Cable for 12v battery

[blinky]

I'm having a wee issue...... My 12v mains adapter is putting out 13v but by the time it gets to my mount over 10m of 10amp 12v rated cable it has dropped by over 1 volt. The thing is, I have just bought a leisure battery but this will only put out 12.5 volt (I believe?) so with the drop over the distance to the mount the voltage will be too low. What do you gus use to avoid this voltage drop?

[pete_l]

What do you gus use to avoid this voltage drop?

A shorter cable.

Seriously, a 10m run is quite long, as you're putting significant current through it. It would improve things if you ran mains power to near the 'scope and then had the 12V adapter close enough to only need a short cable to power the scope.

However, it's usual for a fully charged SLA battery to output 13.8V - definitely over 12.5V (which would be a long way towards being flat), which would do the job. If you are getting such a low output from it, I'd suggest making sure it's fully charged. If you still get a low voltage from it, check that none of the connections are loose or dirty/corroded, that could drop you a fair bit of voltage.

[aball28]

As already said a shorter run of same cable or increase the cable size.

Allan.

[blinky]

so if I run 2 lengths of cable.....?

[Auntystatic]

I run 8m of 25A red/black cable from my Ham radio psu with no problems, most new large SLA batteries come with a carrying handle, so you could shorten your cable, or stick it in one of those wheeled tool boxes for easy transport.

[Islander]

so if I run 2 lengths of cable.....?

If you mean in parallel then as long as the cable types are identical, you should halve the overall resistance and reduce the losses. If the cable length is constrained then you need cable with a greater cross sectional area or higher current carrying capability (this amounts to the same thing).