[Closed] 12v charge 6v battery- death?

I wouldn't - unlikely to explode, but you'll probably overheat it which won't do it any good and may cause the acid to evaporate. Most likely outcome is you knacker the battery. All depends how beefy the charger is and how large the battery. A really high current 12v charger (big diesel engine charger) on a tiny 6V lead acid (eg tiny moped) would probably cook it completely.

Death. You'll cook your battery so avoid - unless for only a very short period.

You can get a dual voltage charger for less than £20 - far safer...

I think mine does both, if you are near Edinburgh/Tweed Valley you can borrow it

Aldi - in store only dual 6v/12v intelligent charger for around £15

This thread is well timed..

My kid has a 12v ride on toy, and since digging it out this year there is something wrong with it as if the battery is flat. Inside are 2 6v batteries in series on the charging circuit, the charger (which we think is the correct one) is labeled 12v and 1a.

When plugged in the charger is pushing out slightly under 12v and after a day charging the batteries are only showing 10.8v. Shouldn't the charger push something like 13 or 14v to charge a 12v battery? Basically I'm trying to figure out if the batteries or the charger is knackered.

Shouldn’t the charger push something like 13 or 14v to charge a 12v battery? Basically I’m trying to figure out if the batteries or the charger is knackered.

Yes, but the charger will be current limited, so if the battey is damaged and doesn't charge up to 12v (or nearly 1513V for a fully charged 12V battery IIRC), the charger will just sit there at max current trying for ever to get it to max voltage.

Yes, but the charger will be current limited, so if the battey is damaged and doesn’t charge up to 12v (or nearly 1513V for a fully charged 12V battery IIRC), the charger will just sit there at max current trying for ever to get it to max voltage.

thanks! so I've left it for a day to charge (should be plenty enough for 7AH batteries and a 1a charger?), and the voltage across the pair of batteries showed 11.8v (which is probably close enough) - the charger when its not plugged into the car shows 12.08v - but I don't know if I need to apply some sort of draw to find out if it will go higher?

Either way, as soon as I add some load to the battery circuit (when unplugged from the charger - pressing the accelerator on the car) - the voltage drops right off - down to 4v then recovers to ~9 quickly (and from there on slowly up) once the draw is removed.

Does this point to the battery being borked, or is it just that the charger isn't juicing it enough to give it a proper charge?

should be plenty enough for 7AH batteries and a 1a charger?

The battery charge current will drop as it approaches fully charged, so the charger starts at 1A then reduces as the battery voltage rises. 10 hours should be plenty to get it fully charged as you get most of the charge at the start and it reduces as it fills up.

Either way, as soon as I add some load to the battery circuit (when unplugged from the charger – pressing the accelerator on the car) – the voltage drops right off – down to 4v then recovers to ~9 quickly (and from there on slowly up) once the draw is removed.

If its a car battery, it will get a good kicking from a cold start turning over an engine. You'd expect the voltage to drop right off then recover a bit. The alternator will then charge the battery back up to full as you run the engine.

However, pressing the accelerator shouldn't do anything to the battery as it's not required to run the engine, which will run off the alternator once started.....

So I'm not really sure what's going on. Normally you'd expect to see 13V or more across the battery terminals once the engine has started as the Alternator is charging the battery all the time.

7Ah is tiny - it can't be a car battery - they're normally 40Ah (small petrol) to 100 Ah+ for diesels.

@footflaps - sorry I wasn't very clear. This is a kids electric ride on car - so pressing the accelerator is what makes it go (slowly) along - should be a light jogging pace, but its now barely crawls.

In which case sounds like you need a new battery......

Voltage drop off is a knacked battery.]#

Charging a 6v battery using 12v will fry it. If you have 2 batteries though, jobs a good'un