Alarm system

[fionn1432]

Hi

All so I'm planning to put a alarm system in my campervan and going to run it from the leisure battery. From a 12v 2x 5v usb socket. The alarm pannel runs on 5v and the siren 5v. I have pics attached on here also would it be safe to have it left on constantly from the 12v 2x 5v usb socket.

Thanks

 

[footsoldier]

I always find either Practical Motorhome - or Camperavan magazine - to be very helpful on these matters.

 

[fredrussell]

you could use a buck voltage converter to bring 12v from leisure battery down to 5v. 12v supply to buck would need to be fused as close to battery as possible.

Pardon our interruption...

 

[Stemar]

What is the power draw of the siren? Could the USB gizmo cope with the alarm and the siren simultaneously?

 

[jakew009]

Use a couple of these:
Amazon.co.uk

 

[fionn1432]

What is the power draw of the siren? Could the USB gizmo cope with the alarm and the siren simultaneously?

5v

 

[fionn1432]

you could use a buck voltage converter to bring 12v from leisure battery down to 5v. 12v supply to buck would need to be fused as close to battery as possible.

Pardon our interruption...

 

[Stemar]

5v

It isn't the voltage that matters - that's right, or it isn't, but the current. USB chargers, especially cheaper ones, tend to have a limited current output, and the rated current is often shared between the two sockets, so a twin socket 5 amp charger might only give 2.5a for each.

I was just wondering, if the siren draws too much power, there may not be enough left for the alarm, which might give problems. fredrussel's suggestion of a buck converter or two would overcome the problem - if it really is a problem.

 

[fionn1432]

It isn't the voltage that matters - that's right, or it isn't, but the current. USB chargers, especially cheaper ones, tend to have a limited current output, and the rated current is often shared between the two sockets, so a twin socket 5 amp charger might only give 2.5a for each.

I was just wondering, if the siren draws too much power, there may not be enough left for the alarm, which might give problems. fredrussel's suggestion of a buck converter or two would overcome the problem - if it really is a problem.

I might buy one of those looks the safer option the one buck with the circuit board. I'd say the siren would run on 3v. So what fuse would I use for this buck

 

[KompetentKrew]

you could use a buck voltage converter to bring 12v from leisure battery down to 5v. 12v supply to buck would need to be fused as close to battery as possible.

Surely that's what the 12v USB adaptor is doing? I'm sure it'll be fine.

My concern would be the risk of running the battery flat while unattended.

What size and kind of battery do you have OP? Do you know what the draw of the devices might be?

 

[fionn1432]

Surely that's what the 12v USB adaptor is doing? I'm sure it'll be fine.

My concern would be the risk of running the battery flat while unattended.

What size and kind of battery do you have OP? Do you know what the draw of the devices might

 

[fionn1432]

The battery is a lesuire battery its constantly charging of a split charging system. Never from the main battery the alarm pannel 500ma and the siren 60ma