Daly BMS Will Not Balance

Jimmynik1

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Charge voltage is set too high. If you can't adjust the voltage on the charger you can draw down the pack some and then plug it back in and watch it charge on your app. When you are drawing on the system they should be in pretty close balance, same as when you start charging again. Then you'll watch the individual cells and see where 3&4 start to rise up way past 1&2. Then at the pack at the point you'll set your BMS to stop allowing charge in. That's only if you can't adjust voltage on that little charger.

In all your photos your BMS cut charging, it's good that it did because that shows it's working but the BMSs intention is to be a monitor and not play a role in every cycle but only get involved if need be. I'm also looking back to see if you out up a photo that shows good pack balance at rest or load. Need to confirm they're balanced before anything else.

So I say

1. Charge voltage too high.
2. Do the test above where you watch the cells rise. When a cell or two start diverging, note the total pack voltage and set the charger to stop charging then.
3. List your components next time so we have a better idea of what you're working with and what limitations there are If any.
The battery is protected with a Daly smart BMS 60A that I still hope is appropriate for a 60Ah battery
Double check battery capacity.
 
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Jimmynik1

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hope you meant to set the charge controller to stop charging
Indeed, you schooled me enough to know what does what now lol. Typed that real early when I was tired, it's been amended. Thanks.

Got to admit though fron my first post about this I think I've come a long way understanding and now I not only understand but I can moderately help others.
 

Jimmynik1

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I hope you meant to set the charge controller to stop charging.
The BMS is a safety cutoff, the charge controller, you know, controls the charging.

Overcharging your cells repeatedly is not going to help anything.
Wanted to get your thoughts on this. I don't have a shunt but I did a pseudo capacity test the other day. App read 99% at start I plugged in a heater with a constant 12.4a ac draw, which came out to 31a dc @ 48v coming out my batteries, plugged in a 110v clock, set it to 12 and sent it. When the system shut down due to low voltage the clock also stopped letting me know how long it ran for. It ran for 9hr 10m drawing 31a per hour. Rough math gave a 285ah estimate. I spent a lot of time on my app and charger settings making sure the high voltage charge setting were right but I didn't do anything on the discharge side, so there may have been more energy to spare I'm not sure, app read 13% upon test completion.
When I unplugged and plugged the hybrid back in it started charging. Overnight it went from 13%-40% then from 7am to 5 pm it went from 40% - 70% and stopped there. My voltage was/is at 53.3 which going off the charts you showed me is 99% or as close to 100% as it can be.
Is it likely the app is just being weird?
 

MisterSandals

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Overnight it went from 13%-40% then from 7am to 5 pm it went from 40% - 70% and stopped there.
Its not uncommon for a battery voltage to bounce back after a hard discharge.
12.4a ac draw, which came out to 31a dc @ 48v coming out my batteries
31A x 48V x 9h = 13,392Wh
12.4A @ 120V x 9 = 13,392Wh

Ok, good.
--------------
Your battery is 100Ah @ 51.2V right?

100Ah x 51.2V = 5120Wh

how do you get 3x this from your test?

-------------
Rough math gave a 285ah estimate.
285Ah at what voltage?
You should use watts when jumping between different voltages. I cannot tell what you are asking as the numbers and units are all over the place.
 

Jimmynik1

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Its not uncommon for a battery voltage to bounce back after a hard discharge.
Figured thanks. Question was why it didn't go back to its previous 99%?
Ok, good.
:)
Your battery is 100Ah @ 51.2V right?
Bank is 16s 310ah (advertised)
You should use watts when jumping between different voltages. I cannot tell what you are asking as the numbers and units are all over the place.
48v or pack voltage whatever it was throughout the discharge.
 
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MisterSandals

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Question was why it didn't go back to its previous 99%?
Because you discharged it for 9hrs.
Bank is 16s 310ah (advertised)
I couldn't find that looking on a tiny screen.
310Ah x 51.2V = 15,872Wh

So your discharge to 13% but recovered to 40% on its own, lets go with 60% discharge and run some numbers.

15,872Wh x .6 = 9523Wh discharged.

31A x 48V x 9h = 13,392Wh
31Ah x 51.2V x 9h = 14,284Wh (using nominal voltage)

14,284Wh/15,872Wh = 90% discharge (looks more like the 87% discharge before bounce back).

What was the BMS low voltage cutoff number? Did it hit low cell or low battery cutoff?
 

Jimmynik1

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Because you discharged it for 9hrs.
I'm getting lost in this math. I know not to expect any substantial bounce back as I drained it pretty heavily.
I meant why didn't it go back to the 99% after my test and I plugged my charger back in. The charger seemingly only charged it to 70%.
The charger shut off so I was thinking it was done but app says different, unless app is not reading right.
So your discharge to 13% but recovered to 40% on its own, lets go with 60% discharge and run some numbers.
No, 13% was what I found it at after it shut it self off. Charging it went from 13 to 40 overnight then to 70 the next day and that was it. Voltage is 53.3/4 but app says 70% and charger stopped charging. No bms codes for over voltage.
What was the BMS low voltage cutoff number? Did it hit low cell or low battery cutoff?
I honestly forget which it was individual cell or total voltage. I wish there was a history on the app to see past codes and whatnot.


Trying to get at after my test I plugged my charger back in and it only took it to 70%. But voltage is the same as it was when it read 99%. Chalk it up to the app not being accurate or you think something else?
 
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MisterSandals

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The charger shut off so I was thinking it was done but app says different, unless app is not reading right.
What charger?
What voltage did it stop at?
Voltage is 53.3/4 but app says 70% and charger stopped charging.
3.3375V per cell. Certainly low for LiFePO4. 70% probably not far off for a BMS app.

Sorry i cannot find your charger. There are so many different people jumping in this poor thread, its impossible to find a single line of thought.
 

Jimmynik1

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What charger?
What voltage did it stop at?

3.3375V per cell. Certainly low for LiFePO4. 70% probably not far off for a BMS app.

Sorry i cannot find your charger. There are so many different people jumping in this poor thread, its impossible to find a single line of thought.
I use the Eco worthy 3500 hybrid inverter.
We had first spoken initially on this thread about me essentially overcharging my pack so I dialed back the charger settings because the BMS was kicking in each time for high voltage cut off. I think I may have dialed them back too far and then when it recovered from the test it didn't bring the pack back up to where it was before.
I just messed with it a little bit ran a couple heat guns and put the boost and charge voltage up a little bit and it's been running for a good while now. I think maybe the charger just had to be kicked on or something since voltage was pretty high but maybe not high enough to initiate charging again.

To make this easier for you what should I set my boost voltage and float charge voltage to? I can go in increments of .4 from 48 to 58.4.
 

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MisterSandals

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To make this easier for you what should I set my boost voltage and float charge voltage to? I can go in increments of .4 from 48 to 58.4.
Thanks for the succinct question! There are dozens of threads follow. This thread was unfortunately started by someone else so i cannot just go back to the first post to see your equipment and issues... it somewhere in the 4 pages (70 posts) that i don't want to reread completely too many times.
I would use boost to 3.45Vpc and float just below (maybe .02Vpc below) where your cells settle an hour after full charge.

I charge to 13.8V (3.45Vpc). My cells settle, with no load to 3.35V. So to prevent micro-cycling, i float at 3.33V.
This is a pretty conservative charge scheme and is a good starting point - you can always tweak it or experiment with different settings to see how they work for you. Everybody has a different use case, different comfort levels and goals so hopefully you can find YOUR sweet spot.
 

Jimmynik1

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Thanks for the succinct question!
Lol can't can't tell if sarcasm or not but I wanted to save you time trying to teach me.
would use boost to 3.45Vpc
So 3.45 x 16 = 55.2
3.33 would give me 53.28 I'll look what my closest increment is to that.
somewhere in the 4 pages (70 posts) that i don't want to reread completely too many times.
Yeah I understand, I know you have a lot of people, i appreciate it.

I'll see what it settles at after it gets done charging. Appreciate it again.
 

Nami

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For DALY SMART bms
Three conditions for smart version equalization
1. Charging will be balanced
2. Equalizing opening voltage (minimum 0.02v, maximum unlimited)
3. Equalizing differential pressure (modifiable)
Active balancer is recommended
U78aaf1e05ea14f99a3fadd482cdfe938B.jpg
 

Jimmynik1

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You should base the float on where YOUR cells settle, not mine.
It was still charging when I checked it before bed and in the morning it was off and settled at 54.0v. No bms code kicked in which is good but I'm back to a not great balance of .150, not as bad as the initial .2 something. Its weird that I can have a good balance of .002 at 53.4v but a little higher throws it out.
 

Jimmynik1

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For DALY SMART bms
Three conditions for smart version equalization
1. Charging will be balanced
2. Equalizing opening voltage (minimum 0.02v, maximum unlimited)
3. Equalizing differential pressure (modifiable)
Active balancer is recommended
View attachment 80581
You sell these or just showing your system?
 

MisterSandals

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Its weird that I can have a good balance of .002 at 53.4v but a little higher throws it out.
EDIT: so this is after charging to 55.2V?

You are mentioning numbers and i cannot tell which are your charging numbers and your settle numbers.
You need to find the charging numbers first that are just below where the cells diverge.
 

Jimmynik1

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That's a good thing to know the limits and characteristics of YOUR cells/battery. If you can live with 53.4V that's only leaving a little on the table.
I'd give that a go for a week and see if that is enough charge/battery for your needs. If you feel you want more or are curious, i'd bump it up .1V to 53.5 for a week and re-evaluate.

Somewhere is where YOUR battery works best for YOU.
Ok thanks. I don't use this daily or at all. It's just to take the place of a generator in a long term outage situation.
I don't think I could do 53.5 since my charger only goes in .4 incriments.
 

MisterSandals

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Ok thanks. I don't use this daily or at all. It's just to take the place of a generator in a long term outage situation.
I don't think I could do 53.5 since my charger only goes in .4 incriments.
Sorry, I reread your post about 53.4V and did not know if that was your charge or float number.
 
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