bluetooth BMS?

[john61ct]

it is heated at low temps with 2 x 30W PTC heaters that kick in at 0c and 5c respectively

Personally I would only use those for after the vehicle has been sitting unattended in the cold in "storage mode".

Other heat sources - the ones keeping your living space warm - should be maintaining the bank temperature while the rig is in use / occupied.

 

[Cowardlyduck]

With such big cells, balancing will take a long time. Let us know how it goes, or do you have a thread for this project?

No didn't bother with this one, although I've posted a fair bit on the DIY powerwalls facebook page:
https://www.facebook.com/groups/diypowerwalls/

Personally I would only use those for after the vehicle has been sitting unattended in the cold in "storage mode".
Other heat sources - the ones keeping your living space warm - should be maintaining the bank temperature while the rig is in use / occupied.

Agree, but this is not for a vehicle. This is for a Powerwall mounted to the outside of my house.
Realistically the temps won't get cold enough for long enough to be of huge concern where I live.

I'm also still learning about how my inverter works, but I think it will charge the battery if it detects the voltage dropping below it's configured LVC so I may not need to worry about a buffer for heating anyway.

Cheers

 

[john61ct]

Just know that you have to watch your C-rate charging, if you might get over 0.4C

you need to throttle it way down, say below 0.1C as temps drop from 25°C down to freezing, and do not charge at all below that.

 

[Hertzelz]

Hey guys,
so I decided to ditch the LLT 200A bms for ANT 400A (the ANT is 40% of the LLT's size btw) because of the ancient android app (the 200A version has different app, not xiaoxiang that is fine),



HOW THE HECK do I connect the LCD? Please see pic of what i got:
https://imgur.com/a/9Xn12ET

A. there's 2 red/black wires with large connector (the only place left for it is in the LCD)
B. there's 2 red/black naked wires connected to a 4pin connector
C. there's 4 'naked' wires - black/red/green/yellow connected to 4pin connector.

if you see cable lugs - I've crimped them, originally the wires came without lugs.


I'd love to hear from your experience, the seller's response was:
"LCD display , DC24V-150V you can use 4p wire to connect bms and lcd display red to red, black to green, yellow to yellow, green to black"

- Which caused me even more WTF....

 

[nicsal]

Very, very interesting thread.

Actually, I just bought one of those BMS 2 days ago, without even knowing they were already discussed here. Pretty happy to see that apparently that wasn't too bad of a choice.

I've purchased the 300A model, for my LiFePO4 23S 2P (72V 40AH) A123 pouch cells battery pack.
This one:
https://item.taobao.com/item.htm?spm=a230r.1.14.147.63171b15jsMHbW&id=554867081787&ns=1&abbucket=6#detail

I think the wiring and configuration should be pretty straight forward, but there is only one thing that I'm not sure of yet:

My plan is to use two of these batteries in parrallel, for a total of 80AH. So I'll need 2 of these BMS in the end. The thing I'm worrying about is the bluetooth: will it work fine if I have two BMS working at the same time? Is the app able to switch from one BMS to another? Can I change the bluetooth device name in order to know which BMS is which? Also, is is possible to change the password for something slightly more secure than 1234?

Any relevant information regarding this particular matter would be greatly appreciated.

Why do you think you need 2 BMS? What's your max current draw? If it's less than 300 amps, then 1 BMS will work. If I'm running LIPO. I like to have each string of packs on their own BMS if I'm using dumb BMS. With smart BMS, I no longer care as much. There's no reason why you can't run from a single BMS if you are running at less than 300 amps. Since you are running LIFE (meh), I see no reason for dual BMS.

I have probably 10 smart BMS. The little 16-20 smart BMS talked about here so much don''t let you name them. My best option is to record the MAC addresses for all of them and that's how I keep track of which one is which. I also label the BMS with the MAC address. For these better 24 and 32S BMS, that's not a problem...name them as you see fit. REgardless of BMS type, connecting and disconnecting from one to connect to another is straight forward and easy. The 16-20S BMS don't even need a password to connect...talk about NOT secure!

There's an option in the phone app that lets you name the BMS something meaningful to you...such as BMS1 o24S100AH. The default name is BMS-ANT. The "Modify BT ADDR" is the option for this. And yes to changing the password.

Hey,

i have two bms but these have the same Mac address how can i change it, the only button i see is: chance macadd but it does nothing.

can someone walk me with this.
thx

 

[Cowardlyduck]

Just know that you have to watch your C-rate charging, if you might get over 0.4C

you need to throttle it way down, say below 0.1C as temps drop from 25°C down to freezing, and do not charge at all below that.

Thanks for this advice.
Unfortunately I can't really control the charge rate that specifically with my inverter. It's a fixed value and I would be crippling it to set it too low to compensate for cold weather. 0.5C is 60A, but I found the cells get a bit warm at that rate so might drop it to 50A. If I set the BMS charge temp cutoff to 4C that will at least let the heaters try and warm it up before charging starts, but that's the best I can do really.

Cheers

 

[j bjork]

Hey guys,
so I decided to ditch the LLT 200A bms for ANT 400A (the ANT is 40% of the LLT's size btw) because of the ancient android app (the 200A version has different app, not xiaoxiang that is fine),



HOW THE HECK do I connect the LCD? Please see pic of what i got:
https://imgur.com/a/9Xn12ET

A. there's 2 red/black wires with large connector (the only place left for it is in the LCD)
B. there's 2 red/black naked wires connected to a 4pin connector
C. there's 4 'naked' wires - black/red/green/yellow connected to 4pin connector.

if you see cable lugs - I've crimped them, originally the wires came without lugs.


I'd love to hear from your experience, the seller's response was:
"LCD display , DC24V-150V you can use 4p wire to connect bms and lcd display red to red, black to green, yellow to yellow, green to black"

- Which caused me even more WTF....

To the display there should be one small connector with a black and a red wire. Those are for powering the display with 24-150v or something like that.There should also be a small connector with 4 wires I think, green, yellow red and black or something like that.

I don't have the same bms, but for my 300A 24s there was a connector with the same color wires to connect those 4 to.
I think the big connector with just 2 wires are for turning on and off the bms with a button, that is how it was on mine.

 

[patrickza]

I'm just about to connect up my bluetooth BMS finally. One question though. I bought the 24s 100A board, so I would have expected to have 25 balance leads, one for the most negative and going positive through all of them, only thing is my BMS clearly has slots for 26 cables (pictures attached). Any ideas?

Is there a guide somewhere on how to connect these?

Thanks.

 

[serious_sam]

I would have expected to have 25 balance leads, one for the most negative and going positive through all of them....Is there a guide somewhere on how to connect these?

Correct. 25 connections for 24S. There's no definitive wiring guide that I've seen. Only many various images shown mostly on AliExpress pages.

Do you have the cables? Are there 25 or 26 wires ?

Alternatively, you could disassemble it so you can see the traces on the PCB, and that should give you a good idea of which terminals connect to where.

 

[john61ct]

Do not buy a BMS until the seller has provided a satisfactory level of support.

 

[serious_sam]

Do not buy a BMS until the seller has provided a satisfactory level of support.

Conversely, why pay the extra cost associated with a "seller supported" product, when we can share our free help and support with like-minded people on forums like this. In effect, providing product support. Boom. Mind blown.

 

[amberwolf]

However, if "seller support" includes providing information or software updates that only they can provide, that no one on the forum has, then it's kinda necessary.


Similarly, if "seller support" means warranty repair / replacement, that's also not something the forum can provide. (sure, troubleshooting help, reverse engineering, etc., migth be possible, but not at no cost like a warranty should be, and some or all of which is beyond at least some, possibly many, people that come here for help, for various reasons).

 

[john61ct]

A detailed wiring diagram of that specific model sold has to be the lowest possible bar.

Let's not let them **completely** off the hooks fer crissakes, don't even need a paper, just include a link in your "thanks been shipped out email"

 

[Cowardlyduck]

They are mostly the same pin-out aren't they?
For example, I've wired several up recently like this:

If you can't get the info, I suggest trying similar to above.

Cheers

 

[serious_sam]

However, if "seller support" includes providing information or software updates that only they can provide, that no one on the forum has, then it's kinda necessary.

This thread is 60 pages of support for these BMSs, including diagrams, apps, and software. Please consider John's comment in that context.

Similarly, if "seller support" means warranty repair / replacement, that's also not something the forum can provide. (sure, troubleshooting help, reverse engineering, etc., migth be possible, but not at no cost like a warranty should be, and some or all of which is beyond at least some, possibly many, people that come here for help, for various reasons).

Again, in the context of this thread/product, nobody buys these things from China with the expectation of returning for repairs or replacement.

People who buy these things want the lowest price, and there is an expectation that some kind of effort will be required to get it working. This thread is a prime example of how a community can provide the support required to make a product like this worthwhile for DIYers.

Bullshit comments like

Do not buy a BMS until the seller has provided a satisfactory level of support.

doesn't help anyone here.

 

[john61ct]

Sorry but I stand by it.

There are hundreds of vendors to choose from, some vetting does not need to mean paying much more.

And buying solely on price is stupid, guaranteed to only get junk that way.

Of course others feel differently, each can do as they like.

 

[patrickza]

Thank u eee291, making progress on this and feeling better about it.
I was also able to contact the seller and they were great and got me the English manual. I have posted a link below to the English manual for what I am calling the
ANT Protection board BMS 8s to 24s.
https://drive.google.com/file/d/1sql94GNH3AtWwd917gn5goxNLKm_RiSE/view?usp=drivesdk
Manual pretty much answers my wiring questions.
To help other novices like me in the future:
The reason there are 26 total JST pins for a Max 24s BMS is because:
The pins go from far RIGHT to far LEFT. The first negative starts on the far RIGHT, then go 24 left for each of your battery connections (making 25 pins so far). Then the last pin is another wire from your last plus connection on the last cell of the battery to the last pin (making 26pins). This last pin on far left is for power to the BMS. So your actual power for the BMS goes to the last pin on the leftmost JST connector therefore making 26 total pins correct.
So, it seems this BMS is able to accept a variable input power supply from your battery. From the minimum of 8s to the maximum of 24s cause the voltage you supply will be what the voltage is on your last plus on the last cell of your battery.
Couple other points just for documenting here:
Manual says it takes 18V minimum to get this BMS going. So u would need to apply 18V minimum to the last JST pin (far left pin) to get this BMS to turn on. Your negative would be on the first JST pin (the far right pin).
Also, the manual says it comes with an on/off switch. Awesome sauce!

Thanks for all the advice everyone. I also did some digging in this thread and luckily MikeBike answered the question as to why there are 26 leads for a 24s BMS. Everything is hooked up and seems to be working.

I do have one issue though. If I close my circuit breaker on the positive power cable while charging, the BMS will charge, but the first time it stops due to a high cell voltage it won't restart and gives me a PrechargeFailure message on the screen. Any ideas?

 

[j bjork]

Well, it seems to happen when the caps in the controller takes too much amps to charge up.
You can set the pre charge to 60A and hope it is enough. It works for me almost all the time. A few times I had to turn on the bms first with the app, then the positive solenoids.

 

[john61ct]

Link to the post with that answer?

 

[patrickza]

This one: https://endless-sphere.com/forums/viewtopic.php?f=14&t=88676&start=700#p1408399

 

[john61ct]

Thanks

this topic really needs a Wiki somewhere

 

[serious_sam]

Link to the post with that answer?

Click that little arrow.

 

[j bjork]

My ant bms broke when I turned it on at last ride:

I took it apart to get a closer look at what is going on.

It looks ok at first glance, but when I measure the discharge fets are shorted.
It looks like all of them are driven from the same source, with just an individual resistor to each mosfet.
I measured to each mosfet, all of them seems ok

When I took a closer look I think I see the broken one:

The solder on the middle one in the picture seems to have melted.

Both charge and discharge mosfets are the same.
What I would like to do is unsolder all of them, solder on a 1mm copper plate on the board and use that to get P-.
Then solder back 12 discharge mosfets and maybe 6-10 charge mosfets on the copper plate. Then the charge mosfets will only be for charging, all discharging will only be trough the discharge mosfets.

But I am not sure if I can do that without damaging the mosfets?
Would it work to just hold a hot soldering iron to the metal part of the mosfets that sticks out, and lift off the mosfet with pliers when the solder melts?

 

[multifrag]

My ant bms broke when I turned it on at last ride:

I took it apart to get a closer look at what is going on.


It looks ok at first glance, but when I measure the discharge fets are shorted.
It looks like all of them are driven from the same source, with just an individual resistor to each mosfet.
I measured to each mosfet, all of them seems ok

When I took a closer look I think I see the broken one:


The solder on the middle one in the picture seems to have melted.


Both charge and discharge mosfets are the same.
What I would like to do is unsolder all of them, solder on a 1mm copper plate on the board and use that to get P-.
Then solder back 12 discharge mosfets and maybe 6-10 charge mosfets on the copper plate. Then the charge mosfets will only be for charging, all discharging will only be trough the discharge mosfets.

But I am not sure if I can do that without damaging the mosfets?
Would it work to just hold a hot soldering iron to the metal part of the mosfets that sticks out, and lift off the mosfet with pliers when the solder melts?

Last time when I was desoldering my bms mosfets it was impossible to do with out hot air rework station. Even with hot air I still used a soldering iron as the pcb acted like a big heatsink...

 

[serious_sam]

But I am not sure if I can do that without damaging the mosfets?
Would it work to just hold a hot soldering iron to the metal part of the mosfets that sticks out, and lift off the mosfet with pliers when the solder melts?

Yep. I used an 80W iron. Before you resolder new mosfets, it helps to "tin" the back of them with solder before putting them down to solder back to the board.

If all the mosfets are blown, there's a chance that other components on the board are too...