Greetings: I purchased a Winbook SI for playing some old games. I researched a battery and discovered (without much difficulty) that Winbook SI batteries are expensive - $100 and up for new and $70 + my battery for rebuilds. I also noted though that the part number for the Winbook battery (OP-570-70001) appears to be associated with others as well, notably the NEC Versa AX. Further research showed that they look indistinguishable, and that batteries marketed as replacements for the Versa seem to have a lower price structure. I have two questions I'd rather not leave to marketplace chance:

1) Are the batteries interchangeable and, if yes,
2) Is there any technical reason not to get the 4000 mAh, which I understand is somewhat better than the original?

Many thanks.

-Ed

Batteries must be compared by their chemical, contacts, size, volts, amps and number of cells to consider their compatability. If the Winbook SI battery you are looking at matches the NEC Versa AX battery specifications, it is possible that they are the same battery.

Contact the seller to confirm. Many of the Winbook batteries are no longer supported by the original manufacturer, so it is important to make sure the specifications match and you should have this confirmed by the seller.

Also, when looking at the battery specification, there can be some variance in the volts and amps, yet remain with the margin of similiar specs. Be sure what ever the battery chemical is, the laptop can accept that battery's chemistry. Many old laptops that were designed for NiCad or NiMH batteries cannot use the new Li-Ion batteries.

Here is a break down of some Volt & Amp info:

There are two ratings on every battery: volts and amp-hours (Ah). The Ah rating may also be given as milliamp-hours (mAh), which are one-thousandth of an amp-hour (for example, a 1Ah battery is 1000mAh). Amp-hours are a rating of the amount of energy that a battery can store. Another way of looking at it is to say that the higher a battery's amp-hour rating is, the longer the battery's run-time will be. Some of our batteries will have higher amp-hour ratings than the original battery found in your device and will not cause any incompatibilities.

On the other hand, while the voltage of the replacement battery may not be identical to the original battery, the voltages must be within a reasonable range.In order to rate the voltage of the cell, a voltage value between 3.0 and 4.2 must be picked. The voltage that is picked is called the "nominal" voltage, which means that it is for naming purposes only, whereas the actual voltage of the cell depends on the state of charge. Historically some manufacturers picked 3.6V while others picked 3.7V to name the cell. The functionality and performance of either cell is identical and cannot be differentiated by the device.

Thank you for that thorough treatment of the topic. I checked the specs as closely as I could and it looks to me like the "Versa" battery is equivalent to the replacement battery for the Winbook.

I find it peculiar that the price differential is so significant depending upon whether you seek essentially the same battery as a Winbook battery or a Versa battery. It pays to comparison shop!

-Ed 9500