Simple Load Shedding Setup Pros & Cons?

[fuzex]

My neighbor has just bought this little setup for R4200, which she uses just for her lounge. She runs her tv, lights and wifi which I think is all most people really need during loadshedding provided you have a gas stove/plate for cooking.

1. What are the pros and cons of this setup for this use case?
2. Is there a better setup for the same cost?
3. How long do these batteries last during power outages?
4. What is the lifespan of these batteries?
5. Does this inverter/ups work fine?
6. Will it over charge the battery?
7. Is there a better setup for the same/similar price range?
   
   So many questions perhaps you can bring some issues she may have in the near future with this setup...

Battery:
6-GSP(G) - 100Ah Gell Battery

Inverter/UPS:
TelePower 1KVA UPS

[Bobster.]

Well you hit a nail on the head. If this is what your neighbour wants, and if that want is fulfilled, then the system is adequate. 

It won't save any money, but that may not be part of the requirement.

But all these systems that are built on lead/acid or gell batteries are really designed for occasional outages. Regular outages such as we currently have will punish those batteries and you may find they need a lot of replacement. There are two potential problems
1) The loads are enough to take the battery past 50% SOC during a load shed. Those batteries don't like being discharged a long way, and doing so regularly will shorten their life span.
2) When load shedding stages get high, the inverter is not able to recharge the battery fully before the next load shed. If I read the labels correctly, this system will have that problem. I note that there's no SOC indication on this system.

It costs more up front, but a lithium battery will do you better over the long haul - you can discharge them deeper, more often. And we're in it for the long haul. We no longer have a situation where there would be spells of load shedding and you wondered IF there would be load shedding today. Now the only wondering is what stage of load shedding we will have.

All that said, I can't think that you will do much better for R4200. That's really not a lot of money to spend on this type of system. 

Edited March 27, 2023 by Bobster.
add note about SOC indication

[Bobster.]

PS: This is how I really started, with this sort of system (though a bit bigger). I also installed something similar for my mother, along with a one plate gas stove. You're right - having some lights and the telly during a load shed makes a difference.

Looking forwards, if your neighbour likes to warm the bed in winter, best invest in some hot water bottles.

In my mother's case we bought some of those emergency LED lamps that charge when there's grid power. This means that the inverter doesn't carry the lights, and also that she doesn't have to run leads around the place. So when she turns in, if there's load shedding she can still read in bed, which makes a difference to her comfort.

[Scorp007]

Batteries will always be something with very diverse views based on our experiences. My non scientific test over the last few months. 

We have 4 small UPSes connected to desktops. This is only to have enough time to shutdown and then go and switch on the power from the genny serving 3 companies in a complex.

My very old UPS is a APC charging at 0.6A. Recently I found the 7Ah batteries don't last. I then started a test. Got 2 old batteries that after a full charge could only supply 6A for 12 seconds. The 3rd battery tested better but I used a 1A load and it took 1hour to drop to 12V(+/-50% SOC) These 3 have never been discharged to below 12V. The other 3 we have to replace the battery every 2 months. These 3 old batteries keep my desktop going for 60min while the others with new batteries are once again only providing power for about 4 min.

Verdict: A few batteries even if old and providing less current each can be a much better system than 1 x new.

[Modina]

@Scorp007 Those UPS systems tend to run very hot.  At my previous company we started cutting holes for cables and placing the battery next to the UPS on the outside, to increase the MTBF of the batteries.
SLA are not "sealed".  I have sometimes "repaired" SLA batteries by simply popping off the top plastic lid, removing the 6 rubber grommets and filling with distilled water.  Then replacing the grommets and giving them a good charge.  SLA's are not wet batteries but still hate heat and dry out.  I could use "repaired" batteries to operate gate motors without problems for many more months.

Heat and vibration are the two killers of lead acids.  Many BMWs and some other cars, had the battery in the trunk.  Less heat and less vibration.  They typically last 5+ years.  I think certain BMW 5s had the battery up front, and people where lucky if these survived 24 months - modern engines are covered in plastic covers and trap the heat.

@fuzex For any TV run from batteries, I would suggest the following:
1. Make sure it is a LED TV and not an old LCD - LEDs use about 1/3 of a LCD TV
2. Try to limit the screen size of the TV.  Large screens = lots of power drawn.

For R3000 you can buy a new 32" Samsung.  A bargain considering what batteries cost.   Your batteries will thank you.

For the small scale user only wanting a TV, WiFi & lights, if he is a bit DIY inclined, I would suggest getting a TV that runs from a 19VDC laptop-type power brick.  Many of the 32" Samsungs use this setup.  Then get a DC-DC boost converter for about R120 and run TV, lights and WiFi straight from 12V.  Advantages are: Safety (no high voltages that are unlikely to have earth leakage protection in these small systems), no noisy fans, no inverter expense (you still need a charger) and most important of all, no power losses due to the inverter.  These losses can be substantial.

I have a 24" Sinotec TV which I brought a few years ago specifically for load shedding.  It runs straight from 12V and consumes about 1Amp when set to a medium brightness. i.e. 12W.   A modern 32" LED TV should be about 20-24W.   An old 32" LCD will use over 70W by comparison.  Large screen LED TVs will likely also use 70W and more.

Similar logic can be applied to PC monitors.  Desktop PCs are not power optimised and are heavy on juice.  I personally have a dislike for laptops and prefer a desktop.  When replacing a desktop, consider one of these mini-PCs (the size of a paving brick, such as the Intel NUCs).  They run much more efficient and are available from a Celeron to i7.  So although small, they have a lot of CPU power.  And again, these are powered by external 19VDC laptop-like supplies.

[fuzex]

For the same price I'm going to buy my dad a 2kw generator. I can't see him replacing a R2500 battery every few months. Thanks for all your comments though. Helped me make a good financial decision. 

[Modina]

A generator is NOT the right thing for powering a TV and lights.  But if your dad say, wants to use power tools then it's perfect.  I rather replace a R2500 battery once a year then schlep around petrol every third day, listen to the racket, having to manually start the genie, twiddle with the choke, tweak it's throttle and inhale stinking exhausts.

In an emergency, I prefer another 4-wheeled genie.  It's called a car - yes it only has 12V and limited power.  At least it is silent, clean burning and I would expect it to not be heavier on fuel than a primitive, carburettor-fed genie.

[Scorp007]

2 hours ago, Modina said:

@Scorp007 Those UPS systems tend to run very hot.  At my previous company we started cutting holes for cables and placing the battery next to the UPS on the outside, to increase the MTBF of the batteries.
SLA are not "sealed".  I have sometimes "repaired" SLA batteries by simply popping off the top plastic lid, removing the 6 rubber grommets and filling with distilled water.  Then replacing the grommets and giving them a good charge.  SLA's are not wet batteries but still hate heat and dry out.  I could use "repaired" batteries to operate gate motors without problems for many more months.

Heat and vibration are the two killers of lead acids.  Many BMWs and some other cars, had the battery in the trunk.  Less heat and less vibration.  They typically last 5+ years.  I think certain BMW 5s had the battery up front, and people where lucky if these survived 24 months - modern engines are covered in plastic covers and trap the heat.

@fuzex For any TV run from batteries, I would suggest the following:
1. Make sure it is a LED TV and not an old LCD - LEDs use about 1/3 of a LCD TV
2. Try to limit the screen size of the TV.  Large screens = lots of power drawn.

For R3000 you can buy a new 32" Samsung.  A bargain considering what batteries cost.   Your batteries will thank you.

For the small scale user only wanting a TV, WiFi & lights, if he is a bit DIY inclined, I would suggest getting a TV that runs from a 19VDC laptop-type power brick.  Many of the 32" Samsungs use this setup.  Then get a DC-DC boost converter for about R120 and run TV, lights and WiFi straight from 12V.  Advantages are: Safety (no high voltages that are unlikely to have earth leakage protection in these small systems), no noisy fans, no inverter expense (you still need a charger) and most important of all, no power losses due to the inverter.  These losses can be substantial.

I have a 24" Sinotec TV which I brought a few years ago specifically for load shedding.  It runs straight from 12V and consumes about 1Amp when set to a medium brightness. i.e. 12W.   A modern 32" LED TV should be about 20-24W.   An old 32" LCD will use over 70W by comparison.  Large screen LED TVs will likely also use 70W and more.

Similar logic can be applied to PC monitors.  Desktop PCs are not power optimised and are heavy on juice.  I personally have a dislike for laptops and prefer a desktop.  When replacing a desktop, consider one of these mini-PCs (the size of a paving brick, such as the Intel NUCs).  They run much more efficient and are available from a Celeron to i7.  So although small, they have a lot of CPU power.  And again, these are powered by external 19VDC laptop-like supplies.

@Modina

The lead acids on our UPSes are not dry for sure. They just have to provide more current than designed for a few times a day due to LS. 

Perhaps you should look at the power used by LED TVs. 

This info from Samsung  support. Most people buy smart TVs and they use a lot more power. 

Edited April 2, 2023 by Scorp007

[fuzex]

12 hours ago, Modina said:

A generator is NOT the right thing for powering a TV and lights.  But if your dad say, wants to use power tools then it's perfect.  I rather replace a R2500 battery once a year then schlep around petrol every third day, listen to the racket, having to manually start the genie, twiddle with the choke, tweak it's throttle and inhale stinking exhausts.

In an emergency, I prefer another 4-wheeled genie.  It's called a car - yes it only has 12V and limited power.  At least it is silent, clean burning and I would expect it to not be heavier on fuel than a primitive, carburettor-fed genie.

Why do you say a generator is not for TV and Lights? We've been using a generator for years with no issues. Yes its a pain at times but it provides reliable energy. Regarding batteries I read that these Gel batteries like the one in this post, is only rated for 200-300 cycles. With the irratic load shedding that will need to be replaced every few months, not once a year. Correct me if I am wrong?

Edited April 3, 2023 by fuzex

[Bobster.]

31 minutes ago, fuzex said:

Regarding batteries I read that these Gel batteries like the one in this post, is only rated for 200-300 cycles. With the irratic load shedding that will need to be replaced every few months, not once a year. Correct me if I am wrong?

Like everything else, it depends on how you use/abuse them. My mother has 2x102aH SLAs, and they are getting on a year now. The inverter runs ONLY her decoder and TV and possibly charges a phone. So the batteries are not heavily loaded and so far they are lasting, despite daily load sheds.

But your general point is correct. A guy I have dealt with for these inverter & battery systems told me that when he started in the business, he wouldn't give you a written warranty, but he'd tell you to expect 5 years from your batteries (be they SLA or gel). Last time I spoke to him (maybe a year ago) he said with the load shedding, if you get 2 years you're doing well. A few months later load shedding became a daily thing, so his expected lifetime will have gone down again. 

Those systems are really designed for occasional outages, not for load sheddng every day, multiple times per day. 

I can't be too rude about them. I had one that served me well for a couple of years, and my mother now has one that is making a big difference for her. Some folks can't afford expensive solutions, but if they can keep the lights on and watch whatever it is they like on TV, then that is a lot better than candle power.

Edited April 3, 2023 by Bobster.

[Bobster.]

10 hours ago, Scorp007 said:

@Modina

The lead acids on our UPSes are not dry for sure. They just have to provide more current than designed for a few times a day due to LS. 

Perhaps you should look at the power used by LED TVs. 

This info from Samsung  support. Most people buy smart TVs and they use a lot more power. 

Those are the commonly repeated figures, but I doubt them. Because my mother has a TV that is 40 inches or less, and a DSTV Explora, and that little lot draws 170W from her inverter. It's not the Explora chewing all that power either. If I turn the TV off and leave the Explora on, her inverter doesn't actually register a draw, so negligible is it's consumption. Here in SA we hardly ever just run a TV, there's always some media stick or decoder that needs power too.

 

[Modina]

54 minutes ago, fuzex said:

Why do you say a generator is not for TV and Lights? We've been using a generator for years with no issues. Yes its a pain at times but it provides reliable energy. Regarding batteries I read that these Gel batteries like the one in this post, is only rated for 200-300 cycles. With the irratic load shedding that will need to be replaced every few months, not once a year. Correct me if I am wrong?

Of course you can run a TV from a generator.  A generator will run nearly anything because it generates a true sinewave.  What I meant is that a generator is not practical if all you want to do is watch TV.  If you insist watching on a 55" screen then you might have to use a generator.  My point is use a modern, smaller sized TV which will not be a high load to a battery system.  Battery and solar systems are so expensive, that if your TV is too power hungry, it would make a lot of sense to replace it.  So doing will reduce the battery/inverter size.  You spend much less on a new TV than to power an inefficient TV from lead acid batteries that will need regular replacement.

Many years ago I brought a 2.5KVA generator.  It had a carburetor problem right from the beginning.  It ran too rich, had high consumption and wouldn't start easily.  Later I brought a 5KVA.  It leaked oil. I never used it.  Good luck to anyone who thinks he can buy a cheap, made in China, genie and use it EVERY DAY to watch TV.  If you do that, you will either need to fiddle with it like a lawnmower, or you will replace it faster than a lead-acid battery.

[Modina]

47 minutes ago, Bobster. said:

Those are the commonly repeated figures, but I doubt them. Because my mother has a TV that is 40 inches or less, and a DSTV Explora, and that little lot draws 170W from her inverter. It's not the Explora chewing all that power either. If I turn the TV off and leave the Explora on, her inverter doesn't actually register a draw, so negligible is it's consumption. Here in SA we hardly ever just run a TV, there's always some media stick or decoder that needs power too.

@Bobster.  170W for a 40" TV is exceptionally high, I don't think that is for an LED TV.  It's what I would expect from LCD cold cathode backlight technology.
What make of inverter does your mom use that is so low on losses?  Many inverters do not specify the efficiency and even less, give the no-load quiescent current.  The Victrons seem class leaders in this regard and I have seen one or two others.  There is junk out there that will have 40% losses.  Those can be used to keep your coffee cup warm.

[Bobster.]

19 minutes ago, Modina said:

@Bobster.  170W for a 40" TV is exceptionally high, I don't think that is for an LED TV.  It's what I would expect from LCD cold cathode backlight technology.
What make of inverter does your mom use that is so low on losses?  Many inverters do not specify the efficiency and even less, give the no-load quiescent current.  The Victrons seem class leaders in this regard and I have seen one or two others.  There is junk out there that will have 40% losses.  Those can be used to keep your coffee cup warm.

Hi @Modina, I can't provide the details. The TV is smart, I think a Hisense. Because it has Netflix and the like built in, I assume it's fairly modern. The 170W I mention is the total of the decoder and the TV and is reported by the inverter, which is one of these trolley jobs (Crystal?) that uses SLAs. Possibly the decoder consumes very little unless it has to provide an HDMI output. I'll measure it when I get the chance, but it's not as big as my 44inch Samsung.

It's no state of the art inverter. I can't even provide a picture because nobody seems to be stocking them anymore. Mod sine output. 

[Scorp007]

4 minutes ago, Bobster. said:

Hi @Modina, I can't provide the details. The TV is smart, I think a Hisense. Because it has Netflix and the like built in, I assume it's fairly modern. The 170W I mention is the total of the decoder and the TV and is reported by the inverter, which is one of these trolley jobs (Crystal?) that uses SLAs. Possibly the decoder consumes very little unless it has to provide an HDMI output. I'll measure it when I get the chance, but it's not as big as my 44inch Samsung.

It's no state of the art inverter. I can't even provide a picture because nobody seems to be stocking them anymore. Mod sine output. 

The other day I measure a friend's LED TV and the draw was 150W. My picture I posted from Samsung clearly states it's a LED TV. We always see these 24-50W values and it is not generally the average draw. 

Another point I have followed when draws are calculated. They always take a kettle as 1.2kw and try and find one below 1.7kW in a shop. I know they are available but not at Makro, Hirsch, Game, Hifi Corp, Clicks etc. 

[fuzex]

46 minutes ago, Modina said:

Of course you can run a TV from a generator.  A generator will run nearly anything because it generates a true sinewave.  What I meant is that a generator is not practical if all you want to do is watch TV.  If you insist watching on a 55" screen then you might have to use a generator.  My point is use a modern, smaller sized TV which will not be a high load to a battery system.  Battery and solar systems are so expensive, that if your TV is too power hungry, it would make a lot of sense to replace it.  So doing will reduce the battery/inverter size.  You spend much less on a new TV than to power an inefficient TV from lead acid batteries that will need regular replacement.

Many years ago I brought a 2.5KVA generator.  It had a carburetor problem right from the beginning.  It ran too rich, had high consumption and wouldn't start easily.  Later I brought a 5KVA.  It leaked oil. I never used it.  Good luck to anyone who thinks he can buy a cheap, made in China, genie and use it EVERY DAY to watch TV.  If you do that, you will either need to fiddle with it like a lawnmower, or you will replace it faster than a lead-acid battery.

Your point is noted on the TV issue. Thanks for making it clear, it does make sense. The TV, Wifi, lights are the basic essentials, not to mention fridges also need to keep running if possible. Just the other day my dad had to throw out all the meat in the freezer (R2000). I don't see a gel battery being the answer for him in the long run.

[Bobster.]

1 hour ago, Scorp007 said:

The other day I measure a friend's LED TV and the draw was 150W. My picture I posted from Samsung clearly states it's a LED TV. We always see these 24-50W values and it is not generally the average draw. 

Another point I have followed when draws are calculated. They always take a kettle as 1.2kw and try and find one below 1.7kW in a shop. I know they are available but not at Makro, Hirsch, Game, Hifi Corp, Clicks etc. 

Anyway, 170W is the reported load. With those two batteries she has 2.4kWh. Half of that is 1.2kWh. At 170W, that's 7.2h, which is why her batteries are lasting.

So to repeat what I said to @fuzex, lifetime of batteries is elastic and a lot depends on how you load them. My Mum's batteries aren't working very hard, so, fingers crossed, she's doing OK at present.

Edited April 3, 2023 by Bobster.
spelling

[Bobster.]

1 minute ago, fuzex said:

Your point is noted on the TV issue. Thanks for making it clear, it does make sense. The TV, Wifi, lights are the basic essentials, not to mention fridges also need to keep running if possible. Just the other day my dad had to throw out all the meat in the freezer (R2000). I don't see a gel battery being the answer for him in the long run.

My understanding is that you don't want to run a fridge on an inverter unless that inverter has pure sine output. Experts can correct if I'm wrong, but I want to put it out there so we can get the answer one way or the other.

Issues like this are what I think of as the soft or hidden benefits of PV. It's not just what you save on the meter. It's knowing that your fridges are always on and etc. Harder to put a rands and cents value to, but still worth something.

[Modina]

1 hour ago, Bobster. said:

My understanding is that you don't want to run a fridge on an inverter unless that inverter has pure sine output. Experts can correct if I'm wrong, but I want to put it out there so we can get the answer one way or the other.

Fridges are a problem for small inverters.  I have seen youtubers claim that they run fridges on modified sinewaves but my advice is not even to try doing so.  They might run, but not for very long.  I suspect the compressor would run very rough and would likely overheat due to all the high frequency harmonic content.   I would go further and say that even pure sinewave inverters rated at or below 500W might not be able to start a fridge.  The inrush current is just so high that the inverter is likely to shut down.  I am sure a 500W Victron will have no problems at all, but a 500W Chinese inverter is probably rated in ponies rather than horses.  It is likely to go on strike if asked to deal with a fridge's start-up conditions. 

There are exceptions and in this case its inverter fridges.  They normally use 3-phase motor inverters that have soft start functions as well as speed control.  These fridges should be OK running from modified sinewave inverters and have very little inrush current.  LG and Samsung sell inverter fridges on the high end at around R18K and upwards.  Inverter fridges are claimed to have higher efficiency.   My recently purchased Defy "solar hybrid" is a small 157L unit and sells for around 6K.  This  has a Danfoss-like inverter.  It has a very slow power ramp-up that takes several seconds.  So no discernable inrush current.

[Scorp007]

8 minutes ago, Modina said:

Fridges are a problem for small inverters.  I have seen youtubers claim that they run fridges on modified sinewaves but my advice is not even to try doing so.  They might run, but not for very long.  I suspect the compressor would run very rough and would likely overheat due to all the high frequency harmonic content.   I would go further and say that even pure sinewave inverters rated at or below 500W might not be able to start a fridge.  The inrush current is just so high that the inverter is likely to shut down.  I am sure a 500W Victron will have no problems at all, but a 500W Chinese inverter is probably rated in ponies rather than horses.  It is likely to go on strike if asked to deal with a fridge's start-up conditions. 

There are exceptions and in this case its inverter fridges.  They normally use 3-phase motor inverters that have soft start functions as well as speed control.  These fridges should be OK running from modified sinewave inverters and have very little inrush current.  LG and Samsung sell inverter fridges on the high end at around R18K and upwards.  Inverter fridges are claimed to have higher efficiency.   My recently purchased Defy "solar hybrid" is a small 157L unit and sells for around 6K.  This  has a Danfoss-like inverter.  It has a very slow power ramp-up that takes several seconds.  So no discernable inrush current.

You can up your pure sine wave to 1000W full time but it must have a 2000W peak for house type fridges. Some time ago I placed the 96A current draw picture from 12V to start a bar fridge. 

Once you pass this test the same bar fridge used less than 40Wh for each hour of the day. This is surprising for an old style unit that is over 13yrs old. 

Mecer simulated sine do indeed work OK on these fridges but only if used for the shorter LS cycles. It was never tested by a friend on stage 4 long periods. He used it this way for over 2yrs. He then upgraded to a 5kW inverter with PV. 

[Modina]

2 hours ago, Scorp007 said:

The other day I measure a friend's LED TV and the draw was 150W. My picture I posted from Samsung clearly states it's a LED TV. We always see these 24-50W values and it is not generally the average draw. 

Another point I have followed when draws are calculated. They always take a kettle as 1.2kw and try and find one below 1.7kW in a shop. I know they are available but not at Makro, Hirsch, Game, Hifi Corp, Clicks etc. 

Samsung normally quotes maximum and average consumptions on TVs.

You can expect ANYTHING from no-name Chinese imports.  They will LITERALY produce and sell stuff that just cannot work, ever.  Youtuber Big Clive has shown many such products.  If mains powered, these can also be very dangerous in terms of personal safety and fire.

If it comes to branded products you can be assured that if the sticker says max power 70W that the item will ALWAYS remain under that threshold.  The German VDE, Euro CE and US standards are very strict and a manufacturer would be in big trouble if found to be less than truthful.  In fact, if an electronic gadget is rated at say 40W max, real-world power consumption is likely to be much lower.  Not so for electric high power devices such as irons, kettles, etc.

I don't know of any 1.2KW kettles.  Users would complain.  Complain why their kettle is so slow.  Perhaps you get 1.2KW kettles for some camper type of application.  We are not so fortunate as the Americans.  They can order a 230V kettle form overseas and it will produce half the power when connected to 115VAC.

[Bobster.]

On 2023/04/03 at 11:05 AM, Modina said:

@Bobster.  170W for a 40" TV is exceptionally high, I don't think that is for an LED TV.  It's what I would expect from LCD cold cathode backlight technology.
What make of inverter does your mom use that is so low on losses?  Many inverters do not specify the efficiency and even less, give the no-load quiescent current.  The Victrons seem class leaders in this regard and I have seen one or two others.  There is junk out there that will have 40% losses.  Those can be used to keep your coffee cup warm.

Ok. So today I checked the TV size with a tape measure, and consumption with a kill-a-watt. 

@Modinawas right (it's an annoying quality he has). 40inch 4k TV plus an explora pulls 70W.

The display on the inverter is showing VA. 

This is why her system is doing so well. 2x102ah batteries. Knock of 10% for losses, and she's still going to run for nearly 8 hours before SOC reaches 50%. The batteries aren't heavily loaded, and there's enough time to recharge between sheds. 

Sure they won't last forever, but they're holding up so far. 

I guess the moral of the story is that if you're going this route, overspec the batteries. 

[Modina]

Ah, @Bobster.  I get many things wrong.  Including the dribble I wrote above when I said Americans can buy a 230V kettle and it will run at 1/2 power on their 115V.  P=V^2/R, so if the American where to buy a 2KW 230V kettle and use it on his 115V grid, it would only run at 500W, a factor 4 difference.

I think that because of the battery costs, the first rule is to make sure you run low power devices, even if that means shelling out some money to replace some equipment.  The second rule is that if you decide to use lead acids, to overspec them as you say and recharge them as soon as you can, even if you think that the SOC is still high.  The third rule, for small scale users with light/TV/laptop & WiFi requirement, is to try NOT to use/need an inverter, but run with 12VDC as much as you can.  I know this has challenges regarding all sorts of non-compatible plugs and even supply voltages. For a person with some DIY capability and some basic electric knowledge this is doable.

[Bobster.]

Another thing that the ever-so-useful kill-a-watt told me, was that the output from that inverter is 60Hz. This surprised me. It doesn't seem to have done any harm, but it is backing up just a TV and a decoder, and occasionally charging a cell phone.