Battery Backup Access Control : Striker Lock

[Other Pineapple Smurf]

Time to put my striker lock and access control onto a battery thanks to load shedding.

Requirement: Gate gets used up to a dozen times an hour. The goal is to open around 20 times on a charge but an MVP of 10 times will be perfect as load shedding hit's just as we have clients arriving or if load shedding is at night and we don't use the genie / alarm company needs access to the property.


Current setup: No backup, needs to be plugged into the generator which I don't always switch on if I / my wife is not working.


Spec:

1 - CISA RIM LOCK (Don't laugh you smutty Pineapple Smurf) : 11630-60-2 – LH

* Steel case and striker, painted aluminium grey
* Dead-locking latch
* 12 V ac CE
* Rated current 2,5A

2 - Have two remote receivers - since nobody has a standard my keypad and remotes are different brands



Question: Would an alarm battery 12V 7Ah be strong enough, or do I need something stronger ? I like the idea of using shared battery size as that is what my alarm uses.

If the above battery will work, to charge, would I just use a common 3.2amp charger: https://www.takealot.com/sherlo-tronics-battery-backup-power-supply-3-2-amp/PLID47439684

I'm comfortable building my own using my existing components and buying anything needed from https://www.robotics.org.za/ etc but I'm still new to electronics. Only just getting into IOT / Arduino this month. (Want to add a ESP32 module still to the gate for open/close status and remote control).




What I currently have, a 12V 3amp power supply and two recievers (flame me with my prototyping). This of course is all going to be installed in a proper housing.

 

[one poster]

I don't need to operate my pedestrian gate much so never thought about backup power for the electric door strike.

A sherlotronic (or whatever flavour) PSU/battery backup unit is actually a nice idea.

BUT seems like the the coil in the CISA locks are AC not DC. The sherlotronic will output DC. From my quick reading it looks like DC might work on an AC coil but at the risk of burning out the coil (these locks are not cheap...). (specs and install info on the lock)

One other potential problem is whether the short pulse from the remote relays will actually be long enough to actually trigger the gate to release (bottom left receiver looks like a Nova -> on them I think you can set to pulse or latch but if you latch even with correct power supply, i.e. AC, you could end up burning out the coil).

If DC as power source is useable then I suspect a 7Ah battery could last for those 20 or so unlock activations. Even if we assume the coil draws a full 3A on activation and even if this is for a full second (probaly likely more like 0.5 sec). If you draw 3A continuously for 1 hour you would have used 3 Ah (basically half of the battery which should ideally be the maximum you deplete these types of batteries) but for the 20 unlock activations you only drew current for 20 seconds. So unless something else is also connected to the battery and drawing power you will likely use very little form the battery.

There is a gizmo you can add to the lock if you want to run it from a DC powersource btw.

 

[Other Pineapple Smurf]

Thank you, I neglected to pick up the VAC part. Both the ET & Nova unit are both DC & VAC compatible but I forgot about that as these were bought a while back.

I remember when setting up originally about making sure the timing was not too long to avoid burning out the coil.

Will look at a standard UPS and that DC thingy .

 

[Other Pineapple Smurf]

Remembered today that I still have a Waeco 100W inverter and my striker lock power supply is 40AH.

Going to test with a 12V7Ah battery I've got lying around. I can always build a failover relay switch if this works.

 

[Other Pineapple Smurf]

Scratch that, killed the battery with a 7w light bulb.

Will just look into a DC replacement.