I am about to get 2 slightly old and used laptops for 180 bucks including shipping. So after a bit of reaserching I decided that I need to get new batteries for them and went on Ebay and found some cheap ones for around 25 bucks. The only problem is that what is Wh(Wattage hours??) I somewhat know how mAH works as in more mAh equal more battery life does the Wh
A watt hour is the amount of energy used by something with a power of one watt in an hour.
Power is a combination of both potential difference and current. So the milliampere-hour rating of a battery is directly proportional to the watt-hour rating (assuming the voltage is constant, which it should be from a battery).
Basically, the larger the mAh rating, the larger the Wh rating.
Ah thanks
Cheap batteries (especially lithium) often lie about how much power they have.
It is not uncommon for the REAL number to be around 50% of what is printed on the battery.
And if it is from a china/hongkong store OR a US/other western country´s that sell cheap kina/hongkong batteries it´s almost a sure thing that the real number is lower.
Other then that the cheap batteries is often crap about how many times they can be recharged, as in it can be half the times of a better battery.
My advice is search around on the modelnumber for the laptops and also the battery serial number/part number and see what other people have bought and ONLY buy batteries that you can verify they are good OR buy a brand battery.
And also make really,really sure that you buy the RIGHT battery it is not uncommon that laptops have different batteries for the same modelnumber and by different it can be both a different shape and/or different voltage (have seen both).
Battery capacity should be rated in amp hours, standard for many types of battery
Watts = Volts x Amps. to get a proper comparison, you need to divide the number given for Wh by the voltage to get the figure for Ah.
Any seller showing battery capacity this way should arouse suspicion, suspect the battery capacity when adjusted to Ah will turn out to be no different or less than most others, They may get a few sales for folks who just see the bigger number