I have these batteries and I use them constantly with many Bosch tools for electrical work since 2019!!! I have not had the slightest problem, on the contrary, the batteries are excellent! I don't understand the comments... where do you guys shop, from the flea market, and then blame the battery?

I should clarify something first. This battery, authentic though, is simply amazing. I have two purchased from a Bosch tool store. Later, I bought similar ones from here but when I received them, the battery was a counterfeit. It looked the same with some differences and no Bosch logo on it. So if someone received the non-authentic one, the reviews might be inaccurate.

I have 4 batteries with 8ah. After 6 months, three of them started charging at 75% and after a year at 20%. It's a shame because the tools are good, but the batteries have poor quality from the brand

Unfortunately, one of the same... 3 batteries 4ah purchase two years ago... and all three have the same symptoms... they don't fully charge. They stop at 70% and show as charged. Money wasted. We need to sell all our Bosch tools and get a serious company to do our work... unfortunately, Bosch has become all about frills and scents, and its quality is now a joke... in the past, you would go to a construction site and see all the workers using Bosch - Makita. Now Bosch has become comparable to Lidl, but with triple the price... not to mention that Lidl's products are better...

I have both the 8ah and the 4ah...
The batteries behave just fine...
In terms of performance, they have minimal extra power compared to the regular ones, for those who have them and understand, but not the difference that Bosch promises...
In terms of runtime, the 8ah lasts around 30-40 minutes and it depends on the material of drilling or puncturing, the exact duration... meaning that in concrete and drilling in tiles with sea sand, it lasts much less than in digging in brick or drilling in a wall (concrete or not)... similarly, around 20 minutes for the 4ah...
As for charging, after about 10 times, the batteries charge fully so far... I don't notice any decrease...
The only downside is their high price, which is not good in terms of competition... That's why 4 stars...
Edit: After 9 months, no change...
The 8ah charges fully...
I bought another one for under 100... which is worth it for this price...!!

After 4 - 5 charges in a relatively short period of time, one of the two batteries (8Ah) reaches 70% and stops charging. I monitor it through the Bosch tool app on my mobile phone, so the charging percentage is not randomly mentioned. The usage is amateur, if it was professional, I would be crying for the money I spent on buying the battery charger set. I will come back with a new review if anything changes.

I was completely disappointed by Bosch; it has clearly lowered its standards for economic reasons. I had bought two 8ah batteries for my angle grinder three years ago on sale, and now both have failed!!! They are of course out of warranty, and I just spent a fortune for nothing (even though it was on sale, it was expensive). The usage, I emphasize, was for Bosch's angle grinder, but now, only with electricity and some Parksides battery, which is decent.

*Update*
I opened the batteries and found that both had defective cells; three in one and two in the other. The cells are Samsung INR21700-T40, which are supposed to withstand a discharge current of up to 30A; however, practice shows that they are unreliable. The batteries were genuine with a production code. Some people, of course, write nonsense here (maybe merchants?), but both were problematic, and I am not the only one with a bad experience from these batteries.