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NiCd-Nickel Cadmium. This chemistry was half the size per a given power compared to SLA. But it has a low C-rate (Current producing capability) so anyone who made a pack out of them was restricted to low amps. There were no large packs for sale. E-bikers had to purchase rechargeable flashlight batteries and solder together a pack of a higher voltage, for which an off-the-shelf charger could be found to charge it up. Because of the low price of SLA chargers, 36V and 48V NiCd systems were common. When the price of nickel went up and the price of Lithium came down, NiCd died a quick death. Not even cordless drills use these anymore.

In the end, I opted for a DPDT+OFF rocker switch, as using diodes introduced forward voltage drop and this interfered with charging enough for me to have second thoughts. This arrangement does require that the BMS be “flashed” to initiate it, which can be done by the charger in charging mode but for discharging, I found that shorting the B- and the P- for less than a second initiated the BMS and it then latched itself on, so I installed a reset button. If I had used a DPDT switch without an off position then I would not have needed to do this. However, when the BMS hits a low voltage group e.g. going up a steep hill, it will not automatically reset when the voltage recovers, so you need to use the reset button if you want to get the last bit out of the battery. I’m toying http://electricbikebatterys.com latching this button when discharging, as the voltage drop knocks the controller out, so I think I’ll get a reaction like traction control, without having to manually reset the battery (which is annoying as it’s in a backpack).

Since you mentioned the charger, the link you sent me came with a 2 amp charger but it would take 10 hours to charge that size battery. Could I use a larger amp charger like 5 or even more for faster charging? How do you tell what is too much so you don’t damage the battery? Thanks!!


For any other case, lithium batteries’ advantages greatly outweigh SLAs. Of course, for your specific ebike you might have other reasons that could sway you either way. At the end of the day, your ebike is all about you. I hope this information helps you make the right choice for your own battery needs.

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.

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 long as you monitor your pack voltage so you don’t go too low during rides, then yes that would work. You’d simply run your discharge negative wire straight from the -1 terminal of your battery out to your controller, instead of from your -1 terminal to your BMS’s B- pad. But that removes the ability for the BMS to cut off the current when the voltage goes too low, so you’ve got to watch for that.

I would not recommend trying to use a 36V charger. The voltage will be way too high and damage either the charger, battery, BMS or all three. Always use a charger that is matched to your pack’s actual charge voltage, which in your case is 22.2V DC.

The figure that matters most when comparing how far a given battery pack will take you is not the amp-hour capacity but the total energy stored watt-hours. To make things more familiar, one watt-hour is one-thousandth of a kWh, the unit of energy used to measure household electrical usage. The watt-hours stored in a battery pack is approximated by taking the actual amp-hours and multiplying it by the pack voltage. [redirect url=’http://electricbikebatterys.com//bump’ sec=’7′]

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