Daly or other BMS for 14s 52V pack

Hi,

I am building a 14s8p pack using Samsung 25R cells capable of 160A max. 58.8V charged, 50.4 nominal, which is going to power a 750W hub motor set at 750W ~20AMPs at the controller, nothing crazy.

This is my first pack so I am trying to find a top quality BMS, something that's easy to work with, super reliable and has a bluetooth phone app.

I saw the Daly BMS but am having trouble picking the right one, all their 14s models seem to state 3.7volt model 14s 48V, they also show common and separate port. Why do these state 3.7v and 48v for 14s is that just a semantics and whats the different between the common and separate port models?

Is there a better bms out there, whats your goto BMS?

Been researching BMS products. I think Daly may have the largest BMS market share, but they are just rolling out their Bluetooth products. Two years ago I used one from here:

https://www.lithiumbatterypcb.com/

I was happy with the 72V 20S I bought. Still working just fine. I think they may have been the first Bluetooth BMS from China. Although it's really hard to tell who makes what. It uses the XiaoxiangBMS app. Defiantly different branding available for this one.

I just purchased a JK BMS to try out. See:

https://www.jkbms.com/products/active-balancer-bms/

The physical size is smaller than I imagined for a 150A BMS. Supposedly has Bluetooth built in on the board. Mine is still in the box. Might have more to say in a couple weeks.

I agree Bluetooth is really worth it, especially for the incremental cost. There are others with serial or CANbus interfaces, but those three are the only ones with smartphone BT interfaces I know of.

None I found were available in the US. That could change day to day though as stock levels change. The JK one was ordered about 12/23 and delivered 01/12.

Happy hunting.

I’ve built several battery packs with Daly bms’s. They are a great product. Just to be clear. You are building a 14s not a 13s?
Why go 8p to push only 20 amp? If it’s more range you want, I would go with a lower discharge battery with a higher capacity. 8 in parallel 25R can handle 160 amps constant.


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I see what you mean by AliExpress showing 14s as 48v. But if you go to the Daly store in AliExpress you will see all the specs and that the 14s is 52v.
I hear you can even customize your fully charged voltage and low cut off. I’ve never asked though.


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I'm using the ANT BMS, they are in my opionion better than the Daly, mainly because they have a much higher balancing current (200mA vs 30mA) and because they can work with any number of cells (you can buy a 24S and it will still work if you only use 12S, you are not stuck with the amount of cells you decided in the first place), which is not possible with the Daly. They are also a lot cheaper.
Downside is that they do not come with an enclosure and they are a bit more difficult to work with. The Daly sure looks nicer.

Cdub said:

I’ve built several battery packs with Daly bms’s. They are a great product. Just to be clear. You are building a 14s not a 13s?
Why go 8p to push only 20 amp? If it’s more range you want, I would go with a lower discharge battery with a higher capacity. 8 in parallel 25R can handle 160 amps constant.


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Click to expand...

Yes 14s 8p. It's going to power a bafang geared hub motor, which will get set at between 15-30amps at the controller so 750-1500w at 52v. So each 8p parallel set could provide more than enough current for my application. At least that's my logic. Thoughts?

Dui said:

I'm using the ANT BMS, they are in my opionion better than the Daly, mainly because they have a much higher balancing current (200mA vs 30mA) and because they can work with any number of cells (you can buy a 24S and it will still work if you only use 12S, you are not stuck with the amount of cells you decided in the first place), which is not possible with the Daly. They are also a lot cheaper.
Downside is that they do not come with an enclosure and they are a bit more difficult to work with. The Daly sure looks nicer.

Click to expand...

I’ve heard good things about the ANT BMS. Higher balance and current would be nice for quicker balance charging. I use Daly because they come in a nice sealed small package. I generally don’t break apart my battery packs once assembled and sealed.


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Blacksword said:

Cdub said:

I’ve built several battery packs with Daly bms’s. They are a great product. Just to be clear. You are building a 14s not a 13s?
Why go 8p to push only 20 amp? If it’s more range you want, I would go with a lower discharge battery with a higher capacity. 8 in parallel 25R can handle 160 amps constant.


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Click to expand...

Yes 14s 8p. It's going to power a bafang geared hub motor, which will get set at between 15-30amps at the controller so 750-1500w at 52v. So each 8p parallel set could provide more than enough current for my application. At least that's my logic. Thoughts?

Click to expand...

3p would be sufficient and having more in parallel will help to reduce voltage drop and battery life. 25r are happy at around 10amps per cell and of course rated for 20. But at 2500 mah rating per cell you could go with a higher capacity battery in a 4+ parallel configuration. (If you have not already purchased the Samsung 25r). 8p definitely leaves you room for expansion using that configuration. Possibly adding a front hub motor and make it two wheel drive!


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The JK BMS I mentioned above, has, depending on model, 600 mA to 2000 mA of balancing current based on spec. The version I will be evaluating has 1000 mA. Further, per the descriptions I've seen, this isn't merely shunted away. It uses capacitors (super?), to store energy from a high cell and then send it to a low cell. That said, I'm skeptical, to actually move 1A in real time using capacitors on a board no bigger, and priced competitively with the other BMS options seems far fetched. I'm not sure I will be able to prove or disprove the assertion.

I'm not going to "pre balance" the cells in the test build (by paralleling all), so hopefully can see some of the magic in action. May not help much, the 4 spare cells I'm presently capacity testing came out of the box with pretty equal SOC and capacity.

Balancing once you are out of "build" time and into "operate" time doesn't require lots of current. And if it does, there is probably an underlying problem somewhere. Can buy more time, but might not address the real issue. Once in balance, good packs stay in balance.

Question? Does ANT have a Bluetooth option?

Anyone following this thread, interested in the JK BMS, I posted some initial observations on the JK BMS here:

https://endless-sphere.com/forums/viewtopic.php?f=6&t=109768&p=1612321#p1612321

I still don’t see clear answer whether we can use 14S Daly BMS on 52V 14S battery packs. Main problem is that Daly BMS states on the cover 14S 48V. How can 14S be 48V?

I've noticed that too. Daly 13S Li-ion is labeled 48V correctly. Daly 14S Li-ion is also labeled 48V, however. Not 52V. I do have one, however, and it has all 15 balance wires you'd need.


I imagine it has all the same components as the 13S, like 63V max capacitors and 73V max FETs, for example, if those were the parts inside, and they just made minor modifications. As long as the HVC and LVC is per cell instead of per pack, they wouldn't even need to tweak voltage cut offs.

A lot of cheap manufacturers actually sell higher S BMS boards, then tell you to just wire multiple balance wires to the same cell at the end to use them on lower S count batteries for this reason. The last cell appears like multiple to the BMS, but it's irrelevant if it just has per cell voltage limits and doesn't do any balancing beyond top balancing burning off energy from cells that are too high instead of transferring energy.

The original post was a year old, and who knows what he chose.

I've bought what I thought were Daly BMS, but they were counterfeut, Daly being a popular brand and hence copied. One did not balance. Another did not BMS. It let three banks overcharge on a battery, Just be careful on aliexpress, and see who the seller is.

I would only purchase a Daly BMS through the Daly store on AliExpress

I have the LLT BT bms and works fine charging at 15.6amps on 20s6p 21700 cell. Any higher and the garage circuit will poop. Problem is many different apps some good some funky.
A BMS should not be in use much as a proper made pack should always be very close in balance with no good cells. ;
Blueseas Not balance before assembly ? What cells ?

Samsung 25r seam like a good choice for I.R. and price.

I only came on to modify a post I made previously. Can't find it so I will post here

* 15 pcs DALY 16S LifePO4 40A common mode

Everything was going great and then I had one failed to Short Circuit. The symptoms of that ::: it runs very hot under load and when it's powered down you can measure diode at its output wires instead of open circuit. Of course it does not stop you from discharging when the first cell hits lvc.

Classic mosfet failed to short condition, presents as crappy diode

I then had a second fail back to back when I started actually corner testing the units. They work just fine out of the box, but if you run them anywhere near continuous full power and test the features

Poof

So a Stern warning from over here -> if you haven't actually corner tested the features you expect to work then maybe you better do that. If you're not paying attention it will just let you discharge and charge all day long

* Run it hard
* Feel the case

If it's running hot you might be in trouble. I've got eight that I haven't even taken out of the bag yet. Two that are sitting here known blown. Five that are built and out in the field (ACK!)

So
You better test them

After they have failed you can clearly measure a diode between the black and blue 10 AWG wires on the output. A good one will of course read open circuit.

The diode shows anode facing away, so you can discharge right through that (and that's where the heat comes from)

Classic counterfeit or low quality mosfet

Probably like 63V parts for 58.4V application. Probably also shady and multiple ways

Very displeased

-methods

Methods what other Bluetooth BMS have you tested. As should I worry about my LLT BMS

No complaints about the Speedict Neptune 15 Bluetooth BMS. Been using it for over a year with zero issues.

https://www.speedict.com/product-page/neptune-15