diy solar

diy solar

Just got delivery of my 280AH CATL batteries

Below is an update to my system. I hope someone here can help me understand what is going on with my battery bank
  1. LiFePO4 battery bank charges as expected.
  2. Daly BMS tries to balance the cells, but I doubt that is efficient
  3. Sun charges the batteries till about 16:00gmt. I set the inverter to charge to 56.0v
  4. Battery starts discharging as expected, BMS always seem to off around 20:00gmt when the battery voltage is around 52.3v
  5. I get up and turn off the battery breaker and turn it back on again. everything works normal till the next morning when the sun comes on around 08:00gmt to charge the batteries
THOUGHTS
  1. Thought it was the temperature, but its always around 31/32 degrees calcium
  2. Thought it was the unbalancing of the batteries, but if that's the case how come the bms doesn't turn off again at step 5 above?
  3. Recently when I connect to the daly bms through Bluetooth, the android app gets frozen (see first picture attached). I can only get the app to show actually readings and use it when I disconnect the battery and have it sit for a while (supposedly it restarts itself). Do I have a faulty BMS?
  4. Pictures 1-5 shows my current settings
 

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If app freeze or doesn't start you could go to (on phone) settings, apps, pick the BMS app force stop then click open. That works for me but I do have a different BMS
 
If app freeze or doesn't start you could go to (on phone) settings, apps, pick the BMS app force stop then click open. That works for me but I do have a different BMS
nope that doesnt work for me. Actually its not the app on the phone that freezes. because i get the same issue with other phones and also after reinstalling the software. I can only get it to work by shutting down the bms and rebooting it up again
 
nope that doesnt work for me. Actually its not the app on the phone that freezes. because i get the same issue with other phones and also after reinstalling the software. I can only get it to work by shutting down the bms and rebooting it up again
Hi were you able to resolve the issues with your battery bank? I've read here and elsewhere that JBD BMS is better at handling things...
 
Hi were you able to resolve the issues with your battery bank? I've read here and elsewhere that JBD BMS is better at handling things...
Yeah. Everything is working now after carefully top balancing my cells again. I'm currently running two banks. One with a jbd and the other with a Daly bms. They both seem to be working okay for now
 
Yeah. Everything is working now after carefully top balancing my cells again. I'm currently running two banks. One with a jbd and the other with a Daly bms. They both seem to be working okay for now
Ok good to hear
 
I just so happen to be selling such a 3.2v - 3.6v 120A power supply :D

And some #10 cables x 3 sets for charging at both ends and middle.

.
where in the name of all that's holy did you find a 3.6 volt 120 amp power supply at? my god that would charge rally quickly!

or was that a typo? Edit: ahhhhhg! got rolled up in a zombie thread!
 
where in the name of all that's holy did you find a 3.6 volt 120 amp power supply at? my god that would charge rally quickly!

or was that a typo? Edit: ahhhhhg! got rolled up in a zombie thread!

Not sure about 120A, but have a look at a Meanwell RSP-500-4

Thats a 4V / 90A powersupply. It does have constant current limiting thus works great as a charger, and can be adjusted from 3.6 - 4.3V so it makes a great 90A / 3.65V unit.

If I need to topbalance, I do the fast method:
- Connecting 4 cells in series, set BMS to 3.6V cutoff for any cell
- Charge with a 125A charger (Meanwell RSP-1600-12, can be adjusted to 14.2V)
- Batteries are (near) full in <2 hour for a 280Ah set. BMS disconnects on a single cell hitting 3.6V

- Rewire in parallel
- top balance with a small 20A adjustable powersupply (Only need to charge the last few Ah's, mostly the cells are pretty close). Usually takes 1-2 hours
- Done

Assuming the cells are about equal in SOC, there is not much of capacity left for the topbalance (only a few Ah difference between the cells in my experience). So total topbalance is done in usually 3-4 hours.
 
Sure beats the 3 days needed for top balancing in parallel at 3.65 with a 10a charger.
 
Not sure about 120A, but have a look at a Meanwell RSP-500-4

Thats a 4V / 90A powersupply. It does have constant current limiting thus works great as a charger, and can be adjusted from 3.6 - 4.3V so it makes a great 90A / 3.65V unit.

If I need to topbalance, I do the fast method:
- Connecting 4 cells in series, set BMS to 3.6V cutoff for any cell
- Charge with a 125A charger (Meanwell RSP-1600-12, can be adjusted to 14.2V)
- Batteries are (near) full in <2 hour for a 280Ah set. BMS disconnects on a single cell hitting 3.6V

- Rewire in parallel
- top balance with a small 20A adjustable powersupply (Only need to charge the last few Ah's, mostly the cells are pretty close). Usually takes 1-2 hours
- Done

Assuming the cells are about equal in SOC, there is not much of capacity left for the topbalance (only a few Ah difference between the cells in my experience). So total topbalance is done in usually 3-4 hours.
you have my full attention good man... this does look interesting. thank you. Honestly, thank you.
 
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