Fitbit Blaze: A quick review

Posted by under Technology, on 17 March 2017 @ 5:39pm.

After a recent health issue I decided it was time to get myself a Fitbit to help me get into shape. I decided on the Fitbit Blaze which combines a smart watch and a fitness watch into one tiny device. I have to say for £140 it’s a very capable device and seems to work very well.

Its main feature is a heartrate monitor and step counter, but it also includes a pressure sensor so it can tell when you have gone up and down stairs for example.

It tracks heart rate 24 hours a day and uploads this via your phone to Fitbit. It does this at 5 second intervals except when you’re exercising. Using this it is able to estimate how many calories you have been burning during your activities.

It can also monitor your sleep to determine how well you slept and for how long. I can say that it does work with some degree of accuracy as I do occasionally get up to use the toilet and it at least records this reliably.

Although I have not yet put it through its paces with any proper exercise, I hope to do so soon. One of the features which I bought it for was reminders to move regularly which will come in handy given I have a desk job. This should prevent me from sitting down for long periods of time (at least that’s the theory!).

Battery life is quoted to be about 5 days. Having had it for just a few days and only charged it once, I can say this is a likely length of time if not a day less than quoted.

Smartphone notifications are I would say adequate but nothing special. If you receive a message it displays on the screen a snippet of the message. This applies to e-mails, instant messengers, etc. too. Each can be turned on and off in the app settings. Phone calls also come through but are delayed a little if you turn off ‘always on’ connectivity, which I have because it drains my phone battery like crazy.

The Fitbit uses Bluetooth 4.0 LE (low energy) to minimise battery consumption. This is good but reduces the range of the bluetooth signal to about 10ft. Perfect if you carry your phone but otherwise you will definitely miss notifications from the other side of the room. That’s not a big thing for me since my phone is usually with me anyway.

I’ll probably write a more detailed review as I use it more, but so far I’m enjoying the data it’s giving me.

 

 

Goodbye BT, hello Plusnet

Posted by under Technology, on 3 January 2017 @ 10:49pm.


I recently got my latest BT bill and noticed that my monthly fee had gone back up to normal. I had been enjoying a £10/month discount over the past 12 months as I felt the cost was far too high, complained, and got that offered to me. Well, it had gone back up to £46/month and I am not prepared to pay that much for broadband. BT have put up their prices significantly in the last 2 years and it’s now what I would consider to be unreasonable, so I decided to look at the deals available elsewhere.

I quickly came across Plusnet, who interestingly are owned by BT themselves. They offer the exact same package I am on now for just £30/month, minus a few things that I never used to use anyway (cloud storage, BT Wifi, free security, etc). I used to use the BT Wifi on occasion, but not nearly enough to warrant the additional £16/month. Comparing with BT for customer satisfaction on Thinkbroadband the scores are better for Plusnet (marginally).

I contacted BT via phone and asked if they were able to do anything about it. Would they match or even reduce the fee to approach that of Plusnet? No. What about any kind of discount? No, “nothing available” I was told. OK, fair enough, the guy at the other end can only offer what he’s been told he can. I was disappointed and let them know as much via Twitter. I was a loyal customer of about 5 years and they wouldn’t do anything to keep me. Their loss in the end!

So on to Plusnet – being owned by BT means that I will get the same level of support if there is an issue. The router I’m being sent is basically a re-badged BT Home Hub, so I know that will work just fine. The line speed should not change at all, though this remains to be seen. Best of all, if I want a static IP address, it’s a one off fee of just £5 – something BT were unable to offer at all.

All in all, I think I am getting a good deal, but the quality of the connection will be the determining factor. After all, they should use the same back-haul as BT, but it might be segmented and limits put in place. Here’s hoping they don’t.

In terms of cost, I’m going to be saving nearly £200 a year with this switch. In this day and age the cost of broadband should not be as high as this as it’s become almost a human right. Sure, you can go with cheaper suppliers such as TalkTalk, but their quality speaks for itself. If you want a connection that actually works, do some research and go with one at an average or higher price. As they say, you get what you pay for.

 

 

Driving a hybrid car – a whole new driving experience

Posted by under Technology, on 20 March 2016 @ 1:36am.

hybridI’ve been looking at new cars again recently and I decided I’d look at hybrid cars. Now I know what a lot of people are going to say – “what’s the point” or “they put out more CO2 to make than they’ll save”, and all that sort of stuff. But this is coming from people who know nothing about how they are made or how they work. I had the chance to drive a hybrid a few weeks ago, a Lexus CT200h, when I was considering what car to buy, and it’s completely changed the way I perceive them.

The driving experience

You would think that no matter what car you drive the experience would be very similar. You get in, you drive, and it feels pretty much the same as any other car, but in the case of a hybrid you’d be wrong. Most people will only have driven a standard manual or a typical automatic gearbox car. There is always the consistent whirring of the engine, and the very slight lurch feeling when it changes gear (or severe if you’re incapable of driving a manual smoothly). In a hybrid you get less of the whirring and none of the lurching feeling.

How is that possible? Well it’s mostly thanks to the CVT (constantly variable transmission) gearbox. Essentially instead of a set number of gears with set ratios like a regular manual or automatic gearbox, a CVT is capable of an infinite number of gears between two gear ratios. It does this through a set of pulleys that can change size and a drive chain/belt. You feel absolutely nothing when it’s changing through these gears. It’s completely seamless and smooth.

On top of the CVT you also have electric motors which can operate on battery only up to a certain road speed without the assistance of the engine (unless speeding up relatively quickly). Both the electric motors and the CVT make the engine overall quieter. Either the engine doesn’t run at all when you’re using electric only, or it runs at a much lower RPM than a regular transmission would (unless you put your foot down). The result is the smoothest transition throughout all speeds than you will have ever felt before. It’s almost a dream world and it’s an absolute pleasure to drive. I’ll admit that this alone almost makes a hybrid worthwhile, but there’s more to it than that.

The potential increase in fuel economy

I say ‘potential’ because you have to drive it right. Don’t expect to get in, mash the throttle and get 55mpg. It doesn’t work like that. You have to take advantage of the technology properly. This is one that everyone will call you out on because they’re not taking proper advantage. It makes them ask the question “is it really more efficient?’.

Well let me come clean here and say that I can’t use my test drive as a basis for one simple reason; The average MPG counter was reset on the car I drove and on this car it works over a tank of fuel rather than on a single journey, so the reading was wildly inaccurate. The 25mpg average that it showed to me was definitely incorrect as it was still rising even after 40 minutes of mixed driving. But anyway, lets look at how a hybrid works.

The most important thing to remember is that speeding up in any car is inefficient, be it petrol or diesel. The time that economy is worst is when idling and speeding up. Any time you put your foot down even the slightest bit your economy suffers massively, so don’t expect to be able to buy a hybrid and instantly get more economy if you have a lead foot. Hybrids are a partial solution to the problem – here’s how…

Internal combustion engines are at best 20-30% efficient at converting the fuel into usable energy to propel the vehicle forward, and this is at best. The rest of the energy is converted to heat. The saving grace is the electric hybrid system. The electric motor and the battery is much more efficient at around 80% or more, so if it’s a higher efficiency then it’s capable of using the energy store much more effectively.

Now consider this – every time you use your brakes, what happens? You turn your forward momentum into heat through your brake pads creating friction against the brake disks. It’s all wasted as heat. You gain no benefit from creating that heat other than bringing the vehicle to a stop. In a hybrid vehicle, the primary means of stopping is regenerative braking which uses your forward momentum to run a generator, which charges your hybrid battery. A large amount of the energy you would normally turn into heat is put into your hybrid battery as electrical power and this slows the vehicle down too. This power can then be used for the electric motor to get the car up to speed again. Instead of wasting the energy as heat, you store it as electrical energy for use later. If you’re doing a lot of stopping and starting then that can add up to be a lot of saved energy.

This is one way hybrids are able to achieve higher economy, especially around town, over a conventional car. But note that I said ‘one way’. That’s because there is another way too. Have you noticed how the hybrid cars have a relatively high displacement engine but a low power output? There is a reason for that. These engines essentially use a lower compression ratio through the Atkinson Cycle to get a more efficiency out of the engine by allowing the fuel to burn more thoroughly, thus extracting more energy out of it. To do this and get any usable power though you need a higher displacement engine.

The car I drove was a 1.8L engine which produced just 103BHP, a fair amount less than a typical 1.8L engine. This power is however supplemented by the hybrid system by an additional 35BHP to create 138BHP when it’s needed to give more power when you put your foot down. The result of this is a higher economy overall through a more efficient but less powerful engine, but still plenty of power to pull away when needed.

Lets be honest with each other – how often do you run your engine flat out for minutes on end? I can bet almost never. What this means is that you can get away with a reasonable sized displacement engine that produces lower power but does so more efficiently thanks to the Atkinson Cycle engine, and gain supplement this with power from the hybrid system when it’s needed.

Knowing how to drive

As I said above, you can’t just mash the pedal and expect results. You have to know how to take advantage of the hybrid system. You need to understand how the process works and how to manage that so that it’s used in the best possible way. So how do you do that? Let me break it down into chunks.

  1. Pulling away/speeding up – Once up to temperature the engine should not be running when you’re stopped. It doesn’t need to because it’s at operating temperature and can start up at any time its required to give the requested power. Instead, the hybrid system will run on its own until the hybrid battery is depleted, you exceed a set speed, or you request more power than the hybrid system can give on its own. So the trick here is to use best use of the electric system as much as possible by pulling away on electric power only without the engine kicking in. The best use of this would be to get to the desired speed (say 30mph) on electric only and once there, the engine can kick in just enough to keep your speed consistent. Remember what I said before about most fuel being used when speeding up. If you’re not speeding up but are just maintaining speed, you minimise fuel use. Most hybrids are limited to 30-40mph on electric only but you still get all the benefits up to that point.
  2. Cruising – Cruising is just like any other car but with one difference, that being that the hybrid system in the car will switch the electric motors on where it thinks that it can be beneficial rather than using extra engine power. That again reduces fuel use by not using any fuel, or less of it, to speed up. Whenever you slow down a little too the hybrid system will regain some energy, as well as a small charge from regular driving to maintain the hybrid battery.
  3. Slowing to a stop – Anticipating coming to a stop is the best thing you can do in a hybrid. Look ahead and predict whether you’re going to need to come to a stop and where that’s likely to be. Once you’re used to the way your regenerative braking works (how much braking power it can give you) you should be able to judge where you’ll stop just using regenerative braking. What you want to avoid is ever using the conventional brakes to bring you to a stop except for the last few MPH where the regen braking becomes inoperative. If you can come to almost a complete stop on regen braking alone, you’ve just recaptured the most amount of energy that would otherwise have been lost as heat. Next time you pull away, that captured power is then used to get you moving again without burning even a tiny bit of fuel that you would in a regular car.
  4. Traffic – Hybrids come into a world of their own in stop-start traffic. When all the conventional cars are sat idling their engines, burning fuel and not really going anywhere, a hybrid sits there using no fuel and moving those few meters every minute or so when needed under electric power only. Economy skyrockets in these situations and it’s one time you can sit there and look smug while everyone else is emptying their wallets into the atmosphere.

 

So admit to yourself, given the above I bet you can finally agree a hybrid can be more economical around town and on motorways, assuming you don’t have a lead foot of course, right? Well, if that’s not convinced you, then there’s no hope :-)!

A comparison with my current car

I currently drive a VW Passat 2.0 TDI with 140BHP. It’s not a slow car and it’s pretty big too. But it runs an older diesel engine which isn’t very efficient. As a result I get a measly 43mpg average from it when modern diesels can approach the low to mid 50’s.

A modern petrol hybrid typically gets 50-55mpg+ without trying too hard based on actual data submitted by owners. I linked to the Toyota Prius because it’s got a lot more data than the Lexus CT200h, but the drivetrain between the two is very similar, and someone I know who owns one achieves similar results too. Getting that sort of miles per gallon from any petrol is very good as you’ll struggle to find any hitting any more than the low 40’s in most other cases. The numbers from actual owners data speaks for itself.

Now of course everyone is not going to get the same figures as another person, because we all drive differently, drive different routes, and drive for different times and distances. But the numbers do show it is possible for the average person to achieve a decent economy figure without trying and with a little work you could easily increase it.

Would I buy a hybrid?

Yes. In fact I am considering it. The things putting me off is the amount it costs to buy one and if they go wrong things can get expensive quickly. But that’s where warranties come in, and most hybrid manufacturers cover the hybrid system (and the rest of the drivetrain) for the full term of the warranty and you can extend it relatively cheaply too. But this said, it would appear from my research that the hybrid systems on the car I drove are incredibly reliable.

Now of course you’re never going to actually save money unless the number of miles you do are huge or all the miles you do are around town and your previous car’s economy was absolutely abysmal. But as I went through at the start of this blog, it’s not all about the economy. The driving itself is in a new realm of its own with its smoothness, quietness and the general comfort that comes from that.

I’m not saying to go out right now and buy one without actually getting in and driving one first as that would be an investment disaster. But don’t just pass it by because you believe without trying it that hybrids are bad, that they don’t get the economy people say they do, that they produce more CO2 to make than they’ll ever save, etc. Look into it. Do the maths. Get the facts. Use your common sense. Make your own judgement based on what you find and don’t take other peoples opinions at face value without working it out for yourself.

 

 

CGO2 Camera Firmware Update for Android Support

Posted by under Technology, on 29 March 2015 @ 10:31am.

I recently had to update my new CGO2 camera for my Blade QX3 350 AP Combo as it refused to work with my Android devices (HTC One M8 and 2013 Nexus 7). It wouldn’t show up in the wifi list so I couldn’t connect to it. This happened on all of my 5.8GHz compatible Android devices even though it claims to be 5.8GHz compatible. A quick firmware update to the latest version seemed to allow it to work. It showed up in the list so I could connect as expected.

Here is the firmware file that I used:

cgo2gb_1.9.01_fps50_firmware.bin (36.8MB)

Here are some older firmware versions if you need them. I have not tested these:

cgo2gb_1.9.00_firmware.bin (36.8MB)
cgo2gb_1.8.02_fps50_firmware.bin (36.8MB)

Update instructions:

Disclaimer: The firmware file is provided as-is. I accept no responsibility if this update process fails in any way.

1. Format a memory card with FAT32 or just remove the contents of your existing card
2. Copy the .bin file to the empty card
3. Put the card into the camera and turn it on
4. The light on the front will begin flashing purple after a few seconds.
5. Do not turn the camera off during the update process or you may brick the camera!
6. It will take a few minutes to update. When the purple light stops flashing and the light is off completely, turn off the camera
7. Remove the memory card and delete the .bin file
8. Put the memory card back into the camera and power it up. It’s now ready for use.

The default wifi password for the CGO2 camera is 1234567890.

 

 

Blade QX2 350 Malfunction

Posted by under Technology, on 7 March 2015 @ 5:40pm.

You might remember the quadcopter from my last blog that I talked about. Well the inevitable happened and it’s malfunctioned quite badly. The end result was horrible damage to the quadcopter and the gimbal has been smashed to pieces beyond repair (outside of purchasing every piece of it separately). You can see below the damage done to the quadcopter and after that I’ll explain what happened.

I planned on showing a few friends the quadcopter at a gaming event we met up at as they had not seen one properly before. What better reason to get it out, right? It was dark outside so I planned just a quick flight to show them what it could do with the intention of a proper one the next day.

The takeoff was normal, but because it was a quick flight I didn’t turn on the camera. The gimbal was on however because it was still connected to the quad. After takeoff I hovered for a few seconds, then decided to do a quick ascent to show how quickly it can move. After 2-3 seconds I got a low battery warning on the status LED, which is not unusual under full throttle and I’ve had it happen before lots of times. I backed off and descended back down from about 30m to 10m or so. I held a slow descent straight down when suddenly after a few seconds the props seemed to go to idle and the quad flipped upside down. Within 2 seconds it was tumbling along the floor with pieces flying everywhere.

Everyone was looking at me as if to ask “what the hell happened?”. I looked back and said, “I don’t know why that just happened”. It was clearly a malfunction of the quadcopter. Now you might be questioning the low battery warning, but I checked the battery after the incident and it still showed ~4.1v on each of the 3 cells and 12.4v total battery voltage – normal for a pretty full battery. I was in the air for under a minute before the malfunction.

The quadcopter has 4 flight modes, SAFE, AP (Aerial Photography), Agility and Stunt. I can only access the first 3 modes, and only in the 4th mode, stunt, is it possible to make the quadcopter go beyond a banking level of 45 degrees. That means it is not possible for it to flip upside down under normal operation in any of the other 3 modes. My transmitter is not able to access stunt mode, nor would I want to use it because you get zero assistance from the gyro, etc.

The only conclusion I could come to was a malfunction of the quadcopter’s software, however the damage was so severe that I decided not to investigate it much further as it would involve opening the quadcopter to inspect it. Instead I contacted the model shop where I bought the quadcopter and they said they would send it back to the manufacturer under warranty. I am still waiting to hear from them, but it has only been a week so it might be another week or two.

I received a lot of flack from friends who are quadcopter pilots which considering they weren’t there is pretty hypocritical in my opinion. One believed that because I was near a gaming event, the masses of 2.4GHz wifi signals floating around probably caused it. I disagreed because the risk of wifi affecting it is no different there than in any typical housing estate, where I can assure you there are more 2.4GHz signals floating around than this gaming event. Also, the quadcopter has built in failsafes to prevent this type of interference from causing a crash. If it loses contact with the transmitter, it will go into return home mode, or land mode, depending on battery life and distance from the home point. It did neither in this case and simply dropped out of the sky. You also have to remember that there is parity involved in the communication protocol so even bad data should never have caused it.

Now this isn’t the first time it’s crashed. Shortly after I bought the gimbal (around Christmas) it crashed on its first flight (and broke the gimbal I should add) after it would not respond to my input except for throttle. I had two theories. Either it lost GPS signal (as with no direction input it should hold its position – it didn’t do this) or it was a similar malfunction. It has never done it before without the gimbal attached, yet it has crashed twice now with it attached. Of course this isn’t proof I know, but it warrants investigation to see if the gimbal caused interference which might upset the processor or related components.

At the end of the day I’m going to have to trust the manufacturer to find any issues that there might be with it. I hope they find one with it so they can give me a new quadcopter because otherwise it’s going to be pretty expensive to fix. I’m looking at a new case, 4 new propellers and possibly motors. The gimbal was a write-off, I’d have to replace the entire thing (which I’m not prepared to do given the cost and fragility of its cheap plastic framework).

I’ll write another post here when I get the verdict, but until then keep your fingers crossed that they find an issue.

 

 

Fiber broadband woes

Posted by under Life, Technology, on 6 February 2014 @ 11:02pm.

Up until about 2 weeks ago I was enjoying a lightening quick 80Mbps down and 20Mbps up from my BT Infinity 2 connection, but one day this all changed and I began to have problems. I noticed I was getting frequent disconnections which would cause my home server to stop pinging. Initially I consulted the BT forums to be told it was an issue with the BT Home Hub 5 firmware, however now I am not so sure.

About 2 weeks ago I was getting sick of the pings stopping, even though my connection felt relatively stable. I decided it was time to investigate further to see if it was a problem with my connection or the Home Hub. I started by running a piece of software called RouterStatsHub which allows you to graph your connection stats for easy troubleshooting. Immediately I noticed I had a drop in speed from my usual stable 80Mbps down to 65Mbps. My maximum line speed (the speed the line is capable of, not what you’re synced at) had also dropped from about 100Mbps to 80Mbps. This suggested a fault on the line somewhere.

I continued to investigate and I discovered that when I picked up the phone, or someone rang in, my noise ratios would plummet. This is consistent with a bad line too as it should stay perfectly stable regardless of whether the phone is in use or not. At this point I realised it was time to get a BT engineer to come and look at the problem. I called technical support and got a mid-week PM appointment.

I took a half day off work for the appointment. The slot was 1pm to 6pm, for which I was in for the whole time. 6pm came around and nobody had showed up! I was annoyed beyond belief so I called BT to find out why. Their online chat rep told me it was because they called to confirm but there was no answer, so the appointment was cancelled (!!!). They then called me and put me through to level 2 support who could arrange a new appointment. I asked them the same question and was told a different answer. They told me that nobody turned up because there were no resources available, IE they were completely over-worked and nobody was assigned. They didn’t think it was a good idea to bother telling me this! I asked what sort of compensation they would give for their missed appointment and was told £10 is all they will give… I had no choice but to accept it but I also asked about discounts but was told they can’t apply any until the fault is fixed. I have to call back to sort those out.

sat-noise
Engineer day: Terrible line noise and lots of
disconnections and shows when the
engineer started work

We finally got around to arranging a new appointment and I asked for a weekend slot. They told me they don’t work weekends. At this point I had already looked online and a friend also did and found that they did in fact do weekend appointments, so I pushed the issue. The rep said she would check again, and what do you know, there was a weekend slot available, two in fact! I could have an AM or PM appointment. Since I would be in all day I took the AM slot so the tech could have all day to work on my issue.

Saturday came around and he turned up at about 10.30am and got to work. He ran lots of diagnostics and listened to what I’d done to test the line. He spent all day trying to locate the problem but all he found was errors on the line. He was here until 5pm when he admitted defeat for the day and was going home. Unfortunately during his tests he had also switched parts of the line but couldn’t get it to sync again. This meant I was going to be without a connection until at least Monday. I was annoyed but I understood. I was thankfully able to utilise a neighbours BT FON connection, although this wasn’t particularly reliable due to the signal strength being low.

thurs-noise
Line noise after the fix, including
DLM decreasing the noise margin (lower is better)

Monday came around and the technician worked on the line again from about 2pm. About 3.30pm he called me to say I was temporarily back online but on 40Mbps instead. This was due to a fault in the green cab in the road which meant that some of the hardware needed to be swapped out. This wasn’t going to happen for a day or two though but at least I had a connection again.

Come Wednesday I was back on 80Mbps again but my sync is still only 67Mbps. This is due to DLM (dynamic line management) keeping my speed down until it’s satisfied my line is stable. This could take about 7-10 days to return to it’s full speed, which I’m now waiting for. However the fault is now fully fixed. I can pick the phone up and experience no drops at all in noise margin and my maximum line speed is above 90Mbps again.

I can’t say I’m 100% happy with BT’s response to my problem due to the missed appointment and no communication about it, but the technician I had did a fantastic job. He was polite, kept me informed and most importantly he kept to his word. From that perspective I couldn’t have asked for better support.

 

 

Fiber broadband

Posted by under Servers, Technology, on 24 December 2013 @ 9:30pm.

I posted a few weeks ago about me getting fiber broadband. Well its finally arrived after I called up to get an earlier appointment.

In was quoted 79.9Mbps and that’s exactly what I got on the sync speed. Speed tests give me 75Mbps down and 17Mbps up which is fantastic! The upload speed has already come in incredibly useful for sending files to friends quickly and uploading photos to my websites.

I’ve seen 9MB/s download on files from Microsoft and 2.1MB/s uploading via FTP. I’m certainly not going to complain at all for the extra £4 it’s costing me. I would highly recommend it to anyone who has FTTC available in their area. So far I’ve seen no throttling either which is brilliant. BT have a superior network to handle fiber so its not surprising.

I’m in the process of utilising it more and hopefully I will have a few servers on it soon. I’ll also be using it to download the 7.5TB backup of my site (yes, TB not GB!). I just need to get my 2nd server set up with the backup drives.

 

 

Fiber broadband is finally here!

Posted by under Life, Servers, Technology, on 4 December 2013 @ 11:45pm.

For many the fiber broadband revolution started many years ago. Those people that got virgin media for example were given quick speeds from an early age. Those of us stuck on ADSL however weren’t so fortunate. The line length was always a factor and prevented most people getting a fast connection. You would have to be no more than 500m away from the exchange to get anything over 15Mbps. Now that fiber is here that’s a thing of the past.

The new fiber cabs are no more than 200m away from most properties. And because it uses VDSL technology instead of ADSL you also get a bump in speed from that as well. It’s currently capable of 300Mbps with trials of higher in progress. Its something we should have got many years ago.

Anyway the point of this blog is that its finally arrived for me! I’ve been checking weekly for almost 2 years waiting to see the long awaited ‘available now’ message and this week it finally happened.

I initially signed up online and was given a date of early January. I was surprised by this as other people got theirs much faster. I decided I’d be OK with it as I understood they were quite busy. But after speaking to a friend who ordered at the same time as me he got his for next week! I asked how and its because he had phoned up and not done it online. I decided to try my luck phone up to see if I could get an earlier date. Thankfully they could! I was expecting a 2 week wait but they said they could do it next Monday! Brilliant!

I was expecting 65Mbps based on BT’s estimates which isn’t too shabby at all. But when I signed up the email I got said 79.9Mbps. I thought it might have been an error but checking their estimate page again it had been changed! So with any luck I’ll get the maximum that the up to 80Mbps package offers (the fastest package you can buy right now).

I’m just waiting for the BT home hub to come in the post in the next few days and then I’m all set. The engineer is scheduled for Monday to get it swapped and all working. Wish me luck! I’ll probably make another post with my speed test results soon enough!

 

 

I’ve owned my iPhone for 12 months now

Posted by under Technology, on 11 July 2013 @ 11:59pm.

That’s right, a phone that I have managed to keep for more than a couple of months! And guess how many times it has crashed? Dozens I hear you say? Nope. None. Not a single crash since I got this phone. Sure, apps have crashed. We all know that the Facebook app has it’s flaws, as do some others, but nothing that is stock on the phone has ever crashed on me. That’s more than can be said for my old phones, the LG GTT540 and the Optimus 2x which not only crashed frequently but they also refused to hold a data/wifi/cell connection for longer than a day.

The battery life is also great. Both of my Android phones struggled to get a day if used “normally”. The iPhone easily makes it through the day of normal use. If I use my running/biking app then it gets a bit of a hammering but otherwise it’s perfectly reasonable.

If and when it comes to the point where I need a new phone, I’d have to think long and hard about going back to Android. After a full year using iOS (with frequent updates I might add), I don’t think I could go back to any phone that I know has the possibility to go wrong because of lack of care by the manufacturer. If I were to go back to Android, I would only go for a high end one such as a Samsung Galaxy because they use stock Android and none of the manufacturer bloated crap.

The big question is though, would I buy another iPhone? Yes, I would. Even at £500 up front.

 

 

Battery Technology and Maintenance

Posted by under Technology, on 20 February 2013 @ 10:41pm.

battery

If you read my last blog about my UPS battery woes and it interested you, then this one might help you further.

Batteries are a horrible technology in many respects. They’re expensive, damaging to the environment and incredibly inefficient. Unfortunately we have nothing better so we have to make do until another technology is found.

When it comes to large batteries, you’ll generally only find one type of battery – lead acid. They come in several forms:

  1. FLA (Flooded Lead Acid) – The type found in cars
  2. AGM (Absorbed Glass Mat) – The type found in UPS’s and alarm systems
  3. SLA (Sealed Lead Acid, commonly mislabeled and are really AGM) – Also found in UPS’s and alarm systems

 

While not the best at energy storage compared to Lithium Ion/Polymer, they are much cheaper and store close to the same amount of energy too.

Taking care of these batteries is important (as with any battery actually) because of the way in which they work.

A lead acid battery is comprised of lead plates and an electrolyte solution of sulfuric acid. This is how the battery holds it’s energy. During normal use, the energy will be released and stored via a chemical reaction. This reaction heats the electrolyte and over time this solution evaporates. If this happens too much and the lead plates become exposed and/or dry, the capacity of the battery will drop. Generally “going dry” is what kills a lot of mis-used batteries.

But this isn’t all, there is also another process called “sulphation”. This occurs when the battery is discharged and sulphur builds up on the lead plates. This inhibits it’s ability to hold and release energy. This also kills batteries when mis-used, especially when left discharged. This is common in cars and other vehicles, especially in winter when the battery is put under more strain.

Battery Charging

Now the problem I had was mainly the cells going dry through what is known as “float charging”. This is when the battery is held at a voltage above it’s natural storage voltage to keep the charge level at 100%. This is constantly putting some energy into the battery so it warms up, and the electrolyte dries off. This is what killed my UPS batteries, because the UPS was in essence over-charging the battery.

How can this be avoided? Don’t keep it on float of course, or if you do, do it at a reduced voltage. My Belkin UPS’s keep a float charge of about 13.3-13.6v. A standard 12v battery will sit at about 12.8-13.3v when fully charged, so if you can keep it around that voltage, you should extend the life of the battery. However, if you don’t bring a 12v battery up to 14.0-14.5v when charging, it will never fully charge and so you will end up sulphating the plates quicker. It’s a tricky situation, but it can be avoided.
The answer is 2 or 3 stage charging. 3 stage charging involves:

  1. Bulk phase – Charging the battery at a constant current (generally 10-30% of the battery capacity, referred to as “C”). For example,   10Ah battery holds 10,000mAh of capacity, so you would charge it at 1000-3000mA or 1-3A.
  2. Absorption phase – Charging the battery at constant voltage (typically 14.0-14.5v for a 12v battery) until the current drops to about 1% of C. For a 10Ah battery this would be 100mA or 0.1A.
  3. Trickle phase – Holding the battery at a reduced constant voltage (the tricky part is what voltage to use here).

 

3-Stage Charge Curve

Image Credit: http://www.infinitumstore.my/2009/07/3-stage-charging-process/

 2 stage charging is the same as above but without the trickle charge phase.

My Belkin UPS appears to do 3 stage charging, and it’s trickle voltage is around 13.3-13.6v. The difference with mine is it’s not constant voltage but rather it pulses on and off. Pulsing has been tested but there is no definitive proof it helps over the long run.

The better way to do this would be to do 2 stage charging, then cut off the charging completely until the voltage drops below a set level. Then you begin the process over again. This is the better way as it lets the battery rest with full capacity, without charging to make the electrolyte evaporate off.

I don’t know why more systems don’t do this. I imagine it’s for simplicity in design, otherwise they would need to incorporate a fully battery monitoring system which would cost more money. Who knows, but it makes sense to cut it off after it’s charged. This is especially important for lithium batteries like those in mobile phones. If you over-charge these (continue to charge when full), they can explode! So why do it with lead acids of any kind?

What about discharging?

Now that you know about charging, what about safe discharge levels? This is one that has plagued many people. Generally voltage would be used, wouldn’t you think? Well no, because lead acid batteries charge/discharge level cannot be determined without use of a hydrometer. This is a device that you use to sample the electrolyte from the battery and uses floats to determine the “specific gravity” of the electrolyte. I won’t go into how this works, but it’s something you can only do manually. Voltage on any battery is not a charge level indicator, you can only use it as a dummy guide and it will often fail you.

That said, you should be aware of safe limits that lead acid batteries work to. Here is a handy table to explain it to you.

slabatterycharge

As a general rule, the battery should never be discharged past 12v when “resting”. Resting means it has been sat for more than 4 hours with zero load connected to it. With a load connected, you should never discharge below 10.5v. If you continue to discharge it, you risk warping the lead plates, and doing so can create a short circuit which will ruin your battery.This is a very basic table of charge level based on voltage and what the specific gravity is expected to be. Going in the standard good to bad colours, you can see that the battery capacity is only good above 50%. This is because below this, sulphation occurs much more quickly. On a totally flat battery this can be as quickly as a day or two.

You should also ALWAYS charge a lead acid battery after it has been used. Even if it was just a few percent, because any discharge speeds up plate sulphation.

This is something I didn’t take into account when building my camping power box. My LED volt meter range goes from 10.7v to 12.5v when really it should have been 12.0 to 12.6v. However, that said, now that I know it’s wrong I can use my own knowledge to determine when to stop using it and recharge it. The added range allows me to see when it’s time to stop using it under load as well.

Hopefully you have learned something from this and it’s a reminder for me if nothing else.

 

 

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