The Most Economic and effective solution for external battery of laptop computer. This design looks simple , but really work for you.
Why you have to spend more than $100 to buy a battery for a old laptop

Features Universal external battery pack made of high quality NiMH 16x Sc cells of 4200 mAh. Output is 19.2V Capacity: 63.4 (wh) Protection 1 pc 420 Polyswitch for limit max current drawn @ 4.2A 1 pc 65o Thermostat in charging terminal to protect Discharge Current: 4.2A Max limited by 420 Polyswitch Fit to any 14.8V -18V DC input laptop computers, Especially for Dell Latitude Inspiron Series ( Please check your original battery voltage before purchase, if battery voltage is 14.8V and connector size matched, it is OK usually ). Need additional battery pack? Please click here to order The battery pack can run up to 3 hours, depending on models. 6 detachable plugs are included to fit the most of laptop computers. (Please check the plug's diameters of your laptop computer before you purchase. If your plug fits one of diameters as below, it is OK ). 5.5 x 2.1 mm (O.D. x I.D) 5.5 x 2.5 mm 4.75 x 1.7 mm 6.3 x 3.0 mm 6.5 x 1.4 mm Rectangular connector for Dell Laptop One standard Battery charger is included. Standard charging time is 8 hrs. ( Please don't use other charger to charge our battery). Universal battery pack has no memory effect, and is assembled with poly-switch and 65o thermo-stat to protect overcharging, short circus and wrong polarity. Can be recharged up to 1000 times. Battery dimension: 7.25" L x 3.5"W x 0.9" Weight: 3.4 Lb Warning: please check and match the polarity of our connector to your device. We are NOT liable for any damage to your device due to reverse polarity

How to use Connect male plug in charger into female plug in battery pack ( Make sure polarity mark is matched), then plug charger into 110V AC and charge battery) Charging your battery overnight ( 8 hrs ) to get full charging. After charging, disconnect charger from battery pack. Find a right size plug from universal detachable plug sets which fit with your laptop input plug ( in back side of your laptop ). Connect the male plug into the female plug of your battery pack. (Please make sure power polarity match each other ). Plug battery pack into DC input of your laptop computer which is located in backside of laptop usually. Run your computer. Please set up automatic data save. Computer can not recognize if the battery run out. We are not responsible for any data lost. This battery pack can not be used for laptop with battery voltage at 10.8V or less.