usb charging

The iPad will also do this when connected to a 2.1A charger that does not have the correct voltages on the data pins.

If you want to charge an iPad (I think samsung also uses the same trick) make sure it says ipad compatable and that it will deliver 2.1A. Chargers like this can be used safely with other devices.
 
Hi Bluechip, do you know if those devices draw any current when not in use? I've been looking at various USB options but have held back as I didn't want to install anything that sapped the battery
 
I've got the single output one running on my desk using a variable power supply.
At 12 V supply and with nothing connected to the USB it's showing 10mA, I'll fit a power switch to mine and turn it off when its not in use.
 
Bosun Higgs said:
getting ready for the annual trip round lands end to the summer mooring, I've just noticed how many gadgets I'm taking with me that need usb charging - kindle, tablet, phones, mifi. 5 in all. I would appreciate adivice:

1/ they all use the same mini usb plug and socket but does that mean they can all use the same charger outputting a standard voltage. Related to that, where is the mechanism that controls charge level and switches the charger off - in the gadget itself or in the charger plug ( mains or ciggy lighter socket)

2/ has anyone found a good way of building multiple sockets into a boat? At the moment my choice is one ciggy socket 12v charger or using a small inverter with both 240 v and a usb socket.
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1 - All current devices connecting to a mini USB connector will expect to see 5 Volts on the cable. Any wall adaptors that you buy these days will put out some current at 5 volts and is therefore compatible. Some devices require more current than others and mismatching devices with chargers will either overheat the charger or simply result in no charge going in to the device. The simple answer to the first part of your question is yes any usb device, any usb charger. The second part of the answer is 'in the device' the phone, ipad, floggle toggle looks after its own charge, the wall socket thingy just converts mains to the right Voltage. Ie Just because there is a 6 megawatt nuclear power station upstream of your wall socket doesn't mean you draw 6 megawatts throught the plug! :)

2 - The bluesea sockets are proving to be a popular solution although I have had several failures and they do not like the power cables being able to move at all. Other solutions are to source a quality 5 Volt output of 2 to 5 amp output capacity high efficiency power supply and wire that to several panel mount sockets.

Some of the cheaper versions plug in to a car cigar lighter outlet. Personally I won't have 'automotive' cigar lighter type sockets on a boat, If nothing else they just look cheap and nasty, they rust too easily and they are not a secure, waterproof connection.
 
If I had had a dream that I would need multiple electric sockets to go sailing when we started cruising in the '70s, I think that I would have thought I was going mad. Is sailing really that complicated?
 
Bosun Higgs said:
getting ready for the annual trip round lands end to the summer mooring, I've just noticed how many gadgets I'm taking with me that need usb charging - kindle, tablet, phones, mifi. 5 in all. I would appreciate adivice:

1/ they all use the same mini usb plug and socket but does that mean they can all use the same charger outputting a standard voltage. Related to that, where is the mechanism that controls charge level and switches the charger off - in the gadget itself or in the charger plug ( mains or ciggy lighter socket)

2/ has anyone found a good way of building multiple sockets into a boat? At the moment my choice is one ciggy socket 12v charger or using a small inverter with both 240 v and a usb socket.
Click to expand...

I recommend you go as high quality on the USB charger as you can. The cheaper ones skimp on the protection electronics to keep the cost down. Given you are probably supplying a several hundred quid mobile is it worth a few quid to protect it?

Technically, older devices will expect USB to provide 100mA at 5v. They will attempt to negotiate more power by communicating with the USB host. If the host is up for it, the device can negotiate for 500mA.

More modern versions of the spec allow for various ways for the charger to indicate that it can provide more power. So if you have a recent mobile, make sure you get a recent charger if the mobile is capable of charging at more than 500mA.

The iPhone disconnects when the supply drops because it is a sign that the supply is ****. It's not meant to drop significantly under the prescribed load and the charger in the phone needs some headroom to work.

3A is pushing it for standard USB - the cable really isn't up to it. If you look at the USB cable that comes with an ipad, it is shorter than most and extremely high quality. This helps to avoid voltage drops as the higher currents are drawn, but 2.1A is about the limit for reliable usage.

USB 3 has better connectors and can supply more current.
 
pteron said:
I recommend you go as high quality on the USB charger as you can. The cheaper ones skimp on the protection electronics to keep the cost down. Given you are probably supplying a several hundred quid mobile is it worth a few quid to protect it?
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That makes sense. Have you got any recommendations for those of us who can't tell good from bad by simply looking? Or do you buy on price?
 
nimbusgb said:
.... Personally I won't have 'automotive' cigar lighter type sockets on a boat, If nothing else they just look cheap and nasty, they rust too easily and they are not a secure, waterproof connection.
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Unfortunately the "standard" sort of co-axial LT power plugs are not much better and come in a bewildering set of sizes which are difficult to tell apart.

I've no opinion on cosmetics and aesthetics; except the smaller the better!

Mike.
 
oldvarnish said:
That makes sense. Have you got any recommendations for those of us who can't tell good from bad by simply looking? Or do you buy on price?
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I usually buy griffin or belkin ( I use the older version of this one in the car and on the boat http://www.amazon.co.uk/Griffin-Pow...72&sr=8-3&keywords=griffin+powerjolt+for+ipad )

If it's stocked by the apple store it'll generally be fine.

Basically, if it costs a tenner or so, I'd be more inclined to trust it than if it's 2.99 from eBay.
 
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