SLA batteries as power supply. What's needed?

[DavidJE]

Hi,

I've read quite a lot of info about this in various threads but there seems to be very little specific details on what components are required and how to wire it all up. Also, most of the info I've found relates to charging the batteries. This is something that I'm not worried about for now.

Basically what I want to achieve is to produce a design that will allow me to power my DAC from a 12V sealed lead acid battery.

I've read that other types of battery are more suited for this purpose but I already have a big SLA battery spare and I need to buy a decent lead acid battery charger anyway, so I may as well use them.

The main part of the design I'm unsure on is what components, if any, should be placed between the battery and the DAC and how they should be wired up.

I've read that 1 or more capacitors are required but the amount of capacitance required seems to be subjective.

Also, I've read that the battery should be isolated from the DAC by some means to make sure the DAC is getting a clean supply.

So is a capacitor or multiple capacitors needed? I guess these are to smooth out the supply? Also is there an upper or lower limit to the amount of capacitance that should be used?

Does the battery need to be isolated from the DAC? What would I use to achieve this? A regulator of some type, or a DC-DC converter perhaps?

Is there anything else required to ensure that the DAC gets nice clean DC?

I'd just like to concentrate on this part for now and then come to the charging problem later.

Thanks.