Most electric bicycle batteries fall into the 24V to 48V range, usually in 12V increments. Some people use batteries as high as 100 volts, but we’re going to stick to a medium sized 36V battery today. Of course the same principles apply for any voltage battery, so you can just scale up the battery I show you here today and build your own 48V, 60V or even higher voltage battery.
In many situations, especially if you are replacing a battery pack on an existing setup, the voltage is defined by the controller electronics and cannot be readily changed. Otherwise, the voltage determines the maximum speed at which your vehicle will travel, and you have a degree of freedom in selecting the voltage to meet your performance expectations. If you know the volts/rpm for the motor, then it is straightforward to calculate how fast it will go for a given voltage. Select a value that gives an unloaded speed of about 20% greater than your desired cruising speed for best performance.
That’s a tough one to answer. It depends on the power of the battery (typically 24, 36 or 48V), the power of the bike (limited in the UK to 250W), the bike’s battery management system, and the way you ride. Some bikes allow you to choose different levels of assist to prioritise speed or battery life, which makes predictions of battery life even more difficult.
I buy that pink cells, Samsung ICR18650-26F. The cells have 3,9V, is a little too, only one with 3,82 and the other 3,87. I want to do a pack with 4parallel and 7serie (28 cells), it is acceptable conect them? Any sugestion is welcome.
However, the description says The monolithic 12V batteries do not have any PCM (any electronics) inside. They consist of finely balanced cells with identical perfomace. The battery must be managed as a single monolithic 12V block.
Please see the video’s on RCgroups under LiPo fires. A simple 2200maH 3S battery pack blew the lid off a secured 55caliber ammunition can. Putting a LiPo pack in a closed metal case is a real “bomb” waiting to happen. See all the videos on RCgroups that show what happens when a battery is over-charged or over-discharged inside air-tight causes. The real solution is to make the case have a “preferred direction” of discharge……which can be very powerful. This is done by drilling holes in the case. But it stops the explosion factor. The best thing is to have a BMS on or inside the battery. Even if the cheapy Hobby King voltage monitor, that is much better than nothing at all. Also consider putting in a voltage monitor that has a temperature guage attached. When ever the pack skin gets above 85 deg C, you are in real danger of “vent and flames”. The temperature and voltage are that two big things that can make your battery pack safe………….also store the pack where if it does go to “vent and flames”, no human being will get burned.
Panasonic and Samsung are the only manufacturers I know of that are producing this chemistry (several other manufacturers buy these and re-label them as their own). Since you would have to buy the bare cells in order to solder together your own pack, I wouldn’t have mentioned these just yet, but…EBAY-seller supowerbattery111 is selling these, and…he will also professionally spot-weld the cells into groups for a small fee, which reduces your pack-building efforts down to about 1/10th of what it would be otherwise. His main business seems to be refurbishing cordless tool battery packs that have worn out.
192 watt-hours is about the smallest battery size you would want for an ebike. Many of the store-bought ebikes have about this much capacity since it keeps the battery cost down. For people who want to actually commute reasonable distances of 40-50km, then I would recommend on the order of 400 watt-hours. While it can vary a lot with usage habits, an energy consumption of 9-10 watt-hrs / km is typical on normal direct-drive setups.
Most lithium batteries that are designed to mount to ebikes also come with some form of locking system. These have varying degrees of effectiveness. The type with a little pin that slides into a thin sheet of steel are the easiest to steal by mangling the thin steel locking plate. Just take a look at your battery and ask yourself “how easily could I steal this battery if I had some basic hand tools and a 60 second window of opportunity?”
I am new to the ofrum and to the ebike world so I would like to seek some advice please. I have recently bought a sondors fat bike to the UK and want to make some tweaks, I would like to upgrade the battery on a budget, I was thinking of 4 x 12v 5ah lead acid batteries in series, would this give me 48v 20ah or have I got this totally wrong? I want to replace the stock contoller for a 48v 25amp one, would this suffice? lastly it comes with a stock 350w bafang motor, if I make the battery and controller upgrades will the motor handle the increase in wattage? could I drill venting holes in the case cover to expell some heat? Your thoughts and advice would be most welcome,
Now take your trip distance, multiply it by the appropriate watt-hours/km from the table above, and you’ll get the total minimum watt-hours required for the trip. Take the watt-hours you’ve estimated and divide it by the voltage, and you now have an estimate on the minimum amp-hours you’ll need from the pack.
I then put one set of welds on each cell end of the first parallel group, effectively tacking the three nickel strips in place. Then I added another set of welds on each of the negative terminals of the second parallel group. This gave me 6 weld sets, or one weld set for each cell. Lastly, I followed up those single weld http://huntnbike.com with another couple welds per cell to ensure good contact and connection.
The chain is a very important bicycle part. It is responsible for turning the wheel when a cyclist pedals the bike. Problems with the chain create major riding problems. Chains commonly get dry or rusty,…
Lithium batteries are also small enough to allow you to place your batteries pretty much anywhere on your bike. This is especially true for people who want to assemble their own pack or use heat shrink wrapped lithium batteries instead of hard case lithium batteries with prefabricated bicycle frame mounts. This can help spread the weight around or hide the batteries to make a stealthier bike.