Almost all consumer electronics that have a plug-in charger these days are powered with lithium batteries because they can store about 3 times more energy than NiMH. Small devices like cell phones, mp3 players, and other gadgets typically have lithium-polymer packs, as these can be formed in conveniently shaped thin rectangular pouches. Larger devices like laptops and the new lithium cordless power tools generally use cylindrical Lithium-ion cells of a size smaller than a ‘C’ but bigger than a ‘AA’. These are spot welded in series/parallel combination to give an appropriate voltage and capacity for the job.

Continue down the row of cells placing a weld on each cell. Then go back and do another set of welds on batteries electrical 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.

Ideally, I would buy a battery with the same type of connection and just carry the spare one unconnected and swap them over but I don’t seem to be able to find the type of battery case for sale anywhere. It’s a quick release bottle type battery that has two sprung terminals about half inch in diameter that contact with two large terminals on what I think must be the motor controller integrated into the bottom of the bottle mounting bracket.

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.

You can certainly use a second 4.4AH battery in parallel to double your range, but you’ll want to make sure the batteries are at the same state of charge when you connect them in parallel, or use a diode in between them, to keep one battery from discharging the other if the charge states are unequal.

I guess I’ll just have to risk some deterioration on the cells. I don’t think there’s much of an effect, as I did it on an old 18650 cell to test. The joint and surrounding areas were cool to the touch within 1-2s of removing the heat.

I’m mostly kidding, but if you use cells that are rated for more current than you’re trying to pull from them, you’ll create a lot less waste heat and both options will be perfectly fine and healthy for the battery.

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.

Just kidding, here’s a little more detail. 1) Yes, actually you could just use one strip of nickel on series connections to make the electrical connection, but one strip of 0.15mm thick nickel strip can only safely carry less than 10A. Ideally you want at least one strip for every 5-7A you plan to pull through the battery. 2) You can definitely do the series connections first, it is just habit for me to do parallel connections first. Also, on larger packs I like to do parallel groups first and then glue them together and do the series connections as I glue each group. 3) People have explored this idea a bit on Endless Sphere, and while it can be done, it has a lot of room for error, mostly in keeping the spring loaded contacts permanently against the cell terminals and in keeping the contacts from corroding. Spot welding is the best method, in my opinion.

Most electric bicycle batteries fall into the 24V to 48V range, usually in 12V increments. Some people use batteries as high as 100 volts, but we’re going to stick to a medium sized 36V battery today. Of course the same principles apply for any voltage battery, so you can just scale up the battery I show you here today and build your own 48V, 60V or even higher voltage battery.

Pedals: Foldable. 26\” wheels with Aluminum Alloy spokes. Opportunity: Outdoor Camping, Mountain. 36V 8AH Lithium-Ion Battery. Material: Aluminum Alloy. Wheel diameter: Approx. Head height (To ground)…

Lead acid batteries are the least expensive and heaviest battery option. They have a short cycle life if used regularly in deep discharge applications. For electric bikes, the most common setups use 12V bricks of either 7Ah or the larger 12Ah capacities, series connected to form 36V or 48V packs. Because of the Peukert effect, the 7Ah gel cell usually delivers about 4 amp-hours of actual capacity, while the 12Ah lead acid packs will deliver approximately 8 amp-hours. So keep this in mind when comparing a lead acid pack to one of the NiCd, NiMH, or lithium replacements. We do not offer lead acid batteries or chargers, but they are not hard to find.

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.

Hi I need help! I am building my own battery pack from old laptop batteries (18650’s). I bought the cheep $250 48v 1000w ebike conversion kit on ebay. I have many questions! It seems the perfect number of cells to connect in series are 13! This is a big problem for me because I am cheep and I already bought the Imax B6 battery balancer charger. I also bought 7x 6s balancer leads and 5x 4s leads. The Imax has a max charge voltage of 22.2v (so it sais in the manual), and a max balance of 6 cells at once. I also bought the parallel balance charging board. I don’t want to charge two or three packs at once to just have to turn around and charge one separately. So now I’m faced with the decision of making a 12 series battery or a 15 series battery (I will buy 5s leads in this case). The problem is with the 12 series battery the nominal voltage is only 43.2. Or a 15 series battery with a nominal voltage of 54. Which I’m pretty sure is a big no no because the controller is only meant to handle 48v within reason (13s max charge voltage of 53.3 and 12s 49.2 at 4.1 v per cell). But if I make it a 12s, running around most of the trip at 44v, will this drain the Amps faster because the motor wants 48v? I’m thinking no but just wanted some confirmation on that and if the controller can handle more volts. I could make a 15 series batter and just charge to 3.6 or 3.7 volts. Is this hard on the cells?

Another excellent answer, thanks so much! Now it has arisen a few related questions, if you don’t mind answering them. I’m using authentic Samsung ICR18650-26FM cells. I had already purchased a 24V 15A BMS before I slightly understood all of this. I was also able to obtain more cells since my original idea, so I was planning a 7S10P pack (around 30Ah), 70 cells total. I see each cell can do around 5A, making a 10P pack put out 50A total. If I stick with my 24V 15A BMS, that will give me 15A * 24V watts, or 360 watts total for my 500 watt motor. I’m going to number these to make it easier:

22f cells are quite low capacity and not very strong. They will work for an ebike (and are about the cheapest good quality cells out there) but they aren’t optimal. You’ll end up with a larger and heavier pack as compared to more energy dense cells like Panasonic 18650pf or Sanyo 18650ga cells. [redirect url=’’ sec=’7′]

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