Thread: 12V power in the rear boot.

Yep, it does.

Many of the double USB ports have a capacity of 2.8? amps and a second at 1.4 , but it is only 2.8 when only one is being used!
Regards PhilipA

Originally Posted by PhilipA

Many of the double USB ports have a capacity of 2.8? amps and a second at 1.4 , but it is only 2.8 when only one is being used!
Regards PhilipA

Not quite.

Many dual port units have 3 ratings.

Port 1 - 1.1a
Port 2 - 2.1a
Overall Current - 3.2a

Port 1 - 2.4a
Port 2 - 2.4a
Overall Current - 4.2a - therefore underrated

Etc.

Some are as you said given a lower overall rating of say 2.4a total. These are rare now as people have demanded more flexibility.
The other problem is cheaper units often cannot even get close to the claimed capacity.


Just to add further complexity - The units I fit are minimum QC 3.0 now.

Tablets can draw more than that, and fridge-freezers definitely can, so I wouldn't use a USB.
That said, our tablets are okay if they are kept reasonably charged.

Originally Posted by DiscoMick

Tablets can draw more than that, and fridge-freezers definitely can, so I wouldn't use a USB.
That said, our tablets are okay if they are kept reasonably charged.

I think you’re confusing conversation. Nobody would try to run a Fridge on a 5v USB

Normal USB Tablets can NOT draw more than their rated input, and that is never more than about 2.1a on the USB side.

The galaxy tablets for example are 2.1a at either 5v or 9v using QC 3.0

That’s only 18w or 10w.

I’d suggest your USB ports are either underrated or they are overloaded or both.

Yes, as you say, certainly can't run a fridge on a USB.
There have been posts referring to running a fridge on a merit plug, but one of them fell apart on me , so I wouldn't do that either.
I mentioned USBs and tablets to say they can't always do the job, so we're agreeing. For example, I'm looking at a battery pack as I type which offers either 1a or 2a ports. A tablet can draw more than 1a. Actually, my phone also charges much faster on the 2a.
I realise the 1a port is limited output, so the tablet would do much better on the 2a port.

Originally Posted by DiscoMick

....
There have been posts referring to running a fridge on a merit plug, but one of them fell apart on me, so I wouldn't do that either.
....

Get good quality plugs and have less issues.
The 12v / cigarette ports on the power board Julian has fitted have a locking feature, twist the plug about a 1/4 turn and they lock in fairly tightly too.

When my cig plug broke in the port, it wasn't a high quality brand, but was close to 20 years old, so still lasted a long enough while.
The replacement I got from the closest town was a Narva 12v plug, only thing available, and much nicer quality so should last a lot longer.

My Merit/Narva plugs have lasted for years without problems and one has never fallen out.

On the other hand I have seen an Anderson plug fall out on a road with grass in the middle when used as a caravan plug to run a fridge . Poor bloke with 2 kids and no fridge when he got to camp .So I am using plugs there which lock into place .

Regards PhilipA