Bosch 4.0 Ah “Cool Pack” Batteries Aspire to Greatness


Although they are a bit late to the party, Bosch has announced that they will be jumping on the 4.0 Ah battery bandwagon in early 2013 with the European release of the 18V Cool Pack. While releases of thins kind have lost their novelty after Metabo, Milwaukee and Dewalt have all announced 4.0 Ah batteries, the thing that really sets the Bosch Cool Pack is their claim of 65% more runtime over 3.0 Ah batteries.

Yes. 65% is the figure they are using.

Now I’m no rocket surgeon, but adding 1 Amp-hour to a 3 amp-hour battery should add a 33% extended run time to your battery, because of math and stuff. However, according to Bosch the reason why these batteries have such a high run time and the reason why they have their really (ahem) cool name is the heat management system in place in the batteries.

With a battery that has that long of a runtime heat management becomes an increasingly important factor. The fact of the matter is, a Lithium Ion battery cannot be operated when it is a temperature in excess of 158 degrees Fahrenheit. Most batteries simply have a failsafe that prevents the battery from working when it reaches temperatures in this range, but Bosch creatively positions the batteries within the pack and uses heat sinks to keep heat away from the battery pack. This results in fewer “forced breaks” while your battery pack cools down, as well as a healthier environment for both the battery and the tool. Along with their boasts of increased run time, Bosch is claiming up to a 100% increase in overall battery life, and a bevy of other factoids (smallest, lightest in class, check out the picture below).


While any guess about a US release of these batteries is purely speculation, you can still get any other Bosch Battery or Charger at Ohio Power Tool. Ohio Power Tool also happens to be a Bosch System Specialist, so if you have any questions about Bosch Tools, be sure to call a pro at (800) 242-4424.

A big shout out to our friends in the UK at for the pictures.

Read the full (European) Press release below:

Cordless tools need to be compact and powerful for professional tradespeople to be able to work efficiently. What matters is a long runtime and lifetime of the batteries. Bosch is now meeting and exceeding these requirements by launching 4.0 Ah batteries for 14.4 and 18 volt lithium-ion professional tools.

Jan Breitenbach, who worked on the battery technology for Bosch professional tools as a project leader, knows that the increase in battery capacity offers advantages to professional tradespeople: “Tests by SLG Prüf- und Zertifizierungs GmbH, an independent testing and certification company, prove that the runtime of our GSR 18 V-LI cordless drill/driver is increased by 65 percent when using a 4.0 Ah battery compared to a 3.0 Ah battery.” The basis for this is a higher energy density in the battery packs and an improved internal resistance. This also has a positive effect on the performance capability of the batteries at low temperatures. “Our 4.0 Ah lithium-ion batteries are now clearly superior to both nickel cadmium and nickel metal hydride batteries in this respect”, emphasizes the battery specialist.

Cooling technology prevents forced breaks caused by overheating
The longer the runtime, the more important it becomes to prevent the batteries from heating up too much, too quickly, therefore protecting them against premature aging and damage. Breitenbach: “Lithium-ion batteries must not be operated at a temperature over 70 degrees Celsius. Many competitors use a system of electronic cell monitoring to shut down the battery or machine in the event of overheating.” This means that the user is forced to take a break and loses valuable work time. This is why Bosch has gone about it another way: “Since 2006 we have been using the Bosch CoolPack technology in lithium-ion batteries and have also equipped the new 4.0 Ah batteries with it”, says Breitenbach.

Bosch CoolPack batteries have a special housing geometry: the lithium-ion cells are pressed precisely into a red heatsink and thermally bound to it. “It is made of HDPE, a very high density polyethylene. This material is very good at conducting heat, while being electrically insulating and increasing the safety of the battery”, explains Breitenbach. The cooling fins fitted on the bottom offer an enlarged surface for heat exchange and dissipation of the heat outwards, similar to the effect in a refrigerator. As a result, Cool-Pack batteries have a considerably longer life: “Our measurements have shown that the lifetime of these batteries is double that of those without CoolPack technology”, says Breitenbach. Although the batteries are very robust and compact due to their special design, they are the lightest batteries on the market.

The proven “Flexible Power System” is also being used for the 4.0 Ah batteries with CoolPack technology: they are freely interchangeable between 14.4 or 18 volt tools within the same voltage class.

The new 4.0 Ah lithium-ion batteries with CoolPack technology will be available from January 2013 onwards for 14.4 and 18 volt professional tools. The prices are 110 and 135 euros (14.4 and 18 volt) plus VAT. Compact batteries with 2.0 Ah and CoolPack technology will also be available from May 2013 onwards.



This entry was posted in Bosch, Cordless Tools and tagged , , . Bookmark the permalink.


  1. Allen Wu says:

    Not understand why the heat controlling tech is the reason that the running time of 4.0Ah battery pack is 65% longer than 3.0Ah, as both of them are COOLPACK so I think the capability of conducting heat is the same for 3.0Ah and 4.0Ah.

    • Jake B says:

      I am not 100% sure either, but remember that Amp-hour is a unit of measurement for the amount of electric charge in a battery, so perhaps the Cool Pack technology helps Bosch push this extra energy storage further and longer than it would in a battery without the special heat dissipating qualities. I haven’t gotten the battery in my hands yet to actually see how much longer they run, but 65% is the figure that Bosch is using.

  2. Andrew says:

    There’s a lot more to amp hours and run time than simple math. Capacity is reduced with a higher c rate. If a tool draws 30 amps, that’s 10c on a 3.0 pack but only 7.5c on a 4.0 pack. The new cells might also have closer to full capacity at high draw than than the old ones.

  3. Pingback: Looking Forward to New Tool Innovations in 2013 |

  4. Pingback: Showing Off at the Bosch Tools CES 2013

  5. Pingback: Bosch RHH181 Releases Today with Cool Pack Batteries |

  6. Pingback: Bosch CORE Brushless Rotary Hammer RHH181-01

Leave a Reply

Your email address will not be published. Required fields are marked *