How to wire a second 4S BMS to my 12V system in parallel

[harbin1234]

I will say again, you don't need a new BMS, the cells are not that badly out of balance. The suggestions about rearranging cells is fine in theory, but may not give any significant improvement.



This I don't understand . You have 4 cells pairs. If the buss bars are making good contact then the cell pairs are at the same voltage. You only have 4 voltages to measure. If on the other hand you are removing the buss bars and measuring each cell , then there could be different voltages. Because under normal operation the BMS 'sees' a cell pair it attempts to balance 4 'big' cells.

I'm just measuring as it is connected, I hate to loosen and retighten these small 6mm nuts. There is great a chance I would stripp a bolts or stud or whatever they are called.
All my connections are tight, I just recheck them yesterday.
Thank you for your reply, I suppose I need not worry since when I run a lot of amps, none of my bus bars or terminals get warm/hot.

 

[MisterSandals]

I have had this issue with the same cells being a little more charged than the other five for awhile.

Oh, this is an existing setup. If you small voltage difference is your only issue i would not change anything, especially if not hitting and BMS limits/disconnects.

Are you able to run this setup without hitting a BMS limit/disconnect?

 

[harbin1234]

Oh, this is an existing setup. If you small voltage difference is your only issue i would not change anything, especially if not hitting and BMS limits/disconnects.

Are you able to run this setup without hitting a BMS limit/disconnect?

Yes, all day long. I guess if the BMS disconnects, I'd lose power?
I have never lose power to my 5th wheel with the new inverter.

 

[MisterSandals]

I guess if the BMS disconnects, I'd lose power?

It is possible that the charging is disabled by the BMS while leaving the loads/discharge intact.

If its working, i don't think you should fix it!

 

[harbin1234]

It is possible that the charging is disabled by the BMS while leaving the loads/discharge intact.

If its working, i don't think you should fix it!

The Daly toggle switch for charging in the smart app. is always off. I don't know how to turn on.

 

[MisterSandals]

The Daly toggle switch for charging in the smart app. is always off. I don't know how to turn on.

Can you post a couple screen shots of your smart app?
I find it easier to add them to a message with a browser on your phone.

Odd that it shows charging off and you can presumably charge thru your BMS?

 

[harbin1234]

My Charge MOS and Discharge MOS is green or on.
What I meant was the far right of those 2 setting is a toggle for Balance charging.
I can not figure out how to turn that on if it is possible..
Plus, me and my 10 year old smartphone Hate Each Other. I don't know how to do a screenshot. LOL

 

[MisterSandals]

Can you get to the "Active Balance" screen?

Pic:

Balancing

Are my cells balanced good enough? Or do i need to balance them more This is my first battery build

diysolarforum.com

 

[harbin1234]

Can you get to the "Active Balance" screen?

Pic:

Balancing

Are my cells balanced good enough? Or do i need to balance them more This is my first battery build

diysolarforum.com

I can when I go out and log onto the app. But I have no idea od how to make a picture or screenshot and save it.
Let me log into the app and click on the Balance charge screen and write down the setting, actually there are no setting set.

 

[MisterSandals]

But I have no idea od how to make a picture or screenshot and save it.

What phone do you have? iPhone? Android?

 

[MisterSandals]

Take a screenshot - Apple Support

Use Markup to draw on your screenshots.

support.apple.com

 

[harbin1234]

What phone do you have? iPhone? Android?

I have an Android.
Here is the contents of the page.
I tap the tab that says: Active Balance.
Then I get.
Balance Status: Off
Balance Current: 0.0A
Position: 0
Below the above is where I can set the Parameters.
Balance Parameter Setting
Balance Current: 0.0A
Battery Strings: 0
dischg High Temp: 70C
dischg Low Temp: -40
Sleep Waiting Time: 3600S
Balance Open diff volt: 0.05v
Balance Open Start volt: 3.34
Cell Volt High protect: 3.65
Cell Volt Low protect: 2.20

Balance Switch: Off

 

[MisterSandals]

Raise the balance current to 2.0A
Battery strings: 4

 

[harbin1234]

Take a screenshot - Apple Support

Use Markup to draw on your screenshots.

support.apple.com

I google and I tried.

 

[harbin1234]

Raise the balance current to 2.0A
Battery strings: 4

It didn't take either setting. It says device timed out or entry invalid, Please reset.
I don't understand why it won't even take the Strings setting.

 

[harbin1234]

Raise the balance current to 2.0A
Battery strings: 4

I just tries a factory reset and that is not available.

 

[harbin1234]

Raise the balance current to 2.0A
Battery strings: 4

I really, really do appreciate you trying to help. I can not find and answers on google.
But at least I guess I don't need a second BMS.
NEEY balancers need a power supply and don't really do 4S.
JK does not make Balancers at all, just a 120 amp smart bms with balancing included.

 

[Samsonite801]

It didn't take either setting. It says device timed out or entry invalid, Please reset.
I don't understand why it won't even take the Strings setting.

Yeah I had these same issues with my friend's Daly BMSs, the phone app is limited in what it will let you change. There are multiple threads here and on other forums talking about what settings to change to get the balancing threshold to occur across a wider window, but you must get the USB-to-UART cable and use a Windows laptop, and there are two Windows programs you can try to use.

The first program is called 'PC Software-2.1.8' and the second program is called 'Sinowealth'. You need the Daly USB-to-UART cable to plug the PC (probably a laptop most likely) into the Daly BMS (we found one on eBay anyways).

PC Software-2.1.8:

Download-PC Software - Daly Electronics Co., Ltd.

CAN Driver DOWNLOAD PC Software for Indian new norms DOWNLOAD PC Software-2.1.8 DOWNLOAD Home Storage Software-1.4.4 DOWNLOAD

www.dalybms.com

Sinowealth:

Daly Sinowealth software

Ive uploaded the Daly Sinowealth tool (used for 3s-4s BMS). The Daly supplied USB-UART cable also needs a "CH340" driver which is also included. Some instructions on how to use it are here...

diysolarforum.com

Some of the Daly models must use the one program, and some of the Daly models must use the other program (same cable).

The thing about the limited function phone app, is that the Active Balancer tab doesn't work on most Daly BMS (ones that don't support active balancing). Most Daly BMSs only have passive balancing, and so that tab won't work for passive balancer Daly BMSs.


Here are some related threads talking about how to get your Daly BMSs to actually balance (what settings to set via the USB-to-UART cable):

Convincing your Daly smart BMS to balance your battery

I have 3 Daly smart BMS with Bluetooth a couple of 100A and one 150A. I am experimenting with various 1P4S or 2P4S 100AH lifepo4 batteries of assorted quality. So I am stuck with the Daly. Apologies for the convoluted lengthy post, but I thought maybe some DALY expert can provide a clearer...

diysolarforum.com

Daly BMS - how does it start balancing

Specs for my 16S Daly says it will balance at cell voltage of 3.50 V. The question is will it start balancing when the first cell hits 3.50 V or must all cells be above 3.50V ? What happens when 8 cells are at 3.60V and 8 and 3.49 V for example will it start balancing?

diysolarforum.com

Daly BMS Will Not Balance

We have a couple of cheap LiFePO4 100Ah drop-in batteries (brand not important) here in the shop that feautre a Daly BMS. When ever we fire up a charge source the immediately trip the BMS on High Voltage. OK, no problem we've seen this before with elcheapo LFP drop-in batteries. We usually open...

diysolarforum.com

Why doesn't my daly smart bms start balancing?

I've got a 4s lishen 280ah bank with a daly 250a smart bms in my van. I did a proper top balance before starting using it a few weeks ago. Seems like the cells since then have drifted a bit, especially cell 1 seems to have higher capacity than the other. This leads to sometimes hitting high...

diysolarforum.com

The issue I had is that I couldn't get the one program which had shown the settings I needed to change, I couldn't get that program to write changes. Then other program, I could get it to write changes (of available parameters) to BMS, but it did not display those parameters I had needed to change in that program, so I could not make those suggested changes. So I gave up, starting to wonder if the Daly BMSs my friend purchased were real Daly or perhaps Daly clones.

 

[harbin1234]

Yeah I had these same issues with my friend's Daly BMSs, the phone app is limited in what it will let you change. There are multiple threads here and on other forums talking about what settings to change to get the balancing threshold to occur across a wider window, but you must get the USB-to-UART cable and use a Windows laptop, and there are two Windows programs you can try to use.

The first program is called 'PC Software-2.1.8' and the second program is called 'Sinowealth'. You need the Daly USB-to-UART cable to plug the PC (probably a laptop most likely) into the Daly BMS (we found one on eBay anyways).

PC Software-2.1.8:

Download-PC Software - Daly Electronics Co., Ltd.

CAN Driver DOWNLOAD PC Software for Indian new norms DOWNLOAD PC Software-2.1.8 DOWNLOAD Home Storage Software-1.4.4 DOWNLOAD

www.dalybms.com

Sinowealth:

Daly Sinowealth software

Ive uploaded the Daly Sinowealth tool (used for 3s-4s BMS). The Daly supplied USB-UART cable also needs a "CH340" driver which is also included. Some instructions on how to use it are here...

diysolarforum.com

Some of the Daly models must use the one program, and some of the Daly models must use the other program (same cable).

The thing about the limited function phone app, is that the Active Balancer tab doesn't work on most Daly BMS (ones that don't support active balancing). Most Daly BMSs only have passive balancing, and so that tab won't work for passive balancer Daly BMSs.


Here are some related threads talking about how to get your Daly BMSs to actually balance (what settings to set via the USB-to-UART cable):

Convincing your Daly smart BMS to balance your battery

I have 3 Daly smart BMS with Bluetooth a couple of 100A and one 150A. I am experimenting with various 1P4S or 2P4S 100AH lifepo4 batteries of assorted quality. So I am stuck with the Daly. Apologies for the convoluted lengthy post, but I thought maybe some DALY expert can provide a clearer...

diysolarforum.com

Daly BMS - how does it start balancing

Specs for my 16S Daly says it will balance at cell voltage of 3.50 V. The question is will it start balancing when the first cell hits 3.50 V or must all cells be above 3.50V ? What happens when 8 cells are at 3.60V and 8 and 3.49 V for example will it start balancing?

diysolarforum.com

Daly BMS - how does it start balancing

Specs for my 16S Daly says it will balance at cell voltage of 3.50 V. The question is will it start balancing when the first cell hits 3.50 V or must all cells be above 3.50V ? What happens when 8 cells are at 3.60V and 8 and 3.49 V for example will it start balancing?

diysolarforum.com

Why doesn't my daly smart bms start balancing?

I've got a 4s lishen 280ah bank with a daly 250a smart bms in my van. I did a proper top balance before starting using it a few weeks ago. Seems like the cells since then have drifted a bit, especially cell 1 seems to have higher capacity than the other. This leads to sometimes hitting high...

diysolarforum.com

The issue I had is that I couldn't get the one program which had shown the settings I needed to change, I couldn't get that program to write changes. Then other program, I could get it to write changes (of available parameters) to BMS, but it did not display those parameters I had needed to change in that program, so I could not make those suggested changes. So I gave up, starting to wonder if the Daly BMSs my friend purchased were real Daly or perhaps Daly clones.

WOW Thank You for all that information. I do have the UART cable, it came with the bms.
Sounds like more trouble than it is worth.
I was checking the Smart JK BMS, the 4S only seems to come in a 200 amp, but it peaks at 350 amps.
I've been asking sellers to send me a how to picture of wiring a 4S. It looks like the bms need a power supply, I don't know, just looks like they have two positive wire on the end terminat, but that is 8S and larger, I just need a 4S.

I talk to a service rep. with Overkill bms and he did understand my question or even how to wire a $s when I sent him a picture of my DIY batteries.
Thank You

 

[Samsonite801]

WOW Thank You for all that information. I do have the UART cable, it came with the bms.
Sounds like more trouble than it is worth.
I was checking the Smart JK BMS, the 4S only seems to come in a 200 amp, but it peaks at 350 amps.
I've been asking sellers to send me a how to picture of wiring a 4S. It looks like the bms need a power supply, I don't know, just looks like they have two positive wire on the end terminat, but that is 8S and larger, I just need a 4S.

I talk to a service rep. with Overkill bms and he did understand my question or even how to wire a $s when I sent him a picture of my DIY batteries.
Thank You

Yeah like I said in the first couple threads, you could always buy two BMSs like the JK 4s 200a you mentioned, and then split your 2p4s, into two separate batteries, it would give the same amps you have now, just splitting the amps across two batteries/BMSs.. so it would be 1p4s per battery, which would then be 4s2p as a double battery pack.

Mine look like this, where the back side of these packs is a mirror image of this side (this aluminum clamp is two 4s batteries with BMS on this side, and BMS on the other side)...