yes, it can but #2 cell is always the first cell to break 3.65 even with balancing starting early.
JBD 150A BMS misreads ah%
- Thread starter tilroh
- Start date
In your screenshot cell #2 is the lowest voltage cell so it's making it more imbalanced currently
yes it can but Starb #2 is my hot cell and always reaches 3.65 first.
I just started charging with 24V.
Will post an after pic later today.
Set it to start balancing at the point where the highest cell is the "real" highest cell or else it will just end up making balancing take longer
I only charge till Starb #2 hits max so the other cells can get more charge.
ok, stopping at 3.5 would prevent me from getting concerned about the growing difference in cell Vs that happens after 3.5v
here's a 1 minute video of the batteries accelerating the boat to full speed and an emergency stop.
It's a sailboat but the mast wasn't on for this test.
The motor will pull over 100A at 24V when applying full throttle from a stand still.
I cruse at 35A which is 4kts.
The boat had no motor for the first 15 years.
It's a sailboat but the mast wasn't on for this test.
The motor will pull over 100A at 24V when applying full throttle from a stand still.
I cruse at 35A which is 4kts.
The boat had no motor for the first 15 years.
MisterSandals
Participation Medalist
You are trying to get your BMS to control your charging. Your charge controller should control the charging.
What charge controller do you have? A good charge controller would let you bulk charge to 3.5Vpc and then absorb until the charge current stops.
I have a Chinese, waterproof 40A charger that I specified to cut off at 28V.
If the batteries are balanced, the charger cuts off before the BMS does.
MisterSandals
Participation Medalist
Interesting, happen to have a link?
28V is mighty reasonable at 3.5Vpc.
Any idea what the charge profile looks like?
Here's the link (Alibaba). It comes standard charging to 29.2V but I asked for 28V.
It starts at 13A then after a few minutes goes to 40A and stays till about 90% then drops back down to 13V.
I wish I'd ordered it with CANBUS so I could customize it.
MisterSandals
Participation Medalist
I see 90% of battery charge on the BMSs about the time it drops from 40 to 13V. But I really don't know.
This is my first build.
If I knew then what I know now......
MisterSandals
Participation Medalist
You're doing better than a lot of us did on our first build! You have not shown any disaster photos that most of us have (and don't always share).
One of my favorites:
Good judgement comes from experience. Experience comes from poor judgement.
Thanks Mr. S. I was and still am scared silly of those caged electrons constantly looking for a way out. (don't drop the wrench!).
I go slow.
I learned about magic smoke from 18650s.
MisterSandals
Participation Medalist
You should try swapping cells. Move Port 1 & 4 to Starb. Move Starb 1 & 2 to Port.
Label your cells. I like using letters A, B, C... and take notes.
This might make your cells within each battery closer in capacity.
So far, in terms of capacity, you know:
P1 > P4 > P3 > P2
S3 = S4 > S2 > S1
Label your cells. I like using letters A, B, C... and take notes.
This might make your cells within each battery closer in capacity.
So far, in terms of capacity, you know:
P1 > P4 > P3 > P2
S3 = S4 > S2 > S1
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that's a good idea. Maybe this winter I'll open them up and perform a different type of cell balancing.
