battery mains replacement

Darr

Hi all ,
Wondering if you could help with this (or even its possible) .
As some may remember I was asking about remote location alarms/cctv .. we have the system all set now and working fine on MAINS power .. now the site is very remote and while it’s in use its powered by a large generator ( much larger then what’s needed)

Now the issue is when we aren’t there we have a few items we would like to run ( low watt lights) .. and now we want to put in a GSM dialer ..

this runs on 10-16 V mains power and we have another item that uses 12V power ..

Is it possible to have a battery style power supply for these that would charge up when the genny is on .. the site is very rarely 2 days without power

so its 3 items , 1 low watt light , 1 10-19v unit and a 12v unit that need to be hooked up ..

any help would be great thanks
Dar

DublinDilbert

Hi,

Its all about how much power you need and how long you need it for.

I'd imagine the GSM dialler would be quite efficient, and not need much power. I've no idea about your CCTV cameras, I'd imagine they wouldn't be too bad either... What watt-age is the light you want to hook up?

There's 2 options, as i see it:-
1) A UPS, similar to what you'd see powering up a computer server, which would give you a 220V output. These are expensive and probably wouldn't get the run time you'd need. Also 220V would need to be stepped down to 12V to run most of your equipment.

2) If you can find a light that will run off 12V, then you could use a 12V battery pack for everything... which gets charged from a battery charger when the generator is running....


I'd go for option 2. You need to work out what current you need to supply form the batter. Then choose the correct size battery. The battery will be rated in Amper Hours, so once you know the current you'll be able to work out how many hours a full battery will last for.

Darr

Hey DD ,

The light inst 12v ... but after your suggestion it will be

Just wondering as you say option 2 ( which is kind of what we were hoping for)
how would we go calculating the current needed ? I think the actual power reqs for the 2 units ( the cameras etc are all battery so it’s only the base units) would be very low

also regarding the charging is this a case of disconnect the units from it and then charge the battery or can it be done all hooked up ..

if anyone knows of a system or a instructions page to something like this it would be of great help ...

Darr

and thanks again DD


and thanks again DD

DublinDilbert

Your effectively creating an "online" UPS.

You need to get an multi meter, and measure how much current (in amps) your drawing off the battery @ 12V.

Say your equipment is taking 2A.

Say you use a standard car battery, typical rating is 45Ah (Ah = amp hours)

Hence your battery would last 45/2 = 22.5 hours!

You should try get a "deep-cycle" 12V battery, rather than just a car battery. although if you were stuck a car battery would work. A marine supplier would be able help get you one of these...

If your using a small car battery charger, there should be no issue leaving the equipment connected during charging. After all this is what your car does when its running. You might want to add some additional protection onto the 12V feeds going to the equipment, to be sure to be sure...

Darr

Hey DD ,
we got a 300Ah gel battery which we should have in the next few days .. our power needs would seem to be less then 5.5Ah so we should be able to manage with that .

Just wanted to say thanks for the help its very much appericated .

again if anyone has info on connecting it all up would be intrested in that , we arent going to attempt it ourselves if complicated,we have a mate who is a sparks but is away for the next few weeks and he can do it when he is back .

but if its reletivly easy we may look at it ( not a complete novice with elec but not used batterys before I admit)

Dar

DublinDilbert

So based on 300/5.5 you'd expect 54 hours of continuous usage....

It might be worth putting some say 5A automotive fuses in series with the 3 loads your connecting... you can pick these up from any motor factors, complete with a little holder...

What sort of charger have you picked out? Are you going to leave the charger connected, when the generator is turned off and the batteries are discharging?

Shouldn't be too bad to set up, but you do have to be careful with a battery that size, it can supply a massive amount of current. If your not sure, best to get someone who is to have a look... where are you based?

Darr

So based on 300/5.5 you'd expect 54 hours of continuous usage....

It might be worth putting some say 5A automotive fuses in series with the 3 loads your connecting... you can pick these up from any motor factors, complete with a little holder...

Yes thats the area of concern we had as aware its a large ampage

What sort of charger have you picked out? Are you going to leave the charger connected, when the generator is turned off and the batteries are discharging?

I belive the battery comes with a changer which can be used as the battery is in use (I have to check tomorrow as another member of our club sourced it )

Shouldn't be too bad to set up, but you do have to be careful with a battery that size, it can supply a massive amount of current. If your not sure, best to get someone who is to have a look... where are you based?

Limerick/Cork area .. and after checking with my mate here he said to leave it to the professions as certainly large enough to kill ya ..

So I reckon we aviod the temptation to do it ourselves ...but its tempting

Dar

DublinDilbert

Darr wrote: »

I belive the battery comes with a changer which can be used as the battery is in use (I have to check tomorrow as another member of our club sourced it )]

The charger will probably be fine... just make sure it doesn't do any pulsing of the battery. By the sounds of it, its a marine battery and charger so should be grand.

Darr wrote: »

Limerick/Cork area .. and after checking with my mate here he said to leave it to the professions as certainly large enough to kill ya ..

So I reckon we aviod the temptation to do it ourselves ...but its tempting

Dar

To be honest if an electrician said it could kill you, he doesn't really have a clue what he's talking about. How many people have you heard of being killed by car batteries? It can supply a large current if you short it, but still this wouldn't kill you. You need a significant voltage to be dangerous... Clearly you still have to show a little respect, but its by no means lethal.

I was more afraid of you damaging your equipment. A simple fuse is enough to stop too large of a current flowing in the event of a fault....

Ahh your down the other end of the country, if you were around this neck of the woods i would of helped out...

Darr

Hey DD ,

he was telling us not to mess with the changing unit and connecting that to the genny ..

decided we are going to wait for him to get back before we do it anyways .

Again thanks for the help
Darr