Quick tech article today about Rugged PDA Battery questions we’re fielding a lot of the past few weeks.  There seems to be a lot of confusion over the types of batteries you can use in a rugged PDA and I wanted to clear up the options.

Battery types

First of all there’s the actual battery type.  I can’t think of any handhelds now that use the old Nickel Cadmium batteries, in fact I am sure these are illegal in Europe now due to the cadmium being poisonous.  95% of batteries still use Lithium Ion, we have a couple of devices like the Dotel H300 that use Lithium Polymer and tests here show that we’re getting about 50% more out of Li-Pol batteries so a 2400mAh Li-POL battery gives you the equivalent of roughly 3600mAh li-ION.

Voltage

Most PDA’s run at 3.7V, running from an input of about 5V.  However we do get PDA’s that use 7.4V batteries or 8.4v in some printers.  If we turn to our GCSE (or GCE for the older ones amongst us) physics then we remember Power = Voltage x Current. Therefore if we double the voltage we roughly double the power a battery will store.  Therefore higher voltage batteries are also a good way to get a bit more bang for your buck although you must have a Rugged PDA that runs at this voltage.

Battery size

Put simply this is rated in Milli-Amp Hours (mAh) and every battery is rated like this.  The larger the value, the bigger the battery is and you can think of this as the size of the petrol tank the device has.  2400mAh is the lowest we really like to see in a Rugged PDA (unless it’s a li-polymer battery of course), 3600 is the average and 4400 is decent.  Some go up to 5000mAh.  However as we know with cars, size isn’t everything, it’s also how the device uses the battery too.

Back Up Batteries

Back-up batteries are also widely varied in their size and functionality.  Some RUgged Handhelds have tiny little crappy watch batteries that do no more than save the time and date settings in the device.  Others have larger batteries that will allow you to swap out batteries and then continue immediately from where you were, with no reboot.  We’re seeing a shift to smaller devices where battery swap out strategies are coming to the fore again as the batteries are smaller so this is a useful thing to ask about.

How long will my battery last!?

It really is a “how long is a piece of string…” question, but you can ask how efficient the PDA is.  We get round this a lot by sending out loan devices and letting you see what you need but some rugged handhelds will fare better than others when using GPS or 3G and some will fair better scanning etc.  You  need to ask, test and then choose.

Is it better to have 2 small batteries or 1 large one?

Again this is really down to you and your users but larger batteries use less charge cycles so in theory they can have a longer overall life than a 2 std batteries, especially if you use 1 std all the time and use the other as standby.  You can also lock a large battery in and leave it, never opening the device to swap batteries out which can have a more rugged approach to the solution.

Smaller batteries make for a smaller, lighter device.  Swapping out batteries can be a doddle in some devices and a pain in others, but they also make for a cheaper device too.

Come talk to us here any time about this and we’ll help you through to make sure you have the right kit for your needs.

The Rugged and Mobile blog.

About The Author

Dave's one of the founders of Raptor, his rants are memorable, his thoughts are stimulating and his heart is set on helping, entertaining and making things like mobile, Android, ruggedness, 3D printing and IOT simple.

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