Can I use a 240V car battery trickle charger in USA (120v)?

Question

I have a car battery charger that I bought in UK and I’d like to use it to charge my car battery in US. The back of the charger says 240v (no mention of 120v). When I plug it in a 120v outlet, it turns on and seems fine. Will it charge just more slowly, will the charger overheat/break, or could it cause any issues (short circuit, damage battery etc). I wouldn’t do the opposite, ie plug a 120v charger into 240v outlet without a transformer, but I fee that this way should be ok, just with half of the normal power. 
Can anyone explain it to me in SIMPLE terms?
Thanks!

Answer 1

Check the voltage across the battery when it is charging with a multimeter.  Voltage should be at least 13.5V.  Check the current with a clamp ammeter (or use the multimeter in series, set to 10A setting).  Current should be at least 3A to 8A.



You can probably use it using a  transformer.  But why bother when you can just buy a real 110V charger. There are tons of cheap Chinese made smart chargers.  They work very well for the price.

Answer 2

No If on overnight most will over heat. Low voltage does that.  If you use a 110 on 220 they will burn up right fast. So a fast fire. But they will over heat. Both ways. Unless a transformer is used. 

Answer 3

You CAN'T physically plug that into a US outlet without an adapter.

The adapter has a built in voltage adjustment that converts to 230V.

Answer 4

There is 240 volts in your fusebox or circuit breaker panel.  It usually goes to kitchen range, electric dryer, large window air conditioner, or central air conditioning.



So you could use the device properly if you had an appropriate receptacle to plug into.



If you're presently plugging it into the 120 volt receptacle through an adapter, the device will likely not work properly.



It "seems" fine?  What is that in output voltage??

Answer 5

6v will not charge a 12v battery as a "trickle charge". Tried it once when I had a 6v/12v charger.

Answer 6

To begin with...240v appliance plugs are different then 120v plugs.

Trickle chargers are under $20. I wouldn't even pay to bring it with you!

Answer 7

Many battery chargers will list on the side or the battery that "Input voltage: 120V-240V to receive the exact same output of "X" volts DC. Just look at the side of the charger and if it's relatively new, post 2010, then it should operate in any country on the planet. If there's no universal voltage input sticker on the charger, then it's not compatible. Most battery chargers are fairly cheap so a replacement isn't a huge financial burden.

Answer 8

it wont work it will be way outside the specs the transformer was designed for Id guess half rated supply voltage  on the primary would equal half rated voltage on the secondary.

Answer 9

You are going to fry the transformer. When voltage goes down the current goes up. Not a good idea. Also the other answer you got is obviously not from a 30 year journeyman.

Answer 10

The resistance/impedance remains the same. If you cut the voltage by half you also cut the current by half. The resulting power is half of half or one quarter and the output voltage? unknown by me. If the output voltage is not high enough it will not charge your battery at all.

Answer 11

Half input results in half output. So it won't charge your battery.