Battery Back Up - Sanity Check / Other Ideas

[JasonOfOz]

Hi Everyone,

 

Got another weird one to challenge you all with.

 

We have a client whose building is doing a power shut down over Easter but they require 3 doors that are access controlled to remain live throughout. 

 

They can't physically lock the doors so they have asked us to boost their battery back up for a total of 84 hours.

 

There are 3 x door controllers + double maglocks + 3 readers. Estimate draw of each door to roughly 2-2.5Amps.

 

 

I was going to simply add some more batteries to their existing system but surely there is a better way than wiring up 20 x 12V 17Ah batteries to each door??

 

 

Please help me get out of this box that I've been stuck thinking in....

[9651]

Can't they just hook a generator up?!

[JasonOfOz]

When people say generators, I'm thinking the fuel powered ones.

 

I'm guessing there are those that you simply charge up on mains - is that what you are talking about?

 

Any suggestions?

[al-yeti]

Leisure battery might be better , will last longer don't you think

[petercts]

tried this used large  2 +12 volt marine /lorry battery and a solar panel to trickle charge  on fire damaged site  worked ok until some idiot tried to boost charge  with a 12 volt generator everything smoked and died

[datadiffusion]

Do they want to use the doors or just keep them physically secure?

[JasonOfOz]

They just want the doors to be physically secure.

 

We were having a debate amongst the team about whether using the doors would actually drain or save power.

 

Obviously the reader and relay would consume power, we were thinking that as the system drops power to the magnetic lock, would that even things out?

 

Not sure if it works like that but I have been told that battery will drain more if the doors are used.

 

 

Spoke to Yuasa Tech this morning to sanity check the numbers.

They suggested that we use either of these 2 batteries:

 - NP65 x 3; or

 - NPL100 x 2

(the L, means long life - i.e. 7 years as opposed to the standard 5 year life - not necessary in this case as it's a one off)

 

I needed roughly around 180Ah on each door based on his calculation. Seems all calculators give out a slightly different figure. 

 

I asked about the Leisure Battery and he said that they aren't generally designed for this sort of application.

 

Hope that helps others....

[al-yeti]

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

Edited February 10, 2016 by al-yeti

[sixwheeledbeast]

Generator for temporary mains supply seems sensible?

[james.wilson]

if fail safe locks then more use will extend but by seconds imo. You can calculate it using batts but bear in mind all A/h stats are based on a 24 hr discharge