Simon_CSK Posted February 20, 2018 Share Posted February 20, 2018 I am trying to set my tablet up in my Disco so it can be used (when not driving) but will be charged while driving. The normal 2.1 amp chargers do not work so I need something more from the USB charger. Can I wire a 2.1 amp and a 1 amp outlet together to hopefully get 3 amps or it there some other way to achieve my target? Quote Link to comment Share on other sites More sharing options...
Scotts90 Posted February 20, 2018 Share Posted February 20, 2018 Blue sea systems do twin USB chargers, 4.8a https://www.ebay.co.uk/p/Blue-Sea-Systems-Fast-Charge-Dual-USB-Charger-Socket-Mount-1045/1560446457 i have this Carling fitment version in the 90 to keep the kids' media systems happy! http://www.mudstuff.co.uk/products/electrical/carling-switch-mounts-and-accessories/blue-sea-carling-compatible-usb-socket.html Quote Link to comment Share on other sites More sharing options...
zardos Posted February 20, 2018 Share Posted February 20, 2018 The short answer is that just wiring 2.1 amp and 1amp outlets together is unlikely to work as the adaptors are a bit more complex than batteries. Have you checked the output spec of the tablets normal wall charger? USB 2.0 Battery Charging Spec max current is 5A (but most don't go this high as the cable cannot usually take this much and most only go up to 2.5A If the tablet is an i Thing then it might not be doing USB standard for power signalling so it would need a specific car adaptor. Also you might want to use a high quality and short USB cable and as with a high current draw on a long cable might mean the voltage drop takes it below 4.75v which is out of spec (See that https://www.adafruit.com/product/1994 actually supply 5.25V for this reason) When looking at a USB power supply for another project, this ebay item looked good https://www.ebay.co.uk/itm/DEOK-12V-5V-Buck-Converter-Step-Down-SR-Adjustable-Module-DC-8-22V-to-1-15V-3A-V/282849858874?hash=item41db2a553a:g:K6MAAOSw-YFahezD (as it can also be tweaked to 5.2v output and should handle most needs - though I have not tested this) I could then also use good quality wire and easier to make water tight connections as the bulky usb plug can be wired on after being passed through a suitable gland) Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted February 20, 2018 Share Posted February 20, 2018 As Zardos says, USB charging (and whatever iThings use) involves negotiation between the device & the charger before (usually) upping the voltage as high as 12v to get more power down the wire. Sometimes just using a better quality cable can help, but often you need one of the more expensive chargers to make sure it's got the correct software in it - doubly so with iThings as they really like to lock their stuff down to genuine-only. Unfortunately, different manufacturers invented different standards / negotiation schemes over the years so it's a bit of pot luck. There's a lot of cheap chinese chargers out there claiming any amperage you want but that doesn't mean they'll actually play well with your device and supply what's needed. Quote Link to comment Share on other sites More sharing options...
Cynic-al Posted February 20, 2018 Share Posted February 20, 2018 I used to use my phone as a dashcam and the USB / lighter socket adaptor I had wouldn't keep up so the phone gradually went flat. I got a higher current USB lighter socket adaptor which did the job fine. It's relatively dumb in that it just supplies 5v at the current the device is asking for and has a little display that tells you imput voltage, output voltage and current draw. You supply your own cable which keeps apple stuff happy. For what they cost off ebay have you tried just getting a higher current one? Quote Link to comment Share on other sites More sharing options...
Ex Member Posted February 20, 2018 Share Posted February 20, 2018 A 2.1 A charger should work with anything. The problem is having a crappy 2.1A charger. You need a proper name brand one. Quote Link to comment Share on other sites More sharing options...
Simon_CSK Posted February 20, 2018 Author Share Posted February 20, 2018 Guys Got to the bottom of the problem. I have a dual output USB socket one at 2.1 amp the other at 1 amp. I have a small (size wise) bluetooth receiver plugged into my 1amp sockets which allows my phone to stream music to the radio without a wired commection. I have a set up that allows my phone also to wirelessly charge so have tried to have everything remote so I didn't need to plug lost of things in when I got in and out of the car. When I disconnected the bluetooth receiver both of my tablets charged adequately and I was able to use the GPS very well. It seems that the (Cheap Chinese) cr**y usb sockets were being overloaded and dragging down the higher rated output. Quote Link to comment Share on other sites More sharing options...
Peaklander Posted February 20, 2018 Share Posted February 20, 2018 The one I use like that describe did state in the instructions that you can’t draw off the 2.1A and 1A simultaneously. I’ve used it for either iPad or iPhones without issue and I don’t know the maker but it was ~£12 IIRC so on the cheap side I’d say. Quote Link to comment Share on other sites More sharing options...
zardos Posted February 20, 2018 Share Posted February 20, 2018 And then you can add in quick charge capabilities, (I think there are only 2 types for that, but they do also come is various versions). These can also increase the voltage over USB, part of why they do this is that battery charging rate is related to input voltage - the battery voltage. i.e as a battery gets charged the voltage difference decreases and thus the power that can be inputed decreases. But it seems that the problem is identified, the original posting was not clear that it was a dual socket converter that probably only had a 2.4A buck so if the 1A socket took 1A there was on 1.4A for the 2.1A socket. Solution buy a better convert like the blue sea one Scotts90 posted Quote Link to comment Share on other sites More sharing options...
Simon_CSK Posted February 20, 2018 Author Share Posted February 20, 2018 49 minutes ago, zardos said: Solution buy a better convert like the blue sea one Scotts90 posted Agree but the cheap ones are very appealing I have been experimenting with various set ups on my cars but this was the first time I had introduced the tablet. Prior to this I has dedicated GPS setups but having used Google Maps I liked the system the only disadvantage is that it cannot track your position if there is no destination set. Guess you cannot have everything. Quote Link to comment Share on other sites More sharing options...
Ex Member Posted February 21, 2018 Share Posted February 21, 2018 34 minutes ago, Simon_CSK said: Agree but the cheap ones are very appealing Until the cheap one destroys your very expensive phone. It is not worth it. Watch some tear downs on these things and you will see how close you are to destroying the thing you plug into it. Quote Link to comment Share on other sites More sharing options...
zardos Posted February 21, 2018 Share Posted February 21, 2018 9 hours ago, Simon_CSK said: but having used Google Maps I liked the system the only disadvantage is that it cannot track your position if there is no destination set. Guess you cannot have everything. Have you tried the app called Viewranger (http://www.viewranger.com/en-gb) very good at tracking your position with lots of map options but no turn by turn or Here ( https://www.here.com/en ) for turn by turn. Quote Link to comment Share on other sites More sharing options...
landroversforever Posted February 21, 2018 Share Posted February 21, 2018 You'll find a lot of the twin USB ones will say they can do two of the lower draw items or only the 1 higher output. Quote Link to comment Share on other sites More sharing options...
Cynic-al Posted February 21, 2018 Share Posted February 21, 2018 A friend of mine uses one of those battery power banks. That way the phone stays on charge when the engine is off and the power bank charges when the engine is running. Obviously you need 1 high current usb adaptor. You also need a dumb power bank as some won't let you charge and draw at the same time. Quote Link to comment Share on other sites More sharing options...
Simon_CSK Posted February 22, 2018 Author Share Posted February 22, 2018 On 2/21/2018 at 1:18 PM, Cynic-al said: A friend of mine uses one of those battery power banks. That way the phone stays on charge when the engine is off and the power bank charges when the engine is running. Obviously you need 1 high current usb adaptor. You also need a dumb power bank as some won't let you charge and draw at the same time. Cinic-al Like that idea and one I might just adopt for the tablet and the phone. Quote Link to comment Share on other sites More sharing options...
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