Installing the Battery
Electric bike batteries
It is not possible to have an electric bike without a battery. The batteries that are used on electric bikes are lithium ion rechargeable batteries that are relatively small, energy dense, and somewhat expensive. It is important to know that all electric bike batteries are a Class 9 hazardous material and therefore cannot be shipped by common carrier (FedEx, UPS, USPS, DHL) without the services of a licensed hazardous materials shipper. It is a $75,000 fine if one is caught shipping a lithium ion battery. Also, handle these batteries carefully as a damaged battery may lead to a fire during charging. Is it dangerous installing this battery? No, it is safe but be careful you do not drop the battery. These batteries can weigh over nine pounds and can be easily dropped while installing. Never assume a dropped battery is not damaged because the case is not cracked. Inside the battery are a number of cells that are bonded together and a battery that has been dropped may cause one of these cells to break free. On the assembly floor of one of the largest electric car manufacturer in the world has a policy that if a battery cell is dropped it is immediately marked for recycling and not used in the pack that will go on the car. All lithium ion batteries of the size used on an electric bikes must be treated with care.
Class 9 Hazardous Material
Before buying
It cannot be repeated enough that all lithium ion batteries are a Class 9 hazardous material and require special handling. All electric bike batteries are lithium ion batteries. It is against Federal law for anyone to ship a lithium ion battery without the services of a certified hazardous material shipper. Fines of up to a millions dollars have been levied by regulating authorities for violation of this law. In addition, anyone shipping a lithium ion battery that catches fire during transit and causes property damage or causes injury or loss of life can be prosecuted criminally. If you have a electric bike battery do not take it with you on any aircraft for any reason. Lithium ion batteries must be ground transit only.
It is important to understand once you purchase a battery from a online source that battery cannot be returned without the services of a Haz Mat shipper. To return a battery would cost far more than you paid for the battery. Therefore, always buy your battery from a trusted source or purchase it locally.
NOTE: There are some on the internet that claim that if they send you the appropriate labels it is legal to ship your battery to them for repair or replacement. That is false. Shipping LI batteries involves far more than a label. Even if the label is correct and the packing is correct, you (the person doing the shipping) are not a certified Haz Mat shipper and as such shall bear full responsibility if caught. The person who advised you to ship a LI battery may or may not be held accountable.
Are electric bike batteries safe? Yes and no. Before purchasing a electric bike battery from anyone ask, "Who made this battery?" If the battery was made by a hobbyist or someone who makes a few hundred a year then find another source. All lithium Ion batteries should be purchased by battery manufacturers. Professional battery manufacturers spend hundreds of thousands of dollars on testing equipment, research and development, and on professional staff and line workers.
We, on a regular basis, purchase batteries from sellers in the US, off eBay and AliExpress. Then we open the case to see if the cells are what they were advertised to be, and if the construction of the battery is such they could withstand impact without causing damage to the cell group. All electric bike batteries sold in the US have to go through rigorous testing per section 38.3 of the UN Manual of Tests and Criteria.
Battery construction
Type of cells in a battery
Opening battery case voids warranty
Opening battery case voids warranty
A single cell is not a battery. A battery is made up of two or more cells. All electric bike batteries are made of certain brand cells and the better the cells the more expensive the battery. High end cells are those made by Sanyo, Panasonic, LG, and Sony. Also, there is the generic cell. Generic cells are cells manufactured in China. Generic cells are not inferior, mislabeled, or counterfeit cells. Generic cells are 18650 Lithium Ion cells that do not carry the brand name of premium cells. If a company producing batteries were corrupt they would not be using generic cells. They would be using counterfeit Sanyo, Panasonic, LG, and Sony cells. I cannot stress this enough, always buy your battery from a trusted source. Before purchasing your battery ask: "Who built this battery?"
Opening battery case voids warranty
Opening battery case voids warranty
Opening battery case voids warranty
First, never open a battery case. It can be very dangerous. Above is a picture of a very poorly constructed electric bike battery. While this is one example, we have seen much worse. Corrupt sellers of these batteries always seal the battery with tamper proof seal forbidding opening the case without voiding the warranty. If one opens the case and sees a terribly constructed battery there is nothing that can be done because the warranty has been voided the moment the case was opened.
Properly built
Opening battery case voids warranty
Cell holder for a cube battery
This is what we like to see. Under the blue heat shrink there are cell holders on each side of the 18650 cells. The cell holders hold the cells in place and allows cooling between each cell. The reason we stopped using the 52v downtube battery is the extra cell prohibits the use of the cell holders and thus causing the battery to have the potential of running warmer than necessary.
Cell holder for a cube battery
Cell holder for a cube battery
Cell holder for a cube battery
This is an example of the use of cell holders. As you can see each battery is held separated from the one nest to it. The cell holders can be cut to adapt to any size or configuration of an electric bike battery. The use of the cell holders help prevent the cells from coming into contact with one another in the event the battery pack is dropped or damaged.
Handle with care
Cell holder for a cube battery
Handle with care
It's not as if these are ticking time bombs that need to be pampered, but one always has to be mindful of the fact that a damaged electric bike battery can be a ticking time bomb. A nine pound battery can be easy to drop when removing. If at any time your battery hits the ground, even though you see no visible damage, charge the battery outside and not in an enclosed area. As you are charging the battery periodically put your hand on the case and check for any hot spots. If the case is hot then stop charging and call an electric bike shop for advice. Do not open the case, do not attempt to repair.
Chargers
Cell holder for a cube battery
Handle with care
There are many electric bike battery chargers available but as a matter of safety always use the charger that came with your battery. If you do buy an aftermarket charger there are two things to consider. First, is the charging cable. Make sure it matches your battery. It might be a small barrel connector, or the larger XLR. The second matter is make sure you have the correct voltage!!!! Do not use a 52v charger on any battery other than a 52v battery. Never use a charger whose voltage is higher than the battery you are charging. If you are unsure, take a minute and call your local electric bike shop and they will help you find the correct charger for your bike.
Types of batteries
Downtube battery
Downtube battery
Downtube battery
This is a typical downtube battery. It is designed to attach to the water bottle inserts on the downtube of the bike. Because of the weight of these batteries it sometimes is necessary to use an adaptor, large Zip ties, or install an additional 5mm insert. These batteries can weigh up to 10 pounds. In my opinion, I think it best to use the smaller lighter battery, such as the side release, as it only weighs 5 pounds 10 oz. The lighter battery is much easier on the base plate attachment points (water bottle inserts) and as a result less likely to damage the bike frame in case of a crash. It is far better to carry a second battery on those days you will be on a very long ride rather than have a large heavy battery that you only use half its range on your dailey ride.
Side release
Downtube battery
Downtube battery
What makes this battery different that a standard downtube battery is that is slides out sidewise. This feature allows the battery to fit in much smaller spaces. A standard downtube battery must have enough room to slide forward and up to both install the battery and remove the battery. If you have a full suspension bike it is highly unlikely a standard downtube battery will fit. In addition to its side release function, this battery only weighs 5 pounds 10 oz. In my opinion, the perfect solution is to always use the lighter battery and carry a second battery for those days you wish to ride 60-100 miles. Yes, you will pay more for two batteries but that is the best approach.
Cube batteries
Downtube battery
Cube batteries
This is a cube battery and you can find them in many different sizes. We used to carry a small cube battery that we would put in a tool bag and mount it behind the saddle. Cube batteries do not come in a protective case so you have to very careful while handling. When installing a cube battery on a bike it is imperative you enclose the battery in some kind of protective shell. Even a small cube battery being used behind the saddle has to have some kind of padding to keep it from abrading against any hard abject. Last year in Australia, during organized cycling event, a gentleman used a behind the saddle cube battery that was not properly protected against rubbing against the seatpost. Needles to say the battery caught fire and the bike was quickly engulfed.
Bottle battery
Triangle battery
Cube batteries
These are typically 36v batteries and due to their small size have limited range. It is a mistake to assume that because it is called a bottle battey it will interface neatly with the water bottle inserts. The base plate still has to align with the water bottle inserts just like any other battery. Are there any advantages to using a water bottle battery? They are one of the least expensive batteries, due to their size, but other than that I would use the side release battery over the bottle battery. That said, the size, voltage, type, and shape of the battery will always be dictated by what will fit on the bike. If the bottle battery is the only battery that will fit the dimensions of a frame then the bottle battery is the best choice for that bike.
Triangle battery
Triangle battery
Triangle battery
This is a massive 52v 20Amp triangle battery. This is a battery we rarely use due to its weight, which is significant. Again, it is my opinion that it is better to have two batteries with your electric bike with only one battery mounted at a time. Carry your second battery for those days you will be riding long distance. Having a massive battery attached to your bike for 20-30 mile rides does not make sense. These large triangle batteries do not fit well on bikes as the triangle of the bike frame (top tube, down tube, seat tube) rarely correspond to the triangular dimensions of the triangle battery. If you do purchase a triangle battery find one in a hard case, not a bag. Some triangle batteries have a on/off switch and others do not. Given a choice, find one with a on off switch.
Rack batteries
Triangle battery
Triangle battery
These batteries can be large and heavy. In fact, I have yet to see one that was not large and heavy. Very rarely do we use a rack battery as people tend to not like them. Remember, to mount a bicycle it is often required you lean the bike in your direction then you swing your leg over the rear of the bike. When you tilt a bike with a rack battery you immediately feel the full weight of the battery. When you you swing your leg over the the rear of the bike you have to make sure you clear the battery. If, the weight of the battery is too much, or you unsuccessfully clear the battery with your leg you can drop the bike. Given a choice we prefer the downtube battery. However, sometimes the only choice will be some sort of rack battery.
Examples of the Battery on the Frame
Downtube
Bottom of Downtube
Top of Top tube
This is an example of the downtube battery install. This battery is the typical 48v 13 top load battery. It is important when you use this type of battery to remember it will need room to slide forward about an inch and then upwards about a half an inch in order to install and remove for charging. Many, who are ordering a battery for their bike will measure the triangle area of the frame and then order a battery that will fit the triangle. Nope...that is not the way it works. There must be enough room for it to slide forward and up in addition to have room for the size of the battery.
Top of Top tube
Bottom of Downtube
Top of Top tube
We have mounted batteries on the top tube of a number f bikes. It is not our first choice but sometimes there is no alternative. When mounting on the top tube I highly recommend using the smaller, lighter, side release battery. To install a battery on the top tube you will have to drill and insert Rivnuts. When possible, we use three Rivnuts. It is very difficult to install a battery on top of the top tube and should only be attempted by an experienced bike mechanic.
Bottom of Downtube
Bottom of Downtube
Bottom of Downtube
On some full suspension bikes the best (if not only) place to mount a battery is on the bottom of the downtube. Most full suspension bikes do not have any way of attaching a rear rack which eliminates the use of a rack battery. Usually, there is no room on the downtube and mounting the battery on the top tube is best to be avoided whenever possible. Note: If you are going to mount the battery on the bottom of the downtube make sure the front tire does not come into contact with the battery when the fron suspension is compressed.
On Folding Bikes
On Folding Bikes
Bottom of Downtube
This is a Dahon folding bike being prepped for conversion. We always use the side load battery for small collapsing bikes. When attaching the battery cable to the motor remember to do it in such a manner that will allow the bike to fold. We take the battery cable and attach it to the existing cables on the bike (shift or brake). By using the existing cables as our guide we know the bike will fold once the battery is installed.
On Recumbents
On Folding Bikes
On Recumbents
This well machined product is made by Terra Cycle (T-cycle.com) and is invaluable for installing a battery on a recumbent. It is an expensive item but it is very well made and worth the cost. There is no downtube on a recumbent bike and nearly every square inch is already accounted for and there space is limited. This product creates space for the battery and if you are converting a recumbent then I recommend you include the Terra Cycle battery base in your budget.
Seat Tube
On Folding Bikes
On Recumbents
This was a custom build we did for a very nice gentleman. He was over 6' 9' and needed a very tall bike. Battery placement was going to be a problem as the frame was round tubes made of steel. The only place we felt we good get a secure fit for the battery was on the seat tube. This can only be done on bikes that have a very long seat tube. When we were finished installing the battery we were pleased with the result.
How to install a Electric bike battery
Water Bottle Cage Inserts
Water Bottle Cage Inserts
Water Bottle Cage Inserts
On almost every bicycle there will be two small threaded inserts that are attachment points for a water bottle cage. If you are going to use a down tube battery these inserts will be your attachment points of the battery base plate. They will be 5MM in size. It seems a simple matter but it can become problematic real quick. For example, sometimes these inserts are to far back causing the battery to come into contact with the seat tube. Other times, the inserts are to far forward causing the battery to come into contact with the top tube. Again, some inserts will be in a position that not a single one will line up with the battery base plate. It is common to encounter the above described. It is important to be able to determine if your battery will fit prior to purchase as batteries cannot be returned because they are a Class 9 hazardous material.
Battery Adapters
Water Bottle Cage Inserts
Water Bottle Cage Inserts
This a adapter that can shift the inserts both for and aft. This is smaller size adapter. It also comes in a longer model. For the most part this can solve the problem of getting the battery on the down tube. Note, this adapter will raise the height of the battery and may cause the battery to come into contact with the top tube. Also, because of the weight of the battery the connection will not be as strong by using this adaptor. Always check the connection points on the battery plate to insure the screws a firmly in place. As stated before, it is always best to use smaller, lighter batteries on your bike. If more range is required then purchase a second battery to carry with you.
Rubber Washers
Water Bottle Cage Inserts
Wrong Installation Method
We use hard rubber washers as an interface between the battery base plate and the bicycle frame. A hard rubber washer allows us to compress the base plate (or adaptor) firmly against the frame without damaging the frame. We have experimented with many types of washers (nylon, rubber, leather, and different types of metal) and have settled on a hard chemical resistant/weather resistant washer. Not only does a rubber washer make for a better interface than direct metal on metal but it also provides vibration resistance. A rubber washer will prevent the battery screws from loosening. However, always check your battery baseplate screws to insure they are tight.
Wrong Installation Method
Wrong Installation Method
Wrong Installation Method
This is a bike that came to our shop and the battery was falling off. The first thing we noticed was the battery was held in place with with wood screws. The weight of the battery and the use of wood screws pulled the battery right off the frame. Of course, this bike was damaged to the point it had to be destroyed. Why so many holes? The builder decided it was easier to drill holes in the frame rather than use a baseplate adaptor.
Rivnuts
Wrong Installation Method
Rivnuts
There are times when the use of Rivnuts will be necessary. A Rivnut is the same as a water bottle insert. At times it will necessary to drill a 5mm hole in the frame of a bike and install a Rivnut insert in order to fit a downtube battery. It is advised that this be done by someone skilled in using the proper tools required for this procedure. It is a "one chance" procedure and you have to get it right the first time.
Warning
Wrong Installation Method
Rivnuts
These batteries are powerful and can reult in injury if mishandled. Make sure red wire (+) goes to red wire (+) and black wire (-) to black wire (-). Do not short out your battery as you can be injured!!!! Be careful, do not mix alcohol/drugs/lack of sleep/fatigue/or anything that might impair your judgement when you work with these powerful batteries. Also, these motors have capacitors. Once power is supplied to the motor the capacitor will store energy. Do not short out the motor as injury can occur and can damage the motor.
Conclusion
What did we learn?
I have been ask many times why I tell others how to do this themselves. The thinking is that if I help people convert their own bikes I would be undermining my own business. Perhaps, but on the other hand there are many out there who will take up the challenge of converting their own bikes with or without my assistance so I might as well help when and where I can.
I think the most people underestimate what it takes to convert a standard bike to electric. First priority must be safety. In this case I mean safety of the one doing the work of conversion. There are a hundred different ways to injure oneself when working on a bike. For example, using power tools, lifting heavy objects, working around sharp chainrings, using high torque tools, breaking free crank bolts, (crank arms, bottom brackets), and other tasks that can cause serious injury. Bottom bracket removal, for example, is a task that has a high potential for injury if the right tool is not used. If one is not mechanically inclined it is highly recommended you proceed with caution. Perhaps take your bike frame to your local bike shop and have their mechanics remove the crank arms and the bottom bracket. If your budget is a bit squeezed then ask a friend who is mechanically inclined to give advice and direct you in the process.
After the safety of the person building the electric bike comes the safety of the end product. Stand back and take account; This bike can travel in excess of 28MPH and if poorly constructed something might fail. Take a look at your tires, are they new and are they of such quality they can withstand sustained high speeds? It is my view that all electric bikes should use electric bike rated tires. A electric bike rated tire has thicker wall and added puncture protection. It is worth the added cost for the level of safety they will provide. Also, take a good long look at the brakes on your bike. Are you brakes sufficient for slowing and stopping an electric bike traveling at 28MPH? A good set of rim brakes that have new brake pads and are properly aligned will be sufficient. If you have disc brakes make sure the brake pads are new and that the rotor is not worn out.
Lastly, take your wrenches, screwdrivers, torx and hex drivers and check every nut and bolt on the bike! Check the cables, cable housing, chain, cassette, pedals, stem bolts, headset, spokes, and insure the wheels are in perfect true. Now...it is ready to enjoy.
