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Bosch Powerpack 400 2014 Battery

How to look after and extend the life of your Bosch eBike Battery

By Martin Brown |

The 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 currently costing around £500+. 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 not true. Bosch actually guarantee 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 8-9 years or 1000 full charge cycles. After 1000 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 so far. Also I would like to point out 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.

Bosch Diagnostics eBike UK DealerWhen a Bosch powered eBike visits our workshop we can use our diagnostics tool to read into 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. 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. etc. Interesting stuff eh? Anyway back to the point.. Certain measures explained in this article can help you look after, extend the life of your eBike battery and keep it well maintained. OK so here are some of the most common questions we hear regarding Bosch batteries (It's the easiest way to structure the article) -

I have just received my brand new Bosch eBike, what's the first step?

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. However if your battery arrives partially charged then it's best to charge it fully before the first ride. This helps condition the battery and gives it a start point from which to gauge the rest of its operation.


How often should you charge your Bosch eBike battery?

The new Lithium cells used within the Bosch battery packs are very advanced.

Bosch UK ChargerUnlike the older style batteries where you had to completely discharge the battery and then fully charge it back up again to avoid any damage; this is not the case on the Bosch PowerPacks. 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 back fully.


Should I keep my battery clean?

Yes of course it is good to keep any component of your eBike clean.

Bosch Battery Cover Classic 2012, 2013, 2014Although this 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 wet sponge or low pressure hose. A typical garden hose is perfect at washing away grime without applying too much pressure. Although the Bosch batteries are weather proof 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 exist (motor, bearing internals, suspension seals etc.). So although it may be quicker to clean please don't use pressure washers at all. I may as well use this opportunity to stick a plug in for our Bosch Battery Covers to keep it clean.

Will my battery range be affected if using a 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.

Car Power InverterThis 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 inverters 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.

Will it reduce my battery life if riding in very harsh conditions or using full power a lot?

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. Think of it this way; 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. I would recommend using an assistance level that works for you. Many people (mainly adrenaline junkies / blokes) 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 (I can't deny that this isn't fun though!). I have actually found to use 'Eco' & 'Tour' modes for the majority of my riding is more than enough, with 'Turbo' mode assisting me on the very toughest of climbs. 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 wont 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.


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

No, we know that some less keen (fair weather) riders may not want to cycle through the cold, wet and grim UK conditions found in the winter. You can store your eBike 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 is perfect. So the eBike can stay in the shed but bring the battery inside with you. 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 its 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 door stop, it's tempting; but you'll end up tripping over it. It's not good for your battery, not good for your toes & certainly not good for your partner when they hear profanity from your mouth! 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). For very long periods 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 its always topped up in storage, but this is simply not the case. The Bosch charger won't 'overcharge' the battery at all but again it does leave the battery under more pressure.


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 on board 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. Cold or very hot conditions can affect your battery range considerably.

Bosch Battery CoverBosch say 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 the battery has to work a lot harder to perform the same function, this 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. Some people use a sock, some knit a woollen jumper for it, we actually 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. You can buy this from our shop by clicking the link above.


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 circuit and damage to the battery itself. My advice would be to clean the battery mount connections on the bike with a cloth and if you are feeling really adventurous apply a small amount of grease (or Vaseline for the less handy users). When I say a small amount i really do mean a small amount, just a tiny bit to wipe over the connectors to keep them from corroding, its not good to plaster these with grease. It will not help at all. All it will do is attract more dirt and dust from the terrain which will stick to these connectors. I would not suggest to play 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 £500+ lighter.


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

Yes this is strongly advised, stick it in a dry & safe place inside the vehicle. Here it is less likely to get knocked and lessens the chances of the battery flying off the electric bike on the motorway if it's not secured properly. The motorcyclist travelling behind you will not appreciate this hitting his visor. 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. It will leave you with a headache! Also by storing in within the car it keeps the battery from getting wet. Although the battery is rain proof, 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 round 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 eBike itself. While I'm on this topic it's advised to use a cycle cover on the eBike and secured down safely.


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

If your Bosch battery is damaged in anyway 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, you could be responsible for a DHL truck travelling down the motorway on fire! You should have the old battery properly disposed of. A faulty Lithium cell can reach temperatures of 1000+ degrees. It's really not worth the risk, visit a Bosch dealer 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 fumes from a burning battery as this can burn your throat. Anyway let's get back on topic..


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 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, in fact a tyre that is half the pressure it should be can affect your range up to 40%! So check them every couple of months and inflate as necessary. 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. Its best to get your eBike serviced once a year to keep it in good shape which can rub off well on your battery. Already described above, but you may notice this during the winter. If the range is significantly reduced, it could be because the battery is operating in much lower temperatures. Buy one of our Bosch Battery covers to help prevent this. Your battery could possibly benefit from a complete conditioning cycle, this allows the battery to re-learn its full capacity and charge state. Please read the topic which is covered further down in this article.


My battery needs replacing, what shall I do?

It may be that none of the above factors are affecting your battery. It possibly time to call it a day and have the battery replaced. But to be sure you should have the capacity of the battery checked first, just to make sure. If you are not competent with a testing meter I do not advise poking around on the Battery connections to test anything. You could easily cross two of the connectors and be in for a shock, you could destroy your battery this way too. You should visit a Bosch dealer and have the battery capacity checked properly. We won't take a meter near it, we will plug it into our computers and be able to give you an 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 purchase date safe.


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

Yes of course it's your battery and therefore you can do what you want with it. But there are various reasons why this should not be done -There is 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. Going at with a screwdriver in the garden shed probably won't end up well. As soon as you open it up, your warranty will be void from Bosch and the CE certification from Bosch will be invalid. This also holds 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 bikes components.

Inside the Bosch PowerPack 300 & 400WhYou probably won't be able to achieve this anyway as the battery is very intelligent and the on board BMS makes contact with the rest of the Bosch system. The chances are you will probably waste money on new cells or the new cells will be a cheap Chinese imitation and won't last very long anyway. It's really not worth the risk.


Should I perform a full conditioning cycle often?

No, the Bosch battery is very intelligent, the on board BMS takes the hassle away to make a really user friendly battery. 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, over charging through to short circuiting. If you do wish to perform a full conditioning cycle then you can do this by simply discharging the battery completely by riding it until it is flat, then charging it back up fully with no interruptions. This can be done twice in a row to make sure it has fully conditioned. This is not recommended to do all of the time. Once a year is sufficient but like I say above it's not necessary in most cases.


To conclude

The main points are - Top the battery up, keep it at a good temperature, make sure the overall eBike is well maintained & keep the battery about 60% capacity 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. By following the tips above, your battery should last 8-10 years in the perfect conditions. It could last even longer.. Who knows?.. You are in charge now (Pun intended!) Find replacement Bosch / Yamaha Batteries & Battery Covers.
Martin Brown at E-Bikeshop.co.uk
About Martin Brown

Martin has been in the electric bike industry for over 15 years & has helped it grow from the start. Promoting eBikes across the UK at events & offering the very best advice, tech articles, blogs & videos. In particular Martin is a major player for progressing the use of eMTB's, today owner of e-bikeshop.co.uk - The UK's largest eBike supplier specialising in Bosch, Yamaha and Shimano, good quality European eBikes.