Bosch PowerMore 250 range extender in the test: Increased range for special cases

E-bike drives / test: Together with the lightweight Bosch Performance SX motor and the CompactTube 400 battery, Bosch also presented the PowerMore 250 range extender last summer. The test shows that Bosch is doing a lot of things right with the first additional battery, but it may not be suitable for everyone - if only because of some pitfalls in terms of compatibility.

Many people may have thought “Finally!” last summer when Bosch introduced a range extender for the first time with the new e-bike components for 2024. While the vast majority of competitors have had such additional batteries in their range for a long time, the industry leader has taken a lot of time with it. Admittedly, this may also have been because a lightweight Bosch electric drive was introduced for the first time with the CompactTube 400 and the Performance Line SX. The range extender with 250 Wh, dubbed PowerMore 250, fits in very well.

The announcement that the additional battery is not only compatible with the new SX motor, but theoretically also with older Smart System bikes was a positive surprise. The fact that the matter of compatibility is a little more complicated in practice – more on that in a moment.

Nice form factor, decent weight

The form factor of the Bosch PowerMore 250 is definitely pleasing. It is handy, only slightly larger than a conventional drinking bottle and appears extremely robust. With his 1,6 kg with 250 Wh capacity It has a similar energy density to the competitors' additional batteries, but falls significantly behind the in-house CompactTube 400 battery, which has 400% more capacity with just 60 g more weight. The price is similar: for the PowerMore 250 (without cable) 469 Euros due, the CompactTube 400 costs 629 euros.

It is attached using a special holding plate onto which the battery snaps firmly. It then has to be connected to the charging port on the e-bike using a special cable. The cable is available in different lengths and with two differently angled plugs on the frame side. Here you should follow the bicycle manufacturer's specifications or, at best, measure yourself.

Which e-bikes are compatible with the Bosch PowerMore 250?

The basic requirement for installing the range extender is an e-bike with a Bosch Smart System. In addition, the respective e-bike must be “Powermore-Ready”. Bosch thus summarizes the various requirements that must be met. Only then is the retrofit really “plug & play” and can be easily carried out by the end customer.

The software must be activated for the range extender by the manufacturer and be up to date

In order for the e-bike to be able to communicate with the PowerMore 250, the software must be activated by the manufacturer. This activation must be done explicitly by the bicycle manufacturer and cannot be granted subsequently by the specialist dealer. It may be possible for the manufacturer to upgrade later, but this is very unlikely due to the effort involved. In addition, the software on the e-bike must be up to date.

The charging socket must be compatible

The cable plug on the PowerMore 250 differs from the familiar charging cable in one key point: two “noses” engage in corresponding recesses in the socket and guarantee a tight fit while driving. Older charging sockets do not have these recesses - this means that the cable cannot be plugged in at all. Although other sockets have recesses, the cable does not lock firmly into place. The socket can be replaced by the specialist dealer with the correct version for the range extender.

The frame must have reinforced mounting points for the bottle holder

In order to be able to mount the Bosch PowerMore 250, the e-bike must have mounting points for a bottle holder. Since the additional battery, including the mounting plate and cable, weighs significantly more than a large, full drinking bottle, the holes must also be strong enough to prevent damage in the long term.

The frame must offer enough space

Last but not least, the frame itself must offer enough space for the range extender and the cable that is plugged in while driving. Since the additional battery is higher than conventional drinking bottles, it can happen that the shock or frame collides with the range extender during compression, especially on full-suspension e-MTBs. The placement of the charging socket must also be chosen so that a cable can be plugged in while driving. This is not always the case, especially with bushings in the bottom bracket area.

How can I check whether my e-bike is compatible with the Bosch PowerMore 250?

Via the display or the Bosch eBike Flow app

The first step is to check the e-bike yourself to see whether the bike is already “PowerMore Ready”. If yes, then the PowerMore 250 is listed under the e-bike components in the system. This list can be accessed either via the display on the bike itself (Settings > My eBike) or via the Flow app (Settings > My eBike > eBike Pass > Components). If the item “PowerMore” is listed there, the e-bike is prepared for this and nothing stands in the way of retrofitting.

Via the specialist retailer or manufacturer

If the dot does not appear on the display or in the Flow app, the only solution is to ask the specialist retailer and/or manufacturer. In advance of this article, we asked numerous bicycle manufacturers and received lists of compatible e-bikes from some of them.

assembly and handling

Installing the Bosch PowerMore 250 is quite simple if you keep one important thing in mind: You should attach the cable before actually inserting the additional battery - otherwise it gets a little fiddly. The mounting plate is screwed to the holes for the bottle holder and the battery is then mounted on it. After a few times you can do this blindly and in just a few seconds. The range extender clicks into place and then sits firmly and rattle-free. Removal is just as easy. Bosch also thought ahead: a special bottle holder can also be mounted on the mounting plate; This means you don't have to unscrew the plate every time you want to travel without a range extender but with a drinking bottle.

We didn't really like plugging the cable into the charging port itself. Although the plug has corresponding lugs for a tight fit, there is no feedback when plugging in whether everything is correctly seated. As a precaution, you should always press again to avoid unpleasant surprises while driving.

If the e-bike is already switched on when plugged in, it will switch off and on again after connecting the PowerMore 250. This is because the additional battery for the Smart System is not an “additional” but is viewed like a fully-fledged second battery in a double combination. This is also the reason why the battery capacity in the display, on the system controller or in the app refers to the sum of the integrated battery and PowerMore 250. So that you can still estimate how full the individual batteries are, the displays (Purion 200 / Kiox 300 / Kiox 500) also show both batteries with five bars each. With the system controller, however, you have to press the corresponding button directly on the PowerMore 250 in order to read the capacity via five LEDs on the battery housing itself.

What will be unloaded first? The range extender or the integrated battery?

As with a regular dual battery system, the range extender and integrated battery are discharged in parallel: The system is programmed so that the batteries are discharged to approximately the same extent and, ideally, are empty at the same time. Of course, the PowerMore 250 can also be used in other situations, i.e. when the integrated battery is already partially or completely discharged.

Can the Bosch PowerMore 250 be used as the only battery?

Since the Bosch PowerMore 250 is a full-fledged battery for the e-bike, it can also be used as the sole energy storage device, meaning you can do without the integrated battery. Possibly an alternative for short after-work rides on the full power E-MTB - compared to the PowerTube 750, you save around three kilograms of weight. However, it should be noted that powerful engines in particular cannot deliver the full performance. How big the losses are depends on the charge level of the PowerMore 250, the temperatures and other factors. However, drivers with CX engines in particular should certainly feel the difference.

Who is the Bosch PowerMore 250 worth for?

It is no coincidence that Bosch introduced the PowerMore 250 together with the Bosch SX motor and the CompactTube 400 battery. The new additional battery makes sense, especially in connection with this system or rather with the bikes that rely on this system. Since the manufacturers do not use removable batteries for weight reasons, the PowerMore 250 gives you a welcome increase in range. On the other hand, if you ride an SX bike with a removable battery, you should consider whether a second CompactTube 400 makes more sense: It offers a better ratio of weight, cost and capacity. Of course, it is not that easy to store on the frame and changing it might require a few more steps than simply plugging in the range extender.

Anyone who rides a Bosch Smart System e-bike with CX, Performance Line and Co. should only think about the PowerMore 250 in exceptional cases. Possibly as a small increase in capacity for e-mountain bikers for whom the range of the integrated battery is not quite enough. Or as a weight-saving measure for quick trips after work or the short commute to the office.