I want to build some custom batteries, but I am hesitant to do the spot welding myself. Aren’t there modular and affordable pieces of hardware one can use to connect the batteries? Something like this?
To answer your question, you can definitely build your own auxiliary battery. It looks like they used a fancy right angled female XLR connector, but I imagine a standard female XLR connector will fit just as well. I’m not sure if you’ll be voiding your warranty though by connecting your own battery. Those XLR connectors can be purchased all over ebay and probably even at your local electronics shop.
Its low C-rate of 1C means you need a large pack if you want higher amps. Justin at ebikes.ca was an early adopter of LiMn for his E-bikes because his customers wanted a trouble-free product that wasn’t fussy and lasted a long time. Makita cordless tools use LiMn, as do many laptop computers. Last year Zero E-motorcycles were using LiMnO2, but this year they moved up to NMC (found listed below). [edit: Due to customer desires and safety concerns, LiMn has been improved and now in 2014, there are high current LiMn]
I see, so regarding the question about building backup batteries, applications where the existing backups are NiMH or NiCd and are already designed into a charging system should really get NiMH replacements rather than Li-ion. I didn’t realize older batteries used something other than CC-CV.
Once I’ve got all the cells I need checked out and ensured they have matching voltages, I like to arrange them on my work surface in the orientation of the intended pack. This gives me one final check to make sure the orientation will work as planned, and a chance to see the real-life size of the pack, minus a little bit of padding and heat shrink wrap.
The only thing left to do at this point is to add the connectors, unless you did that before you soldered the wires on, which I actually recommend doing. But of course I didn’t do that, so I added them at this step, being careful not to short them by connecting only one wire at a time.
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).
Most people find that once they have an ebike, they use it for all kinds of applications and trips outide of just commuting, and the ability to go 50+ km on a charge opens up possibilities that wouldn’t have been possible otherwise. Plus, as the battery ages and declines in capacity, it still has more than enough range for your key commuting needs. Imagine if instead of getting an 8Ah pack, you purchased a 15Ah battery. Even if after 4-5 years it has lost 30% of its original capacity, that’s still over 10Ah and leaves plenty of reserve for your 24km commute.
We like to use Anderson Powerpole connectors as the standard discharge plug on all of our ebike battery packs. These connectors are ingenious since they are genderless, allowing you to use the same plug both on both a load and a source, and the connector design allows them to withstand the arc of inrush current when plugged into capacitive loads much better than bullet style plugs. For the charging port, we like to use the female 3-pin XLR plug standard. This is directly compatible with the Satiator charger, and the quality Neutrik XLR plugs are rated for a full 15 amps per pin allowing very rapid charging. Unfortunately, this option is not available for the smaller Hailong frame batteries and we are forced to use the lower current DC 5.5mm barrel plug instead.
What a great article! It has opened my eyes to lots of possibilities. Being new to this I had a couple of questions. I am interested in building a spare battery to give me more range on the Faraday Porteur. My question is how to batteries for electric bikes the battery I would build to the bike. The main battery resides in the downtube and the connection is hidden. They offer an ancillary battery that plugs into the charging port which is what I would like to build myself rather than buy. Do you think this would be possible? Where could I find a connector that would match? Any concerns? If so, what other options do you suggest? Thanks so much for the help!!
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i noticed that bms installation is different (as i guess) from the video (https://www.youtube.com/watch?v=rSv9bke52eY&index=10&list=LLDXj2cy8mbQoc0dz3RO3zFw) i have watched before. In this video bms wires were connected on the negative poles of batteries lifepo4. In my amateur opinion i could not understand how we organize BMS connections for my 13s pack. if you illuminate me, i will be preciated.
The other thing to consider is that if you have one 48-volt 10-Ah battery putting out a measly 20 amps, you can add a second version of the same battery, wire them together in parallel, and you will have a 20-Ah pack with a 40-amp capacity, thus effectively doubling your range and doubling your amp output performance.
1. The extra amperage that the battery could output isn’t wasted, it’s just sort of a safety factor. It means you aren’t stressing the battery to its limit. Also, batteries only get their full rated capacity at lower discharged. So you’re more likely to get the full capacity now than if you actually pulled 50A out of it.
1C charging is too high for most Li-ion. It’s too much to ask for right now, to be able to charge an entire pack in one hour. It can be done, but it’s not healthy for the cells. Aim for 0.5C at the most. I usually don’t go past 0.3C on charging.
Next, we’ll need to wire multiple 18650 cells in parallel to reach our desired pack capacity. Each of the cells I’m using are rated at 2,900 mAh. I plan to put 3 cells in parallel, for a combined capacity of 2.9Ah x 3 cells = 8.7 Ah. The industry abbreviation for parallel cells is ‘p’, meaning that my final pack configuration is considered a “10S3P pack” with a final specification of 36V 8.7AH.
Oh, one last thing. If you have a poorly formed connector or the wires are fraying, that can increase resistance and cause a voltage drop that might trip a cutoff condition. Just another thing to check for.
When it comes to layout, there are two ways to assemble cells in straight packs (rectangular packs like I am building). I don’t know if there are industry terms for this, but I call the two methods “offset packing” and “linear packing”.
There are formulas out there for calculating the exact size of heat shrink you need but I often find them overly complicated. Here’s how I figure out what size I need: take the height and width of the pack and add them together, and remember that number. The size of heat shrink you need when measured by the flat width (half the circumference) is between that number you found and twice that number (or ideally between slightly more than that number to slightly less than twice that number).
If you’re like me, then you like hearing and seeing how things are done, not just reading about them. That’s why I also made a video showing all the steps I took here in one single video. The battery I build in this video is not the same exact battery, but it’s similar. It’s a 24V 5.8AH battery for a small, low power ebike. But you can simply add more cells to make a higher voltage or higher capacity pack to fit your own needs. Check out the video below:
This makes sense. Yes, it would be possible. You could wire balance connectors and extra discharge plugs to make three packs out of your one 13s pack, such as two 6s packs and a 1s, or two 5s packs and a 3s, etc. Then you’d charge each one, one at at time, using your imax B6 charger. It would take a while, but that’s how you’d do it. Just be careful to not get your connectors confused, as you’ll have three sets of balance wires and three sets of discharge wires.
I purchased the 220v welder, which obviously was intended to run on non-US half of a phase 220v, Of course we have full single phase 220v, so could you supply me with a hint on how to wire the unit for US 220 v.
In the rush to upgrade from lead acid to the latest NiMH and lithium packs, it seems that most companies forgot about the old venerable Nickel Cadmium battery as a suitable option for ebikes. Although they are somewhat heavier than the NiMH and lithium options, they are still a substantial weight savings over lead. NiCd packs have had a solid and proven track record in demanding rechargeable battery applications.
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
hi i was considering adding a second set of batteries to my ebike in parallel to double the range but heared on a thread somewhere that this can damage/overload the controller which i suspect is a load of tosh but can anyone confirm/clarify this as i assumed the amp hour capacity was just that and the max amp output was just that, the maximum that can be drained at once, my understanding is it doesnt matter what amp hr the pack is as the amps drawn into the controller is governed by the demands of the motor which wont change if i have 2 packs connected.
It says it is 110 volts (220 are available) but this welder needs a 60 amp circuit (breaker) to work properly so it is not advisable to use at home! anyway, have you found this is a certainty? that you must use a 110 volt (single phase) 60 amp circuit? is this what you are using? have you been having breakers flip when you use your welder on a smaller breaker? (most homes are 20 amp breakers) Or would it just be better to go with their 2 phase (220 volt) 60 amp breaker? I guess I could just pick up another breaker and run it directly from the panel.
18650 cells, which are used in many different consumer electronics from laptops to power tools, are one of the most common battery cells employed in electric bicycle battery packs. For many years there were only mediocre 18650 cells available, but the demand by power tool makers and even some electric vehicle manufacturers for strong, high quality cells has led to the development of a number of great 18650 options in the last few years. [redirect url=’http://electricbikebatterys.com//bump’ sec=’7′]