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Runtime Testing The Bosch CORE18V 4.0 Ah VS Fatpack 4.0 Ah VS CORE18V 6.3 Ah

We have often wondered if the new 1P Bosch Core18V 4.0 battery was going to have a similar runtime to the older Bosch 2P FatPack 4.0 Ah battery. Before we get into that, let’s start with some explanation of what some of the terms we use. P stands Parallel and S stands for Series. In all of our 18-volt batteries, we have 5 cells wired in series. Basically Series means if you have a battery, then wire another one “in line” + to – chaining them up it will retain the same Ah, but add up the voltage from each cell (5 cells times 3.6 volts equals 18-volts). Parallel is still wiring together but instead of a chain, both the + and both the – leads are wired together and that will result in the same voltage, but increase the Ah.

To recap, the number before the S is the number of cells in series will tell you the voltage and the number before the P is the number of parallel batteries in your pack. We currently see 1P, 2P, and 3P in the tool world at this time.

The next topic is the cells used in our tool batteries. In the past, 18650 cells (18mm wide 65mm long and 0=round) were used as they were mass produced and cheap. Currently, tool manufacturers are starting to use 21700 batteries (20mm wide 70mm long and 0=round) as they are the new norm and provide a bit more watt-hours.

So in this video, we are comparing the old 2P technology with a 4.0 Ah rating with 18650 cells to the new 1P 21700 batteries with a 4.0 Ah rating. Clear as mud? Maybe the video will help!

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4 Responses to “Runtime Testing The Bosch CORE18V 4.0 Ah VS Fatpack 4.0 Ah VS CORE18V 6.3 Ah”

  1. Tammy Bauer #

    Thanks for showing BIGGER is NOT always BETTER!

    February 20, 2019 at 9:42 am Reply
    • Our Pleasure. Good tools make it easy for us to share the great things happening with technology in the tool world.

      February 22, 2019 at 8:07 am Reply


    November 12, 2019 at 7:34 pm Reply


    November 12, 2019 at 7:36 pm Reply

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