I originally wanted to charge to 53.60 but found they would slip out of balance faster, so I upped it to 53.80 and that helped. I was going through the logs and saw that wife had started the dishwasher the day they never got a full charge late that evening. That night they only went down to 52.91 but diverged a lot and I believe that what caused the trouble I have now. When it comes to float, I read many times to never use it. I set my inverter to 50v to make sure it does not come on, even batrium warns not to use the extra bypass as its similar to float. Do you have a reference for float and its safety with lifep04?
Help with 128 batteries each one is 280ah, and want to configure for 48v system.
- Thread starter kromc5
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Thank you for video I actaully watched the other day as I'm subbed to his channel, I orginally set everything for 80-20 for charging but found that 53.80 got them with in +-.03 and seem to stay closer during the evening.
I based my settings on various sources but most notably Sol-Ark and Victron. The setting you do not want to use is equalization.
When you hit 54.0v does it slow down a lot? I set mine today to charge higher and they were going very well but when I hit 54.05 it slowed down a lot.
Shawn Hayes
Learning Everyday
I don’t intend on using/charging the upper limits. In another thread you had shared your Sol-Ark settings. I intended on using that as a guide for my setup and see how things go. Choosing the Blockmons to me was the best choice for now to see how it works. I believe you have Blockmons as well? I assume your system functions well. Do you have one Blockmon per each 2p cell pack?
I have that disabled in the settings for my inverter.
“Slow” do you mean charge rate? If so then yes the mppt controller starts to slow the rate as the batteries fill and get near the bulk setting. Some folks push the bulk setting to ensure they are not wasting sun but the result are cells getting out of balance. I would say test what bulk rate works for your controller and your needs but is still safe for your cells. And when I say test I mean change the bulk rate on the fly if you can, ie. 54.2 to 54.4 to see how the charge is impacted (assuming there is no dramatic changes in the sun...)
Correct, M8s, for a total of 32, one on each 2p groups. Outside of testing the balance / bypass function the system has not had to passively balance based on my settings. I allow for up to a .03 delta.
Hedges
I See Electromagnetic Fields!
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Good luck with that - maybe you'll have a lighter touch than me. Welding tubing or sheet metal with a stick welder, I always blow holes through it.
If it is something like 1/4" wall pipe, then I can attach plates or whatever. Some of that in my PV racking.
Could be a wire-feed would do better, I think those are used for bike frames and the like.
But then, I also use an oxy-acetylene torch as a nut splitter. At least that's what I do for something a 1 1/4" Ingersoll-Rand won't turn.
Some welding rods are easier to use, "contact", just drag on the surface. Some are prone to sticking. Maybe get a variety pack and see what works for you.
@kromc5 To troubleshoot I would do the following. 1 - loosen and then retighten the fastener (per spec. I do 40in/lbs) for that battery and see if that makes a difference. If not then remove the fastener and clean the terminal, very light sand and dry wipe the terminals of block 9, so if 2p then 4 terminals, etc.. I did the 1st option for a 'runaway cell block (2p) and it addressed the issue.
Hedges
I See Electromagnetic Fields!
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With zero charge current, is one still higher voltage? With discharge does it go lower?
Resistance will cause voltage rise only during charging, drop during discharge. Higher SoC would be higher voltage at rest.
Once you exceed the charge voltage you reached during top balancing of course there would be runners, but presumably you're lower now.
Resistance will cause voltage rise only during charging, drop during discharge. Higher SoC would be higher voltage at rest.
Once you exceed the charge voltage you reached during top balancing of course there would be runners, but presumably you're lower now.
I did this last night and then let them fully balance, cleaned the terminals and reapplied the ox.
They were even last night and stayed at the same voltage before I started the charge. Checked resistance and all were .18, I even checked cells 10 and were at the same voltage and resistance. I was wondering if a cell group after 9 could have issues causing 9 to charge more.
Next, I took 4 cells from the second battery bank got them to the same voltage as the rest and replaced cell group 9 and had same issue. Cell group 9 just keeps running away so I'm at a loss why this is happening. I still suspect that a group is causing resistance as that is all I can think of? Also consider they ran fine for 4 days of testing then this suddenly started.
After replacing the entire cell group same condition.
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It sure did exhibit the same issue, I'm not using any balancing during the charge so I'm not sure if that would be the cause. I did switch out the m8 on group 8,9 even though there were all verified with no issues.
1: Thinking pull all the bars clean and redo them but I question why this started after 4 days of operation with no issues.
or
2. Pull the busbars and re-top balance the whole pack?
I upped the amps on the balance after the second test this morning to get it back down before pulling the busbars.
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Maybe try using a volt meter and manually check that the voltage values match what the batrium says and what all the voltage values are of each cell in that group? also check resistance across busbar for that group and compare to another group.
I calibrated all batrium last night again just to be safe before I started charging this morning, I have not check resistance though.
Sanwizard
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Does your BMS display sense wire resistance? Need to make sure that is as low as possible. On my Heltec BMS, i have been able to cut in half one lead by using better wiring than what came with the BMS.
Resistance values:
1. Checking cell groups connected by bursars are all .08 to .10
2. Checking each cell in a group of 4 using busbars shows .04 to .06,
I looked up the heltec is appears to be an active balancer, when they are charging I’m not using in balancing. In my case the batrium can only be set for passive discharge so I do not think the wiring would cause the runner. The batrium does have resistance values that can be set in hardware but recommends to leave those default unless you modified the leads.
