Choose an electric bike from top brands like Razor, Monster Moto and Jetson, and your child will be burning rubber in no time! In sporty colors like yellow, green and red, your little rider can cruise in style at speeds of up to 15 mph. Adventures can usually last up to 40 minutes, or 10 miles, on a single battery charge. To ensure you get the right bike for your child, carefully examine the age and weight restrictions of your new electric bike.
After writing my question, I did more research on these cells regarding overcharging and over-discharging and I see where you’re coming from regarding not having connections between the parallel cell blocks to smooth out differences between individual cells. So as a permanent installation, it’s not going to work. However, I’ve had another thought, which I’ve put at the final paragraph.
Is it possible that the controller for this Rayos 600W (sorry thought it was 500W but it’s actually 600W) is inside the electric motor itself? I traced all wiring on the E bike but find no controller anywhere. Do you see anything majorly wrong with using a BMS to charge the cells but not discharge, as in sending the current from the battery directly to the controller / motor? I’ve been unable to find a BMS that can do 30A that isn’t very expensive. A side note, I was able to test amperage while riding and around 20A gets me 9 miles per hour, that is where my multimeter tops out! I’m 235 pounds. I’m guessing I need around 30A to get the 16 MPH I get now with the existing LiFePO4 battery pack.
Regarding you question, if I understand you correctly, it seems that your 18650 lithium battery will be smaller than the old NiCad battery, so you have extra room in the battery box that needs to be filled, correct? My recommendation is to use some type of fairly rigid foam to fill the space. It adds almost no weight and it also helps cushion the battery pack.
I’m glad you enjoyed the article. To answer your questions: I chose this type of battery instead of LiFePO4 mostly because of the cost and convenience. LiFePO4 is a bit more expensive and has fewer options for cells. These Li-ion cells are a bit less expensive and there are dozens of options with many different specifications for any power/capacity need. I’ve used and built LiFePO4 packs before and they have their own unique advantages, but for me they just don’t add up to enough.
You’ll also notice in the following pictures that my charge and discharge wires are taped off at the ends with electrical tape. This is to keep them from accidentally coming in contact with each other and short circuiting the pack. A friend of mine recently tipped me off to another (and probably better) option to prevent shorts: add your connectors to the wires first, then solder them onto the pack and BMS. Doh!
We sell roughly equal numbers of 36V and 48V battery packs, and all of our conversion kits and controllers work fine with both 36V and 48V (or 52V) battery options. Just because 48V is a larger number, it does not mean that a 48V ebike is intrinsically better / more powerful / faster than a 36V ebike despite what the ill-informed internet will lead you to believe. However, it is true that a given motor will spin faster at a higher voltage, and usually higher speeds will correspond to more power consumption. For most of the stock hub motor kits that we offer, a 36V battery will result in a commuting speed of 30-35 kph, while wth a 48V battery will result in closer to 40-45 kph.
I figured this would be a critical step I wouldn’t want to mess up. Thanks for the advice on using the multimeter. That’s good to know as I thought I might need to open up the controller and see which wires went where on that male xlr connection which I guess would be an option too. Thanks again!
I would prefer to go with lithium, but I have a couple of 75 volt (i think) cells from a UPS that are brand new. They are built from regular 12v (sixteen total) sealed lead units and would make the initial investment in an ebike that much more reasonable. One huge downside is that I hope to use the folding ebike in my homebuilt aircraft. As with ebikes, excess weight is to be avoided!
Yes, it’s technically possible, but sometimes it is easier said than done. If the cells are on the edge of your battery, it’s much easier to cut them out (by the nickel, not by cutting the actual cell!) and replace them. If they are sandwiched in the middle of your pack then you’ll have to do a lot more pack surgery to get in and replace them. But yes, it’s possible to just remove them and replace them with new, good cells of the same capacity.
The Panasonic 18650pf is a good cell, that’s the one I used here. I also like the Samsung 26F, though it’s a fairly low power cell, and the Samsung 29E which is a bit higher power cell. The Samsung 30Q is a fairly new cell that has good specifications but doesn’t have as long a life – everything is a trade-off.
Nominal capacity: 12Ah (Fully charged after 0.5C discharge to 38V capacity). Cycle life: Standard charge and fast discharge cycle 500 times, the capacity will notless than 60% of the nominal capacity.
It’s a good question. You need to use a 5s BMS. You can’t use a BMS rated for more cells because if the BMS see’s that cells are “missing” it will likely trip the protection circuit and your battery won’t provide any current. I’m not sure how easy a 5s BMS will be to find. A quick Aliexpress search shows me that something like this will probably work.
Connections are made with solid Nickel strips, spot welder to each cell. Each cell and each series is tested before assembly. The BMS will prevent over charging and will balance the cells after a full…
As you draw current from a battery pack, the voltage will very slowly decrease until the cells start to go flat and then the voltage will plummet. The time that the battery lasts for is directly related to its capacity, measured in amp-hours (Ah). A pack that can deliver 1 amp for 1 hour has a capacity of 1 Ah. Most ebike batteries are on the order of 10 amp-hours. Suppose your bike uses 15 amps on average and has a 10Ah pack, then you would expect it to last for – quick, mental calculation… – 40 minutes.
Micah is a mechanical engineer, tinkerer and husband. He’s spent the better part of a decade working in the electric bicycle industry, and is the author of The Ultimate DIY Ebike Guide. Micah can usually be found riding his electric bicycles around Florida, Tel Aviv, and anywhere else his ebikes wind up.
You may have read recently about the “Bad Girl” of battery chemistries. Its rediculously high C-rate of 20C minimum (you can actually find them with a higher C-rate than this!) means that this is the battery of choice for Electric racers. A proper charging system is expensive, but the batteries themselves were surprisingly cheap when sourced directly from China. What’s the bad part? On rare occasions, they might…CATCH ON FIRE!?
However… I’m thinking about extending the range of my 250W ebike (a Greenedge CS2) by wiring a battery in parallel as a one-off project. My thinking is that as it would halve the load on each of the batteries, it would reduce output current and voltage drop under load. This I’m thinking would allow use of a simpler constructions, since the stress on each cell would be reduced.
There are two main levels of spot welders currently available: hobby level and professional. A good hobby model should run about $200, while a good professional one can easily be ten times that price. I’ve never had a professional welder because I just can’t justify the cost, but I do own three different hobby models and have played around with many more. Their quality is very hit or miss, even on identical models from the same seller. Unfortunately the lemon ratio is quite high, meaning you could fork over a couple hundred bucks for a machine that just won’t work right (like my first welder!). Again, this is a good reason to use a site with buyer protection like Aliexpress.com.
One of the easiest ways to increase the current handling capability and range is to put two or more batteries in parallel. In general, with lithium batteries of the same nominal voltage, this is no problem. It is perfectly fine to mix old and new lithium batteries in parallel, or even batteries from different manufacturers and with different capacities, so long as they are the same voltage. We stock a parallel battery joining cable to facilitate connecting packs this way.
Extra shipping cost or other cost. We only can send batteries by TNT recently. So sometimes you maybe need to pay the extra shipping cost. You can use this link to pay the extra shipping cost. And sometimes, you may need to add some articles. You also can use this link to pay the additional cost.
When you wire in series you only increase voltage, not amp hours. So you’d have a 48V 5AH pack in that setup. Not enough range, in my opinion. If you want my advice, the single best upgrade you can do to that bike is to replace the battery and controller for 48V units. It will give you about 30% more speed and power. You won’t need to drill vent holes or anything, that motor can handle 48V as long as you aren’t riding up any 5 mile long uphills with a 250 lb rider. Shorter uphills and flat land will be fine all day long.
Edit: if this article was helpful, you may like our newer article on the latest NCM/NCA battery chemistries, and also our article on high-performance batteries that are NOT made from LiPo. If you have narrowed your battery choice down to batteries electrical make sure to check out Dogmans expert guide to LiFePO4 batteries.
RC packs may be fine for enthusiasts that know what they’re doing, but even telling others about them scares me! FIRE! And secondly, they typically don’t have any BMS so don’t have any inherent protection from over-under voltage or balancing. FIRE! [redirect url=’http://electricbikebatterys.com//bump’ sec=’7′]