except on a smaller scale and with no switch time, you are good to go.

UPS units come in essentially two flavors. Standby units, which start up when the utility power fails. Equipment connected to a standby UPS is likely to see the power failure, the question is how long can they 'ride through' the outage, because it will take at least a fraction of a second for a Standby UPS to come online and pick up the load. What you are probably looking for is an on-line UPS. These units are connected to the utility power at all times, and operate at all times. The equipment is always being powered from the UPS. When the Utility power fails, the battery (which are float charged while the utility power is on) take up the load, and there is NO interruption in the power that the equipment sees until the batteries are depleted, so there is no need for any ride through capability. Places where maintenance of the power is critical utilize online ups units.

Generally the on-line units are a good deal more expensive because they have to be designed for continuous operation (and often have a longer run time if the lights go off), where as the backup unit only have to run as long as there is battery power, and that usually is measured in tens of minutes. In the largest and most critical installations the on-line ups is backed up by a generator. If the power remains off for more than a few seconds, the Generator will start up, close the transfer switch, and begin to
supply utility power to the UPS within a minute or two of the outage. Obviously such systems are fairly expensive, but prevent disruption of services that are deemed critical.

Most low power UPS for home use are the 'Stand by' type. You are looking for a commercial unit that is 'on-line'

TBH, I don't think an online ups will be required for such a job as OP describes. The <4ms transfer time of the cheap consumer type ups's should be sufficiently fast to prevent a power cycle of the equipment specified.

A normal UPS comes on fast enough as most electronics have capacitors in their power supplies that can ride the short time for a UPS to switch on. I've had several inexpensive UPS that when power glitched they came on so fast you couldn't tell they weren't always on or not.

Hi,

When I lived in the countryside in England power outages were a very frequent occurence for me. On average we would get:
- Every week: 2-5 second outage
- Every month: 1 minute outage (usually night time)
- Every 6 months: 1 hour+ outage

I ran lots of computer hardware including a home server so this was a problem. I invested in a couple of UPS units like those recommended here. One was a small standby only unit like the photo posted earlier, and it had the duty of running a small server and networking gear. I installed it 7 years ago - and it was still doing that job on the original battery (which could still support the load for 40 minutes when I tested it) when I moved out of that house.

I also had a larger unit that was classed as line interactive. These work in a similar way to the standby units with the inverter only kicking in once power fails, but they also include a large autotransformer. This allows them to step the voltage up/down without wasting battery power running the inverter. I used this unit to run everything else in my room - including a powerful desktop computer + accessories, a TV + games consoles and lighting.

The only issue I ever noticed with not using a real on-line UPS is that my flourescent desk lamp (which is NOT designed to run off a modified sine inverter anyway) would flicker very slightly when the power switched to the inverter. In real life the very small drop out of a modern standby UPS is not enough to upset equipment.

tl:dr; A standby UPS of appropriate capacity will be perfectly fine for backing up TV gear. Just make sure you buy a quality brand and that you size it well enough. Right now I have an APC ES 750G on my desktop computer and monitor. The power in Tokyo is reliable, but they give us a breaker with a stupidly low rating (30A at 100V - only 3KW) so it is easy to trip it by accident in the winter.

It comes with some software that lets you monitor it - here is mine:

Thanks a lot for all the great advice. I do have a UPS. But the batteries are far too small to handle my TV etc for even 5 minutes I am sure. Can I possibly power this UPS with an external bigger lead acid? I am thinking of getting a 102A deep cycle that will stand next to it to power it. Will it work? I have read somewhere of someone who did it and it worked, but another guy said his UPS went up in smoke the moment the power came back on after a extended power failure.

In my country we have severe power shortages, new power stations are in the process of being built. For now I get about 2 power cuts per week, each lasting 2 hours. Sometimes we get load shedded more than twice a week.

As long as you match the battery voltage, it will work. HOWEVER, the charger on a small ups is also sized appropriately for a small battery and will take a very long time to recharge a 100Ah battery. One option would be to get a decent sized charger (10-20A, intelligent, 3-stage) to work in parallel with the ups's built in charger. This will get you some decent recharge times on that larger battery.

mellowhead said:

One option would be to get a decent sized charger (10-20A, intelligent, 3-stage) to work in parallel with the ups's built in charger.

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So the second charger connected will not damage the charger of the UPS? I never knew one could couple multiple chargers together, especially intelligent fully automatic chargers.

Yep, there should be no problem doing that. I design and build power systems every day with multiple charge sources (solar, wind, micro hydro, grid, generator, etc.)

lightseeker2009 said:

Thanks a lot for all the great advice. I do have a UPS. But the batteries are far too small to handle my TV etc for even 5 minutes I am sure. Can I possibly power this UPS with an external bigger lead acid? I am thinking of getting a 102A deep cycle that will stand next to it to power it. Will it work? I have read somewhere of someone who did it and it worked, but another guy said his UPS went up in smoke the moment the power came back on after a extended power failure.

In my country we have severe power shortages, new power stations are in the process of being built. For now I get about 2 power cuts per week, each lasting 2 hours. Sometimes we get load shedded more than twice a week.

Click to expand...

I run a HP workstation with flat panel monitor,and my digital read outs off of an APC 2200 volt amp UPS. I get around 20 minutes of run time on the two 12 volt batteries inside. APC sells an axillary battery unit that plugs into their UPS units to extend run time. My reason for the UPS was two fold. First, they produce clean power, perfectly regulated between 120 and 123 volts. I have seen issues with the local power company where early morning they supplied over 138 volts. The in-line units show when they have to make up the difference in voltage and when the in coming voltage exceeds the +/_ 4% rating. Secondly my UPS protected me from a power loss and having to recalibrate the zeros on my machines.

Unlike consumer surge protectors, UPS units in the event of a lightning strike get fried instead of the items connected.

NoNotAgain said:

Unlike consumer surge protectors, UPS units in the event of a lightning strike get fried instead of the items connected.

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I'd like to emphasize this quote! That's another reason to get a quality UPS.

If you are only running a TV and set top box, assuming your TV is a modern LCD TV with an LED backlight a fairly large APC 2000VA line-interactive unit should be able to hold up for 2 hours. You are looking mostly at the capacity of the batteries supplied with the unit - you don't need to actually draw that much power from it. While the nicer true-sine models are better, you need to consider your budget. When I bought my large UPS I had enough budget to either buy a 1500VA line-interactive unit or a 1000VA true-sine unit. I went for the line-interactive unit not because of the extra load capacity but because it had larger batteries fitted as standard.

Most of the APC models from 1500VA and upwards support connecting an additional battery pack like those mentioned by NoNotAgain. That might be a good idea for you as you can buy an extra battery unit for it later if it does not last long enough for your needs.

There is just one problem - these units are fairly big and heavy, and often designed for rack mounting. However APC supply some of them with stands so you can run them standing on their edge safely.

I would advise against connecting a second charger in parallel with a UPS - atleast with APC models. They use semi-smart battery monitoring and it would confuse the BMS, because the battery would store more energy than the BMS charger has pushed into it.

I also have a APC ups, but mine does not have the external slot for an extra battery.

lightseeker2009 said:

Thanks a lot for all the great advice. I do have a UPS. But the batteries are far too small to handle my TV etc for even 5 minutes I am sure. Can I possibly power this UPS with an external bigger lead acid? I am thinking of getting a 102A deep cycle that will stand next to it to power it. Will it work? I have read somewhere of someone who did it and it worked, but another guy said his UPS went up in smoke the moment the power came back on after a extended power failure.

In my country we have severe power shortages, new power stations are in the process of being built. For now I get about 2 power cuts per week, each lasting 2 hours. Sometimes we get load shedded more than twice a week.

Click to expand...

I wouldn't recommend using a lot larger battery with the electronics of a small UPS for one reason is that the small UPS may be made to only be able to handle a certain load for a certain amount of time and if you are loading it down already for a short runtime it is probably approaching its maximum load and possibly that amount of power puts a strain on it that it can manage for a short while (5-10 minutes) but it will not be able to maintain that level of power output for a long long time without slowly frying the electronics. Smaller UPSes typically don't have very good heatsinking compared to the larger ones which some of them have larger fins on components and even fans and ventilation in the case to remove heat generated from the components.
As for the charger circuit having to deal with a larger battery it would put a strain on it for sure having to run a lot longer and if you were to drain the battery down to nearly nothing your UPS could be useless for half a day while the small charger caught up the large battery in charge. In other words if you had a 10Ah battery in a UPS and it took 2 hours to recharge and your outages drained a 100Ah battery to dead it would take 20 hours to recharge that larger battery to full which means until that 20 hours was completed your 100Ah battery would not be restored to capacity if another outage ensued. It is possible that some units the charger is designed with the idea that the battery is a certain sized and isn't smart enough to adjust charging levels for a larger battery to either increase power to it or to protect the charging circuit from being loaded to heavily for it to handle.