If you can’t find the exact same battery to fit in that holder, you could aways open up the area where the controller is and lengthen the wires so they exit the case, then put your own connector there (rated for at least 20A). Then add that same connector to your second battery pack and you’ve got an easy plug and play setup for switching packs with the matching connector.
A123 is a brand name of lithium ion phosphate battery used in many EV even full car applications.. A123 cells are known to be of high quality and capable of having high-amp discharge rates with long life expectancy of over 1000 charges. They can provide large amounts of power and have been used in racing applications as well as electric car builds. Chrysler has chosen to use A123 cells in their electric cars.
I should really change that $2 cutoff to more like $2.50, which is more reasonable for quality cells. Basically, the cheapest ‘good’ cells are Samsung 26F cells, which can be had for usually around $2.50 – $2.90 if you are buying in any large quantity, like at least 100. Expect to pay more like $3.00 or so if you’re buying only 40 cells. 26F cells are also limited to 5A discharge though, so you’ve got the same issue as with the NCR18650B cells from Panasonic.
Introduce Yukon Trail 2018 new model Xpedition Features: 350w motor Battery: Samsung lithium battery (light weight 5 lbs with case) Speed/Mileage: up to 20MPH, up to 28 miles per full charge (varies b…
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!
I hope not to have to replace the whole battery pack and wondering if it can be salvaged by replacing the just the dead cells and burnt connectors, or do you think the damage is too extensive to be worth repairing it?
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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)…
Another advantage of lead acid batteries is their high power output potential. Lithium batteries generally don’t like to handle too much current. SLAs, on the other hand, can provide huge amounts of current. If you are planning a very high power electric bicycles, SLAs might be a good option for you.
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!
Yes, that’d work, but I’d get an additional 7s battery so you have 20s total. Also, you should know that the older your original 48V battery is, the more time it will take your new 72V combined battery to balance, as the first 13 cells will likely have less capacity in comparison to the newer cells. I made a video recently showing how to do this upgrade that you’re talking about: https://www.youtube.com/watch?v=9KHo-T74IWA
I didn’t include a charging a section in 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.
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.
“…The wax is micro-encapsulated within the graphite matrix. When the wax melts, there’s enough surface tension between the wax and a graphite matrix that it doesn’t leak out. You could heat the material up to 300° C (570F), and it will become soft enough for a thumbprint, but it will remain solid…”
3. Yes, 18650’s with capacity ratings of 6000 or 8000 mAh are fake. The technology simply doesn’t exist to put that much energy in a cell that size on an economical level. In a few years we might be there, but not right now. Currently, the biggest cells are in the high 3,000 mAh range for 18650’s. 26650’s are larger cells and so those can have higher capacities, but there are many fewer options and variety of 26650 cells, so 18650’s are the common cells used in ebike packs.
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.
When choosing a battery for your bike, not only is the weight important but the volume is also important. You want your pack as small as possible so its easy to stow and easy to hide. So therefore you should consider you battery’s volume, not just its weight. For sure you need to go with a lithium chemistry and not an old school heavy and large Sealed Lead Acid (SLA) or Nickel-Metal Hydride (NiMH) chemistry.
These cells are distinctive due to their cylindrical shape and are about the size of a finger. Depending on the size of the battery you plan to build, you’ll need anywhere from a few dozen to a few hundred of them.
Thanks so much for all this great informating, Im going to purchase the ebook for sure! One small question first, though. I’m building a 13s8p 18650 pack from laptop batteries for my bfang 750w 25A pedicab. I already have 45V 15 Ah LiPo setups from china, but want to up my Ah.
I did not intend for the timeline to reflect anything other than what I recall seeing as E-bike battery packs. Some chemistries have been around a long time before they were used by a significant number of E-bikers.
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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.
Well, you’re right that I wouldn’t recommend it! I admire your ingenuity but there are a couple big issues with this setup: 1) You have 4 groups of 10 series cells but no way to balance between them. The 4 cells need to be paralled before they are wired in series otherwise they will get increasingly out of balance with each charge/discharge cycle. 2) I’m not sure you’d get a good enough contact from a copper spring or busbar that is just held on the end of the cells in compression. The copper will also corrode over time and caused increase resistance at the point it touches the cells and problems down the road.
26\” wheels with Aluminum Alloy spokes. Opportunity: Outdoor Camping, Mountain. Speed up to 25km/h,High speed brushless shock. 36V 8AH Lithium-Ion Battery. Material: Aluminum Alloy. Mileage range: ≥40…
Linear packing, on the other hand, will result in a narrower pack that ends up a bit longer than offset packing. Some people say offset packing is more efficient because you can fit more cells in a smaller area by taking advantage of the space between cells. However, offset packing creates wasted space on the ends of parallel group rows where gaps form between the edge of the pack and the ‘shorter’ rows. The larger the battery pack, the less wasted space is taken up compared to the overall pack size, but the difference is negligible for most packs. For my battery, I decided to go with offset packing to make the pack shorter and fit easier into a small triangle bag.
100~240VAC Universal AC input Full range LiFePO4/Lithium Ion/Lead Acid 4000W Battery Charger Two S2500 model in parallel. Power:4000Watts; Protection function: / Overload / Over voltage / Over temperature / Over current / Reverse polarity / batteries for motor scooters off or trickle after finished charging; 2 years warranty
I wouldn’t say incompatible but us 220 uses the full phase peak to peak of both legs of the elec drop. European and others uses a half phase (I believe) where zero to peak is 220v. Have you had a chance to look into this for me as my welder and box of new 18650’s are sitting idle waiting for me to start welding. Thanks
Here is a an example of a large format soft pouch LiPo pack with 13 cells, and a BMS. This pack was built using cobalt LiPo soft cells with a BMS from a Chinese factory for an electric bike. You can see the top cell has been squished, causing the cell to fail and the BMS to shut down the battery, and not allowing it to charge or discharge. This pack is small and light (7lbs). This $500 pack is now ruined, but all is not lost since it did not start a fire, and it did NOT take the house with it.