bluetooth BMS?

csc said:
Thanks again

Do you confirm that it is possible to set custom balancing values, such as 4.11 balancing and 4.12 full charge ? I can't understand in the product description where that setting would be

On both of the smart BMS types talked about here, you can set the voltages.

24/32S smart BMS
24S%20param1%20page%202.png


24S%20param1%20page%201.png


13-20S smart BMS
16-20S%20smart%20BMS%2011.png


16-20S%20smart%20BMS%2012.png


16-20S%20smart%20BMS%208.png
 
Email me the links or zip files.
They both look newer than my apps.

Never did get bt working on pc.
 
This may seem like a dumb question, but can you use the larger 24S/32S boards with 14S battery pack? I saw that some of them are adjustable via software, but it looks like its still limited to 16S at a minimum.
Why is this a limitation and why cann't you run anything from 1S to the max of the board?

I'm looking at purchasing this BMS and it asks for how many batteries will be in series. Is there any difference between them? if I get a 14s, I could go upto a 15s?

Thanks.
 
Hi,
i have question for balancing current. I have 4s 80A BMS with bluetooth, but 50mA balance current is not too much. Chip is bq7692003, transistor for resistor SMD Y2, and bleeding resistor value 75ohm. I try 10ohm in paralel, slightly better, but still little. I would need to get around 1A, some ideas? Thank you
 

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at 1A you are bleeding off 4W of power on each activated resistor.

that is yuge amount of power for such a small pack. might i recommend fixing the pack and prehaps redistrubute the cells to the pack is naturally more balanced.
 
Pack in background is only test 12V battery (app 7Ah from defective assistant starting car box). Determining of BMS is 12V 100Ah LFP battery for boat motor. I carefully select the cells according to their capacity, the charging voltage is 3.5V/cell, discharging not exceed 3V. At the end of the charge, a higher balancing current is needed.
 
i would put in a second transitor instead of the resistor and use a external power resistor to bleed off if you have such a big pack. but seriously: why have such a kiddy bms for such a huge 12V pack?

basically with a 12V LFP battery you only need a balance board, not a full blown BMS of your cells are identical and from the same batch.

just get these: http://bestechpower.com/balanceboard/HCX-D162.html

add a big ass megafuse rated at triple the current the battery will ever see and be done.

you can still keep the bms connected (without the P- connected, just bypass the BMS for main load. if you want the bleutooth stuff.
 
zipoman said:
Hi,
i have question for balancing current. I have 4s 80A BMS with bluetooth, but 50mA balance current is not too much. Chip is bq7692003, transistor for resistor SMD Y2, and bleeding resistor value 75ohm. I try 10ohm in paralel, slightly better, but still little. I would need to get around 1A, some ideas? Thank you

Where did you find that? I can't find a 6s with bt.
 
I asked the seller for it and put it on the web.
https://www.aliexpress.com/item/4S-80A-smart-board-LiFePO4-BMS-PCM-PCB-battery-protection-board-for-4-Packs-18650-Battery/32858251761.html?spm=a2g0s.9042311.0.0.cgm0eP
 
Secular said:
This may seem like a dumb question, but can you use the larger 24S/32S boards with 14S battery pack? I saw that some of them are adjustable via software, but it looks like its still limited to 16S at a minimum.
Why is this a limitation and why cann't you run anything from 1S to the max of the board?

I'm looking at purchasing this BMS and it asks for how many batteries will be in series. Is there any difference between them? if I get a 14s, I could go upto a 15s?

Thanks.

Any BMS is going to have a minimum voltage needed to operate it. Smart BMS need to have some kind of on board power supply as well to power the CPU and other things that are central to the "smart" functionality. That power supply will have a voltage range that it operates within. Quite often these sorts of things define the minimum cell counts for a BMS. I have a BMS that is 20S. The design of the charge controller disables the mosfets if it can't detect 20 cells. The charge controller assumes it has a bad cell and does exactly what it was intended to do...protect the battery pack. You will run into this sort of thing.
 
flippy said:
basically with a 12V LFP battery you only need a balance board, not a full blown BMS of your cells are identical and from the same batch.

just get these: http://bestechpower.com/balanceboard/HCX-D162.html

Flippy...
Do you know how to set these modules? I've looked at them in the past and wanted to use them on LTO. Bestech doesn't openly support LTO and getting them to say "X product" can work at LTO voltages is virtually impossible.
 
ElectricGod said:
Secular said:
This may seem like a dumb question, but can you use the larger 24S/32S boards with 14S battery pack? I saw that some of them are adjustable via software, but it looks like its still limited to 16S at a minimum.
Why is this a limitation and why cann't you run anything from 1S to the max of the board?

I'm looking at purchasing this BMS and it asks for how many batteries will be in series. Is there any difference between them? if I get a 14s, I could go upto a 15s?

Thanks.

Any BMS is going to have a minimum voltage needed to operate it. Smart BMS need to have some kind of on board power supply as well to power the CPU and other things that are central to the "smart" functionality. That power supply will have a voltage range that it operates within. Quite often these sorts of things define the minimum cell counts for a BMS. I have a BMS that is 20S. The design of the charge controller disables the mosfets if it can't detect 20 cells. The charge controller assumes it has a bad cell and does exactly what it was intended to do...protect the battery pack. You will run into this sort of thing.

Thanks for explaining that. Looks like the 14s or the 15s selection from their website might be the range for that particular BMS.
 
ElectricGod said:
flippy said:
basically with a 12V LFP battery you only need a balance board, not a full blown BMS of your cells are identical and from the same batch.

just get these: http://bestechpower.com/balanceboard/HCX-D162.html

Flippy...
Do you know how to set these modules? I've looked at them in the past and wanted to use them on LTO. Bestech doesn't openly support LTO and getting them to say "X product" can work at LTO voltages is virtually impossible.
if you have a actual LTO battery (i would not understand why considering the size, weight and cost are usually worse then a lifepo4 or 18650 solution) you can replace the resistors on the back of the unit for different trigger values. i dont know if the transitors would trigger properly at 3V but bestech makes custom batches, you might be able to get them to make a dozen or so that trigger at 3V. if you spend that money on LTO cells a handful of those boards should not be that much of a issue.
 
flippy said:
ElectricGod said:
flippy said:
basically with a 12V LFP battery you only need a balance board, not a full blown BMS of your cells are identical and from the same batch.

just get these: http://bestechpower.com/balanceboard/HCX-D162.html

Flippy...
Do you know how to set these modules? I've looked at them in the past and wanted to use them on LTO. Bestech doesn't openly support LTO and getting them to say "X product" can work at LTO voltages is virtually impossible.
if you have a actual LTO battery (i would not understand why considering the size, weight and cost are usually worse then a lifepo4 or 18650 solution) you can replace the resistors on the back of the unit for different trigger values. i dont know if the transitors would trigger properly at 3V but bestech makes custom batches, you might be able to get them to make a dozen or so that trigger at 3V. if you spend that money on LTO cells a handful of those boards should not be that much of a issue.

You are right that they weigh more and are larger than pretty much any other lithium solution, but they have advantages too. Like any lithium battery, they don't tolerate over charging.

1. 10,000 charge cycles!!! If you charged every day, they would last something like 25+ years.
2. They tolerate being ran down dead flat with no harm. However, below about 1.95 volts they have spent their capacity.
3. VERY safe...virtually no possibility of going thermal.
4. Highly tolerant of low temperature...far better than LION.
5. I can get them super cheap! 11,000mah cells for $8.33 or less each...for new cells. I know they handle 30C without issues.
6. I already have 24 of them and will probably buy another 200+ soon.
7. You don't need a BMS since the only thing that matters is balancing and over voltage.

AKA..cheap resilient solution that will last longer than you will.
 
if you can get them basically free it is a nice fun project.

but lifespan is not really much of an arguement if a properly sized pack of 18650's and 4.05v top charge will last you several thousands of cycles and is half the size and a fraction of the weight i dont see the advantage in a mobile solution.
i have seen them used in buses and stuff that get charged every few stops or so but it is not a battery type anyone should invest in for their daily driver.

i think you can get bestech to make a LFP series if you ask nicely. you can either sell them with a balance board or use them yourself but if you get 200 you can probably get your own custom ones made.
 
flippy said:
i think you can get bestech to make a LFP series if you ask nicely. you can either sell them with a balance board or use them yourself but if you get 200 you can probably get your own custom ones made.

Perhaps a group buy for LTO balance boards? It may not be necessary though if the SuperCap boards work out well enough. Unless you want to downsize the board because they will have allot of wasted PCB space for mounting the actual caps.
 
themelon said:
flippy said:
i think you can get bestech to make a LFP series if you ask nicely. you can either sell them with a balance board or use them yourself but if you get 200 you can probably get your own custom ones made.

Perhaps a group buy for LTO balance boards? It may not be necessary though if the SuperCap boards work out well enough. Unless you want to downsize the board because they will have allot of wasted PCB space for mounting the actual caps.

That's my current solution...super cap boards.
 
flippy said:
if you can get them basically free it is a nice fun project.

but lifespan is not really much of an arguement if a properly sized pack of 18650's and 4.05v top charge will last you several thousands of cycles and is half the size and a fraction of the weight i dont see the advantage in a mobile solution.
i have seen them used in buses and stuff that get charged every few stops or so but it is not a battery type anyone should invest in for their daily driver.

i think you can get bestech to make a LFP series if you ask nicely. you can either sell them with a balance board or use them yourself but if you get 200 you can probably get your own custom ones made.

I'll post my LTO build in my battery build thread. It's not really relevant to this thread.
My excellent adventure through some battery builds: https://endless-sphere.com/forums/viewtopic.php?f=14&t=76013

LTO's at 10X the charge cycles of LION...that sounds like a really big argument for LTO IMHO. Admittedly by the time you run out of life in your LTO pack (20-30 years is a loooong time for technology!) there will be LOTS of new battery tech that just destroys anything we have today.

You are right about weight when you compare on capacity alone. Four 21700's in parallel have the same capacity of a single 11Ah LTO cell and do weigh a good bit less than the LTO cell. However to get 300 amps discharge, that's going to take quite a few MORE 21700's to deliver that much amperage. So depending on how you measure "apples to apples", then LTO can be the same weight or LESS and similar size as LION to get the same discharge rate. I think it has it's place. My next EV build will start out hybrid (LIPO and LTO), but later will go all LTO. IE: The proof will be in the pudding. At the price I'll pay for a couple hundred LTO's, that will be cheaper by 80% as compared to LION for way higher discharge rates and similar capacity. What's more, the LTO build will be far easier to do than any amount of cell welding could ever be.
 
ElectricGod said:
That's my current solution...super cap boards.

I just received a couple of them today not realizing that what I had ordered didn't actually have board space dedicated for mounting the caps. It has balance leads. So there is likely not much point, at least right now, in trying to get custom ones made. They do have a fair bit of open space but not enough for me to care about for my needs.
 
Slighty more ontopic:

If you want to keep the bms from cutting out the bluetooth you can, The bluetooth dies when there is no current flow. On itself that is fine for most people but i would like to see the bms settings when it is done charging the next morning without having to turn on the controller to wake it up again.
Right now i tried setting the sleep timer to 9999 and see if it sticks. That should be 7 days before it sleeps.
 
flippy said:
Slighty more ontopic:

If you want to keep the bms from cutting out the bluetooth you can, The bluetooth dies when there is no current flow. On itself that is fine for most people but i would like to see the bms settings when it is done charging the next morning without having to turn on the controller to wake it up again.
Right now i tried setting the sleep timer to 9999 and see if it sticks. That should be 7 days before it sleeps.

I noticed that too. My BMS turns off if it's just hooked up but not actively charging or discharging regularly. I had intended to mess with settings to get this behavior to either stop or extend beyond the 1 or 2 days I see right now. BTW...0 typically means off. If you are wanting week long on periods, then 999 ought to accomplish that, but I think if you want the sleep function disabled, that's probably 0.
 
themelon said:
ElectricGod said:
That's my current solution...super cap boards.

I just received a couple of them today not realizing that what I had ordered didn't actually have board space dedicated for mounting the caps. It has balance leads. So there is likely not much point, at least right now, in trying to get custom ones made. They do have a fair bit of open space but not enough for me to care about for my needs.

Let's move our LTO discussion to this thread. This is something of great interest to me and very few people know much about this battery tech.

https://endless-sphere.com/forums/viewtopic.php?f=14&t=91976
 
ElectricGod said:
Hey Circuit...
I have an idea for you. Your BMS is an all in one device. How about split out the power mosfets to a separate board and then make the balancing and monitoring boards stack-able. This allows your product to reach a far broader market (people like me!!!) where 16S is flat out a show stopper. The larger my pack is, the more it costs and the more I'm willing to pay for battery protection. At 16S, IMHO, I'm going to go with whatever is cheap for no other reason than the battery pack cost is not that great. IE: It's NOT compelling to spend a lot of money on a BMS that costs almost as much as my batteries do. With a stack-able board option and separate mosfet board, you can build 16S BMS all you want and then expand it to a 32S option that works at 20-32S. Add a third balance board and now you've reached 95% of the DIY market and probably a lot of the high end commercial builders too! The mosfet board can then be built in several options...such as 50, 100, 200, 300 amps. And of course build them to voltage requirements. The Chinese do this all day long. Why can't Western world BMS makers figure this out and then do it for a reasonable price?

This one looks interesting:

https://www.aliexpress.com/store/product/112S-200A-Lithium-Li-ion-LiFePO4-LTO-Lipo-Battery-Protection-Board-Extended-BMS-Balance-Bluetooth-APP/2856009_32862522313.html

Modular balance section, from 3s to 112s, mentions Bluetooth, separate power board. Not enough detail on the product listing page though. I'll contact the seller and probably order what appears to be the basic needed modules.


Another not quite as modular one:

https://www.aliexpress.com/store/product/112S-35S-Lithium-Li-ion-LiFePO4-LTO-Lipo-Battery-Protection-Board-BMS-Balance-Bluetooth-APP-7S/2856009_32861093603.html


And yet two more:

https://www.aliexpress.com/store/product/147S-Lithium-Li-ion-LiFePO4-LTO-Lipo-Battery-Protection-Board-200A-150A-100A-50A-BMS-Balance/2856009_32861352304.html
https://www.aliexpress.com/store/product/Cascading-High-Power-Smart-Protection-Board-Li-ion-Titanate-LiFePO4-Lithium-Battery-22S-24S-Cell-BMS/2856009_32856365318.html

I'm going to end up going broke today...
 
ElectricGod said:
I noticed that too. My BMS turns off if it's just hooked up but not actively charging or discharging regularly. I had intended to mess with settings to get this behavior to either stop or extend beyond the 1 or 2 days I see right now. BTW...0 typically means off. If you are wanting week long on periods, then 999 ought to accomplish that, but I think if you want the sleep function disabled, that's probably 0.

9999 does not work, came back after 8 hours and BT was off. 999 is only 16 hours. will mess around but 0 did not turn it off.
i will email them and ask if they can add the option.
 
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