New CORE18V 6.3 Ah Battery Pack From Bosch

Bosch recently upped their high capacity battery offering with a CORE18V 6.3 Ah battery.  This new battery pack is a completely new pack built from the ground up.  There are many benefits beyond just the jump in amp hours.

Lithium Ion Cell Change

18650 versus 20700 Cell

The main change in this new pack other than the physical construction which we’ll get to next are the cells being used.  Previous packs by Bosch and others have used the popular 18650 cell which measures 18mm x 65mm.  The new CORE18V packs use the slightly larger 20700 cell which measures 20mm x 70mm.  This cell only makes the pack 5mm wider yet these cells hold 33% more capacity.


CORE18V Pack Construction, CoolPack 2.0

Bosch Core Internal

The above image shows how the pack construction has changed compared to other packs.  The first thing you’ll notice is the CoolPack 2.0 plastic battery cradle which has separate compartments for each cell.  Most packs of this nature are just stacked cells touching each other.  By creating space between the cells encased by this heat transferring plastic this allows far better heat dispersion through the cooling fins on the underside.  Heat is the killer of any battery pack.  From both a use and also from a charging standpoint.  This cooler running pack has many benefits.  A deeper discharge of the pack without hitting a thermal threshold.  Because the pack runs cooler it can be recharged sooner since packs need to cool to a safe temperature before most chargers will initiate a charge.  And as an added bonus Bosch testing has shown a 135% increase in pack life due to this decreased heat.  To you that means more charge cycles which means an overall cheaper overall cost of ownership.

Laser Welded Copper Connectors.

Most packs are resistance welded using galvanized steel to connect their cells together.  Bosch has raised the bar significantly by using copper instead of galvanized steel and by using a laser welding process instead of resistance welding.  This drastically reduces the internal resistance in the pack which equates to less heat which is a good thing.


Charge Times.

The best way to compare charge times is by looking at how quickly each brand can charge a set amount of capacity.  The below breakdown shows what each brand charges a full Amp Hour of capacity in minutes.

Bosch – 8.7 Minutes per Amp Hour
Milwaukee – 9.0 Minutes per Amp Hour
Makita – 9.2 Minutes per Amp Hour
Dewalt – 10.0 Minutes per Amp Hour


Large Capacity Battery Pack Size Comparison.

Bosch Core Size

In comparison to the other major players with high capacity batteries this image shows the much smaller footprint.  The red lines represents the new Milwaukee 9.0 Ah pack and the yellow line represents the new FlexVolt packs.


The Bottom Line.

Among the big cordless contenders we now have an interesting game playing out in the high capacity category.  Dewalt and Milwaukee are jumping to the extreme with capacity and which is creating a heavy and bulky pack.  This isn’t necessarily a bad thing.  Heavy and bulky isn’t always a deal breaker when you need corded performance in a cordless tool.  But with Bosch you are gaining a significant efficiency advantage which gives you great capacity mixed with decreased runtime and longer battery life.  If using a drill, impact, jigsaw, screwgun, etc., you would benefit from this smaller alternative in a large capacity pack.  But if you are looking at running a circular saw, reciprocating saw, miter saw, rotary hammer, etc., then possibly looking at the Milwaukee 9.0 Ah or Dewalt Flexvolt platform would be the ticket for you.  In the coming months we plan to do some in-depth comparisons of this new CORE18V pack versus the Milwaukee 9.0 Ah and Dewalt Flexvolt in real world usage.  Stay tuned!

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