Table 2 provides a brief comparison of lead acid to LiNMC on a pack level. It should be noted that both chemistries have a wide range of parameter values, so this table is only a simplified representation of a very complex comparison.
Now buckle up, grab a drink and get ready for some serious reading, because this isn’t a short article. But it will definitely be worth it in the end when you’re cruising around on your very own DIY ebike battery!
Amazing article, just what I needed. Have been doing LOTS of research but have struggled to find any real answers on which charger I should buy for my homemade battery. I am making a 48V 13s4p battery with a BMS (with balancing) like yours but am stuck as to whether I need to buy a normal bulk charger or a ‘smart charger’ that will balance the battery. My question is will the BMS balance the battery on its own or will I need to get a charger that balances also?
That’s exactly correct. You’d start by welding 10 parallel groups of 4 cells each, then you’d connect those 10 parallel groups in series to make one rectangular battery. I’ve done many 10s4p packs just like that for 36V 10ah ebike batteries.
So let say main point to count the power is to count the power is to know what type of the controller i have (i have check my batt connection goes to PCB which has sensors it self and whole unicycle controller… ) how to know ? Or in primitive way i can count like my batt is 20A and 36W so max power can be 720W but its peak on continues?
I’ve been building a 13s6p Li-ion battery based on your article, and everything went swimmingly (except underestimating the amount of nickel I’d need) until I started hooking up the BMS. I was in the middle of hooking up the sense lines, and the BMS smoked. Opening it up, it looks like a few of the caps that couple adjacent nodes burned. Have you seen this before? Any thoughts on what I may have done wrong, or does this just happen sometimes when a cap’s voltage tolerance is outside spec?
I’m mostly familiar with BesTech’s 72V BMS’s and haven’t used a 52V BMS from them, so I can’t give you a recommendation on a specific 52V (14s) BMS from them, sorry. I have used this 14s BMS twice and it’s worked great for me on two 14s7p packs I made with Samsung 26F cells.
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.
Yea lead acid is a great way to cheaply get into ebikes and test new motor/controller combinations. Keep in mind though that your performance will increase when you switch to lithium. It’s easy to do though, as the bike doesn’t care what chemistry it receives, it just sees volts and amps. Good luck!
Absolutely, a relay is the way to go. Use the keyswitch you bought to activate the relay, then the relay will carry the heavy current flowing through your battery’s positive discharge wire. Alternatively, you could install 9 or 10 of these switches in parallel. Just make sure you mark your keys accordingly 😉
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!
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.
If your electric bike isn’t giving you the range it used to, it might be time to replace its battery. Batteries Plus Bulbs has a wide variety of scooter and e-bike batteries that will give your ride new life. Just look for your specific model, then pick the battery you want.
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.
9S, 32.85VDC, 2890MAH, 94.93WH. THE ENERGY DENSITY OF THESE CELLS ARE SPECTACULAR. YOU GET A POSITIVE AND NEGATIVE LEAD WIRE AND ALSO BALANCE CONNECTORS IF YOU WANT TO BALANCE THE CELLS. IF YOU BUILD …
Regarding your first question: as long as your BMS has a balancing function (most do) then you do NOT need a charger that does balancing, and in fact you should not use one. The BMS takes care of all the balancing, so all you need is a simple ebike charger. What is important though is that it is a CC-CV (constant current, constant voltage) charger. Most ebike chargers are, but just check to make sure it says that somewhere in the description, or ask the vendor if you can’t find it. The CC-CV part means that the charger will supply a constant current first, bringing the battery voltage up slowly until it reaches the full voltage (54.6V for your 13S battery). Then it switches to CV mode and holds a constant voltage while it gradually backs the current down to zero, which is the ‘finishing’ part of the charge.
Continue down the row of cells placing a weld on each cell. Then go back and do another set of welds on each cell. I like to do 2-3 welds (4-6 weld points) per cell. Any less and the weld isn’t as secure; any more and you’re just unnecessarily heating the cell. More and more welds won’t increase the current carrying ability of the nickel strip very much. The actual weld point isn’t the only place where current flows from the cell to the strip. A flat piece of nickel will be touching the whole surface of the cell cap, not just at the points of the weld. So 6 weld points is plenty to ensure good contact and connection.
I didn’t include a charging a section http://electrichuntingbikes.com this article, as this was just about how to build a lithium battery. But here’s a video I made showing you how to choose the appropriate charger for your lithium battery.
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,
In my video reviews I often suggest that ebike owners store their batteries in a “cool dry location” to maximize the usable life of the cells and make charging convenient. In some cases this cold mean inside the house (either the entire bike or just the battery if it’s removable). So how can you charge these packs safely? What are some options for preventing electric bike fires? To help answer these questions I reached out to Edward Benjamin, Senior Managing Director of eCycleElectric LLC and Chairman of the Light Electric Vehicle Association for insight. Ed travels the globe doing consulting for large ebike firms, teaches ebike classes to shops (of which I have attended two myself!) and I consider him an expert but these tips are just that… the best information we have to help guide you towards making your own decision. Nothing can be truly guaranteed and some of the tips Ed shares below focus on what to do if a fire does break out.
i have the exact same BMS but i only have 6 cells, 2p x s3 , i have 2x 3.7v @ 2000 mah batteries in parallel connected to another 2 parallel batteries in series and another parallel pack in series if that makes sense to make a total of 11.1 v @ 12mah for a small project.
The lithium iron phosphate (LiFePO4) battery has had a lot of hype and media attention lately. This is the same chemistry used by A123 in the Dewalt power tool battery packs, where it has a 2000 charge and discharge cycle warrantee and has phenomenal current handling capability. The LiFePO4 batteries sold for ebike use generally have much lower current ratings, and the actual number of charge and discharge cycles that these generic packs will provide remains to be seen, although most manufacturers seem happy to claim 1500 to 2000 cycles. Iron Phosphate lithium packs are only slightly lighter than NiMH and a fair bit more expensive, but they could be the most economical in the long run.
If you want to mount the ElectroRideTM Ultra High Performance batteries above in the frame of your bike consider our Triangle Bag. Our batteries are so compact, even two of them can fit, which is useful for 72V operation or more range.
This is also why the common and affordable RC smart-chargers are powered by a separate DC power supply. Many RC enthusiasts spend a day at a park, and while flying an RC plane, they have several other battery packs that are charging from their cars 12V system.
There are different models of welders out there but most of them work in a similar way. You should have two copper electrodes spaced a few millimeters apart on two arms, or you might have handheld probes. My machine has welding arms.
The battery packs from Allcell are unique in that the cells are surrounded in a phase change material supported in a graphite matrix, which allows these batteries to handle higher sustained discharge currents without the cells overheating, and they have longer cycle life as a result of this thermal management. However, being ‘naked’ packs, they do not come in a rigid enclosure or bike mounting solution, The 48V 23Ah packs now come in a very nice rigid casing, though they still do not have ane explicit mounting mounting hardware and it’s up to the user to install them in protective case or bag on the bike. These batteries are available in 36V 17Ah, 36V 23Ah, 48V 17Ah, and 48V 23Ah options, and can handle 40A motor controllers just fine. They are assembled in the USA and have UN38.3 certification.
As you sugested in one of your articles, using lead acid is a great way to prototype the build, so if I am happy with the performance if not the weight of the lead-acid, I can convert to lithium in the future and save some big weight.
HERE ARE 100 GENIUNE LG LGDAS31865 18650 2200MAH CELLS. YOU CAN’T FIND A BETTER DEAL THAN THIS. Capacity: 2200mAh. THE PHOTOS SHOW HOW WE GET THESE IN AND BREAK THEM DOWN. STOP GETTING RIPPED OFF AND …
Have a fire extinguisher located at the spot where you are going to be standing when you discover a fire. For example, hanging next tot he door from the house to the garage. Maybe a second one on the other side of the garage. Additionally, have a bucket that can be used to carry water to the fire – reasons explained below. Use a 5 lb. or larger ABC extinguisher, or a big CO2 extinguisher, or both.
The only two ebike companies that sell LiPo to the public are Optibike and Pi-cycles, and both contain the battery in a strong metal box which makes up of the frame. The companies fire tested these enclosures and are confident that their frame are effective and safe vessels for LiPo storage.
A lithium battery is the heart of any electric bicycle. Your motor is useless without all of that energy stored in your battery. Unfortunately though, a good ebike battery is often the hardest part to come by – and the most expensive. With a limited number of electric bicycle battery suppliers and a myriad of different factors including size, weight, capacity, voltage, and discharge rates, finding the exact battery you are looking for can be challenging and lead to unwanted compromises. [redirect url=’http://electricbikebatterys.com//bump’ sec=’7′]