Question about Daly Smart BMS 500A s4p4 12V « nominal capacity »

[EvilChuck]

Since October 2021, I have been running my homestead with a S4P2 configuration (8 x 3.2 cells @ 302Ah cells -> 12.8V @ 604Ah) managed by a Daly Smart BMS 500A Which has been running fine since its inception.Now, I just received my second « batch » of 8 x 3.2 cells @ 302Ah and wanted to add them to the original setup. The new cells are ready (Top balanced, etc…). The purpose of this upgrade is to gain autonomy, not to output more power; 500A is more than enough for my situation.

The question: when I go in the App (iOS), under « cells characteristics » (Loose translation -> I’m French Canadian), there is a field called « nominal capacity ». Right now, this is set at 604Ah. Obviously, my next move would to simply set it to 1208Ah and go on my merry way with my new-old cells. But… this field does not support more than 999Ah!

I don’t know if it’s a software bug, an omission or a hardware limitation (Which I highly doubt). Anybody out there having a similar issue? What is the REAL impact of not having the right value beside the fact it will probably screw up the main display (Odometer and such)?

For those who will mention the way to go would be to have a second BMS with my new pack and put both strings in parallel are right. It’s not a way I can go at this point in time as I would need to acquire a 2nd Daly Smart BMS (@500A ?) plus 2 Daly parallel kits + another smartshunt (Victron), etc… It’s a lot of $$$ I can’t afford.

 

[Damon YIP]

Since October 2021, I have been running my homestead with a S4P2 configuration (8 x 3.2 cells @ 302Ah cells -> 12.8V @ 604Ah) managed by a Daly Smart BMS 500A Which has been running fine since its inception.Now, I just received my second « batch » of 8 x 3.2 cells @ 302Ah and wanted to add them to the original setup. The new cells are ready (Top balanced, etc…). The purpose of this upgrade is to gain autonomy, not to output more power; 500A is more than enough for my situation.

The question: when I go in the App (iOS), under « cells characteristics » (Loose translation -> I’m French Canadian), there is a field called « nominal capacity ». Right now, this is set at 604Ah. Obviously, my next move would to simply set it to 1208Ah and go on my merry way with my new-old cells. But… this field does not support more than 999Ah!

I don’t know if it’s a software bug, an omission or a hardware limitation (Which I highly doubt). Anybody out there having a similar issue? What is the REAL impact of not having the right value beside the fact it will probably screw up the main display (Odometer and such)?

For those who will mention the way to go would be to have a second BMS with my new pack and put both strings in parallel are right. It’s not a way I can go at this point in time as I would need to acquire a 2nd Daly Smart BMS (@500A ?) plus 2 Daly parallel kits + another smartshunt (Victron), etc… It’s a lot of $$$ I can’t afford.

1.the norminal capacity only could set maximum 999AH, if you need set over 999Ah, need make customize
2.the norminal capacity not correct will lead to the SOC not correct, cause daly SOC calculation relates to capacity
3.As i know , your single pack capacity is 604Ah, and you will make 2 604Ah in parallel , total 1208Ah, i not suggest you use just one 12V 500A BMS for such a big bank, 100% you need the 2nd BMS to handle it.
I will not brag blindly that our 1 BMS can handle a 1208Ah pack. I highly recommend that you connect batteries in parallel and buy a second BMS

notice：if u have interest you could try our active balancer 5A，we will release it Next month 5th on Amazon and Aliexpress

 

[EvilChuck]

Thanks for the reply!

"...1.the norminal capacity only could set maximum 999AH, if you need set over 999Ah, need make customize"

-> You mean, ask Daly to make a customize "image" so 1208Ah would be supported? If possible, I highly doubt this would be done in a timely manner.

2.the norminal capacity not correct will lead to the SOC not correct, cause daly SOC calculation relates to capacity

-> I agree 100%. I was thinking about that last night... Everything would become "out of whack"

3.As i know , your single pack capacity is 604Ah, and you will make 2 604Ah in parallel , total 1208Ah, i not suggest you use just one 12V 500A BMS for such a big bank, 100% you need the 2nd BMS to handle it.

-> And there's the issue: if I go this way with Daly, assuming they have what it takes to work in a "paralleled" environment, it would mean 2 parallel units plus an additional BMS... That's a lot of "doe" not fully knowing if it WOULD work. They have a product (1A, 5A and 15A) but it's unclear of their compatibility with Smart BMS 500A 4S

I will not brag blindly that our 1 BMS can handle a 1208Ah pack. I highly recommend that you connect batteries in parallel and buy a second BMS

notice：if u have interest you could try our active balancer 5A，we will release it Next month 5th on Amazon and Aliexpress

Now, what or who is "our"? Are you aware of a BMS that will support 1208Ah (Or more) capacity while maintaining "control" over 400 to 500A output current range? I'd be more than interested knowing/learning about it. If it has a controllable active balancer, that would be great!

Regards

 

[littleharbor2]

You could add 4 more cells making a 906 ah, 3p4s, not p3s4, pack

 

[EvilChuck]

You could add 4 more cells making a 906 ah, 3p4s, not p3s4, pack

It's not like I"m on the verge of ordering the cells; I have them (Waited 2 months) fully charged and balanced (And waiting...). It's a homestead, so I need all the "juice" I can squeeze from each unit/cells in hands. 3PS4 is out of the question. What will I do with the rest (A full 12,8V pack and NO BMS)? Thanks but no thanks!

 

[littleharbor2]

It's not like I"m on the verge of ordering the cells; I have them (Waited 2 months) fully charged and balanced (And waiting...). It's a homestead, so I need all the "juice" I can squeeze from each unit/cells in hands. 3PS4 is out of the question. What will I do with the rest (A full 12,8V pack and NO BMS)? Thanks but no thanks!

Then buy another BMS and be done. It's not like you need to take out a loan for a 60 dollar BMS

Daly 12V 100A BMS - 4S LiFePO4- Bluetooth

What's Included Daly 12V 100A BMS 4S Bluetooth Module Built-in Protections Overcharging Overvoltage Unbalanced cells Temperature damage Over-discharging short circuits

www.18650batterystore.com

 

[EvilChuck]

Then buy another BMS and be done. It's not like you need to take out a loan for a 60 dollar BMS

Daly 12V 100A BMS - 4S LiFePO4- Bluetooth

What's Included Daly 12V 100A BMS 4S Bluetooth Module Built-in Protections Overcharging Overvoltage Unbalanced cells Temperature damage Over-discharging short circuits

www.18650batterystore.com

How would this work exactly for a 100A unit (In addition to 500A I've got)? I would imagine I'd run 2 x 608Ah packs (2 X S4P2) in parallel; one with the 100A and the other one with the 500A.

or I'd run with S4P3 (500A for nominal capacity 906AH) + S4P1 (100A for nominal capacity 302Ah). Again, in parallel.

In any case, don't they need to be aware of each other in order to behave properly? Will they dynamically adjust to one another through "natural" behavior?

Let's say I'm using option "A" (Both packs are of equal nominal capacity -> 604Ah each); if I draw a current of 300A, which pack will give what? Will it go all on the 500A? Will it be shared between the BMS's? In which proportion? Will the 100A one react and shutdown (Since 300A is > 100A)? Will this create an "unbalanced" situation where 1 pack is cut off (No current is drawn as BMS has shutdown) and the other one is being used for 300A? I would be worried that once the current drawn (300A -> 0A) is off and the 100A BMS has restarted, the only option for the pack (100A BMS) would try to recharge the second one (500A BMS) and "crash" again as the charging current would be a) over the 100A BMS limit and b) the

 

[littleharbor2]

I'm no expert but I was picturing 3s4p and 1s4p packs connected to bus bars, possibly with isolated charging for each individual battery pack. Maybe the guys who know better will chime in.

 

[EvilChuck]

and to complete ...

100A BMS has restarted, the only option for the pack (100A BMS) would be to try to recharge the second one (500A BMS) and "crash" again as the charging current would be over the 100A BMS limit and the cycle would repeat again.

The only option as I understand the situation is the need for a second 500A unit... which is not 60$.

I don't want to run as a standalone pack (S4P1 @ 302Ah) because I have no use for it.

 

[Damon YIP]

Thanks for the reply!


-> You mean, ask Daly to make a customize "image" so 1208Ah would be supported? If possible, I highly doubt this would be done in a timely manner.


-> I agree 100%. I was thinking about that last night... Everything would become "out of whack"



-> And there's the issue: if I go this way with Daly, assuming they have what it takes to work in a "paralleled" environment, it would mean 2 parallel units plus an additional BMS... That's a lot of "doe" not fully knowing if it WOULD work. They have a product (1A, 5A and 15A) but it's unclear of their compatibility with Smart BMS 500A 4S



Now, what or who is "our"? Are you aware of a BMS that will support 1208Ah (Or more) capacity while maintaining "control" over 400 to 500A output current range? I'd be more than interested knowing/learning about it. If it has a controllable active balancer, that would be great!

Regards

As Daly team ，
When your battery pack exceeds 100Ah, we recommend using 15A
our=Daly BMS
I do not recommend that you use a 4S 500A battery to connect with a 4S4P 1208Ah battery. Our 500A BMS limit is about 750A. The 1208Ah battery may generate a Spark current exceeding 750A. The probability of mosfet damage is very high.

 

[Damon YIP]

Thanks for the reply!


-> You mean, ask Daly to make a customize "image" so 1208Ah would be supported? If possible, I highly doubt this would be done in a timely manner.


-> I agree 100%. I was thinking about that last night... Everything would become "out of whack"



-> And there's the issue: if I go this way with Daly, assuming they have what it takes to work in a "paralleled" environment, it would mean 2 parallel units plus an additional BMS... That's a lot of "doe" not fully knowing if it WOULD work. They have a product (1A, 5A and 15A) but it's unclear of their compatibility with Smart BMS 500A 4S



Now, what or who is "our"? Are you aware of a BMS that will support 1208Ah (Or more) capacity while maintaining "control" over 400 to 500A output current range? I'd be more than interested knowing/learning about it. If it has a controllable active balancer, that would be great!

Regards

Also, if you use two sets of batteries in parallel, you don't need to customize the rated capacity setting of 1208Ah. You only need to set the rated capacity of 604Ah for each BMS and it will be ok, as long as the SOC calibration of each pack is correct, there will be no problem

 

[Scph9002]

1.the norminal capacity only could set maximum 999AH, if you need set over 999Ah, need make customize
2.the norminal capacity not correct will lead to the SOC not correct, cause daly SOC calculation relates to capacity
3.As i know , your single pack capacity is 604Ah, and you will make 2 604Ah in parallel , total 1208Ah, i not suggest you use just one 12V 500A BMS for such a big bank, 100% you need the 2nd BMS to handle it.
I will not brag blindly that our 1 BMS can handle a 1208Ah pack. I highly recommend that you connect batteries in parallel and buy a second BMS

notice：if u have interest you could try our active balancer 5A，we will release it Next month 5th on Amazon and Aliexpress

Even if daly bms could calculate soc properly that would be dumb.