My Honda Activa has an Exide maintenance-free battery, but the electrical starter is not working well. The battery is not getting a response, so can we charge a sealed battery?
Yes, all car batteries (secondary cells) are designed for charging. Only primary cells are those that cannot be charged, and such cells are not used in automotive applications. Consider this: the car alternator is continuously charging the battery, so what damage could you do by charging it with an external charger?
However, that said, if the battery is not just lacking charge but is dead, you may need to change the entire battery. Lead-acid batteries do not in general like to spend lots of time in a state where they lack charge. So, if the problem is not a recent problem but has been there for a long amount of time, the battery charging may not necessarily fix your problems.
Overall, it is much cheaper to recharge a battery than to replace it. So, I would give charging a try! If the charging fails to solve the problem, you may need to replace the battery.
"Maintenance Free" just means that you don't have to top it up with distilled water regularly. It's fine to charge it up - but I recommend you take it to a car spares store - they can test whether it's worth charging, or if the battery has just reached the end of it's life. If you can get the car there, they can also check if the alternator is OK - the two are connected, and if one fails, it often takes the other out.