Daly Smart BMS “Discharging” while charging???

[SemperFiSeaCoral]

I have a Daly 100a 8s smart BMS.

I have wired everything according to the instructions and when I go to charge my batter the app is reading negative current like it is discharging and it also made the variance between the cells voltage grow larger rather than balancing the cells.
Is my Daly BMS wired internally backwards?
B- and P- flip flopped?

Any help would be greatly appreciated!

 

[Scph9002]

It is just reversed in the software/firmware i think.
I have several 4s 200 amp and one 16s 200 amp.

The 4s ones display incoming current to batteries as positive but the 16s one displays incoming current as negative.

There is alot of software differences between board revisions and between 1-5s and 6s and above.

Daly balance at 35mA only. You wont notice it.

 

[SemperFiSeaCoral]

It is just reversed in the software/firmware i think.
I have several 4s 200 amp and one 16s 200 amp.

The 4s ones display incoming current to batteries as positive but the 16s one displays incoming current as negative.

There is alot of software differences between board revisions and between 1-5s and 6s and above.

Daly balance at 35mA only. You wont notice it.

Thank you for all the useful information!

If these setting are correct is it going to cause any actual issues with the operation of my battery/BMS? Or is it just how it is displayed to the user?

Can you elaborate on the Daly balancing and why you aren’t able to see it?

I don’t understand why at 50% SOC I will have a variance between cell voltages of 2.2% but after charging to 100% SOC the variance has gone up to 3.4%

 

[Scph9002]

Voltage between 5% to 95% soc is 3.0-3.4:ish only. Last 5% goes upp to 3.65 with very little current same as last 5% when discharging. Goes down to 2.75 with very little current.

Therefore soc variance shows greater voltage differnce when battery is close to full.

Noticing voltage drop when discharging 35mA balance current from a 100ah cell that is 50% full is like noticing a lake getting emptier when taking a bucket of water from it

 

[Scph9002]

I believe these small balance currents are just meant to counter cell aging differencen over a long period of time or internal reistance variances between cells

 

[maydayone]

Noticing voltage drop when discharging 35mA balance current from a 100ah cell that is 50% full is like noticing a lake getting emptier when taking a bucket of water from it

Could you explain how do you calculate the balancing delta on a given cell with 35mA? what would be the "rate" of change on a cell with a given capacity i.e. 120Ah?
Thanks

 

[Scph9002]

(120 000/35)0.9

That many hours over 400mv.

So anywhere between 5% soc to 95%soc 3.000v to 3.400v if you stare on your bms app for 8 hours you may se 3.302 voltage drop down to 3.301

Have fun ?

 

[maydayone]

So anywhere between 5% soc to 95%soc 3.000v to 3.400v if you stare on your bms app for 8 hours you may se 3.302 voltage drop down to 3.301

So what's the point of having it to begin with, especially on a high capacity cells if it can do pretty much nothing at all?

 

[maydayone]

If my math is correct your equasion gives roughly 128 days of constant balancing, of course it will be much much more in practice since it only balances when charging and with at least 2A current.

 

[Scph9002]

Im guessing its for counter the small differences between cells over time when aging differently.

 

[maydayone]

ok, so I got the battery replaced today, as it came it at 45% charge it's still charging so we'll see how well balanced the cells are this time.

In a mean time I've noticed that the BMS(Daly) is not reporting "Current" (charging / discharging) unless is above about 10 A. I was getting about 16A today from solar and this was displayed fine - BMS value was in agreement with the Victron mppt charger app. But once the current dropped to below approx. 10A the battery BMS shows 0A. On the old battery the BMS was reporting everything above 2A. The natural consequence of that will be no balancing below current of 10A(but we know that 35mA is pretty much useless anyway) and wrong reporting on SOC since I assume this is calculated on "number" of amps the BMS counts going in and out, so if it's less than 10A it won't be reported?

Is there a setting in the BMS which has to be adjusted to make it /show read values of lower current? When the battery came today, some of the BMS settings were completely wrong i.e. max discharge current 999A, max charge current 350A (it's a 120Ah battery). So maybe something else with the settings is off?

Thanks in advance.

 

[liufu.ty]

ok, so I got the battery replaced today, as it came it at 45% charge it's still charging so we'll see how well balanced the cells are this time.

In a mean time I've noticed that the BMS(Daly) is not reporting "Current" (charging / discharging) unless is above about 10 A. I was getting about 16A today from solar and this was displayed fine - BMS value was in agreement with the Victron mppt charger app. But once the current dropped to below approx. 10A the battery BMS shows 0A. On the old battery the BMS was reporting everything above 2A. The natural consequence of that will be no balancing below current of 10A(but we know that 35mA is pretty much useless anyway) and wrong reporting on SOC since I assume this is calculated on "number" of amps the BMS counts going in and out, so if it's less than 10A it won't be reported?

Is there a setting in the BMS which has to be adjusted to make it /show read values of lower current? When the battery came today, some of the BMS settings were completely wrong i.e. max discharge current 999A, max charge current 350A (it's a 120Ah battery). So maybe something else with the settings is off?

Thanks in advance.

I have a Daly(MGod) BMS and I have more or less the same issue with you, and no current reading below 2A - which makes my SOC go way off after hours of low current charging/discharging. I treid to contact the sellers and they can't give any suggestions to fix it.

 

[maydayone]

I have a Daly(MGod) BMS and I have more or less the same issue with you, and no current reading below 2A - which makes my SOC go way off after hours of low current charging/discharging. I treid to contact the sellers and they can't give any suggestions to fix it.

I got the battery replaced and now it's not reading anything below 5A... Basically there is a setting in the BMS (don't remember the exact name) where you can set it(don't know what th minimum value is though), but you can't do it over the Bluetooth, you need to connect the PC, so if you have a sealed unit like me than you can't do it.

 

[rickst29]

In my 12V "2 battery packs in parallel" configuration, I'm not attempting to use my Daly BMS modules as a 'monitor' for SOC. Even if set correctly at a full SOC, it appears to lose track very quickly: It's not linear with my Coulomb Counter, and they don't even show "full" at full pack Voltage (being 14.4V with my 3.6V per cell top-balancing maximum).

The Daly display could perhaps be based on coulomb counting with errors in current measurement, or it might just be a Voltage-based display with some graphical curve built into the microcode - but its NOT reliable. After a only a few charge/discharge cycles, my batteries now show only "65%" and 72%on the two BMS units - at full balanced pack voltage of 14.4V on both packs, and with the more accurate Coulomb Counter showing that full capacity has been stored.

My only reason for even looking at the Daly "SOC" is the convenience of seeing it on the cellphone, while keeping in mind that "65% on the Daly is virtually full". My two units are recent 4S models with BT, 100 and 120 maximum amps.

 

[liufu.ty]

In my 12V "2 battery packs in parallel" configuration, I'm not attempting to use my Daly BMS modules as a 'monitor' for SOC. Even if set correctly at a full SOC, it appears to lose track very quickly: It's not linear with my Coulomb Counter, and they don't even show "full" at full pack Voltage (being 14.4V with my 3.6V per cell top-balancing maximum).

The Daly display could perhaps be based on coulomb counting with errors in current measurement, or it might just be a Voltage-based display with some graphical curve built into the microcode - but its NOT reliable. After a only a few charge/discharge cycles, my batteries now show only "65%" and 72%on the two BMS units - at full balanced pack voltage of 14.4V on both packs, and with the more accurate Coulomb Counter showing that full capacity has been stored.

My only reason for even looking at the Daly "SOC" is the convenience of seeing it on the cellphone, while keeping in mind that "65% on the Daly is virtually full". My two units are recent 4S models with BT, 100 and 120 maximum amps.

If that is the case, then all I can say is that Daly BMS sucks

 

[wholybee]

Current measurements of small currents are not accurate. Very small currents could even be measured in the wrong direction. That is why measuring of small currents is disabled, and why you need to charge to 100% often to resync the SOC. I am not familiar with the Daly in this respect, but the Overkill is "pretty good" but not nearly as good as my Victron meter.

No new cells are balanced when you get them. Even if you are told they are. This is something you must do yourself. A voltage difference of 2% at 50% SOC is likely very far out of balance. As the pack gets over 95% charge that difference will show as the cells getting much further apart in voltage. My cells, anywhere between 10% and 90% are exactly the same voltage to 3 decimal places.

 

[liufu.ty]

I got the battery replaced and now it's not reading anything below 5A... Basically there is a setting in the BMS (don't remember the exact name) where you can set it(don't know what th minimum value is though), but you can't do it over the Bluetooth, you need to connect the PC, so if you have a sealed unit like me than you can't do it.

I have tried a PC software and I don't see it. There are two versons the cheap set on Daly as I heard, one kind is some sinowealth or something, that version could probably set it but my works with the "normal" BSMMonitor software they provided and there is no parameter to change on this. Also the sellers hasn't provided any guide or suggest on adjust any parameters.

 

[wholybee]

In my 12V "2 battery packs in parallel" configuration, I'm not attempting to use my Daly BMS modules as a 'monitor' for SOC. Even if set correctly at a full SOC, it appears to lose track very quickly: It's not linear with my Coulomb Counter, and they don't even show "full" at full pack Voltage (being 14.4V with my 3.6V per cell top-balancing maximum).

The Daly display could perhaps be based on coulomb counting with errors in current measurement, or it might just be a Voltage-based display with some graphical curve built into the microcode - but its NOT reliable. After a only a few charge/discharge cycles, my batteries now show only "65%" and 72%on the two BMS units - at full balanced pack voltage of 14.4V on both packs, and with the more accurate Coulomb Counter showing that full capacity has been stored.

My only reason for even looking at the Daly "SOC" is the convenience of seeing it on the cellphone, while keeping in mind that "65% on the Daly is virtually full". My two units are recent 4S models with BT, 100 and 120 maximum amps.

I sounds like some settings in the Daly are not correct. I am not familiar with the settings the Daly makes available. I am sure you set the capacity correctly. There may also be a setting for the full charge voltage. Other Lithium Chemistries have a higher charge voltage, and if the BMS is set for that, then it will not reset to 100% at 14.4V Maybe that setting isn't made available the user, but is factory set for other than Lifepo4.

 

[halibut58]

On the Daly there seem to be some settings from the factory that make things work very poorly. These can be fixed with the sinowealth software to a certain extent.

Current readings: Some Daly BMS only show currents above a certain amount: 1,2 ,3 10A have been reported.

Set the ‘DfilterCur’ to 200mA or something reasonable. Any current below this value will be changed to (and displayed as) 0. Note that this parameter is the primary reason why the ‘Balance open current’ acts like an on-off switch for balance.

Calibrate the current in Sinowealth (0 current and active current like 10A)

The SOC will reset to 100% when you hit high voltage disconnect (it sucks but that is what it seems to be). Now SOC will wok better. Not perfect, but better.

The 'Balance open current’ should be changed to 0 (or even negative) if you want to balance at low or zero current. It was set to 30mA on mine. Changing this to 0 will give you maximum balance time. This parameter kind of acts like a balance enable switch. The cool thing at 0mA it will balance after high voltage disconnect, which is likely with an out of balance pack.

Other parameters may have to be changed to fix the sign on the current reading(a problem some people reported, not on mine).

Note: Should someone can post a standard settings file for comparison (dumped from a perfectly working Daly BMS)?
I am not sure if I should post mine - if someone loads it into their BMS they could damage their batteries?

 

[Berseker]

Great