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Review of Bosch’s PowerMore 250 E-Bike Range Extender

Arleigh

July 13, 2024

If you’ve ever experienced range anxiety on your e-bike or wished your bike could have a second battery – then the new Bosch PowerMore 250 range extender battery is something you should know about. 

This isn’t a battery as you know it, but a battery “extender” that plugs into your charging port. It allows you to expand a one-battery eBike to two or run the small 250Wh battery instead of your large one. It is a bit more nuanced than that and won’t work on all bikes, so let’s dig in.

Bosch PowerMore 250 Key Details

Bosch PowerMore 250

492.50

Extend the range of your Bosch Smart System Ebike with this range extender battery.

Pros:

• Lightweight & small
• Easy to use
• Powers bike on its own

Cons:

• Requires Bosch eBike smart System
• Needs additional cable
• Can't mount on all bikes

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The PowerMore kit includes the 250Wh battery, harness, bolts, and a water bottle cage for when you aren’t running your battery.  You’ll also need to purchase the proper PowerMore cable for your bike. There are currently six cable options with different lengths and angles of the plug head. 

The harness mounts with bolts to water bottle bosses that must already be on your bike. Besides adding bottle cage bolts with hose clamps, your frame may be limited if you can use this battery. The harness is plastic with metal reinforcement at the bolt holes, but it feels flimsy if you rock the battery.

My Experience Using the PowerMore 250

There were two main reasons I wanted to get to get my hands on the Bosch PowerMore 250. The first was because it seemed like a really cool concept that could help lighten up eBikes when you don’t need the range of a 400Wh+ battery. The second reason was because of how much confusion swirled around the battery. Could it work on its own? Did it work on any smart system bike? And more. Let’s answer those questions as I share my experiences.

I primarily used this on the Tern HSD Gen 2 S00 cargo bike. This is my almost daily ride right now for life with a toddler. For multiple reasons, I liked not running a large PowerPack battery on this bike for my short 3-5 mile rides around town. The first reason is that getting the battery in and out is a pain if you lock on your child’s seat, so I wanted the option not to run a PowerPack battery. The second reason is that when I lock up to go to the movies or later nights out, I take my battery with me, and carrying a 3.5 lb relatively small battery in my “mom bag” is much easier to deal with. I’m also not looked at as funny by the movie security that searches bags.

My second use case has been the Trek Marlin+. This is an eMTB with a built-in battery, and it isn’t always possible for me to charge it fully if my garage is insanely hot in the summer, so I added the PowerMore 250 to extend my range.

Changing between the two bikes was pretty straightforward once I figured out all the parts. I needed to order a second harness and a cable for each bike since the charging port isn’t in the same place. It is nice to use the same PowerMore 250 battery between bikes. Typically, my electric mountain bikes use PowerTube batteries, which are not easily interchangeable with other bikes.

Some Random Things I Experienced

• The PowerMore does work independently, but due to the CX’s higher power demand, the ride experience will be about 80% when it comes to full CX power delivery
• All Bosch eBike batteries are rated to IP55 if all cables and connectors are correctly connected, then it will meet the IP55 rating
• The connector cable clicks into the PowerMore 250 and requires a two-button push to unlock it
• I would use a tow strap-on for heavy-duty mountain biking and not rely on that plastic harness
• Your standard Bosch smart system charger works on this battery
• It would be cool to see these used in swapping applications like bike touring or eMTB rides or along popular trekking routes

Can the PowerMore 250 work on its own?

Yes, the larger Performance CX motors may have less power, but both of my bikes felt perfectly normal.

Do all Bosch Smart System eBikes work?

Yes*

*The actual smart system can take it as long as you have run that update, but the bike itself may not. Which leads me to the next section.

Does the PowerMore 250 work on your bike?

On the software side,  you need an ebike with Bosch Smart System. You want to make sure you have the Bosch Flow App updated, and your bike is updated. 

On the hardware side, you need water bottle bosses close enough to your charging port and in an area with enough space to slide the battery in. Not all bikes can work. I have found that full suspension frames and smaller eMTB frames don’t have enough space in the triangle. If you have a bike that works or doesn’t, please note it in the comments below, including the bike size and extension cable you used.

This Tern HSD Gen 2 works great because the harness can be mounted directly to the top tube near the charging port.

The Trek Marlin+ also works very well.

Bosch PowerMore 250 Pros

• Extra range without having to lug an additional battery. 
• A necessary accessory for bikes with built-in batteries that may be left out in the cold or can’t be brought in to charge in all scenarios. 
• I really like the small form factor for easy transportation, especially for shorter trips. Say, I’m commuting to movies 3 miles away and want to bring my battery—this is much easier to deal with than unlocking my large power pack battery and carrying that into work.

Bosch PowerMore 250 Cons

• Only works on Bosch’s smart system
• Compatibility depends on frame design
• Can’t be locked on, so you are always going to be bringing this in if you lock it up
• It cannot be added to a DualBattery system if there are two batteries already installed, aka you can’t run 3 batteries on a Bosch system
• I wish they had gone with a design that uses two 160wh batteries that connect together so you can fly with them since the max battery you can take on a standard airplane is 160Wh

Who is it for?

• You want a smaller battery for shorter rides
• You need to be able to top off and extend your battery range
• If you have a bike with a built-in battery, like the Trek Marlin+ or Riese & Muller Culture, and you won’t be able to bring the bike in to charge the main battery, you’ll need this.
  

Final Thoughts

This battery and connector cable will set you back about $550. There are a handful of bikes that feel like this battery pack is made for, two of them I tested – the Tern HSD Gen 2 and an integrated battery bike, the Trek Marlin +.

The HSD could really benefit from this battery because getting out the main PowerPack when you have kid-carrying accessories installed can be a huge pain. I also love the ability to pop off the small battery and throw it in my bag without breaking my back.

I hope we see some bags and accessories to accommodate this battery and improve upon it, like a better harness that locks or mounts for frames that don’t have the proper water bottle bosses needed.

The Marlin+ or Riese & Muller Culture really needs this battery option for hotter or colder climates when you can’t bring the bike in. At the end of it, I would mentally include this as a line item at the time of purchasing those bikes, and I believe a lot of people will appreciate electric bikes more if they have a smaller battery to add to their mileage range.

What do you think?