a 2.5 amp  current will end up ok, think about a car battery this  will be like leaving side lights on  day and night  this will be a constant current drain  is not like the max current required to start  car batt's are sold  in starting amp requirement on a cold day ie amps  output for a very short period.  leisure batt's are used for caravan  and boat lights etc lower current for a longer period  this worked for a long weekend ok it needs some form of trickle charge  to try and stop the volt drop as i said in previous post used solar panel 

Generator for temporary mains supply seems sensible?

 

Agreed but if it's in the middle of a city centre like some of my customers, poor road access, no 'outside' other than the street, or office between one above and below etc...

 

If it's an industrial estate or the like seems a very sensible option.

Because he hasn't used leisure batteries perhaps , standard batteries you will need to many, they will drain quick and die

What about a battery monitor send a low battery warning

 

Agreed, if you really wanted to do this route than I see no other sensible option than a couple of large leisure type batteries.

 

As far as using them vs. not using them, I also thought many maglocks went into 'power reduction' once the magnet had been attached?

Edited February 11, 201610 yr by datadiffusion

Depending on the standby time you could have the geny on during daylight hours.

When work is complete recommend the batteries to be replaced.

 

I recommended this same thing for a customer that was having a three phase supply installed to replace a single phase supply.

The system worked overnight and recharged on the geny during the day, was over a weekend IIRC.

Worked well, replaced the 8x 7Ah in the ACU's the Monday after they had finished.

RE mags, should have a constant current however there is a higher inrush when energising.

https://www.batterystuff.com/kb/tools/solar-calculator.html

Might help Jason

Edited February 12, 201610 yr by J&D Security