12v electrics problem

[TheGrapeEscape]

Hi All,

My cousin has a T5.1 Camper, bought fully converted with full kitchen but no fridge. He has the wires there and switch panel, powered off a sergeant ec160. There's 12v dc at the two cables, but as soon as you put a load on it, the live drops to 5v dc.

When the sergeant panel is turned off, the voltage is still at 12v dc, I've advised him that this will kill the LB if a fridge is left on.

Any ideas why it's dropping to 5v when under load?

 

[Pauly]

There’s a few possibilities
I think most likely is the battery has low charge or is just knackered ?
Other options could be a loose joint/high resistance on the supply cable or the cable could be way undersized for the load being applied

 

[TheGrapeEscape]

Its an AGM battery, but also, brand new with the conversion. There is a 12v usb cbe switch next to it. We unscrewed that and plugged fridge in which worked fine. We then tried to run a simple air bed pump off the wires and same again, voltage dropped, couldn't even power a 96watt pump

 

[Anakin]

5V is suspiciously like a USB voltage. Are you sure there isn’t a converter in the circuit somewhere?

 

[TheGrapeEscape]

5V is suspiciously like a USB voltage. Are you sure there isn’t a converter in the circuit somewhere?

Thats a thought!

As its built in kitchen, the wires disappear behind the unit. There's never been a fridge in, just the space for it.

Would make sense what you're saying, it's just the fact that there's 12v present until you put load on it. It's fused on a 15a blade fuse and labelled fridge on the sergeant panel

 

[TheGrapeEscape]

FIXED

After tracing the wires to his Sergeant EC160, we found an inline fuse holder with no fuse in. As soon as we put a 10a in, it gave constant 12v