The car battery has 12 volts; you need MORE than that to charge it. You can't charge it with 6 volts, unless you somehow raise the voltage. In that case, how long it takes to charge the car battery will depend on the capacity of the charging device. Usually a few hours.
It would depend on the condition of the battery.
if you charge it for too long. keep a close eye on it as it is charged.
No set answer to that. Depends on the power rating of the motor and how hard you're running it.
I would say it depends on how long the battery sat around at the retailer. If you bought a battery that is very popular and fits many models then it probably has not sat around very long. If your battery is an oddball, and has been sitting, then it may need a charge. I would recommend a charger with an automatic setting which will cut off when the charge is complete. Rick.
It would only run as long as the battery had a sufficient charge.
With a charger specifically designed to charge this battery.
Depends on how low of charge the battery is. I would guess around 6 hours on a dead battery. I suggest you use an automatic charger so you do not have to guess.
I have learned that when i get new batteries for my hobby cars you want to fully charge the battery to the recommended hrs, you want to charge the battery fully because it will improve how long your battery will last on one charge and how long the battery's life will be.
How long does it take for an 18v battery to charge
around 30 to 45 mins depending on how well it works and how much battery power is left.
I'm not really sure what you're asking here, but if it is about using a battery to power a motor that turns a dynamo that charges the battery it isn't going to work very long. The motor isn't 100% efficient, the dynamo isn't 100% efficient and the battery isn't 100% efficient, so each time you hand over a bit of energy from one part to the next, you lose some. It'll run until the battery runs out, that's it. If the object of the exercise is to run the motor, it'd run longer if you ignored the dynamo.
How long it takes to charge any battery depends on how much electrical charge it can hold. The physical size of a battery can give an indication of how much charge it may hold: the larger the battery, the more electrical charge it is likely to be able to hold. or you could just divide the mAh of the battery by the output rate of the charger. ex: 5000 mAh on a 3000 milliamp output charger would be 1hr 36min. and 3300 mAh on the same charger would be 1hr 10min. and so on.