OT: using tablet as a Sat nav

[jon lopgel]

Its not the app that does that, it?s the screen and gps receiver.

[Max Demian]

I'm not surprised. My 8.3" tablet comes with a 2A charger. Plugging it into my laptop doesn't provide enough current to charge it. The 'standard' output of USB supplies is 0.5A - perhaps that's all your car socket can provide.

[NY]

Though it suggests that the screen and GPS are using an excessive amount of power, if a typical 5V car charger can't provide way more power than the tablet needs.

[Robin]

I used a Tesco Hudl tablet with TomTom for a while which did the same - with a charger from CPC supposedly capable of 1A. I have no idea if the internal charging circuit limited the current, if 1A was just not enough, or ...

[Dave Plowman (News)]

Is there a standard? I have a 13 amp socket with four of them - and one is marked 2.1 amp, and 5.1 being the total.

[polygonum_on_google]

It is certainly common.

The very first time I used an app for satnav was on a phone, and plugging it in only slowed the discharge.

My current tablet has enough juice, when charged, to run for hours so plugging it is not necessaary (for my journeys).

Try turning down brightness of the screen.

[Peter Hill]

Yes original USB port was rated at 0.5A. Most phone USB chargers are now 1A.

I have a Goodmans 4 port car USB charger 3.4A on 2 ports for front seats and 1A + 2.4A for rear seats. Total 10.2A so it's going to be pushing the 10A cig lighter fuse. Got it at B&M at end of last year.

[Andy Burns]

Install a charge/battery monitor app such Ampere to see for yourself.

With USB-C charging, my phone can run satnav and increase the battery charge on a long journey, but tends to be 'screen off' due to projecting onto the car's screen with android auto.

[bert]

The car charger can deliver up to 15 amps typically - limited only by the fuse. However the adapter you use will have limited output. You need to check it.

[Peter Johnson]

In my limited experience, car sockets are being uprated. I keep a cool box with bottled plugged in in mine. In the old car the water was just cool. In the present car, now 18 months old, the water is nicely chilled. I would suspect that the change was made in response to the OP's situation.

[Peter Hill]

Replacing the car just because the USB port(s) aren't up to supplying a tablet is a bit excessive. Is this about to become the 21st century's equivalent of "when the ashtray is full".

All you need is £9.99 and a trip to B&M for a 4 port charger. Just don't have 3 kids, cos then you have to pick your "least favourite" to decide which one doesn't get a USB charge cable.

I nominate the under 10 year old that demanded to sit in the front. You just know it's parents don't love it.

[polygonum_on_google]

Or use a power bank...

[Steve H]

Be careful with cheap and cheerful no brand chargers.

I spent a lovely half hour with my arm embedded in the back of the glove box of my BMW trying to pull the right fuse to replace after a cheap charger took out all the accessory sockets in my car (which are all on separate fuses).

Not an experience I wish to repeat!

[Dave Plowman (News)]

As an aside, I bought a decent sized mains USB power supply with 6 outlets. To tidy up things audio and video related. One being the toslink to analogue converter. Rather than having a wall wart for each. Only to find is superimposed a sound like a distant burglar alarm on the audio output of it. ;-)

[Robin]

The /advertised/[1] output of the adapter was the 1A I mentioned. I measured what it was drawing from the car - which I could do easily as I have a plug and cable terminated with croc clips for ad hoc power. That was somewhat less than 1A. But, as before, that could have been the Hudl declining to draw more. I couldn't be arsed to make up a USB lead to measure the current into other (eg resistive) loads to decide which it was as the Hudl never stopped working despite the discharge.

[1] in the sense of by CPC *and* by the manufacturer's packaging

[Roger Hayter]

Ignoring inefficiency, 1A from the car at 12v could provide 2.4A at 5v. Even with practical limitations well over !A at 5v from a DC to DC converter would draw much less than 1A from the car.

[Robin]

sorry, I did in fact allow for that so should have said the "equivalent of 1A". As for inefficiency, I thought those adapters were typically well over 80% - especially as I was measuring without the engine running so 12-and-a-bit V in rather than >14.5

[Brian Reay]

Look on Amazon, there are several higher output 5V USB adapters - eg 2.4A or more. One good maker is Anker it think - or similar spelling.

[Andy Burns]

Much as I discovered with a chromecast audio, and an external speaker, run 'em both off the same USB PSU and it's unlistenable :-(

[Dave Plowman (News)]

Ah - right. This happened with only the Toslink adaptor powered, so wondered if something sort of designed as a charger might have worse smoothing and filtering etc? Two core mains lead, so not a ground loop.