Too slow charge

With a 1440 watt and 12 volt, the battery must be over a thousand AH. (ampere/ hour) because for the 1440 watt, you need a current of more than 100 ampere. But even with a few hundreds of watt, you need a very powerful battery, because 300 watt, will pull 30 amps from the battery. A car battery with even 100 AH can't deliver that.

Are you using the provided charger, or are you using an after market "Universal" charger?
If you're using a universal charger, it could be charging the battery too hot and the computer just doesn't understand why the battery is putting out more than the system is expecting.
It could also be that the battery is wrong type. The voltage may be the correct, however the Ah may be too high. This being the case, the computer doesn't understand what why the it's getting a higher Ah reading than it's expecting. The system can not reason that that if it detects more amp-hours than the it should have that it has that much more charge time. It just sees "ERROR" and since you're dealing with a system function that is designed to prevent loss of data the default action is to shut down to prevent loss of data.
You may be able to fix by resetting the Power Management Options. Unfortunately, with out doing test on the machine, it is impossible to tell. I could be software or hardware. If nothing else works, try replacing the battery again.

Absolutely. Let me explain what "Ah" means. "Ah" stands for Amp Hours. A 32ah battery will run a 1 amp motor for 32 hours...or a 32 amp motor for one hour...a 16 amp motor for two hours etc.. As long as the battery voltage is the same it's absolutely fine. As long as your chargers are the correct voltage, they'll be fine as well. So basically, the higher the "Ah", the longer the battery will last. This is why higher "Ah" batteries are more expensive. Hope this helps : )

Ifthe cell phone battery is more than 3 - 4 years old then the battery could be wornout. Rechargeable batteries have a finite number of charge and discharge cyclesand will lose their charge capacity over time, i.e. won't charge to 100% andgradually the charge reduces until the battery won't charge up atall. ORThe battery shows a 100% charge but when the adapter is disconnected thebattery drops off to zero capacity in a very short time. Ifthe battery drops to an unacceptable charge level then the battery needs to bereplaced.

Time for a new battery. My Toshiba "ate" batteries every 6 months. They will onyl recharge a number of times and then...that's all, folks. Replacements are on ebay, etc... BE SURE TO GET ONE with more milliamps than the standard one. They will stay charged longer.

Your batteries are shot. If they haven't been charged for a year you won't charge them now or ever. Replace the batteries, charge before use and regularly as you use the chair. The new batteries need to be broke in and must receive use to get them to 100% Use your chair daily and charge daily for at least 20 days. Hope this helps

The motor is fine, what happens is that the internal battery loses the ability to fully charge and run the motor for a long period of time. While you "could" change the battery out with a newer one using solder, it's unlikely that it would cost less than buying a newer model at the store or from ebay. The average life of good shavers made a few years ago was about 3-5 years due to the type of batteries in it. I used mine with a charging cord for a while but that became an issue once while traveling. I bought a new one.

Yes, the amperage your charging at determines charging time. The higher the amperage, the faster it charges. Your battery is rated in mAh or milliamp hours. One Ah means the electric charge transferred by a steady current of one ampere for one hour. A mAh would be 1/1000th of an amp for one hour. If your battery is a 1500mAh battery it means 1.5 amps for one hour. This charge current should not exceed the rating of the battery. It would cause possible excessive heating and possible a fire or explosion, especially on newer more volatile batteries like lithium polymer batteries. The life of the battery charge when fully charged will be similar no matter how you charged it, but slower, lower amperage charges will maintain your battery better than quicker, higher amperage charges and help extend it's life to its potential.