Options for UPS not for computers

[littlespark]

Background.

Existing customer, the one with the German built kit home. He has a detached double garage. 2x electric garage door openers that can be opened inside or with a key switch outside.
There is no other doors into the garage.
There is a manual way to open the doors but only from the inside.

Last year during the storms, they lost power for 7 days. They could not get their car out of the garage to go anywhere.


What he has asked for is some back up power supply that will allow him to open the doors from the outside in the event of a powercut.
It would need to automatically switch over to the back up when main power drops.

He has also asked if it can be portable. Ie, once the door was opened, could he take the unit into the house and use it there for powering laptop, phone chargers etc.
(This could be a separate unit if it becomes too tricky to make it portable)

Each door opener is rated at 170W, and the garage board also powers lights and general sockets.

What sort of time would they last for? A couple of hours maybe? Enough time to open the door and get the car out?

 

[DefyG]

I'm just in process of replacing a 1500w unit and would hardly call it portable (probably something like 2 concrete blocks) so maybe something like a 600w unit might just about be??

 

[James]

How about this?

outside the garage fit a box with a changeover switch so the garage distribution board can be powered either from the original feed from the house or an appliance inlet mounted outside the box.

then the home owner can use either a small generator to supply the garage or a battery module like this

https://www.hampshiregenerators.co.uk/product/generators/portable-power-stations/ecoflow-river-600-portable-power-station/

 

[Lucien Nunes]

The quiescent load of the door opener is probably a few watts, it only has to power the receiver. So unless the door is actively moving, the load on the UPS is so low that the backup time is likely to be limited as much by internal losses in the UPS as by the load of the door opener. UPS makers usually quote the backup time at various loads but not, it seems, at near zero load. Therefore unless one actually tests this for a specific model, it's to even give a ballpark figure for backup time. I'm tempted to try this on a couple of UPS's if I get time. Just putting an ammeter in series with the battery when the inverter is running unloaded, and with say 5W of SMPSU load and separately with 5W of iron-core transformer load.

One problem with the UPS being inside the garage is that if the power fails when unattended and it then keeps the door alive in standby for most of its available battery capacity, because the load is low the battery will present a favourably high terminal voltage to the UPS's monitoring algorithm. It might then be unprepared for the very sudden increase in load and drop in battery voltage when the motor starts up, resulting in the UPS cutting out almost immediately. This could leave the door unlocked and slightly ajar, with no means of opening it to get at the UPS nor closing it to make it secure again. Hence the advantage of @pc1966's external inlet, although placing the UPS in the house would suit too.

Definitely better to back-up only the door opener. If the entire garage board is on the backup supply and a dehumidifier or similar load that has high starting current is plugged in, it might trip a UPS that is otherwise plenty big enough to operate the door.

 

[SamG340]

Transfer Switch, Mini Dual Power Switch Automatic Circuit Breaker Dual Electronic Power Generator Changeover Switch Transfer Switch 220V 63A 2P : Amazon.co.uk: DIY & Tools

Transfer Switch, Mini Dual Power Switch Automatic Circuit Breaker Dual Electronic Power Generator Changeover Switch Transfer Switch 220V 63A 2P : Amazon.co.uk: DIY & Tools

amzn.eu

Something like this, a leisure battery or two, a smart charger and a small inverter

 

[pc1966]

If going for back-up power of some sort then really better to allow the whole house to be switched over to an external supply (UPS even) for all sorts of other reasons.

But really a garage you can't open without power and a working electro-mechanical control system? That is just asking for grief further down the line!

 

[DPG]

If going for back-up power of some sort then really better to allow the whole house to be switched over to an external supply 9UPS even) for all sorts of other reasons.

But really a garage you can't open without power and a working electro-mechanical control system? That is just asking for grief further down the line!

Indeed. Wait while the motor start capacitor goes in a few years. Or one of the limit switches fails. If the door is down then it will stay down.

 

[pc1966]

It is bizarre not to have a mechanical override option, even just for safety of anyone who happened to be in the garage when it closed.

Next thing you will be telling us it needs an internet connection to some servers in Germany!

 

[SamG340]

Maybe their money would be better spent adding a personnel door to the garage rather than a UPS ?

 

[nicebutdim]

It is bizarre not to have a mechanical override option, even just for safety of anyone who happened to be in the garage when it closed.

Next thing you will be telling us it needs an internet connection to some servers in Germany!

Unless I've misread the OP, the problem isn't that a manual override doesn't exist inside, but that there is no means of accessing it from outside.

 

[pc1966]

Unless I've misread the OP, the problem isn't that a manual override doesn't exist inside, but that there is no means of accessing it from outside.

Ah, sorry on re-reading it is there.

But as above, adding a personnel door would seem a good use of money. Maybe not in to the house directly if any fire-risk aspects to consider that make that impractical or too expensive, but somewhere sure would be good!

 

[DPG]

I don't think an electric door is a good idea at all where it is the only means of access.

 

[SamG340]

I don't think an electric door is a good idea at all where it is the only means of access.

Yea what if it breaks all together ? Have to take a wall down to get your car out , doesn't make sense to me.

 

[snowhead]

If the garage is fed from the house then the UPS would be better in the house at the D.B or near to where the feed goes out.
Then if the UPS fails during a power cut they can connect an alternative UPS / generator to lift the door.
Also if the UPS is inside the house they could use it for other things, assuming it's got the capacity.

 

[littlespark]

Good ideas and I will suggest it goes in the house end..

I think the electric opener was added as an afterthought to existing mechanical doors, nobody thought at the time, so hence there was no normal door….. but to paraphrase…

“I’m a sparky, Jim, not a joiner”