Daly BMS - Large Discharge Current Reading Errors

ELEL

New Member
I am testing/trying the settings of my new Daly 4s 250A smart BMS. So far, I found that all those end/over/under voltage protection settings work. However, I found that the errors in the discharge current reading in the PC App (Sinwealth) are large.

- No discharge current is displaced (when the battery is in fact discharging via the BMS) until the current goes above 2.3A (then the PC App jumps from 0 to 2.1A, a -10% error)
- When the discharge current is 50A, the PC App shows 51 to 52A up&down (+4% of error)
- when the discharge current is 100A, the PC App shows 107 to109A up&down (+8% of error)

I have been following up with Daly support/engineer for over a week regarding the large current reading errors and they asked me to send them videos, asked me to do the discharge current calibrations....etc and finally they asked me to do the calibration at exactly 30A discharge current. All these didn't help to lower down the error rate.

Today, it seems that they gave up and just simply replied me that 10% of error in discharge current reading is normal!

Are such large errors in discharge current reading really "NORMAL"? Is it a common problem for all brands of BMS? What were your experiences?

The primary function of the BMS is to protect the battery from being over charged or over discharged. An added value is that it can display the countdown of the "RemainingCapacity" which is calculated from the discharge current readings. When the discharge current reading has such large non-linear error, the "RemainingCapacity" displayed is not that useful.

I don't have too much hope on Daly engineers/support and am thinking installing an energy meter to count/check the Ah discharged.....but why can't this be done properly by the Daly BMS when it has such built in basic feature that I already paid?

PS Large error also occurs in the charging current readings but I don't have too much concern on this.
 

Sharky722

Solar Enthusiast
I am testing/trying the settings of my new Daly 4s 250A smart BMS. So far, I found that all those end/over/under voltage protection settings work. However, I found that the errors in the discharge current reading in the PC App (Sinwealth) are large.

- No discharge current is displaced (when the battery is in fact discharging via the BMS) until the current goes above 2.3A (then the PC App jumps from 0 to 2.1A, a -10% error)
- When the discharge current is 50A, the PC App shows 51 to 52A up&down (+4% of error)
- when the discharge current is 100A, the PC App shows 107 to109A up&down (+8% of error)

I have been following up with Daly support/engineer for over a week regarding the large current reading errors and they asked me to send them videos, asked me to do the discharge current calibrations....etc and finally they asked me to do the calibration at exactly 30A discharge current. All these didn't help to lower down the error rate.

Today, it seems that they gave up and just simply replied me that 10% of error in discharge current reading is normal!

Are such large errors in discharge current reading really "NORMAL"? Is it a common problem for all brands of BMS? What were your experiences?

The primary function of the BMS is to protect the battery from being over charged or over discharged. An added value is that it can display the countdown of the "RemainingCapacity" which is calculated from the discharge current readings. When the discharge current reading has such large non-linear error, the "RemainingCapacity" displayed is not that useful.

I don't have too much hope on Daly engineers/support and am thinking installing an energy meter to count/check the Ah discharged.....but why can't this be done properly by the Daly BMS when it has such built in basic feature that I already paid?

PS Large error also occurs in the charging current readings but I don't have too much concern on this.
I'm experiencing the same with my 300a.
I tried playing the current calibration with no success.
 

Sharky722

Solar Enthusiast
I am testing/trying the settings of my new Daly 4s 250A smart BMS. So far, I found that all those end/over/under voltage protection settings work. However, I found that the errors in the discharge current reading in the PC App (Sinwealth) are large.

- No discharge current is displaced (when the battery is in fact discharging via the BMS) until the current goes above 2.3A (then the PC App jumps from 0 to 2.1A, a -10% error)
- When the discharge current is 50A, the PC App shows 51 to 52A up&down (+4% of error)
- when the discharge current is 100A, the PC App shows 107 to109A up&down (+8% of error)

I have been following up with Daly support/engineer for over a week regarding the large current reading errors and they asked me to send them videos, asked me to do the discharge current calibrations....etc and finally they asked me to do the calibration at exactly 30A discharge current. All these didn't help to lower down the error rate.

Today, it seems that they gave up and just simply replied me that 10% of error in discharge current reading is normal!

Are such large errors in discharge current reading really "NORMAL"? Is it a common problem for all brands of BMS? What were your experiences?

The primary function of the BMS is to protect the battery from being over charged or over discharged. An added value is that it can display the countdown of the "RemainingCapacity" which is calculated from the discharge current readings. When the discharge current reading has such large non-linear error, the "RemainingCapacity" displayed is not that useful.

I don't have too much hope on Daly engineers/support and am thinking installing an energy meter to count/check the Ah discharged.....but why can't this be done properly by the Daly BMS when it has such built in basic feature that I already paid?

PS Large error also occurs in the charging current readings but I don't have too much concern on this.
Do you have the sinowealth software? I may have found a solution to this error.
 

ELEL

New Member
Do you have the sinowealth software? I may have found a solution to this error.
Yes, I do. I followed the advice from Daly engineer to do the calibration but it didn't help. Glad to know that you may have a solution to this problem.
 

Sharky722

Solar Enthusiast
Yes, I do. I followed the advice from Daly engineer to do the calibration but it didn't help. Glad to know that you may have a solution to this problem.
In the software under the calibration tab there is a parameter called "cadc gain" the more positive this number is the more it over reads. The more negative the number the more it under reads. Mine was set to -160 i changed this to -170 and its now within 100mA.
Have a play with it you'll see what I mean.
 

ELEL

New Member
Thanks a lot for sharing your experience. I did wonder what those items under the tab MCU-Calibration do and asked the Daly engineer whether those items can help in the calibration but the Daly engineer asked me not to touch them as they are not for users......even I kept pushing them for a solution. Your experience gives me more confidence in trying it out. I will come back with what my result is when I get to my boat/battery/BMS later this week.
 

Sharky722

Solar Enthusiast
Thanks a lot for sharing your experience. I did wonder what those items under the tab MCU-Calibration do and asked the Daly engineer whether those items can help in the calibration but the Daly engineer asked me not to touch them as they are not for users......even I kept pushing them for a solution. Your experience gives me more confidence in trying it out. I will come back with what my result is when I get to my boat/battery/BMS later this week.
Also mine wouldn't read anything under 3a.
So there is a parameter called DfitterCurr. Mine was set to 3000mA (coincidence?).
I lowered mine to 500, now it reads down to 100mA. Hope this helps
 
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