Great job. Thanks for sharing with us. Just 2 minor corrections to prove I was watching carefully 🙂: This JBD BMS (and almost all BMSs) use thermistor (NTC) not thermocouple as you said, and YR1035+ (I have one) use 1kHz, not 10kHz AC voltage.
Hey Todd! I just wanted to tell you how extremely helpful this video has been for me with understanding my first battery build. I can’t tell you how many times I’ve watched this video lol. Seeing your battery builds and you describing all the details has helped me a lot in understanding all of this. I ordered the WELLGO busbars from Ken, the 1.0 mm for a 28s S 11P Pack. It’s a large battery for my first build but it’s for my Suzuki Rmz conversion. I have a couple of test videos on my channel with the bike but I was just using a 72 V battery for the testing. Can’t wait to see how the 28S battery performs! Anyways, I just wanted to tell you how helpful this video has been! If I was in the market of buying batteries, I would definitely give you the business but I always DIY everything lol Are you on endless sphere? You might be able to advertise your battery builds on the “New items for sale" section.
@@HOTPAXX Do you even need a bms on the battery if you have propper configuration on the motorcontroller realtive to the battery capacity and a suitable fuse between the battery and the controller and between the battery and the charger/bms (while charging)? Isnt it good enough to have the bms between the charger and the battery for balancing over night while charging?
You can run without BMS but eventually the voltages of your cell groups will get out of balance. You will also loose all the cell protections that BMS offers like over-discharge, over-charge, short circuit protection, over temp, ect... not sure why you would want to do that. A Quality BMS with proper current rating has become a standard for a reason - it works well.
@@HOTPAXX reducing weight and space on the bike. But the bike will charge then you connect to bms and balancer, so after the bike has charged up it will keep balancing for the rest of the night? Then your only left with the protection from over discharged, when the battery is powering the bike. But the settings in the vesc is supposed to be able to limit the discharge and a proper fuse can help too?
When using those busbars can i use just a normal spot welder to weld them to the batteries? Also im looking to make a 20s8p or maybe a 20s10p with molicel p42a, would this bus bars be sufficient?
FYI: WARNING For anyone using 26650's should be aware that ALL, regardless of brand, contain a 18650 battery inside the 26650 can. I do not know if this is true for the 21700 battery. I did not have any to open. The 26650 battery is Chinas biggest lithium scam ever. If someone wants to open a 21700 to see if they also contain a 18650 i would really like to know.
Counterfeit cells are not limited to a particular size. Battery capacity testers for $25 can verify cell ratings. www.aliexpress.us/item/3256804909652648.html
So I’m doing a build with Molicel cells 21700 P42A. Since I’m starting with new quality cells, do you think I should do a self discharge test, like fully charge each cell and check to see if they’re self discharges over Couple weeks? The problem is my battery pack is 360 cells so it would take forever and I’m just not sure if it’s necessary considering the quality of cells I’m using. I plan to check the IR of each cell for sure, but just not sure about the self dain test. Thanks for any input!
Likely those cells have been sitting for some time since they were charged by the manufacturer. my resistance tester also displays the voltage so I look at that while I am checking resistance. if the voltage on each cell is in line with the others, it is not self discharging. after this test if the cells are all very similar in voltage as I suspect they are, I would verify capacity on one or two cells and call it good. Sounds like a fun pack!
Do you consider problematic receiving new lithium ion cells at 3.44v? I received my new 21700 Samsung INR 40T3 4.000mA, 35A cells with 3.44v. Is that too low? I've builded an 2.8 kw 24s8p battery for an electric paramotor and has a huge voltage drop at 10-17kw full throttle and it should handle it like other similar batteries. I'm trying to find out why. Thanks.
Cells are shipped with partial charge so I would not be concerned with 3.44v. I would discharge test and confirm fully charge voltage and capacity. 17kw is 25A/cell and you will see a lot of sag. For less sag use more cells in parallel or lower resistance cells. 40T are good cells. I would check internal resistance at 1kHz AC and compare with data sheet. I can support this application with a custom built pack. hotpaxx@gmail.com for further support.
I'm upgrading my factory ebike battery from 2500mah 18650 to the same amount (40) of 5000mah 21700. I'm having to reuse the factory bms as it does a handshake with the bike to allow it to electrically connect. My question. I see you have the charge/discharge sense wires connected in a seeming order, does the bms know what order that is, or even care? does it matter what order they are connected, would it make a difference if they were different?
The balance leads have to be attached in the correct order. The BMS will look at voltage difference between each lead to determine the subgroup voltage and keep them in "balance". It will also disable charge/discharge if voltage is too high or low. they all have to be attached in the exact order you remove them. JBD states in there documentation to check with volt meter before plugging in harness as it can damage the BMS if connections are incorrect. more support can be found at hotpaxx@gmail.com.
How do the busbars connect the two different packs together or the two different cell walls? Since normally packs are folded with the nickel strip, was wondering, how do you connect this cell busbar, since it cannot be folded?
the pack is assembled like one long 20s pack. the busbar between cell strings 10 & 11 is folded and the connections insulated with fish paper and fiberboard to prevent shorts between adjacent busbars.
Ken sold me the bus bars and he said 0.5mm copper folds ok. for higher current applications with thicker bus bar, he offered a bolted connection at the fold.
Thermistor diode? thermocouple palladium wire heat makes voltage hold secondary magnetic valve and senses heat like a Sterling seeback peltier effect seeback can freeze from heat and make Electric
I am still rather skeptical of using nickel plated steel being used as a primary contact material. I've done some testing of pure nickel and then placing a pure copper bus bar under the nickel to simulate a battery that has pure nickel spot welded to the battery and then copper soldered to to the nickel. I'm only seeing a 25% decrease in resistance. For example using a 0.15mm thick x 8mm wide piece of nickel thats about an inch long I'm getting an AC IR reading of 1mΩ. Placing the copper bus bar below it (3mmx20mm) and measuring the at the same spot (the ends of the nickel strip) I'm getting an IR reading of 0.760mΩ So there is a benefit to including copper as it will be a lower resistance material for the electricity to travel through but the difference I think is minimal. Spot welding pure nickel would just make more sense. Those Sunkko units are garbage, there's no nice way of saying it, no one has ever had success meeting the specs of given by Sunkko without modifying the transfer with their own welding cable wrarps on the secondary winding. I'd love to see some IR readings of these packs compared to one that is just welded with nickel plated steel or pure nickel. I'd bet a pack welded with two layers of 0.15mmx8mm pure nickel would come very close to matching those custom bus bars with the nickel plated steel material attached to the cell.
Yes, these bus bars look good and the 0.5mm thick copper is better than I’ve seen on some much more powerful batteries, but I too wondered about the junction between the battery and the nickel and the nickel and the copper. Lets say you are using 21700s with a 45a rating (to make something that runs doe 6 minutes per charge lol), if you compare the best Nickel strips you can realistically spot weld vs these which clearly have less resistance in the copper portion. I think you need an optimum number of spot welds also to carry 45a continuous through that tiny pad. With 3 choices of copper thickness (0.3 mm, 0.5 mm, 1.0 mm), and cells in hexagonal holders, can the nickel portion even come close to feeding the 0.3mm copper sheet? When i made my LiFePO4 “erector set” battery, using 32650 cells with threaded terminals, i used 0.2mm thick copper sheet, but no need for nickel. Lol. Since the cells are wider I estimate each cell to cell series connection is is at least 5mm^2 which is super overkill for a 20s6p 30AH battery feeding a 30a controller. Lol Using basic math, the 0.5mm copper sheet 20mm wide is 10mm^2 per cell in parallel. That can carry 30 per cell (150a in 5p) all day, 24/7, in the Sahara. So we need a thermal imaging with 150a (bypassing the BMS) and see if it gets hot at any of the junctions. It definitely makes for a good looking battery.
@@imho7250 Heat generated is a function of resistance and length. Consider the short length of the nickel plated steel and the thermal conductivity of the copper. The heat generated is drawn and dissipated. I know a battery manufacture that mass produces 120a packs with this same hybrid busbar. 20s5p kit is now available at www.hotpaxx.com.
Great job. Thanks for sharing with us. Just 2 minor corrections to prove I was watching carefully 🙂:
This JBD BMS (and almost all BMSs) use thermistor (NTC) not thermocouple as you said, and YR1035+ (I have one) use 1kHz, not 10kHz AC voltage.
That corrections are accurate. Thank you.
Hey Todd! I just wanted to tell you how extremely helpful this video has been for me with understanding my first battery build. I can’t tell you how many times I’ve watched this video lol. Seeing your battery builds and you describing all the details has helped me a lot in understanding all of this. I ordered the WELLGO busbars from Ken, the 1.0 mm for a 28s S 11P Pack. It’s a large battery for my first build but it’s for my Suzuki Rmz conversion. I have a couple of test videos on my channel with the bike but I was just using a 72 V battery for the testing. Can’t wait to see how the 28S battery performs!
Anyways, I just wanted to tell you how helpful this video has been! If I was in the market of buying batteries, I would definitely give you the business but I always DIY everything lol
Are you on endless sphere? You might be able to advertise your battery builds on the “New items for sale" section.
Sounds like real nice pack ur putting together. Glad I could help. Thank u for the advertising tip!
@@HOTPAXX Do you even need a bms on the battery if you have propper configuration on the motorcontroller realtive to the battery capacity and a suitable fuse between the battery and the controller and between the battery and the charger/bms (while charging)? Isnt it good enough to have the bms between the charger and the battery for balancing over night while charging?
You can run without BMS but eventually the voltages of your cell groups will get out of balance. You will also loose all the cell protections that BMS offers like over-discharge, over-charge, short circuit protection, over temp, ect... not sure why you would want to do that. A Quality BMS with proper current rating has become a standard for a reason - it works well.
@@HOTPAXX reducing weight and space on the bike. But the bike will charge then you connect to bms and balancer, so after the bike has charged up it will keep balancing for the rest of the night? Then your only left with the protection from over discharged, when the battery is powering the bike. But the settings in the vesc is supposed to be able to limit the discharge and a proper fuse can help too?
When using those busbars can i use just a normal spot welder to weld them to the batteries? Also im looking to make a 20s8p or maybe a 20s10p with molicel p42a, would this bus bars be sufficient?
Can you make one of these for a csc city slicker?
FYI: WARNING For anyone using 26650's should be aware that ALL, regardless of brand, contain a 18650 battery inside the 26650 can. I do not know if this is true for the 21700 battery. I did not have any to open. The 26650 battery is Chinas biggest lithium scam ever. If someone wants to open a 21700 to see if they also contain a 18650 i would really like to know.
Counterfeit cells are not limited to a particular size. Battery capacity testers for $25 can verify cell ratings. www.aliexpress.us/item/3256804909652648.html
So I’m doing a build with Molicel cells 21700 P42A. Since I’m starting with new quality cells, do you think I should do a self discharge test, like fully charge each cell and check to see if they’re self discharges over Couple weeks? The problem is my battery pack is 360 cells so it would take forever and I’m just not sure if it’s necessary considering the quality of cells I’m using. I plan to check the IR of each cell for sure, but just not sure about the self dain test. Thanks for any input!
Likely those cells have been sitting for some time since they were charged by the manufacturer. my resistance tester also displays the voltage so I look at that while I am checking resistance. if the voltage on each cell is in line with the others, it is not self discharging. after this test if the cells are all very similar in voltage as I suspect they are, I would verify capacity on one or two cells and call it good. Sounds like a fun pack!
Do I need a bms wen I already v pmw/mppt
Do you consider problematic receiving new lithium ion cells at 3.44v? I received my new 21700 Samsung INR 40T3 4.000mA, 35A cells with 3.44v. Is that too low? I've builded an 2.8 kw 24s8p battery for an electric paramotor and has a huge voltage drop at 10-17kw full throttle and it should handle it like other similar batteries. I'm trying to find out why. Thanks.
Cells are shipped with partial charge so I would not be concerned with 3.44v. I would discharge test and confirm fully charge voltage and capacity. 17kw is 25A/cell and you will see a lot of sag. For less sag use more cells in parallel or lower resistance cells. 40T are good cells. I would check internal resistance at 1kHz AC and compare with data sheet. I can support this application with a custom built pack. hotpaxx@gmail.com for further support.
@@HOTPAXX Thank you!
I'm upgrading my factory ebike battery from 2500mah 18650 to the same amount (40) of 5000mah 21700.
I'm having to reuse the factory bms as it does a handshake with the bike to allow it to electrically connect.
My question. I see you have the charge/discharge sense wires connected in a seeming order, does the bms know what order that is, or even care? does it matter what order they are connected, would it make a difference if they were different?
The balance leads have to be attached in the correct order. The BMS will look at voltage difference between each lead to determine the subgroup voltage and keep them in "balance". It will also disable charge/discharge if voltage is too high or low. they all have to be attached in the exact order you remove them. JBD states in there documentation to check with volt meter before plugging in harness as it can damage the BMS if connections are incorrect. more support can be found at hotpaxx@gmail.com.
@@HOTPAXX Thanks for your prompt reply. I can figure that out and follow the original sequence. thanks
How do the busbars connect the two different packs together or the two different cell walls? Since normally packs are folded with the nickel strip, was wondering, how do you connect this cell busbar, since it cannot be folded?
the pack is assembled like one long 20s pack. the busbar between cell strings 10 & 11 is folded and the connections insulated with fish paper and fiberboard to prevent shorts between adjacent busbars.
Ken sold me the bus bars and he said 0.5mm copper folds ok. for higher current applications with thicker bus bar, he offered a bolted connection at the fold.
Ok good to know! Bolted might be my best bet since I will be using 1.0mm busbars. Thanks for the reply!
I’m looking for a battery for my bike could you give me a quote if you can make one for me. Thanks.
Quote requests to hotpaxx@gmail.com
Nice busbars, alibaba supplier?
I found Ken from Wellgo on Alibaba. He is a good applications engineer. His pricing on cell holders is nice too.
@@HOTPAXX they sell massive heatshrink sized tubing aswel? im still looking to wrap my 21s15p pack..
@@glenluyckx12 I use Shenzhen Passional Import & Export Co.,Ltd. They offer thick black matt up to 390mm roll width.
Thermistor diode? thermocouple palladium wire heat makes voltage hold secondary magnetic valve and senses heat like a Sterling seeback peltier effect seeback can freeze from heat and make Electric
Sold im buying one..
Is it dangerous to touch 72V?
good question. I did a video on that. th-cam.com/video/zGt5Dce1EwQ/w-d-xo.html
Do you make to sell? How much if you did sell 1
$550 free shipping and in stock. www.hotpaxx.com
How to diy charge 50 batteries?
Any module.
@@deone-entity3935 TP4056 modules are cheap. Get the slightly larger ones that have the protection circuit built in
@@ericklein5097ip2312 is 3A.
Are you selling these?
I sell a similar product with Lishen LR2170LA cells. WWW.HOTPAXX.COM
I am still rather skeptical of using nickel plated steel being used as a primary contact material. I've done some testing of pure nickel and then placing a pure copper bus bar under the nickel to simulate a battery that has pure nickel spot welded to the battery and then copper soldered to to the nickel. I'm only seeing a 25% decrease in resistance. For example using a 0.15mm thick x 8mm wide piece of nickel thats about an inch long I'm getting an AC IR reading of 1mΩ. Placing the copper bus bar below it (3mmx20mm) and measuring the at the same spot (the ends of the nickel strip) I'm getting an IR reading of 0.760mΩ
So there is a benefit to including copper as it will be a lower resistance material for the electricity to travel through but the difference I think is minimal. Spot welding pure nickel would just make more sense. Those Sunkko units are garbage, there's no nice way of saying it, no one has ever had success meeting the specs of given by Sunkko without modifying the transfer with their own welding cable wrarps on the secondary winding.
I'd love to see some IR readings of these packs compared to one that is just welded with nickel plated steel or pure nickel. I'd bet a pack welded with two layers of 0.15mmx8mm pure nickel would come very close to matching those custom bus bars with the nickel plated steel material attached to the cell.
It would be interesting to compare packs. on paper, copper outperforms pure nickel by a factor of 4. copper 1.68x10^-8 Ω*m, Nickel 6.99x10^-8 Ω*m.
Yes, these bus bars look good and the 0.5mm thick copper is better than I’ve seen on some much more powerful batteries, but I too wondered about the junction between the battery and the nickel and the nickel and the copper.
Lets say you are using 21700s with a 45a rating (to make something that runs doe 6 minutes per charge lol), if you compare the best Nickel strips you can realistically spot weld vs these which clearly have less resistance in the copper portion.
I think you need an optimum number of spot welds also to carry 45a continuous through that tiny pad.
With 3 choices of copper thickness (0.3 mm, 0.5 mm, 1.0 mm), and cells in hexagonal holders, can the nickel portion even come close to feeding the 0.3mm copper sheet?
When i made my LiFePO4 “erector set” battery, using 32650 cells with threaded terminals, i used 0.2mm thick copper sheet, but no need for nickel. Lol. Since the cells are wider I estimate each cell to cell series connection is is at least 5mm^2 which is super overkill for a 20s6p 30AH battery feeding a 30a controller. Lol
Using basic math, the 0.5mm copper sheet 20mm wide is 10mm^2 per cell in parallel. That can carry 30 per cell (150a in 5p) all day, 24/7, in the Sahara.
So we need a thermal imaging with 150a (bypassing the BMS) and see if it gets hot at any of the junctions.
It definitely makes for a good looking battery.
@@imho7250 Heat generated is a function of resistance and length. Consider the short length of the nickel plated steel and the thermal conductivity of the copper. The heat generated is drawn and dissipated. I know a battery manufacture that mass produces 120a packs with this same hybrid busbar. 20s5p kit is now available at www.hotpaxx.com.
👍👍
How much
www.hotpaxx.com
I was wondering would you make me a 72 vt 50 amp battery, with 150 discharge rate?
Sell me some batteries ???