One Show - Dodgy Chargers (electrical)

DevCoder

The expert on the couch at the end of the item said that you can't just mix and match as the device could draw too much current.

My electrical theory is a bit vague these days but I thought

Current (Drawn) = Voltage / Resistance (Load)

As the Voltage is constant (just make sure you use the same voltage charger) and Resistance is the Load generated by the device, then surely the current drawn is only as much as the device load asks for?

Therefore there is no difference in the current drawn on a device which has an original 1A charger and you then use a 2A charger?

beeg0d

krisdorey wrote: »

Therefore there is no difference in the current drawn on a device which has an original 1A charger and you then use a 2A charger?

I beleave the danger lies when things are the other way round. Sure a device will only draw what is needed so a 2A rated charger will be perfitly safe (in theory) for a 1A device BUT a device that draws 2A on a 1A rated charger could lead to problems.

forgotmyname

A 2A charger may allow the battery to charge at a higher rate.

If the device has a circuit to detect charging voltage then it shouldnt matter what amperage the charger is. Fot a 20A one and it will still only draw 1A.

Poor voltage stabilisation ans the lackoff any safety cutoff is the problem.

Instead of charging your 3.7v battery at 5v and dropping down once charged they start off at about 8volts and stay there for as long as its plugged in.

I bought a radio controlled toy. Not thinking its a chinese product i plugged the charger in and POP... Nasty smell.

Bought from a UK source i i assumed it would have a decent charger.

DevCoder

Agreed with both your points, some interesting discussion.

I was assuming that the voltage was correct and a constant factor.

Can a device draw more current, surely then the (and again I may have this wrong) voltage decreases and thus it just charges slower. I assume the case mentioned by beeg0d is where there is a lack of voltage stabilisation devices?

dealer_wins

I think the problem is with "fake" chargers that have been built with sub-standard components that are liable to burn your house down at random!

forgotmyname

I was looking into LED lighting and found an ebay clip where a guy took one apart.

GU10 style fitting with just 2 pins. A wafer thin layerof board was the only thing separating the mains power.

And with just 2 pins the bulb would fit either way. So a 50/50 chance of the front face being live. With no shield to prevent someone touching it.

paddyrg

Never underestimate just how bodged and nasty cheap electronics can be. I've got a Chinese (bought overseas) 'USB adaptor' which outputs 6vAC as opposed to a stabilised 5vDC. It's only because decent electronics will sanitise the power they're connected to that means they work at all. Just because a socket fits, don't assume the voltage etc is correct.