Batteries for digital locks

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Summary: Alkaline type batteries (eg. Energizer Max or Duracell) should be used and changed every 8-10 months as a rule of thumb. 

1. How often to change batteries?
   
   Gateman and most Samsung locks requires 12 months cycle change (assumption:   10 entries a day and alkaline batteries). To avoid battery liquid leaks, we suggest a more diligent 8-10 months replacement cycle (never used beyond 1 year) and to check the battery compartment for battery liquid leaks every 6 months. ​Digital locks are designed to give you low battery warnings but you should not wait until then; they are warnings!
   
   [Additional notes: ​The battery cell expands near the end of it's power due to chemical changes so the risks of battery liquid leaks rises towards the end. Err on the safe side, change earlier than later]
   
   
2. What batteries type and size to use?
   
   Use AA-size alkaline type batteries. These batteries have the word "alkaline" printed somewhere on the battery body. If the prints are too small for you to read, go with the following two: Energizer Max or Duracell. 
   
   What not to use: You should not use carbon-zinc batteries because these runs out of power 3-4 times faster than alkaline batteries. Battery power will fall fast near the tail end and you may not hear or see the low battery indicators. Eveready Super Heavy Duty is an example. The wordings may lead you to believe it is super heavy duty but the low price tells you the truth.
   
   [Additional notes: You do not need expensive lithium batteries because digital locks are not high currents discharge devices like your flashlight, cameras etc. You should not use rechargeable batteries because the manufacturer says so]
   
   
3. How many batteries? 4 or 8 pieces?
   
   Most locks have requirements for just 4 batteries. So, that's about it.
   
   Some locks allow up to 8 batteries: the additional 4 pieces could be useful if your lock is optionally equipped with remote control or bluetooth option. If they are not fitted with those options, then the rule of thumb is 4 batteries are enough.
   
   [Additional notes: Some locks come overloaded with functions and it may state 8 batteries when replacing batteries. Good luck with that. Stay with simple locks if you have not decided on your next lock.]
   
   
4. What brand of batteries?
   
   We are not intimately familiar with every battery brand and their supply chain. We can however put on our thinking hats and rationalise along the following lines to minimise chances of poor quality battery (which may lead to unexpected issues):
   
   - buy from high traffic​ outlets (supermarkets, petrol kiosks) on the assumption that the batteries have not been on the shelf for a long time (alternatively you can try interpreting the dates on the batteries)
   
   - avoid heavily discounted batteries or batteries priced very low 
   
   We think Energizer Max at NTUC supermarket could be decent brand to use. Avoid Eveready , IKEA and GP batteries.
   
   
5. What if the batteries run out of juice?
   
   Fear not as this has been a design consideration since the first iteration of digital locks from many years ago. When the battery is low (and requires replacement within the week), the lock will play a melody and there is also a visual indicator. In the event you miss all these indicators (say when you are away on vacation), and the batteries are completely depleted, just get a 9V battery from the supermarket and plug it in from the outside to give it enough power for you to unlock using one of the access methods (pin etc.).
   ​

Hummingbird

See pictures below for AA size and 9V Energizer Max alkaline batteries.
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