New batteries are no longer that complicated, but here is a guide on how to extend the life of your eBike Battery.

The Basics

The 300Wh, 400Wh, 500Wh & 625Wh PowerPacks used on Bosch-powered eBikes are amongst the most advanced batteries currently on the electric bike market. They offer a superior range, reliability & longevity compared to many other batteries. However, this all comes at a price; with a replacement pack currently costing around £600+.  Some people are put off by the price of a replacement battery, thinking that it will have to be replaced every other year, but this is just not true.

Bosch actually guarantees their batteries for 2 years or 500 charge cycles (whichever comes first). This doesn’t mean your battery will pack up after 2 years and 1 day. In fact, Bosch themselves state that the battery should be good for around 10 years or 1500 full charge cycles.  After 1500 cycles the battery will still work, but any battery will age over time so it will start to lose capacity and therefore not power your electric bike as far.
Also, it’s worth pointing out now that many people think that a part charge counts as a full charge cycle in Bosch’s terms. Well, it doesn’t, if you just top the battery up a small amount, only this is recorded and will not be counted until there are enough of these partial charges to count towards a full charge cycle.

When a Bosch-powered eBike visits our workshop we can use our diagnostics tool to read the battery itself. The Bosch battery is very clever and records many different parameters, these are then saved within the system for us as a Bosch eBike dealer to consider. Also, we can tap into the system and see exactly how many ‘Full Charge Cycles’ this particular battery has had.  We can also view many other parameters for example – maximum/minimum battery temperature, charge state, usage, etc.

We can also analyse other brands of batteries including Brose (Specialized), Giant, Yamaha & Shimano. Not every battery has such a good warranty as Bosch, but we can still help you get the most out of your system.
This article can help extend the life of your eBike battery and keep it well maintained.

Bike rack with battery

Here are some of the most common questions we hear regarding Bosch batteries:

If your eBike came from us, we normally charge the battery fully just before letting it out of the workshop as we know you’ll be itching to ride it the minute you receive it. This helps condition the battery and gives it a start point from which to gauge the rest of its operation. If you find it’s not fully charged, please charge it to 100% before riding. This applies to all brands of electric bike batteries too.

How often should you charge your Bosch eBike battery?

The new Lithium cells used within the Bosch battery packs are very advanced. Unlike the older style batteries where you had to completely discharge the battery and then fully charge it back up again, the new Bosch PowerPacks do not need this. In fact, it’s much better to just top up the battery after every trip. So if you have just cycled 10 miles on your electric bike, it’s better to top it back up to full when you get home rather than incorporating a few trips before charging fully.

Should I keep my battery clean?

Yes, it is good to keep all components of your bike clean. Although it will not affect the internals of the battery at all if the exterior case is dirty. The best way to clean the battery, or any components of your electric bike for that matter, is with a specialist bike cleaner, wet sponge, and low-pressure hose. A typical garden hose is perfect for washing away grime without applying too much pressure.

Although the Bosch batteries are weatherproof, it is never advised to use any sort of high-pressure jet/pressure washer on your bike. This pressure can force water into the battery case itself and cause problems. It can also force water into other parts of your electric bike where you don’t want water to be (motor, bearing internals, suspension seals, etc.). So although it may be quicker to clean please don’t use pressure washers at all.

Will my battery range be affected if using an inverter in from my vehicle or motor home?

No, you can use inverters to charge your electric bike – for example – from the cigarette lighter port in most cars. This can be handy if you are out and about or wish to charge on the move. But please make sure that the inverter itself is rated for the correct output for the Bosch charger. You can normally find all of this information on the inverter’s packaging or on a sticker on the inverter itself. The Bosch charger is designed for a rated voltage between 207 – 264 volts with an output of 42v.

The charger only charges the battery at a low 4 amp current, so is fine for most inverters and car batteries. Please check these values to make sure the inverter is compatible before plugging it in. Also, remember depending on the inverter itself that the battery may take a little longer to charge than if it was plugged into the mains.

Most importantly of all make sure the vehicle engine is running whilst the battery is on charge because it could drain your vehicle battery faster than you think.

How you can extend the life of your eBike battery easily:

Remember the power of the motor can peak at 500w so can draw power from the battery quicker and put a higher load on it. The harder you use your eBike the faster the battery will discharge.

The faster it discharges, then the more you will be charging it back up. This means that you could end up performing many more charge cycles than someone who is using their eBike lightly in the same time period. After a long time, the capacity of the battery will gradually drop. So you could be replacing it sooner if riding the bike very hard for the majority of the time (this is especially prevalent in de-restricted bikes).

I would recommend using an assistance level that works for you. Many people (mainly adrenaline junkies) could use their eBike flat out in the maximum assistance mode ‘Turbo’. The eBike will use more power and therefore you will get a shorter assisted distance out of it.

Quite honestly you don’t ‘need’ to use the eBike flat out in ‘Turbo’ all of the time (it is fun though!). The use of ‘Eco’ & ‘Tour’ modes for the majority of riding is generally more than enough, with ‘Turbo’ mode assisting me on the very toughest of climbs.

You can also put your Bosch eBike in EMTB mode, which will vary the motor’s input depending on what you are putting in yourself. This will give you the most bike-like ride feel and will give you an even drain on your battery.

Obviously, everyone’s fitness levels are different so you will need to work out what works for you, it is far too easy to hit ‘Turbo’ mode for the majority of your ride. The bike won’t go any faster (mph) but it will have more ‘grunt’, in fact, the eBike will only go as fast as you pedal, it’s just the amount of assistance the motor gives you that changes.

Bosch Motor
I’m putting my eBike away for the winter, will this damage the battery at all?

No, we know that some (fair weather) riders may not want to cycle through the cold, wet and grim UK conditions found in the winter. You can store your bike away, it’s not a problem; however, there are some steps you can take to keep your battery healthy during these times:

If you are keeping your eBike outside in a shed or garage, then it’s always best to bring your battery indoors. The Bosch batteries are capable of being stored in temperatures between -10 through to +60 degrees centigrade. But the cells don’t like to be stored in very low or very high temperatures. In fact, the best possible temperature for storage is room temperature – around 15-20 degrees.

Once in the house at room temperature, store the battery in a dry and secure place. Sticking it on a shelf in the kitchen above the kettle runs the risk of moisture travelling up from the kettle and into the battery case. The perfect place is tucked away in a cupboard where it’s kept at optimum temperature, away from moisture and where it’s not vulnerable to being knocked at all.

I know it can make a very good doorstop, it’s tempting; but not good for your battery.


When storing your eBike battery for long periods of time it’s best to keep the battery partially charged. If you store the battery completely flat then you run the risk of damaging the internals of the cells themselves. Also if you store the battery fully charged this can leave the cells under more pressure. So it’s best to keep the battery stored in between.

For the Bosch battery in particular the optimum charge state to leave it in is 60% (Or 3 LED’s lit on the battery level indicator). Try to check the capacity every 6 months or so. When the battery reaches 1 LED showing, then top it back up to 3 LED’s again. Many people think it’s best to keep the battery on the charger so it’s always topped up in storage, but this is simply not the case. The Bosch charger won’t ‘overcharge’ the battery at all and does not trickle charge.

Will it harm the battery if I run it completely flat on a ride?

No, it’s never recommended to run the battery completely flat, but for longer rides, it obviously can happen. The Bosch Battery is protected by its onboard BMS (Battery Management System). This means it’s protected for deep discharging, the BMS won’t allow the battery to run completely flat.

It may seem that you have no power left, but the BMS will have already shut off the power to the motor before it can hurt itself. We all know that the beauty of the Bosch drive is you can still ride without any resistance with the power switched off. On a side note here, if you are running lights directly powered from the Bosch motor and you do run out of power, the BMS will allow a small amount of power still to the lights so you will still remain visible!

I ride in very cold conditions during the winter will this affect battery life?

The simple answer is yes. Bosch says it can be affected up to 30% in sub-zero conditions. So if you are consistently riding in these conditions it can really affect not just your range but will decrease the overall lifespan of the battery as well. There are certain actions you can take to prevent this. You can wrap your battery up to keep it to temperature.

We provide a perfect neoprene bosch battery cover that really hugs all styles of the Bosch battery to not just keep them within temperature but can keep the battery clean, protected from knocks and out of direct sunlight.

Should I clean the connections between the Bosch Battery and the eBike itself?

Yes, it is always good to keep these connections clean. This can minimize the risk of short circuits and damage to the battery itself. My advice would be to clean the battery mount connections on the bike with a cloth.

I would not suggest playing with the connections on the bottom of the battery itself as you run the risk of short-circuiting here, although 36v won’t kill you it could make your hair stand on end and your wallet will end up £600+ lighter.

Should I remove the battery when transporting my bike on the bike rack of my car/motor home?

Yes, this is strongly advised, put it in a dry & safe place inside the vehicle. It is less likely to get knocked and lessens the chances of the battery flying off the bike on the motorway if it’s not secured properly.

The best place to store the battery is under the driver’s seat, this means it’s out of the way and also shouldn’t move around too much. Wrap it in a towel to prevent any knocks. Do not leave the battery on your parcel shelf, if you end up braking hard, the 2kg+ battery is the last thing you want hitting you in the back of the head.

Also by storing it in the car it keeps the battery from getting wet. Although the battery is rainproof, people don’t realize that if you’re travelling at 70mph down the motorway, the water & air travelling over your car is then doubled in speed as it wraps around the back of your vehicle. This means the battery could be being sprayed with water at around 140mph. This is stronger than a pressure washer and can force water into the battery and components of the bike itself.

eBike Battery

I dropped my Bosch battery and the case is cracked what shall I do?

If your Bosch battery (or any eBike battery for that matter) is damaged in any way, then it should be replaced. Even if it seems OK on the outside one of the cells inside may be damaged, this can then move onto other cells and the whole pack can become a ticking time bomb. The battery could seem fine and work but weeks later the effects of the damage could become apparent. The battery could heat up or even ignite.

Do not under any circumstances ship this battery anywhere. A faulty Lithium cell can reach temperatures of 1000+ degrees. It’s really not worth the risk, visit us in-store and have it replaced.

If your battery was damaged and did ever ignite, then get it outside immediately, the best way to put out a Lithium cell is with water and lots of it! Be careful to never inhale any fumes.

I have had my Bosch eBike a while now and it’s not going as far as it did when new, does the battery need replacing?

Yes, quite possibly, but not always. There may be certain other factors causing this:

Are your tyres inflated correctly? 

It’s important to keep your tyres inflated to the correct pressure as stated on the side of the tyre. It’s amazing how much effect this can have.

When was your eBike last serviced? 

Something as simple as a brake pad rubbing can slow you down considerably. With the extra assistance on an electric bike, you may not even notice the extra drag. But the motor will be working much harder to assist you and therefore will drain the battery faster. It’s best to get your eBike serviced once a year to keep it in good shape which can rub off well on your battery.

When was the system last checked? 

If an update is required, the system may not be running at its optimum – so it’s a good idea to get this checked out to eliminate this being an issue.

So my battery needs replacing, what shall I do?

You should visit a Bosch dealer and have the battery capacity checked properly. We won’t take a meter near it, we will plug the entire bike into our computers and be able to give you a decision straight away if the battery needs to be replaced. On request, we can also print diagnostics reports for your records. When a new battery is purchased it comes with a new Warranty from a Bosch dealer, so be sure to keep the receipt of the purchase date safe. 

Can I open up the case & replace the cells myself?


There is a big risk of short-circuiting, burning your fingers, fire and even harmful acids. Batteries are assembled in strictly controlled environments by specialists to ensure maximum safety.

If you open it up, your warranty will be void from Bosch and the CE certification from Bosch will be invalid. This also makes you responsible if you or others are harmed by the battery in the event of a future problem.

Fitting an aftermarket battery or new internal cells not only could harm others but could harm the rest of your electric bike’s components.

You most likely won’t be able to achieve this anyway as the battery is very intelligent and the onboard BMS makes contact with the rest of the Bosch system. The chances are you will probably waste money on new cells. It’s really not worth the risk.

We recommend that the battery be sent to your local Bosch approved service centre.

Should I perform a full conditioning cycle often?

No, the Bosch battery is very intelligent, the onboard BMS takes the hassle away to make a really user-friendly battery. Really all you have to do is charge it and the Bosch system will take care of the rest.

The BMS will self balance the cells when charging, it will control everything from deep discharging, overcharging through to short-circuiting.

To conclude:

Top the battery up, keep it at a good temperature, do not drop/knock or damage the battery, make sure the overall eBike is well maintained & keep the battery about 60% capacity and inside when not being used for longer periods of time.

Remember if you treat your Bosch eBike Battery well it will treat you well in return. We hope that this guide will help you to extend the life of your eBike Battery.

Visit our specialist page for everything you could possibly want to know about eBikes and how they can help you.

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