A/C chargers

George · Post by **George** » 10 Feb 2011 21:25

My Garmin's dedicated A/C charger has a power output of 5V x 1A. But it charges up fine from my laptop's USB port, which I believe is 5V x 0.5A; presumably it just takes twice as long.

My phone's dedicated A/C charger has a power output of 5V x 0.5A. If I connected it to the Garmin's charger, would it charge up twice as quickly, would it only draw the O.5A it needs (even though the charger can deliver 1A), or would twice the rated current flow through it, buggering it up?

Andy Terry · Post by **Andy Terry** » 10 Feb 2011 21:32

Lost me there. Connect phone charger to Garmin charger

Andy Terry · Post by **Andy Terry** » 10 Feb 2011 21:35

No. I get it. Connect the phone to the Garmin charger.

I think the answer is 'get Phil to carry both chargers to Brecon'.

George · Post by **George** » 10 Feb 2011 21:53

Andy Terry wrote:No. I get it. Connect the phone to the Garmin charger.

I think the answer is 'get Phil to carry both chargers to Brecon'.

Nice idea, Andy. I think I already have the answer to the practical problem behind the question: "take the phone charger and charge the Garmin from that, since it delivers the same current as the USB port, which works fine." However, I don't know the answer to the technical question that arose from the practical problem. I'm sure that the answer to everything is out there on the net, but I just thought one of my knowledgeable club mates might know off the top of his/her head.

George · Post by **George** » 10 Feb 2011 21:57

And, by A/C charger, of course what I meant was the rectifier that takes an A/C supply, and delivers a D/C charging current. Which probably shouldn't really be referred to as an A/C charger. Apologies for any confusion caused by the imprecision.

Post by **CakeStop** » 10 Feb 2011 22:15

I'm not sure so don't risk anything on the basis of this but I think I recall reading that when it comes to chargers you need to at least match the output current required to charge the battery or it won't charge (half the current doesn't mean double the charge time). 0.5 amp difference doesn't sound like much though, I'm not sure whether 0.5/1.0 is equivalent to 3.0/6.0 (for example) if you see what I mean.

However, somewhere I've got a freeby Marmite hand wound charger with a selection of adapter plugs, meant for mobile phones but I haven't found a use for it yet. I can't imagine it's that clever at voltage / current regulation but then again I haven't tried it so I don't know if it works.

George · Post by **George** » 10 Feb 2011 22:50

Thanks, Steve. I'm going with the lower-rated charger, because it appears to charge the Garmin (hard to be sure, since it's already charged), and I can't see how a weaker current could do any damage -- I should think that the worst-case scenario is that it won't charge properly.