So continuing this week’s theme on Rugged PDA technology, we’re taking a look at the Rugged PDA Battery. Batteries for Rugged Handhelds come in all shapes and sizes and we’re going to clear up all the questions we get right here in one post.
Size does matter! – Battery capacity explained
The most common question we get asked about Rugged Handheld Batteries is “how long do they last!” We’ll cover this off here first and i’ll start by answering with the classic answer…”What are doing with the Rugged PDA?” It’s not as dumb an answer as you might first think because its asking the essential question. Much like a tank of fuel in your car, if you use your aircon and want to drive at 100mph then you’re going to get fewer miles than if you’re doing a steady 60mph on the motorway and batteries are no different.
Typical Rugged PDA Battery Capacities
Battery size is measured by mAh (Mill amp hours) and the larger the battery, the larger the mAh, the longer it will last. So a 4000mAh battery in the same device will last in theory twice as long as a 2000mAh battery. Most rugged Rugged Handheld Batteries are 2000mAh or over (Smartphones tend to be no more than 1200mAh) but its common to see sizes as large as 3600mAh being the standard now.
Rugged PDA Battery Strategy
Are 2 smaller batteries better than 1 large one? The pros are:
- You can share if you are working close by other PDA users.
- You can charge a battery whilst using the PDA.
- The device is lighter.
- Larger batteries require more charging time.
- Sometimes the larger battery requires different accessories or won’t fit into the standard charges/cradles.
- People do lose the spare batteries!
- You have to fiddle with the case opening and closing it properly putting the device at more risk of damage. You might also want to try to lock the casing down and will not be able to do this.
- You have to effectively switch the device off to change the battery and this can happen at bad moments for your application.
- 2 smaller batteries usually cost more than 1 large one.
You really need to look at what you are doing to make the right choice here but by and large we find that an extended battery is the best option for most.
Different Rugged PDA Battery Technologies
80% of what we use is now Li-ION. These batteries like to be kept charged up, the old “Memory” issues are no longer applicable as they were on older NI-Cad or NI-H batteries that we no longer see much off now. Li-Polymer batteries, like in the iPhone or iPad are making their way on to some Rugged devices now and these improve battery life markedly so what out for these.
The other are that can change battery life is changing the Voltage. You will see devices with higher voltage batteries that will mean the current and thus power used should be less for the same demand. It’s not quite like this but in the rugged PDA world batteries with higher voltages are definitely longer lasting for their capacity.
Different manufacturers tend to manage batteries better than others and this is down to the CPU, firmware and power management offered. Although a little odd, Motorola do some to get an awful lot of power from their 3600mAh battery on the MC55/65, although the MC75 is not nearly as good, probably the CPU and HSDPA. Psion go for the whole hog 5000mAh battery strategy but they also do have a nice power approach making the IKON very strong. I think the XScalePXA320 CPU generally gets a good wrap as does anything with a lI-Pol from Ganedata and with the RIsc architecture in the Janams and Newer Intermecs.
The big battery drainers and what to do about them
In this rough order its LCD, Voice or GSM, GPRS/3G, Scanner, GPS, WiFi, anything using a timer in software and the rest!.
Your LCD and especially the LCD brightness will be the single biggest drainer of your battery so make sure you manage how it is used. Rugged PDA’s come with a range of built in power and LCD management tools to help you with this so if the device has been idle for 2 minutes, switch the LCD off. Also remember the larger the LCD, the power it drains so a small Rugged PDA with a 2,8″ screen will last a lot longer than one with a 3.5″ screen, everything else being equal.
Of course we all know that using the phone is a battery heavy task, but not a lot of people realise that the signal strength also hurts battery life hugely. If the lower the signal, the higher the battery usage is, even if not using the phone and this goes for GPRS usage too. GPRS or 2G also uses far less energy than HSDPA so if you’re going to be doing a lot of data syncing but at low levels of data size then consider a GPRS enabled Rugged PDA rather than the latest HSDPA one. Another big mistake we see a lot here are applications that do not switch automatically to WiFi when they detect they are in range but instead continue to use GPRS to sync data.
Anything with moving parts is a killer, anything that emits lights is a killer so barcode scanners of all types, cameras, flashes and RFID readers all fall into this category. They will drain the battery significantly if used consistently. A lot of people leave their scanners in an on state not closing them in their software application so make sure your scanner is not enabled when it doesn’t need to be.
This is of course using a lot of energy, but not as much as compared to GPRS. We do a lot here with GPS and the trick is to either ping your position less where you can actually put your GPS chip to sleep in between readings and also when sending any live position data back, adjusting the intervals you do this will help significantly. Of course there’s a live tradeoff in doing this. Later GPS chips are also far less energy-consuming. A SIRF III chipset will lock on quicker, track more accurately and use less power then an older chip.
Surprisingly WiFi is not a huge demand on the PDA unless you have a poor or conflicting signals. Of course the more data being passed over it the higher the energy usage.
Don’t forget theat badly designed software can still affect your battery markedly. The more threads, timers and use of all of the above, the less time your battery will survive.
There we have it, everything yo need to know to ask the right questions about Rugged Handheld batteries. Its more of an art if you ask me but knowing this and dealing with a good Reseller like us here will be the path to Battery utopia!!
The Rugged and Mobile blog.