After countless hours of research and agonizing over the thought of purchasing products from China I have finally taken the plunge and purchased what I need to build my first battery pack. I decided to go with a 24 volt 10amp battery pack because I currently have a ladies bike I set up with a 24 volt 12ah SLA battery pack. I purchased the batteries and charger for this locally. Consequently this will give me a great opportunity to run side by side comparisons test for both cost and performance.
Ultimately I will be selling two types of Li-Ion batteries from two manufacturers. For local sales I will be using Headway LiFePO4 batteries (lithium ion iron phosphate ) manufactured by Zhejiang Headway Communication Equipment Manufacturing Co., Ltd. in mainland China. These have become a very popular choice for EV’s. They do not have the power density of LiNCM batteries but they operate at lower temperatures and therefore are inherently safer to use. Especially when your building your own battery packs.
For Internet sales I will be using ALLCELL lithium-ion battery packs distributed by E-BikeKits. These are made using LiNCM battery cells not LiFePO4. They have a higher power density than LiFePO4 batteries but are more prone to overheating and what is called thermal runaway. (3 mile island on a tiny scale) Some companies will not knowingly sell these batteries for use in consumer built battery packs. ALLCELL solves the thermal problem by using their patented PCM technology in all of their battery packs. Consequently you will not be buying these cells individually. See ALLCELL Technologies and PCM evaluation.
ALL LITHIUM BATTERIES REQUIRE SOME FORM OF BATTERY MANAGEMENT SYSTEM (BMS) FOR SAFE OPERATION & LONG LIFE. Cheap lithium battery packs with no BMS may turn out to be the most expensive purchase you’ll ever make ! BUYER BEWARE !
This is not a primer or a DIY guide to building battery packs. For that please read some of the these:
There is huge amount of information available on battery technology as well as on building battery packs. Hands down the LiFePO4 battery offers the best combination of performance and safety for the DIY person. That said, let me start with the basic premise for deciding on lithium batteries and specifically LiFePO4 Headway batteries over some of the others.
Although Headway batteries do come from China the company and their products have been around long enough to have been thoroughly scrutinized by the ebike community. Do a search for Headway batteries and you’ll see what I mean. The biggest disadvantage of these cells is the size. At about 1.5″ x 5.7″ (size varies a little by cell rating) these things are a little bigger than toilet paper tube or a little smaller than a 12 oz. can of soda. This large size however is also it’s biggest advantage for the DYI’er. They are very easy to work with and they dissipate heat exceptionally well. They also come with “Lego” style spacer blocks that allow you to easily create just about any size or shape battery pack you want.
Having now decided on the Headway battery I had to find a supplier I could trust that had a good price. Zhejiang Headway Communication Equipment Manufacturing Co. themselves was not an option because of the small quantities involved. Prices can vary as much as $5 per cell and shipping is expensive regardless of where they are coming from. Lithium batteries have a Hazmat or dangerous goods designation making it illegal to ship them in the same way you might ship something else. See hazmat.dot.gov. Add to that the expense of freight from some place in east Asia and you can see how the actual delivered cost can start to add up. After a few days of searching the Internet I decided to go with ELife Bike in China.
ELife Bike was certainly riskier than some of the many familiar names I had come across. However, the information I found on them was positive and their prices with shipping where among the best I found anywhere. A couple of emails proved their English to be rudimentary at best but their replies were prompt and I could understand them. I studied their listings and pricing closely in order to satisfy myself that I would I get what I thought I was ordering. My order consisted of a 24V 10AH LiFePO4 Battery Pack kit and a 24V 350W M100 Front E-Bike kit. After placing it they followed up promptly with a conformation message and a tracking number about a day later. I also checked my PayPal account to make sure there where no additional charges. So far so good. To my surprise the order arrived six days later. The order arrived in good shape and complete. The packaging wasn’t pretty but it was well protected. As I suspected the documentation was non existent. Click here to see how it all goes together.
As with any product where shipping is a significant part of the overall price the more you buy the cheaper each item becomes. Consequently group buys are a viable alternative to making a large purchase and selling the remainder. EV and hobby forums are a good source for this information. Check out Endless sphere and V is for Voltage.
Some of the runner ups in my supplier search looked like this: (in no particular order)
Other useful sources of information are:
- What battery to buy?
- Engineering Guidelines for Designing Battery Packs
- Electric Bike Lithium Battery Primer
- A123 Cell and Packs
- Battery University
Another reason I choose ELife Bike was their DIY kits. Having never built anything other than than an SLA battery pack I wanted to be sure I had the correct parts. ELife Bikes was among a handful of suppliers offering these kits. You can find these kits on ebay easily enough but I’m very cautious about buying anything along these lines from ebay. I’m an ebay seller so I’m not beating up on ebay, but, it is what is. I was initially going to go with a US company called Headway Headquarters LLC in Issaquah, Washington. They where very knowledgeable and great to work with. Their kits were exceptionally well documented and came with step by step instructions. Their components where first rate. In the end however because I plan to sell these kits their prices had no room for any type of mark-up. If this kit was for my personal use I would have not thought twice about spending the extra money. I know for sure I will be using their instructions to assemble my Chinese battery pack. Their information can be found at : Headway Headquarters LLC. http://stores.headway-headquarters.com/StoreFront.bok. And thank you Headway Headquarters for the time you spent answering my questions and for a great web-site.
If I where to list the most important things to consider prior to making your purchase they would be:
- Must accept PayPal or similar and or Credit Cards. If yes proceed. If not do waste another minute-
- What’s the total cost with freight delivered to your door. If that’s OK then check:
- What’s the length of time until arrival. (may or may not be important) If that’s OK then search for-
- Customer feedback & product reviews. If that’s OK then email the company with some questions. I.e. who makes your BMS?, Does it come with instructions?, Is there anything else I might need? etc.
- Assuming a speedy response that makes sense and no other red flags have popped up then go ahead and place you order.
Now that my battery supplies have arrived and have been unpacked I will be building my first LiFePO4 battery pack. I will write about that as soon as I’m finished. In the mean time you can read How to buy a motorized bike kit or Required knowledge for making a successful ebike kit purchase elsewhere in this publication.
Shortly after placing my ELife Bike Headway order I heard back from E-BikeKit about my dealer application I had recently submitted and learned that It had been approved. This was great news. Now that I have an actual brick and mortar (actually wood & cinder-block) shop I need some quality products to keep in stock. The E-BikeKit headquarters is only about a 100 miles from my location in Pennsylvania which means I can pick the products up myself and save freight. I’ve been following E-BikeKit for a number of years and I’ve seen their product offering, service and dealer network improve substantially over the years. Very recently and quite notably has been their decision to team up with ALLCELL Technologies in Chicago, Illinois. ALLCELL Technologies builds high quality LiNCM battery packs. These have a slightly higher energy density than LiFePO4 batteries and are smaller in size than the Headway batteries. They use ALLCELL‘s patented PCM technology in all of their battery packs to get around the thermal issues found in the individual LiNCM battery cells. With this addition to an already great product line E-BikeKit becomes a one stop shop for all your ebike needs. There kits are assembled right here in PA using both American& Chinese components. Please stay tuned to EZgo-Now.com for more information about E-BikeKit batteries and E-BikeKit conversions.
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