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,…

Please do not ask us to overvolt or otherwise modify your eBike to exceed 20 mph. First off, we have yet to have a customer who has (on their own) overvolted their bike to go above 25 mph and avoided a hospital visit within their first 6 months of doing so.

A quick note: when you get into large sizes of heat shrink, the method of quoting the size often changes from referring to the diameter of the tube to referring to the flat width (or half the circumference when in a circle). This is because at these large sizes, it’s not so much a tube anymore as two flat sheets fused together, sort of like an envelope. Keep that in mind and know what size is being quoted when you buy your large diameter heat shrink tube.

Finally found it. WOW!! Exactly what was needed. I struggle with conceptualizing verbal descriptions. You solved that! With the new JP Welder from Croatia my first welded build will soon be a reality. Thanks for all you do for eBiking!

Be warned: some less-than-honest vendors try to pass off nickel plated steel for the pure stuff. They often get away with it because it’s nearly impossible to distinguish between to the two with the naked eye. I wrote a whole article on some methods I developed for testing nickel strip to make sure you get what you paid for. Check it out here.

LiPo’s are the smallest, cheapest, lightest and most powerful lithium batteries. Their disadvantages include short lifespan and propensity to combust into giant fireballs if not cared for correctly (I’m not kidding, check out the short video clip below).

When it comes to lead acid batteries for ebike use, you’ll generally be looking for what’s called a “sealed lead acid” or SLA battery. SLAs come sealed in a hard plastic case and can be turned in any orientation safely without leaking acid. This makes them appropriate for ebike use. Wet cell lead acid batteries, like many car batteries, would leak dangerous acid if turned on their side or upside down, making them a bad idea for use on an electric bicycle, which is a lot more likely to get knocked over than a car. Remember to stick with SLAs – not wet cell lead acid batteries – for electric bicycle use.

Also, since the negative electrode is the entire bottom and sides of the cell (formed by a metal cylinder) these cells can take some bouncing around. Be aware if you scratch the plastic wrap on the cylinder, the metal shell underneath is energized to the negative electrode, so…an electrical short may be possible.

If not possible, try charging them individually. Some of them might come back but others might be dead. The tricky thing is that they will likely not be able to deliver their full capacity anymore and the actual capacity will likely vary from cell to cell. Two year old cells at a very low voltage are quite a gamble.

36v 10Ah Bottle Type Battery. Rated capacity: 10Ah. 36v 14Ah Rear Rack Type Battery. Rated capacity: 14Ah. 48V 14Ah Rear Rack Type Battery. Recommended to be used with 36V 250W electric bicycle motor.

Regarding the cell question, its a mixture of both. Cheap ebikes use cheap cells. You can bet the Sonders ebike had the cheapest cells available. Name brand ebikes usually use Samsung cells, but sometimes LG and occasionally Panasonic cells can be found in name brand ebikes (the Panasonics are some of the most expensive and so they are rarer). That being said, I’ve seen some shadier internet sites selling high quality (and genuine) Samsung/Panasonic packs, and I’ve seen some nice ebikes with some no-name cells. You should always check with the vendor/manufacturer if you want to ensure you’re getting good cells. Unfortunately, it can be hard to verify the cells yourself though without voiding the warranty, as they are usually sealed under shrink wrap. A good vendor will be happy to confirm the cells for you ahead of time and may even be able to show you some pictures of opened packs to verify.

Lithium Ion electric bike batteries are ideal for those that plan to ride longer distances and or more frequent trips. The commuters dream battery, lithium batteries can stand two complete 100% discharges a day for years. Discharging the battery half way riding to work or school, then parking all day at half charge does no damage to a lithium electric bike battery. So the urgency to recharge immediately is not like SLA’s. Since discharging to 100% empty does not significantly harm lithium electric bike batteries, the usable range of the lithium electric bike battery is roughly double that of SLA’s. In typical electric bike use, Li-Ion batteries last from two to four years. Proper storage of Lithium Ion batteries is important when the electric bike will not be used for more than a few weeks. Unplug the battery from the electric bike, charge fully, and then store in a cool but not frozen, dry place.

As a side-note, the Boeing 777 Dreamliner battery fire was using LiCo. They wanted a battery that was as light as possible, and as compact as possible. I am not an engineer, but I agree with the statement made by “Tesla” electric car maker Elon Musk, when he said that there was NOT adequate heat insulation between each cell. Better individual cell insulation would prevent a bad cell that was getting hot from heating up the surrounding cells. That is what led to a domino effect. The Tesla cars have a cell cooling system, and the on-board computer can detect and cut-off any cell-group that is getting hot.

Next, regarding your question of paralleling the batteries. Yes, you can parallel them, and you can do it even before connecting to the controller. The biggest safety issue (and damage issue) though is to always be sure they are at the exact same voltage when you connect the two batteries in parallel. The easiest way to do this is only to connect them in parallel when you’re sure they are both fully charged.

I would like to know what input in terms of voltage and current i should provide to my battery of 36V 8.7AH. And also how the calculation goes if i want to build a battery for some other Voltage and current specification ?

The single best manufacturer is BesTechPower, but their BMS’s are really expensive and they have a minimum order quantity of 2. For ‘best bang for your buck’ BMS’s I’d recommend Greentime BMS’s. They are great for most ebike applications outside of serious hotrods and speed machines. I use them on most of my packs.

I’m deeply uncomfortable with recommending RC LiPo from the likes of Turnigy for people who don’t know what they’re doing. The above 3 options are plug and play and require no special skills. And they’re essentially safe when bulk charged with the associated charger.

That’s right, every customer we know who has broken the speed requirement for their eBike has injured themselves. Secondly, if we did the modification and someone injured themselves, they might sue us, and it simply isn’t worth losing our shop for a few dollars.

This is what I refer to “small cells”, the 18650 (cordless tool) type cells which need to be spot-welded or soldered together to form a large pack. The big advantage of these cells is they offer better cooling because of the nature of their shape to the LiPo soft pouches, and therefore have the capacity to last longer.

Also, the best method for adding an auxiliary battery would be to connect it when both batteries are full, or at least at similar discharge states. That means the auxiliary battery won’t have to work as hard transferring energy to the internal battery, as they’ll be depleted together at similar rates. And the diode in the auxiliary battery will ensure energy only flows one way (towards the internal battery).

Yep, that explains it. I was going to say that it sounds either like a defective BMS or more likely a connection error. B1 is definitely the negative end. Also some BMS units have B1- and B1+, others just have B1+. If it has it will have X+1 sense wires, where X is the number of series cells in the pack.

A High-performance Motor acheives a top speed of 20-30km/h with a range of 20km means your ebike commute just got easier. 36V 8AH Lithium-Ion Battery. Motor: 36V 250W brushless. Rang: 18-25km(36v 6ah)…

You’ll need someway to hold your cells in a straight line while welding, as free-handing is harder than it looks. I have a nice jig (that I received as a free ‘gift’ with the purchase of one of my welders) for holding my cells in a straight line while welding. However, before I received it I used a simple wooden jig I made to hold the cells while I hot glued them into a straight line.

A BMS isn’t necessarily strictly required – it is possible to use the pack as is, without a BMS. But that requires very careful monitoring of the cells of the battery to avoid damaging them or creating a dangerous scenario during charging or discharging. It also requires buying a more complicated and expensive charger that can balance all of the cells individually. It’s much better to go with a BMS unless you have specific reasons to want to monitor your cells by yourself.

If I regroup my 12 paralled cells in 10 modules, can I then join these in series using single wires (one for neg, one for pos) between modules, instead of wiring each terminals of each cells like you are doing. Could this affect BMS and/or have any negative impact on cells balance?

LiMn was by far the most common chemistry in cheap (and expensive!) built up electric bikes for a long time. It’s a cheap, light, safe chemistry. The problem is low C, but much more importantly short life. And not just a short number of cycles but a short shelf life as well. Losing 20% capacity a year even if you don’t use the battery much leads to a lot of expense and warranty claims. LiNiCoMn has the same low cycle life, light and cheap characteristics, but it seems to have a longer shelf life and a slightly higher C.

I’m sorry but I’m not certain. Here in Israel we are on 50hz so I haven’t tried that model on 60hz. I do however have some friends in the US that have that model on 60hz. They have been happy with it, but I haven’t used it myself so I can’t say how it compares to my experience.

LiFePO4/Lithium Ion/Lead Acid 120W Battery EBike Charger. 12V6A,24V3A,36V2.5A,48V2A;  Li-Ion Battery Charge Voltage = 4.2V x the number of cells in series; LiFePO4 Battery Charge Voltage = 3.55V x the number of cells in series.

the problem i have and the bit im confused on is this, i understand the negative on the entire pack goes to the negative on the BMS and the positive of each parallel cells goes to each sense wire but where are the charge and discharge wires going ? am i corrrect in saying that the positive of the pack goes to the charge and discharge socket on the BMS and that when the pack receives its charge it charges the pack and the discharge is when the pack is under load from the output of the pack i.e what ever its connected to for example your bikes motor? in your tutorial you havent shown how you connected the parallel groups of batteries together in series to give you the final pack voltage and capacitance but i’m assuming you linked them in series to get the toal 36v but on the pictures the first and last cells are split compared to the doubled up cells you have through out. am i also correct in saying that if you have 2 batteries connected together to form a cell then you dont need a sense wire on each battery because the two batteries are considered to be the same battery and when they charge and discharge they equalize as one shunts the other ? sorry for so many questions i have googled and googled and googled and as Einstein once said the definition of madness is doing the same thing over and over and expecting a different result, many thanks in advance .

Capacity: 30Ah. output: 71.4V 5A. Lifecycle of single cell: >85% capacity after 700 cycles, > 70% capacity after 800 cycles. (<1C discharge rate and <1C charge rate). Lifecycle: > 85% capacity after 5…

Landcrossers Hailong E-Bike Battery. Case Material:ABS Aluminium alloy. Fuse Installation position:Inside on the PCB. Fuse Diameter(mm):5. Fuse Length(mm):30. Fuse Current: 30A. 1 x Lithium Battery wi…

Just kidding, here’s a little more detail. 1) Yes, actually you could just use one strip of nickel on series connections to make the electrical connection, but one strip of 0.15mm thick nickel strip can only safely carry less than 10A. Ideally you want at least one strip for every 5-7A you plan to pull through the battery. 2) You can definitely do the series connections first, it is just habit for me to do parallel connections first. Also, on larger packs I like to do parallel groups first and then glue them together and do the series connections as I glue each group. 3) People have explored this idea a bit on Endless Sphere, and while it can be done, it has a lot of room for error, mostly in keeping the spring loaded contacts permanently against the cell terminals and in keeping the contacts from corroding. Spot welding is the best method, in my opinion. [redirect url=’’ sec=’7′]