DALY "Superior" BMS - the most simple, easy to use BMS we can find!
This listing is for the 52v, 14s BMS unit rated at 40 amps continuous discharge / 20a continuous charge rate. Full specs below. This BMS unit has a cell level cutoff voltage of 2.7v, which makes it suitable for cylindrical type 18650 and 21700 type cells with a 3.6-3.7v rated nominal voltage.
We only sell Daly brand BMS units because of their ongoing commitment to the providing the highest quality, most robust, most reliable and efficient BMS units currently available (outside of OEM battery production). After reviewing Daly's designs, reliability, capabilities, production capacity, and attention to detail, it's no wonder why we stopped using other types of BMS units, and now only stock Daly for both custom battery packs and repairs.
Sense wires are always included with purchase of the BMS unit.
To use this unit in a DIY battery:
1. Soldier the B- wire onto the nickel strips you're using to build the pack (thick + enough quantity of strips to carry >40a), then spot weld this onto the negative side of the battery pack.
2. Make the battery negative connection onto the P- wire. We usually use Anderson PP45 connectors.
3. Cut a short section of 10ga wire to the appropriate length to run from the positive side of the pack around to meet the negative P- connection, then put the positive battery connection on this wire. Then solder the other side to the nickel strips, and spot weld this onto the positive side of the pack. We usually use red, high flex, high strand count, high heat rated silicone cased wire for this part to match what's already coming out of the BMS unit.
4. Solder each sense wire onto a small section of nickel strip, then spot weld each of these onto the pack. Each red sense wire corresponds to the positive side of each series string, as shown in the diagram below. The last wire is black, which goes onto the negative side of the last cell group (where the B- wire is connected to the pack). Be careful when spot welding the sense wires onto the battery so that they are each on the correct cell, and that they don't have the potential to touch the negative side of the cell over time (you can fold the nickel strip back on top of itself to avoid any potential issues like that).
5. Carefully package the battery using heat shrink, or whatever else is available.
6. Mount this finished & packaged battery into a case of some kind. Empty Hailong style cases can be found online for under $100, or you can make your own battery case out of whatever material you want (wood, carbon fiber, fiberglass, polycarbonate, flax fiber composite, steel, etc).
7. Test this battery through a full discharge cycle to make sure it is functioning properly, not getting too hot, and giving the expected amount of amp hours. You can do this by riding your bike, from full charge all the way until it cuts off, if it is equipped with a Cycle Analyst. If not, then find another way to measure either the amp hours of the battery, or wh/mi of your bike, and do the same. We use the Grin Tech Battery Grinspector to do discharge tests on all the batteries that come into our shop, new and old, to compare the actual amp hour capacity of the battery to its original rated capacity. Another quality battery discharge test system is available from West Mountain Radio.
8. Congratulations, you've built your own battery. You probably saved some money, and ended up with a custom battery of exactly the right physical size to fit on your e-bike. If you ever have a problem with the battery, you'll know you can simply open it back up, and test the voltage using the sense wires and a multimeter to check if it's gone out of balance. Time to go for a ride! These BMS units allow for up to 20a max continuous charging rate, so make sure your battery cells are rated to be able to handle this amount of charge current.
9. This BMS unit can handle up to 20a input, so make sure the max regen amps + max solar input amps on your bike adds up to less than 20. If you build a second battery and run it in parallel, you can double this to 40a, and so on. We've done this with up to 4 batteries in parallel, which would give your bike a max discharge rate of 160a, and max charge rate of 80a, though you need to make sure you have adequate connectors and wires to carry this much current if you'll be doing it. Similarly, take care to limit each battery's continuous discharge to 40a. This is very easy to do if you happen to be using a Baserunner motor controller. If not, you can also limit the discharge power of your bike using a Cycle Analyst.
Note that if you completely discharge your battery, to the BMS cutoff, you need to 'force start' the Cycle Satiator charger by holding down the start button, otherwise it won't start charging. Most other chargers will probably just start charging right away. We recommend the Cycle Satiator - it's a good investment if you care about the health of your battery pack, and want it to last as long as possible. Plus it does multiple voltages, meaning you may never have to buy another charger ever again once you have a Satiator or two :).
Common Port vs Separate Port
We only stock the 'common port' BMS units, which means that both the charger AND load (motor controller) are connected to the same wires on the BMS. The other type of BMS is 'separate port,' which means the charger and load are connected to a different set of wires on the BMS. While very common on e-bikes, separate port BMS units do not always allow for simultaneous charge & discharge, which is required in any solar EV application; in other words, if you're building a solar e-bike, you want to use a common port BMS to ensure your solar power is going directly to the battery AND motor controller with no interruptions. This way, even if your battery dies, your solar array can actually still power the e-bike if you have enough power coming in from the sun! These common port BMS units are about as simple as it gets when it comes to BMS units, which helps keep battery as straightforward as possible.
Product Description (provided by the manufacturer)
3.7V Li-ion 14S 48V 20A 30A 40A 50A 60A 18650 PCM battery protection board BMS PCM with balanced lithium-ion lithium battery module Model: DL14S (3.7V rated Li-ION Battery not for 3.2V Rated LiFePO4) common Version : common port for charge/discharge separate Version : separate port for charge/discharge We can customize any PCB from 1S to 30S lithium batteries with different current. Highlight：For the same model, its charge current is less than discharge current because Daly PCBAs were updated to well protect customer battery. Any request, Please contact us. Daly: Jan 2020 1. Overview ◆DL14S48V20/30A/40A/50A/60A bms is used for 14 series 48V battery pack. ◆We can design it for various lithium batteries like LiFepo4, LiMn2O4, and Li-polymer etc. ◆The main functions are: over charge protection, over discharge protection, over current protection, short-circuit protection, temperature protection etc. ◆According to the customer request we can develop PCM in different sizes and structures. ◆BMS manufactured by high quality Mos and IC imported . Keep your battery long cycle serivce life time. 2. Advantage ◆Use top quality (A-level) protective integrated circuit IC, from the solution of Seiko of Japan. ◆Strong load ability, constant discharge current 20/30A/40A/50A/60A , use high voltage resistance, low inner resistance power Mosfet. The heat sink will greatly help cooling. ◆IC itself has power balancing function. The circuit is simple and reliable. ◆Typical voltage detection for each cell. So each battery will be prevented over charged or over discharged. Over current and short circuit protection function is very reliable.Long time short circuit of the load won’t affect the PCB and the battery.Temperature protection during charging and discharging. ◆Extreme low power consumption. The consumption of the whole device is less than 50uA. ◆PCB use high anti-corrosion, high water resistance, high impedance ESD conformal Coating.